PLANT PROTECTION For Second Year Agriculture Plant Protection Course

AJI C. S.

AJI C. S.

PLANT PROTECTION For Second Year Agriculture Plant Protection Course

PLANT PROTECTION - II

For Second Year Agriculture Plant Protection

Prepared by,

AJI C. S. Vocational Teacher in Agriculture

Govt. VHSS, Pallarimangalam, Ernakulam

ajics@rediffmail.com, (9446805972)

“If a country is to be corruption free and become a nation of beautiful

minds, I strongly feel there are three key societal members who can

make a difference. They are the Father, the Mother and the Teacher”

- Dr. A.P.J. Abdul Kalam

Who said can’t ?............

“Someone is always doing something

someone else said, was impossible”

Try trying………..

CONTENTS

Unit No.

Name of the unit

Page No

1 Importance of Plant Protection 1 - 3

2 Introduction to pests 4 - 5

3 General characters of insect pests 6 - 11

4 Insect pest control 12 - 21

5 Biological control of insect pests 22 - 25

6 Environmental aspects of pesticides 26 - 32

7 Insect pests of major crops of Kerala 33 - 56

8 Non-insect pests of major crops 57 - 65

9 Pests of stored products 66 - 70

10 Introduction to plant diseases 71 - 76

11 Plant disease control 77 - 81

12 Diseases of major crops of Kerala 82 - 98

13 Weeds 99 - 107

14 Plant protection equipments 108 - 116

15 Compatibility of plant protection chemicals and fertilizers 117 - 118

Model question papers 119 - 124

Unit - 1 INTRODUCTION TO PLANT PROTECTION

Cultivation of plants for food began in the Neolithic period (latest period of Stone Age) sometimes between 12,000 and 10,000 BC. Until then, man finds their subsistence from hunting and food gathering. The genesis of agriculture lay better germination and greater yields. Dependence of man on plants increased with complexity of civilization.

Plants are economically important in other ways such as checking soil erosion, improvement of soil fertility, provision of food and shelter to many animals. Plants are also grown for beautification and aesthetic purposes. Whenever plants are grown whether for subsistence or for meeting other necessities, the growers are keenly interested in having an assured yield or return. Accordingly, constant attention is paid to ensure proper growth and production. Successful Cultivation of plants necessitates cultivation of suitable varieties, supply of inputs and efficient management of the same and constant care and protection from pest and disease, which may cause yield reduction. Here in comes the importance of plant protection.

Pests have been known to cause damage to plants from ancient times; though the exact causes might not then be known. They are considered to appear due to the wrath of gods. Late blight to potato caused by the fungus Phytophthora infestans in Ireland in the 1840’s resulted in a potato – famine and the consequent migration of ½ a million people from Ireland to U.S.A. Bengal famine of 1943 caused death of a very large number of people which was due to the failure of rice crop due to brown spot disease. In SriLanka Coffee Cultivation is abandoned and they adopted tea cultivation towards the end of 19th century, due to the disease Coffee rust. Diseases like Bunchy top and Panama wilt disease are serious threats to Banana crop. From studying all these instances, it is shown that pests are potential threats to the successful cultivation of crops and they can pose serious problems if adequate steps are not taken to protect the crops. To feed the increasing population man started intensive farming, which lead to an increase in pest and disease incidence. Approximately the loss due to pest is 30- 50% of the total production. To stabilize production and to avoid famine, various plant protection measures are to be adopted.

Plant protection may be defined as safeguarding of crops against attack of pest, disease and other harmful physiological conditions

Assessment of Losses Caused by Pests and Diseases Assessment of pests and the effect they produce on host plants is important as it constitutes

a base for decision on pest control measures. In pest management the major consideration is economic threshold, which is based on the relation between yield and infestation of pests. Assessment methods can be divided into two 1. Direct Counts - On plants or in the environment 2. Indirect Counts - Of some effects caused by the pests such as injury or damage. Both can be

assessed as an index, score or on a rating scale.

“Pest has been defined as any organism detrimental to man and his property in causing damages

significant of economic importance”.

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Classification of pest based on the extent of damage 1. Major Pest - cause a yield loss of more than 10% (>10%) 2. Minor Pest - 5 - 10% yield loss 3. Negligible Pest - a loss of less than 5% of yield (<5%)

Economic Threshold Level (ETL)

E.T.L is the level of pest incidence beyond which significant damage of the crops and yield loss occur, if no control measures are adopted. Pest control measures are to be adopted only if the pest population exceeds the economic threshold levels.

Damages caused by pests may be quantitative or qualitative or both. Quantitative loss is recorded when there is an overall reduction in yield. In case of qualitative damages, the gross yield may not be affected but the presence of markings, blemishes, wart or offensive odour may fetch much less price and the net income from unit area is reduced. Eg:- Potato Scab (blemishes appear on potato and storage quality will be low). Red rot of Sugar Cane (Quality of Juice affected).

Damage caused to plants due to pest attack may again be either direct or indirect depending on the parts affected and the resultant effect.

• Direct damage - eg:- Vascular wilt, Rice ear head bug, Rice Stem borer • Indirect damage - eg:- Leaf Spot, Banana aphid – transmitting Bunchy top virus.

Classification of insect pests based on occurrence 1. Regular pests - Certain insects occur most frequently on a crop and such insects closely

associated with a particular crop are called as regular pests. E.g. Thrips on chillies. 2. Occasional Pests - Insects which occur in close association with a particular crop become

serious in certain period irregularly. Eg. Case worm of rice, mango stem borer. 3. Seasonal Pests - Insects which occur mostly during a particular part of the year are called

seasonal pests. eg. Red hairy caterpillar or ground nut. 4. Sporadic Pests - Insects which occur in a few isolated localities are known as sporadic pests.

E.g. Rice swarming caterpillar. 5. Persistent Pests - Insects which occur on a crop almost through out the year is called

persistent pests. Eg. Scales and mealy bugs on a number of crops. INSECT INFESTATION IS CLASSIFIED AS EPIDEMIC AND ENDEMIC

• Epidemic – if the infestation is not a regular feature to a particular locality but when the infestation occur it become serous in that area.

• Endemic - If the infestation is a regular feature and confined mostly to a particular area or locality it is referred as Endemic.

• Pandemic – occure world over such as across a country or continent eg- locusts

Percentage of loss caused by different groups of pests Weeds - 45%

Insects - 30%

Disease - 20%

Other factors - 5%

Total 100%

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PEST OUTBREAK “If the natural forces controlling the pest population are upset or disturbed there will be a

sudden increase in pest population and consequent damage to crops which is termed as pest outbreak”.

Pest outbreak means the sudden and enormous increase in the biotic potential of certain species which occur as a result of upsetting the equilibrium in nature. When the action of the forces of the environmental resistance is suddenly decreased that result in a population explosion or post outbreak. One of the major causes of pest problem is the unlimited supply of food for the pests due to the intensified growing of crops. Causes of Pest outbreak 1. Destruction of natural enemies -The natural enemies namely parasites and predators keep the

insects under check. Destruction of these natural enemies will lead to the increase of pest population. Insecticides may affect natural enemy more than the host insects.

2. Destruction of forest or brining forest area under cultivation - In this case insects migrate to nearby cultivated field in search of their food.

3. Intensive and extensive cultivation of crops - Cultivation of one particular variety over large area makes more favourable conditions for pest. There is no competition for food and shelter for the insects since their host plants are cultivated in large areas.

4. Introduction of new crops and improved strains - They usually have succulent growth so they become more agreeable to pest for their food. Sometimes the insects which are considered of minor importance become of major importance with the introduction of new varieties.

5. Improved agronomic practices - timely irrigation and application of chemical fertilizers (especially nitrogenous fertilizers) improve the growth of crops and pest attacks.

6. Introduction of a new pest in new area - When introduced, no natural enemies are present so pest multiplies rapidly and become more abundant.

7. Accidental introduction of a foreign pest - Accidental introduction of some pests a long with their host plants.

8. Resurgence of sucking pests - When same types of chemical is continuously applied against sucking pests, they develop some degree of resistance against that particular chemical and their population come back in more severe form.

9. Large scale storage of food grains also lead to pest problems 10. Mutation – a sudden change in the genetical make up of an organism

Locust out break

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Unit - 2 INTRODUCTION TO PESTS

Insects and disease producing organisms are normally recognized as pest. Pest has been defined as any organism detrimental to man and his property in causing damages significant of economic importance. Pest can be controlled by suitable protective methods. The pest in general means enemy. It includes organisms which are harmful to man. It causes significant damages of economic importance. Different groups of pests like insects, nematodes, rodents, weeds, snails and slugs attack crop plants. Their morphological features, nature of damage and control measures are to be studied in detail.

Different Pest Groups Insects, arachnids (Mites), nematodes, rodents, weeds, birds and other animals, slugs and

snails, angiospermic parasites, disease producing pathogens including fungus bacteria, viruses, mycoplasma etc are the important group of pests.

Classification of different pest groups

a) Vertebrates

Phylum Class Characters Examples Nature of damage

1) Chordata Mammalia Hairy, four footed,

milk secreting Rats, squirrel,

rabbit, monkey etc

Eat plant parts, flowers, seeds and

fruits etc

2) Chordata Aves Wings, feathers and

beak Sparrow, parrot, pigeon, crow etc

They eat grains, seeds, fruits etc

b) Invertebrates

Phylum Class Characters Examples Nature of damage

1) Arthropoda Hexapoda Body divided in to head,

thorax and abdomen. Three pair of legs and wings.

Beetles, butterflies,

moths, bugs, flies etc

Adults or immature stages damage plants by chewing of external parts or sucking plant sap. They also bore in

to fruit, seed, and bud or feed on plant stem or mine

leaf surface.

2) Arthropoda Arachnida

Minute creatures with an oval or elongate oval body, head and thorax fused to

form cephalothorax, abdomen distinct, four

pairs of walking legs and no antennae.

Red spider mites, tea

mites, eryophyid

mites

They pierce through the plant tissue with their sharp mouth parts for

sucking the sap and destroying chlorophyll. As

a result of feeding, discolouration of leaves or

galls appears.

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3) Arthropoda Crustacea Hard limy chitinous

exoskeleton, two pairs of antennae.

Crabs

Cut basal portions of rice seedlings, make holes on

field bunds thus cause water to drain off.

4) Mollusca Gastropoda

Soft bodied, non-segmented, no jointed

appendages. Body enclosed in calcareous shell.

Slugs and snails

They feed on foliage of plants mainly ornamentals like orchids and anthurium.

5) Nemata Nematoda

Tiny cylindrical, elongated un-segmented body with tough cuticle. Some forms

are microscopic. size generally less than 2mm.

Root knot nematode, burrowing nematode

They posess a protruding stylet for feeding. They

form knots or galls.

Insects Mite Nematode Crab Slug Snail Pigeon House Rat

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Unit - 3 GENERAL CHARACTERS OF INSECT PESTS

The science of Entomology deals with the study of insects. The word entomology is derived from two Greek words entoma (Insects) and logos (to study). About 80% of the known species of the animal kingdom consists of insects. Both beneficial and harmful insects are present around us. To study such a large number it is necessary to classify them into distinct groups. Insect are tracheate arthropods with distinct head, thorax and abdomen, single pair of antennae, a pair of compound eyes, three pairs of walking legs confined to the thorax and two pair of wings. The integument is hardened to an exoskeleton covering the body muscles with striated fibres arranged segmentaly. The head is usually composed of 6 segments fused immovably together. Thorax is composed of 3 segments – prothorax, mesothorax and metathorax. Abdomen is usually composed of 11 segments.

Classification of Insects

Insects are found in all parts of the earth where life can exist. Their food includes every kind of living or dead organic material from plant tissues to the blood of mammals. The study of insects in their various aspects is known as the science of Entomology. Class Hexapoda of phylum Arthropoda to which the insects belong includes 29 orders. Out of which important orders containing insects of economical importance are listed below

1. Coleoptera - (Beetles and Weevils)

Minute or large, hard bodied insects with forewings modified into elytra which is not fitted for flight but adapted to support body during flight and protecting the membranous hind wings when at rest. Mouth parts biting (Cutting) and chewing type. Young ones are called grubs. eg:- Rhinoceros beetle, Red palm Weevil, Pseudo stem weevil of banana etc.

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Beetle Weevil

2. Lepidoptera - (Moths and Butterflies)

Adults with four membranous wings usually covered by overlapping flat scales forming coloured patterns. Mouth parts modified into a coiled sucking proboscis called siphoning type mouth parts. Larvae called caterpillars and have chewing mouth parts. Larvae only cause damage to plants. eg: Moths, Butterflies, silkworm, Rice stem borer, rice case worm. Butterflies are diurnal in habit and brightly coloured. Moths are nocturnal in habit.

Butterfly Moth 3. Diptera - (True flies)

Adults with only two wings, hind wings modified into a knob like halters which help to balance during flight. Mouth parts sponging and sucking type. Larvae called maggots.

Eg;- House fly, Fruit fly, Melon fly, Galls fly of rice.

House fly

4. Hymenoptera - (Bees and Wasps)

Minute to medium sized insects with four membranous wings, hind wings always smaller than forewings. Venation few or absent. Ovipositor conspicuous and often modified as sting. Larvae chewing type mouth parts and adults have got chewing and lapping mouthparts. Eg: Bees, ants, saw

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flies, Wasp, hornet etc.

Bee Wasp

5. Hemiptera - (Bugs)

a) Heteroptera

Minute to large sized, phytophagous or predacious insects with piercing and sucking mouth parts. Forewing modified into hemelytra, hind wings membranous. Eg: True bugs, rice bug, cowpea pod bug.

b) Homoptera

Small sized bugs with suctorial mouth parts. Active forms with four wings. Sedentary forms are also present. eg: Aphids, Scale insects, leaf hoppers etc.

Bug Aphid - Homoptera

6. Thysanoptera (Thrips) Minute, mostly phytophagous, mouth parts rasping and sucking type. Wings when present

with long marginal fringes of hairs (fringed wing). eg. Marginal gall thrips of pepper.

Thrip

Types of Mouth parts and feeding habits

The appendages found on the head capsule around the mouth are collectively called mouth parts of insects. The following are the important types of mouth parts 1. Chewing type of mouth parts - This type of mouth parts permits the insects to bite off and chew on

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into external parts of a plant or tunnel its way into some parts of the plants. Crop pests having this type of mouth parts defoliate plants or bore into plants including fruits. They can be controlled by application of stomach poison.

2. Piercing and Sucking Type - The insects with this type of mouth parts cause discolouration, curling of leaves and their eventual weakening and death of plant parts. They may also attack young twigs and other parts of plant and cause them to dry up. Contact poison or systemic chemicals are effective.

3. Rasping and sucking type - Thrips are characterized by this type of mouth parts. Due to the mechanism of action in rasping the tissues, exudation of juice from inside the plant takes place which is sucked up by thrips. Parts damaged present a whitish mottled appearance. Thrips can be controlled by stomach and contact poisons.

4. Siphoning or Sucking Type - Mouth part is a long coiled tube which acts as simple sucking or siphoning system which help in sucking honey or sweet exudates. eg: Moths and Butterflies.

5. Sponging type of mouth parts - The mouth parts consist of a hinged fleshy proboscis party concealed in a cavity in the head with a sponge like organ at the end for sucking the liquid. These insects fist let out Saliva for pre-digesting or dissolving the food and then suck the same up. Controlled by stomach and contact poison. eg: House flies.

6. Chewing Lapping Type - In this case mandibles retain their original function of chewing but maxillSae and labium are modified into slim lapping organ for taking up liquids. eg: Honey bees.

Classification of insect as solid feeders and liquid feeders.

a) Solid feeders – They have biting and chewing types of mouths parts. eg. Beetles, Caterpillars of butterflies, grasshoppers, termites, cockroaches etc.

b) Liquid feeders - they have sucking type of mouthparts 1. Butterflies and moths - adults Sucking/Siphoning type & have a coiled proboscis. 2. Bugs (Adults and Nymphs) - Piercing and sucking Type and have a stylet. 3. Thrips - Rasping and sucking type 4. Flies - Spongy type of mouth part with a hinged proboscis

Chewing type Chewing mouth parts Piercing & Sucking

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Siphoning Sponging Chewing & Lapping

Important Stages in Insect Development

The development of insect is often attended with pronounced metamorphosis. Metamorphosis refers to any change in form, structure and appearance of an insect between birth and maturity. Insects may be divided into three groups with reference to metamorphosis.

1. Insects without metamorphosis (Ametabola) - These insects on emerging from egg are essentially like the adults except for size. They undergo a series of moults till attaining maturity. E.g. - Silver fish, spring tails.

Ametabolous development

2. Insects with Partial or Incomplete Metamorphosis - These insects on hatching out from the eggs show a resemblance to adults but do not possess any wings. The immature once are known as nymphs. Nymphs grow through a series of moults each time becoming larger in size. The period between two moulting is known as instar. The number of moults and instars remain constant for the species but varies in different species. eg. - Grass hoppers, plant bugs, aphids, thrips etc. These insects can be easily controlled in the nymphal stages. Adults are more resistant or they fly away on application of pesticide.

3. Insects with Complete metamorphosis - The young stage of insects of this group do not show resemblance to adults. They look worm like and are known as larvae. Larvae do not show any traces of wings and differ greatly from the adults in habit. Larvae also undergo moults and pass through instars. These insects cause maximum damage at the larval stage, when feeding and growth takes place. When larva attains full growth it sheds its skin and enter pupal stage. The

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pupa is concealed in the soil or bundled up in a silken case known as cocoon. During this stage change over into adult organs takes place. When the change over is complete insects come out of the pupal case and fly away. Pupal stage is most resistant to insecticides. Some types of larvae are known by definite names. Larvae of moths and butterflies – Caterpillar, larvae of flies – Maggots and larvae of beetles - grubs.

Incomplete Metamorphosis Complete Metamorphosis

Insects with Incomplete Metamorphosis

Insects with Complete Metamorphosis

1. Hemiptera - Bugs 1. Coleoptera – Beetles & Weevils

2. Orthoptera – Grass hoppers & crickets 2. Lepidoptera – Moths & Butterflies

3. Thysanoptera - Thrips 3. Diptera – House flies, Mosquito

4. Isoptera - Termites 4. Hymenoptera – Bees & Wasps Destructive stages of insect pest

1. Beetle - Adults and grubs 2. Butterflies and moths - Caterpillars 3. Flies - Maggots 4. Bugs - Adults and nymphs

5. Thrips - Adults and nymphs

Consolidation

Sl. No Order Insects Wing Mouth

parts Metamorphosis Young ones Damaging stage

1 Coleoptera Beetles & Weevils Elytra Biting &

Chewing Complete Grubs Adults & Grubs

2 Lepidoptera Moths & Butterflies Scaly wing

Siphoning type C P -

Chewing

Complete Caterpillars Caterpillars

3 Diptera Flies Hind wing Halters

Sponging Sucking Complete Maggots Maggots

4 Hemiptera Bugs Hemelytra Piercing & sucking Incomplete Nymphs Nymphs &

Adults

5 Thysanoptera Thrips Fringed Rasping & sucking Incomplete Nymphs Nymphs &

Adults

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Unit - 4 INSECT PEST CONTROL

Insects appeared on earth very long before descend of man. They depend upon the same sources on which man depend for his food, shelter, clothing and other needs. The fight between man and insect will continue till human race endures on earth. Pest Control may be defined as any method or procedure employed to reduce the pest population and prevent damages caused by them. Pest control signifies any action taken by man to prevent losses caused by pests. Regulation of population in nature without any manipulation by man normally does not come under the purview of pest control measures.

There are two methods of insect control,

1. Natural Control 2. Artificial / Applied Control

Natural Control - Control of insects without intervention of man is called natural control. Insect population is kept in a check by the natural factors like climatic factors, topographic factors and natural enemies. Climatic factors include temperature, atmospheric pressure, rainfall, light intensity, wind and relative humidity. Temperature affects growth of the insects. Small insect seen on leaves are washed out and killed by heavy rainfall. Strong winds will affect the flying insects. Topographic factors – Mountain Ranges and Oceans act as physical barrier for the spread of insects. Natural enemies include parasites, predators and pathogens. They kill insects and check the insect population.

Artificial / Applied Control Methods - The controlling methods adopted by human agencies are called artificial control measures. There are several methods. In general these control measures are divided in to two.

i. Prophylactic control (Preventive methods) ii. Curative Control Methods (Direct methods)

Prophylactic Method is the preventive measure taken before the actual occurrence of the insect pests. Curative methods are the measures taken to eliminate the insects after the actual occurrence of the pest.

a) Prophylactic measures - are adopted in the case of insects which occur in certain season. They include 1. Field and Plant Sanitation - That is the removal of affected plant parts and removal of weeds in the

field. Many insects lay their eggs on weeds, by removing weeds we can control such insects. 2. Proper Cultural Methods - Seeds are to be soaked before planting. If paddy seeds are kept in hot

water at 50 0C for 15 minutes it will kill white tip nematode. By ploughing the field after harvest rice stem borer can be controlled because it lays eggs on stubbles. Growing of Resist ant Variety - Certain crops are less damaged by insects; such varieties are called resistant varieties, treat the seed with insecticides before planting, raking manure pits to control Rhinoceros beetles, periodical drying of stored produce prevent pest attack, application of oil on stagnant water will prevent mosquitoes etc.

b) Curative Control Measures: The methods include 1. Cultural methods

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2. Physical methods 3. Mechanical methods 4. Biological methods 5. Legal methods 6. Chemical methods.

1. CULTURAL METHODS Some of the ordinary farm practices which are done to keep the insect infestation under

check are called cultural methods. They are adjusting the time of sowing or planting, using resistant variety, crop rotation, flooding, mulching, trap cropping, cover cropping, Digging and ploughing etc.

a) Crop rotation - Cultivation of one crop after another belonging to different botanical groups. e.g:- Rice + Pulses + Vegetables.

b) Trap Cropping - Susceptible crop is cropped near the major crop and when the insects are drawn to the susceptible crop they are destroyed. eg: Bhindi is often cultivated in a small area near the cotton crop to attract cotton jassids. Then the pest is destroyed along with the bhindi crop before the pest start attacking cotton crop.

c) Mixed Cropping - Growing more crops in the same area. By this we get additional profit from the area.

d) Tillage Operations like summer Ploughing / deep ploughing - During ploughing the organisms below soil are get exposed and killed by sunlight, birds etc.

e) Trimming and Plastering of bunds - Grass hoppers lay their eggs in the holes of the bunds. If we plaster the bunds the eggs are killed.

f) Clipping of leaf tip of Rice Seedlings - Rice stem borer lays eggs on the tip of rice plant leaf before transplanting. By clipping the leaf tip at the time of transplanting the egg mass can be destroyed.

g) Flooding of Rice Nursery - will eliminate army worm attack. 2. MECHANICAL CONTROL

It is a control method by using mechanical devices or by manual operation. These methods include.

a) Collection and destruction - Handpicking and destruction of egg masses of insects, caterpillars etc.

b) Provision of preventive barriers and traps - Tin bands are provided around tree trunk of coconut palm so that rats cannot climb the tree. Provision of polythene or paper cover to protect fruits from melon flies attack. Ant pans are kept on the base of table legs to prevent ants. Light traps are kept in fields to attract and kill nocturnal insects.

3. PHYSICAL CONTROL Controlling insects by using physical forces - Activated Kaolinic clay is mixed with stored

products to prevent attack of storage pest. This clay gets adsorbed to cuticle of insects and it breaks. There by losing water from the body. The insect will die due to de-hydration.

a) Artificial Heating or Cooling - The storage pests are killed if they are exposed at 55 0C for three hours. Soil can be steam sterilized to kill soil borne insects.

b) Male sterilization Technique - Male insects can be sterilized by gamma radiation or by certain chemicals. When these sterile males are released in field reproductive capacity of the population will be lowered.

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c) Irradiation with UV light – generally followed to control pests in canned and preserved food items

4. LEGAL CONTROL MEASURES Some dangerous exotic pests introduced to our country from foreign countries such as

Cottony cushion scale of citrus, Wooly aphid of apple, San Jose scale of apple, Golden cyst nematode of potato etc. Government of India has passed an act called “Destructive insect and pest act, in the year 1914 to prevent entry of any insect pest or disease causing agents to our country. Legislative measures are taken to prevent introduction of new pest, disease etc and to prevent spread of already established pest and disease from one part to another. The laws enforced by government are called ‘quarantine’ laws. (Foreign quarantine & Domestic quarantine laws) To import a plant or plant material is done through quarantine stations. Quarantine stations are situated at various air parts and seaports – Bombay, Chennai, Calcutta, Kochi and Vishakhapattanam are the seaports. Air ports – Bombay, Chennai, Calcutta, New Delhi and Amrutsar. A phytosanitary certificate is to be issued by the agriculture department of the exporting country stating that the particular consignment is free of pest, weeds or disease. Only along with this certificate, the plant is received in the quarantine station. 5. BIOLOGICAL CONTROL (BIO CONTROL or BIOTIC CONTROL)

It is the pest control by using living organisms. Bio control can be classified in to two. 1. Macrobial Control 2. Microbial Control

1. Macrobial control - is by using parasites and predators. Predators include insects, mites, spiders, birds, reptiles etc.

2. Microbial Control - is by using pathogens. Pathogens include disease producing virus, fungus, bacteria, protozoa and Nematodes. Study and utilization of parasites, predators and pathogens for the regulation of pest

population comprises the field of biological control. 6. CHEMICAL CONTROL METHODS

It is the control of insects by using chemicals. Pesticides are substances used to control pest and they include insecticides, fungicides, nematicides, rodenticides, acaricides, weedicides or herbicides, molluscicides etc. The chemical used to control insects are called as insecticides. Insecticide can be defined as a substance or a mixture of substances intended for killing, repelling or otherwise preventing insects from attacking crops.

Classification of Pesticides 1. Insecticides – used for killing insects. eg - Ekalux 2. Fungicides – used for killing insects. eg - Mancozeb 3. Acaricides – used for killing mites. eg - Dicofol 4. Weedicides/ Herbicides – used for destroying weeds eg- Paraquat 5. Nematicides – used for killing nematodes eg:- Carbofuran 6. Molluscides – used for killing slugs and snails, eg. Metaldehide 7. Rodenticides – used for killing rodents. eg:- zink phosphide 8. Antibiotics – These are substances which are produced by micro organisms and

which act against micro organisms. eg:- Streptomycin.

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Naturally occurring insecticides like nicotine were used in the earlier period. Use of modern insecticides commenced in the year 1867. That is Paris green was used against Colorado potato beetle. D.D.T. was discovered in 1939. It marked a milestone in the history of insect control. Insecticidal property of B.H.C. was discovered in 1943. These two are chlorinated hydrocarbons with stomach and contact action. These two were widely used but now use restricted due to residue effects.

Classification of Insecticides For easier and meaningful study, insecticides are classified into certain groups.

1. Classification based on mode of entry of insecticide in to insect body. 2. Classification based on mode of action. 3. Classification based on chemical nature.

I). Classification based on the Mode of Entry. Based on mode of entry into insect system, there are four types of insecticides.

1. Stomach poison 2. Systemic poison 3. Contact poison 4. Fumigants.

1. Stomach Poison - It is a toxicant which is ingested by insect and kills the insects by action on digestive system. It is used mainly on chewing insects. These are to be applied on plant parts which provide food to insects. Eg - Arsenicals, Fluorides 2. Systemic Poison - These are capable of being absorbed to various plant parts like leaf, root etc. Systemic insecticide is one in which the toxicant penetrates into the plant tissue and get transported in insecticidal quantities from the point of application and making the plant insecticidal. Most of these chemicals are transformed to highly toxic compounds inside plants. In essence a systemic poison is a stomach poison because poison enters into stomach of the insects. Systemic insecticides are used for control of sucking, insects, leaf miners, tissue borers etc. Eg: - Organo-phosphorus compounds like Phorate, Quinalphos.

Advantages of a systemic insecticide are, • Not subjected to weathering. • Since the toxicant is translocated in the apical direction, the fresh plant growths do

not require application of pesticide for a long time. • It is comparatively safer to natural enemies.

Disadvantages of systemic Insecticides are, • Insect has to feed sufficiently longer period to get lethal dose • Some of the systemic insecticides are highly toxic to higher animals and it causes pest

resurgence. (After giving protection initially, pest may develop resistance to this chemical and pest number may increase considerably)

3. Contact Poison - It is a chemical which kills insect by means of contact to the body wall and getting absorbed and penetrated in to body to certain vulnerable sites such as sutures, base of setae etc. These chemical enter body through mere contact. It lacks selectivity. All the insects which get contact of these chemicals get killed. Chemical have lipophyllic nature eg:- Carbaryl (Sevin) 4. Fumigants - These are chemicals which in its gaseous form enter tracheal system of insects

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through spiracles and kill the insects. Fumigants are applied to control pest in storage and nematodes which are seen in soil. eg :- Aluminium phosphide (celphos trablets) II). Classification based on mode of action

There are four types, 1. Physical poison 2. Protoplasmic poison 3. Respiratory poison 4. Nerve poison or Neuro toxicant

1) Physical poison - It is toxicant which brings about lethargy and kills insect by exerting physical effect. The insect will die due to the lack of air or due to the dehydration caused by breaking of cuticle. eg.:- heavy oils, tar oils, Silica Gel, Aluminium powder etc.

2) Protoplasmic poison - It is the chemical which causes precipitation of protoplasm, especially destroys the cellular protoplasm of midgut epithelium. eg.:- heavy metals like mercury and fatty acids.

3) Respiratory poison - These chemicals block cellular respiration and also inactivates enzymes involve in respiration. eg:- HCN, carbon monoxide, phosphine gas etc.

4) Nerve poison - It is a toxicant which inhibits the nervous system. These chemicals inhibit the enzyme acetyl cholinesterase, which cause continuous stimulation and death of insects. Eg. Nicotine, O. P. compounds.

III). Classification based on chemical nature

Inorganic Organic 1. Arsenic compounds 1. Plant origin -- eg. Neem, Pyrethrin, Nicotine, Rotenone 2. Sulphur compound 2. Animal origin -- eg. Neries Toxin 3. Fluorine compounds 3. Hydrocarbon oils -- eg. Mineral oil, tar oils 4. Borax 4. Synthetic Organic Chemicals 5. Zinc ( Modern synthetic chemicals)

a) INORGANIC INSECTICIDES - are those which do not contain carbon. Arsenicals are stomach poisons. They are used as poison baits. Sulphur compounds are prepared as dust. It is contact poison. eg - Flourides, Arsenicals, Zinc phosphide, Sulphur, lime sulphur etc. b) ORGANIC INSECTICIDES - are those which contain carbon in their structure.

1. Organic insecticides of plant origin (Botanical insecticides) • Nicotine - Tobacco was used as an insecticide from 1763. The alkaloid nicotine contained in

tobacco leaves is having insecticidal property. Nicotine is extracted from the leaves of tobacco plant and Nicotin is a nerve poison. Tobacco decoction is used to control aphids.

• Pyrethroids Chief source of pyrethroids is the plant Chrysanthemum. Insecticidal properties are due to the presence of esters pyrethrum and cinerin.

• Rotinoids - Toxic substance contained is rotenone. This is extracted from the roots of a plant Derris. It is stomach and contact poison.

Insecticides

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• Azadirachtin – Neem plant is the chief source. Insecticidal properties are due to the presence of alkaloid azadirachtine. Neem seed kernel suspension is sprayed to control locusts. It causes a repellent action. Neem oil and neem oil cake are also having insecticidal properties.

2. Organic insecticides of animal origin - Neries toxin is separated from marine annelid Lumbrineries heteropoda

3. Hydrocarbon oils – heavy oils are used as a physical poison to control scale insects.

4. Synthetic Organic Chemicals (Modern synthetic chemicals)

Synthetic Insecticide:- 1. Organochlorines – eg. D.D.T., B.H.C., Dicofol 2. Organophosphorus compound – eg. Ekalux, Malathion, Rogor 3. Carbmates – eg. Carbaryl, carbofuran 4. Organic Sulphur Compounds – eg- Endosulphan 5. Dinitrophenol – eg. Binapacryl 6. Thiocynate – eg. Thanite 7. Synthetic pyrethroids – Eg. Permithrin, cypermithrin etc. 8. Fixed soaps and oils – eg. Fish oil soap 9. Fumigants – eg. – Aluminium phosphide, Carbon monoxide 10. Other miscellaneous organic compounds.

1. Organic Chlorine insecticides - Main constituents of these insecticides are carbon hydrogen and chlorine. eg. D.D.T., B.H.C. D.D.T is a stomach and contact poison. It has longer persistence and residue effect. It affects sensory organs and nervous system of vertebrates and invertebrates. D.D.T. has got affinity towards fatty tissues and lipid tissue. If animals are fed with foliage on which D.D.T. is sprayed it accumulates in the fatty tissues and secreted through milk. D.D.T. cannot be used on cucurbits because it causes phytotoxicity. Use of D.D.T. is banned now. Endosulphan is an organic sulphite as well as chlorinated hydro carbon. Stomach and contact poison. It controls aphids, caterpillars, plant bugs and borers. It is not much harmful to honeybees.

2. Organophosphorus Compounds (OPs) - Many of organic phosphorus compounds are contact and stomach poison. Some got fumigant action also. Most of the o. p. compounds have got broad spectrum action. i.e, their action is towards a number of pests, not specific. Some the o.p. compounds are highly toxic to mammals also. eg – Quinalphos, Phorate

3. Carbamates – contact and stomach poisons, neurotoxins action similar to O. P. compounds. eg. Carbaryl, Carbofuran etc. FORMULATIONS

Insecticide manufactured in pure form is called technical grade material or active ingredient (a.i ). We require a very small amount of technical grade insecticide for a large area. But to apply over a large area it is to be diluted. There fore the pure form is formulated. What we get in the market is the formulated products. Formulation is the processing of a pesticide compound by any method which will improve the properties of storage handling and safety of the pesticide. A pesticide may be available in more than one or several formulations. The best formulation to use should be determined by a consideration of such factors as the nature of the target pests, the type of crop, where the pesticide is to be applied, the equipment available for application, the environmental and

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human hazards involved and the relative costs. Pesticide Adjuvants - A pesticide adjuvant may be defined as any substance that when combined with a pesticide increases its sticking, spreading or wetting qualities, makes it safer; aids in its dilution or uniform dispersion or increases its toxicity to the target pests. Pesticide adjuvants may be divided into the following.

a) Sticking Agents - These substances have the function of increasing the retention of spray or dust deposits on plants. eg - milk products, blood albumin and gelatin.

b) Spreaders and Wetters - These are substances that lower the surface tension of a spray and therefore increase its spreading and penetrating power.

c) Emulsifying Agents - Many pesticides are not soluble in water. Since these organic solvents will not normally mix and stay dispersed in water substances known as emulsifiers must be used with them to form stable, milky suspensions of the pesticide. Such a spray is called an emulsion. Emulsifying agents reduce the tendency of an emulsion to break up into its component parts.

d) Safeners or Correctives - These are substances that are added to sprays to prevent loss of effectiveness or to reduce the danger of foliage injury.

e) Synergists - These are compounds when used in conjunction with a pesticide; increase the toxicity of the mixture over the sum of the toxicities of its components. Some synergists in use are piperonyl butoxide, and sulfoxide.

f) Diluents or Carriers - A carrier may be any material used to dilute or decrease the amount of active ingredient in any spray or dust. Sulphur is valuable both as a diluent and as a fungicide in many dust formulations.

Important formulations are,

1) Dust (D or DP- Dustable Powder) - Dust is prepared by mechanical mixing of technical grade material and carrier compound or by impregnation of the technical grade by very fine powdered carrier. The inert compound with which the technical grade is mixed with is called the carrier or diluent. Carrier materials usually used are wood bark, sawdust, talc, gypsum, kaolin, Clay etc. Concentration of a.i. in a dust varies from 1% to 25%. eg. Sevin 10% Dust

Disadvantage of dust formulations - it causes drift problem (may be carried away by wind). So it is better to apply in the morning when plants are wet with dew drops. 2) Granules (G) - are prepared by applying carrier materials and technical grade material on surface

of granules. eg:- Furadan 3%, G., Thimet 10% G. Advantages of granules are,

• No problem of drift, granules can be broadcasted so water is not required, • No residue problem so it is less harmful to natural enemies.

Disadvantages are, • granular formulations are not as effective as others to crawling insects • If the concentration is more scorching on burning of leaf occur.

3) Wettable Powder (W.P.) - It is prepared by blending technical grade material and carrier with a wetting agent. If the wetting agent is not there, the powder does not mix with water.

4) Water Dispersible Powder (W.D.P) - It is like wettable powder. But during spraying agitation is required, otherwise it settle down to bottom.

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5) Water soluble Powder (S.P) - Here technical grade material is finely powdered and the formulation is water soluble.

6) Oil Solution - It is an oil concentrate which diluted with water before application. 7) Ultra low Volume concentrates (U.L.V) - The technical grade material is dissolved in minimum

quantity of solvent so that there is no need of further dilution. 8) Emulsifiable Concentrate (E.C) - It contains toxicant + solvent + emulsifying agent. When E.C is

sprayed, solvent evaporates leaving deposits of toxicant. 9) Aerosols - Minute particles suspended in air, as a fog or mist. Toxicant is dissolved in liquefied gas

and released through small hole. So toxicant particles float in air with evaporation of released gas. 10) Fumigants - Insecticides in gaseous state. Usually formulated liquid under pressure, sometimes

available in the form tablets. eg:- Celphos tablets, used in godowns. 11) Insecticide Cum Fertilizer Mixture - This is formulated by mixing granules with chemical

fertilizers. It gives nutrients as well as protects plant. 12) En-Capsulated Materials - Insecticides are wrapped in tiny beads made up of poly vinyl or plastic

covering when applied insecticides are released at a slow rate for a long time.

Sl. No

Formulation Physical state Texture Solubility in water Appearance after mixing with water

1 WP Solid Dust Soluble Suspension

2 EC Liquid Oily Fluid Mixes with water Emulsion

3 SL Liquid Fluid Soluble Solution

4 SC/AF Liquid Fluid Mixes withwater Suspension

5 SP Solid Powder Soluble Solution

Some common Insecticides

Chemical Name Trade Name & Formulation Remarks Organo-phosphorus compounds

1) Mercaptothion Malathion 25% WP Stomach and contact action safe insecticide for controlling pests of vegetables

2) Quinalphos Ekalux 25% EC/AF Broad spectrum toxicity; particularly effective against mealy bugs and scale insects

3) Dimethoate Rogor 30 EC Systemic insecticide Cum nematicide 4) Monocrotophose Nuvacron 40 EC Systemic, persistent, Long residual action

5) Phorate Thimet 10G Systemic granular insecticide cum nematicides.

6) Methyl parathion Metacid 50 EC Rapid knockdown action

7) DDVP Nuvan 100% EC/AF Contact and fumigant, less residual; toxicity lasts for only 24 hours; safer to be applied on vegetables.

Carbamates

1) Carbaryl Sevin 5% DP Effective against a wide range of pests. Not recommended for control of mites. Should not be sprayed in crops at flowering.

2) Carbofuran Furadan 3 G Systemic, insecticide com nematicide

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Calculation of quantity of commercial formulation required for given area

a) For all formulations except granules

Quantity of commercial formulation = Quantity of spray fluid x Concentration of spray fluid Concentration of commercial formulation 1. Calculate the Quantity of Ekalux 25EC required to spray rice cultivated in an area of 2Ha at a

concentration of 0.025%? Volume of spray fluid for 2Ha of rice = 2x500=1000 L, Concentration of spray fluid = 0.025% Concentration of commercial formulation =25%. Ans; Quantity of commercial formulation = Quantity of SF x Concentration of SF Concentration of comm. Formulation = 1000 x 0.025 = 1 litre 25

b) For granular formulation

Quantity of commercial Formulation

= Rate of Application per Ha x Area in Ha x 100 Concentration of Comm. Formulation

2. Calculate the quantity of Thimet 10G required for 1Ha rice when applied at the rate of 1.25 Kg ai per Ha?

Ans: Quantity of Thimet 10G = 1.25 x 1 x 100 = 12.5 kg 10 BOTANICAL INSECTICIDES

Botanical pesticides are those pesticides, which are derived from plants. Such pesticides are cheap and easy to make. They are ecofriendly compared to synthetic chemical insecticide. Preparation of some safer insecticidal materials for common use are described here,

1) Kerosene emulsion - This is a contact insecticide useful against many sucking insects. For preparing this, slice 500 g of ordinary bar soap and dissolve in 4.5 litres of water by boiling. Cool and add 9 litres of kerosene under violent agitation till the oil is fully emulsified. The stock solution may be diluted with 15-20 times of water before spraying. 2) Tobacco decoction - This is very effective for controlling aphids and other soft-bodied insects infesting vegetable crops. Tobacco decoction can be prepared by steeping 500 g of tobacco waste in 4.5 litres of water for 24 hours. Dissolve 120 g of ordinary bar soap separately in another vessel. The soap solution is added to tobacco decoction under violent agitation. Dilute this stock solution 6-7 times before spraying. 3) Neem kernel suspension (NKS) - This is very effective as a repellent/deterrent against locusts, grasshoppers and other chewing insects particularly lepidopterans larvae. The kernel should be ground into a coarse powder. The effective concentration of NKS ranges from 0.1 to 0.3%. For obtaining 0.1% concentration, 1g of powered neem seed is required per litre of water. The required quantity of the coarse powder should be put in a small muslin cloth bag and dipped in water for

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about 12 hours. Thereafter, squeeze the cloth bag repeatedly so that the out-flowing fluid turns light brownish. The NKS is now ready to be sprayedoasosuchoonocrops. 4) Neem Oil Garlic emulsion (2%) - To prepare 10 litres of 2% neem oil + garlic emulsion, 200 ml neem oil, 200 g garlic and 50 g ordinary bar soap are required. Slice the bar soap and dissolve in 500 ml lukewarm water. Grind 200 g of garlic and take the extract in 300 ml water. Pour the 500 ml soap solution in 200 ml neem oil slowly and stir vigorously to get a good emulsion. Mix the garlic extract in the neem oil + soap emulsion. Dilute this one litre stock solution by adding 9 litres of water to get 10 litres of 2% neem oil + garlic.

5) Preparation of Kandhari nulaku (Hot Chilli) – Cow’s Urine mixture: The preparation is used for the control of soft bodied insects especially caterpillars. Add one litre cow’s urine in 10 lit of water. Add extract of Hot Chilli taken from 30 g of Hot Chilli. Mix well and spray

6) Preparation of Nattapoochedi (Hyptis Suaveolens) Soap Solution: Effective for controlling aphids. Take one litre Nattapoochedi extract by crushing leaves and tender items. Add 500ml soap solution (60g ordinary soap in 500ml of water) to the extract under violent agitation. Dilute in 15 litres of water to get 16.5 litres of spray solution.

7) Preparation of Kiriyathu - Garlic solution: Effective against sucking pests, especially for the management of Thrips, Aphids, White flies and Chilli virus. Crush Kiriyathu leaves and tender items to get one litre of extract. Dissolve 60 g ordinary soap (Bar soap) in 500 ml of water. Add soap solution to Kiriyath extract under violent agitation. Dilute in 15 lit of water and add garlic. Filter and spray on the lower and upper surface of leaves

8. Preparation of Turmeric powder Baking soda Solution: Turmeric is a traditionally used botanical pesticide. Turmeric powder Baking soda Solution is effectively used against amaranthus leaf blight. Prepare solution of Turmeric powder – Baking soda mixture in 10 litres of water under violent agitations. Filter and spray.

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Unit - 5 BIOLOGICAL CONTROL OF INSECTS

Nowadays due to ill effects caused by chemical pesticides on eco system and environment, biological control of pest has gained a significant attention. The idea of biological control came up in the 16th to 18th

centauries. During this period various observations and descriptions of parasites and predators among insects were noted. Various bio agents were introduced and were successfully used for the control of pests.

Biological control - When a particular species of insect is controlled by a living organism (Natural enemy), which is introduced, encouraged and disseminated by man. Biological control involves human interference. Study and utilization of parasites, predators and pathogens for the regulation of pest population comprises the field of biological control.

Natural control - A natural enemy under natural conditions controls insect pests. Eg. Spider feeds on stem borer larvae in paddy field.

Principles of biological control

1. Collection of a natural enemy from an area where it is available in plenty (Introduction). 2. Multiply the natural enemy under lab conditions (Augmentation). 3. Disseminate the natural enemy when and where it is needed (Inundation).

a) Parasites - Parasitism is a relationship between two species in which one form parasitise and obtains its nutritional requirements from the body materials of the other. A parasite is an individual which depends on another individual for its food requirement. A host is one, from where the parasite takes its nutrients. Two Types of Parasites 1. Ectoparasite: is one which develop externally on the host eg - Head louse.

2. Endo parasite: is one which develops internally with in the host. eg - worms. Based on stage of the host individual there are, 1. Egg Parasite - is one which feeds on egg stage of the host. 2. Larval Parasite - is one which feeds on larval stage of the host. 3. Pupal parasite - is one which feeds on pupal stage of the host. 4. Adult parasite - is one which feeds on adult stage of the host. Eg,

1. Bracon brevicornis - Larval parasite of coconut caterpillar 2. Elasmis nephantidis – Larval parasite of coconut caterpillar. 3. Xanthopimpla punctata – Pupal parasite of coconut caterpillar.

b) Predators - Consume a large number of host individuals. They are larger in size, stronger and more intelligent also. The host of predator is called prey. Predator is an organism which consumes several host individuals to attain its maturity.

Examples are, 1. Coccinella arcuata - predaceous on Brown Plant hopper of Rice 2. Cyrtorhinus lividipennis – Predaceous on BPH 3. Platimeris laevicolis - Predaceous on Rhinoceros beetle 4. Chelisoches moris - Predaceous on eggs of Redpalm weevil

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5. Rodolia Cardinalis - Predaceous on Cottony cushion scale of citrus 6. Coccinella septumpunctata – predaceous on insects like mealy bugs, aphids .

Coccinella septumpunctata Rodolia Chelisoches

Difference between parasites and predators 1. Parasites are smaller, weaker and less intelligent than its host. A predator is larger, stronger

and more intelligent than its host. 2. Parasites live only on a single host individual where as predator consumes large number of host

individuals. 3. Death of host of a parasite is slow, while a predator directly kills the prey and feed it.

QUALITIES OF A SUCCESSFUL NATURAL ENEMY (Factors Regulating the Efficiency of a Parasite) 1. Searching Ability - A natural enemy should have high ability to search and find out its host

individual. 2. Oligophagy - An oligophagous parasite is preferred because an oligophagous parasite feed on a

main host and one or two related other species. 3. Broad habitat Coverage - Natural enemy should be able to survive in all habitats occupied by the

host individual. 4. Amenability for Lab rearing - A natural enemy should be able to be reared in lab. The mass

multiplication of natural enemy under laboratory condition is known as augmentation. 5. Spreading Capacity - Natural enemy should be able to spread quickly in the field.

6. High fecundity and Short life cycle - Natural enemy should have high egg-laying capacity and very short life cycle. The life development of natural enemy should coincide with the development of host individual.

Agents of Biological control 1. Parasitic insects - Living organisms remaining in close association with their hosts and

gradually derive their food from the host. They live and feed internally or externally on the host e.g. Trichogramma chilonis , Epiricania Melanoleuca

Trichogramma

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2. Predatory insects - Insects which catch, kill & devour prey e.g.Chrysoperla carnea , Cryptolaemus montrouzieri

Cryptolaemus

3. Pathogens - Micro-organisms causing diseases in pests & inhibiting the harmful fungi. • Bacteria - Bacillus thuringensis • Fungi - Trichoderma, Nomuraea, Paecilomyces, Verticilium, Metarrhizium • Viruses – N.P.V.(Nuclear polyhedrosis virus)

Field application of Trichogramma Egg cards

There are approximately 100,000 Trichogramma parasitized eggs per card. Each card can be broken into 30 squares with 4,000 parasites per square inch -- this permits even distribution in fields and orchards. Loose eggs can be divided into paper cups; there are approximately 20,000 eggs in a cubic centimeter. Trichogramma wasps emerge from cards in two to five days, depending on temperature, which should ideally be 80º to 90º F. Emergence can be delayed by holding parasitized moth eggs at cooler temperatures (not less than 40º F). Emerging wasps are usually seen in the morning. To maximize pest fighting time, don't delay release after adult wasps emerge. Keep Trichogramma cards in the shade, out of the hot sun.

Trichogramma egg card Microbial Control

It is a phase of biological control in which pest management is brought about by the artificial release and colonization of disease causing micro-organisms like bacteria, fungi, virus, nematode and protozoa.The various microorganisms, which cause diseases in insects, are called Entomopathogens. Entomopathogens can be used as bio control agents. Formulations containing such entomopathogens are called Bio-insecticides (Biopesticides).

Group of Pathogen Name Effective against Bacteria Bacillus thuringiensis Lepidopteran Larvae

Fungi Green Muscardine fungus Rhinoceros Beetle Grub Fusarium pallidoroseum Cowpea aphids

Virus Baculovirus Rhinoceros beetle adult NPV &CPV Lepidopteron larvae

Chrysoperla

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Example for commercial bioinsecticides (microbial insecticides) containing formulations of bacteria (BT) are Thuricide, Bacillin, Larvetrol, Endo bacterin etc.

Advantages of Biological Control

1. Biological control has no side effects like residue hazards, environmental pollution, pest resurgence etc.

2. Biological control is permanent 3. Biological control is more economic in long run, cost of chemicals and labour charges are

very low in biological control. 4. Biological control is successful against concealed pests like tissue borers, stem borers etc.

Disadvantages of biological control

1. Biological Control is unpredictable - We cannot predict the success of this method because the success depends on climatic conditions.

2. Biological control is slow in action - It will take one or two years for complete control 3. Phenomena of hyper parasitism and multiple parasitisms reduce the efficiency of natural

enemy. (Multiple parasitism means secondary or tertiary parasites parasitise on a primary parasite. That means parasite of a parasite.)

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Unit – 6 ENVIRONMENTAL ASPECTS OF PESTICIDES

Invention of DDT and its extensive possibilities in agriculture was a milestone in plant protection. It equipped the farmers for effective pest control. Years of indiscriminate use of pesticides ended up with many problems like environmental pollution, pest resurgence, bio-magnification, health hazards and destruction of natural enemy complex. At this juncture man started to think about other methods of pest control and judicious use of pesticides.

TOXICITY HAZARDS Chemical methods of control have been found to be extremely effective in controlling pests.

But unfortunately the use of chemical pesticides has created a number of problems, which have indicated their limitation for pest control. The major problems pertinent to the use of chemicals are the development of species resistant to various pesticides and the toxicity hazards resulting in environmental pollution and affecting the health of human beings and livestock. The toxicity of a chemical is it’s innate ability to cause injury to living beings. Hazard is defined as the probability that a substance of given toxicity is likely to cause damage or injury in a particular set of conditions.

RESIDUAL TOXICITY It is the amount of pesticide residue remaining for a long period in plant parts after its

application. Many of the chemical pesticides leave their residue in plant parts after its application. This is mainly due to their ability to resist degradation for a reasonable period of time. This character of pesticide is somewhat essential in effective pest control. The chemical is said to have residual toxicity, if the chemical remain on the plant part for a longer period of time after completing its function. The quantity of residue left on the plant part depends on the,

1. Nature of chemical 2. Crop and its variety 3. Climatic conditions 4. The dosage of application 5. Method of application 6. Treatment of the produce 7. Soil conditions such as pH and texture etc.

Residual toxicity will lead to environmental pollution and bio-magnification. Toxic residues left on food and fodder cause serious health hazards in man and other higher animals. There are two types of toxicity,

• Acute toxicity - refers to the toxic effect produced by a single dose of the chemical. • Chronic toxicity - It means the effects produced by the accumulation of small amounts of

toxicant. Chlorinated hydrocarbons like D.D.T and B.H.C have got longer persistence and residue effect. They accumulate in the fatty tissues of higher animals and produce chronic effects. They will not degrade for a longer period.

BIOMAGNIFICATION - an accumulation of toxicant in living tissues (in fatty tissues) and is the phenomenon in which pesticide residue gets accumulated at higher concentration with each tier or trophic level in the food chain.

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Long ago DDT was used for pest control in the forests of American continent. The residues of this chemical washed down to the Clear Lake through rainwater. The phytoplankton and zooplanktons became contaminated with the chemicals. Concentration of the chemical further increased in the body of fishes, which consumed the zooplankton. Birds, which consumed the fishes of clear lake, were killed in large numbers. On examination, it was found that the pesticide residue concentration increased 10,000 times when it reached the bird’s body through the food chain. “The silent spring” - written by Raechel Curson an American journalist to create awareness among people about the ill effects of indiscriminate use of pesticides. In this book the author narrates her painful experience, when the spring was silent due to the mass killing of birds.

Biomagnification of chemicals through the food chain Organo-phosphorus insecticides are more toxic but they do not persist in the environment.

Systemic organo-phosphorus compounds do not leave any toxic residues. Hazard is caused by consumption of treated grains or by exposure of man to chemicals during manufacturing, formulating and application stages. The chemical dust or vapour may be inhaled by workers or it might penetrate their skin or get in to their eyes or accidentally ingested. Workers also may be contaminated when carrying out pesticide treatment. Some chemicals damage body surface by direct contact. Some others cause damage to genetic structures (mutagens and carcinogens). Other type of injury include dermatitis, asthma etc. which are generally grouped are allergic sensation. Maximum Residual limit – (MRL) is the maximum quantity of a pesticide residue permitted in a foodstuff. It is based on the assumption that good agricultural practice has been employed for the use of pesticides in farming. It is also assumed that the product has been used in an appropriate manner and suitable waiting periods have been permitted.

Insecticide Crop MRL Furadan Cereals 0.2 p.p.m (milligram in1Kg) Carbaryl Vegetable 5 milligram/kg

Waiting period - is the time gap between the application of a pesticide and harvest of a produce to reduce its toxicity to a safe level. It is the period of time given for a pesticide to degrade and reduce its level of toxicity to a safer level after its application. Waiting period depends on the chemical, crop treated, dose and method of application.

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Insecticide Crop

Waiting Period

Malathion Brinjal 3 days Bhindi 3 days Bitterguard 4 days

Carbaryl Brinjal 5 days Bhindi 5 days Bitterguard 11 days

Quinalphos Brinjal 3 days Bhindi 3 days Bitterguard 5 days

LABELS AND LABELING OF INSECTICIDES - According to the Insecticide act 1968, Insecticide rules 1971 and its amendments in 1977, no person is permitted to stock, exhibit for sale or distributes any insecticide unless it is packed and labeled in accordance with the provisions of the act. Label - means any printed, written or graphic matter on the immediate package or any such material

accompanying the insecticide. Manner of labeling - The label should contain information like,

1. Name of manufacturer 2. Name of insecticide (both generic/chemical name and trade name), 3. Registration Number 4. Kind and name of active ingredient and its percentage contents 5. Net content/Volume 6. Batch No. 7. Expiry date 8. Antidote statement etc.

Toxicity label should occupy not less than 1/16th of the total area of the face of the label. It is a square set at 45 degrees divided into two equal triangles. The upper triangle shows symbol and signal word and the lower triangle shows the colour specified for the toxicity of the insecticide. Symbol and Signal word Specified Colour

Classification of insecticides based on toxicity

Sl No

Classification of insecticide

Oral LD50 Mg/Kg

Dermal LD50 Mg/Kg

Colour band on label

Symbol/signal word

Warning

1 Extremely toxic 1-50 1-200 Bright Red Skull and cross bones POISON in red

1,2

2 Highly Toxic 51-500 201-2000 BrightYellow POISON in red 1,2 3 Moderately Toxic 501-5000 2001-20000 Bright blue DANGER 1 4 Slightly toxic >5000 >20000 Bright green CAUTION 1

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Label of an Insecticide

PRECAUTIONS TO BE TAKEN WHILE HANDLING PLANT PROTECTION CHEMICALS

Most of the poisoning results from careless handling of pesticides. Accidents can be avoided if safety measures are strictly followed.

1. Keep the insecticide in closed and properly labeled container in a dry and cool place, away from food, fodder etc. and in a place where children and animals cannot reach.

2. Use insecticide according to the instructions given on the container or leaflet and adhere to the dosages recommended.

3. Children or domestic pets should not be allowed near the mixing place and do not mix the chemicals near open wells used for drinking purposes.

4. Persons handling insecticide should avoid contact of the insecticide with their skin and inhalation of dust, vapours or mist. The minimum precaution of wearing rubber gloves and covering the eyes and nose should be taken.

5. The operators must not smoke, eat or drink anything while applying the chemical. 6. Empty bottles should be destroyed immediately after use by burying in soil. 7. After finishing the work they should take a bath or wash their hands and face with soap and

water thoroughly and change their cloths. 8. The cloths worn by them during spraying operations should be washed properly and

seperately. 9. Spraying or dusting must not be done when the wind is high. 10. Clogged nozzles or hoses must not be blown out with mouth for clearing. 11. Workers regularly engaged in spraying oprations must under go frequent medical checkups. 12. If any symptoms of poisoning is noticed immediately contact doctor.

Warnings should appear in an appropriate place outside the triangle. 1. KEEP OUT OF THE REACH OF CHILDREN 2. IF SWALLOWED OR IF SYMPTOMS OF POISONING OCCUR CALL PHYSICIAN IMMEDIATELY

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Protective clothing

INTEGRATED PEST MANAGEMENT (I.P.M.) IPM is the use of various control measures like physical, chemical, biological, legal, cultural,

mechanical and modern plant protection methods in an integrated and compatible manner so as to reduce the pest population below economic injury level without much disturbance to the ecosystem.

1) Economic Threshold Level (ETL) - is the level of pest population at which suitable control measures have to be taken to prevent the pest population from reaching EIL.

2) Economic Injury Level (EIL) - is the level of pest population at which the damage caused by the pest is no longer economically tolerated.

Integrated Pest management (IPM)

The various cultural methods such as use of disease free seeds and planting material, agronomic practices, proper management practices are advocated to control pest and disease attack. But these methods alone have not been found to be adequate for the control of sudden outbreak of pest and disease particularly in severe form. The uses of resistant variety and biological methods have their own limitations. Undesirable consequences of indiscriminate pesticide application have

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I P M

Modern techniques

Mechanical

Legal

Cultural Biological

Chemical

Physical

resulted in the development of resistant strains of insect pest. The situation has evidently created environmental hazards apart from toxic effect on man and animals. Agricultural ecosystem has been upset with the use of more homogeneous, narrow genetically based varieties and pesticides. Hence a combination or integration of practices; namely the use of resistant varieties, judicious use of mixtures of pesticides and biological pest suppression has been considered necessary for effective pest management.

I.P.M is a methodology of keeping pests below injurious levels. It is really a system of approach towards the suppression of pest by an integration of several methods. IPM methods include phenomena like host resistance, biological suppression and use of pesticides and cultural methods together with other compatible methods.

Growing resistant or tolerant cultivars are of course major part of I.P.M. Another method is by limiting of reducing the source of pest inoculum and pest in the multiplication stages. Adjusting the time of planting, crop rotation, destruction of crop residues, clean cultivation, destruction of alternate host etc help to reduce pest inoculum.

Chemical methods are to be adopted in the most judicious manner. Extreme care should be taken to use pesticides only to supplement the natural methods of control.

The general principles to be observed when adopting chemical methods are, 1. Need based application 2. Use of selective insecticide 3. Adopting selective method of application. Eg. Seed treatment, seedling and root

dip method etc. 4. Use of pesticides which are harmless to the natural enemies. 5. Avoid broad spectrum pesticides 6. Avoid excess doses of pesticides

Use of 3rd generation pesticide (Autocidal methods) such as

1. Juvenile hormones (JHs) 2. Pheromones 3. Attractants 4. Repellants etc

Where ever possible, these materials also may be attempted to. Attractants are chemicals which will induce movement towards their source. When insects come they may be killed by insecticides. Eg. Methyl euginol for male Daccus dorsalis (Oriental fruit flies)

Repellants are chemicals which cause insects move away from the source. Action is opposite to attractants. Eg. Naphthalene, Neem oil etc.

CONTROLLING RICE STEM BORER UNDER IPM APPROACH 1. Cultural Methods

a) Destruction of stubbles of previous crop b) Use of resistant varieties like IR-20, Kanchana. c) Destruction of collateral hosts

2) Mechanical methods a) Collection and destruction of egg masses

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b) Light traps 3) Legal methods

a) Restriction on the transport of infested planting materials. 4) Biological method

b) Trichogramma c) Xanthopimpla

5) Chemical a) Insecticides like Carbaryl, Quinalphos

6) Modern plant protection methods Pheromone Traps, male sterile technique, use of hormones.

Importance of Integrated Pets Management 1. Eco-friendly 2. Cheaper and more effective 3. Reduces pollution 4. Chances of pest resurgence minimum 5. Preserves natural enemies

ETL of major pests of Rice

Crop stage and pest Economic threshold levels A. Nursery

1. Green leaf hopper 1-2 insects/m2 2. Gall midge 1 silver shoot (gall)/m2 3. Stem borer 1 moth or 1 egg mass/m2

B. Planting to pre-tillering 1. Leaf folder 2 freshly damaged leaves/hill 2. Yellow stem borer 5% dead hearts or one egg mass or one moth/m2

3. Gall midge 1 gall/m2 in endemic areas or 5% affected tillers in non-endemic areas.

4. Brown plant hopper 5 to 10 insects/hill C. Mid-tillering

1. Leaf folder 2 freshly damaged leaves/hill 2. Stem borer 10% dead heart or 1 moth or 1 egg mass/m2 3. Gall midge 5% silver shoots 4. Brown plant hopper 10 insect/hill

D. Panicle initiation to booting 1. Stem borer 1 egg mass or 1 moth/m2 2. Leaf folder 2 freshly damaged leaves/hill 3. Green leaf hopper 20 insects/hill 4. Brown plant hopper 15 to 20 insects/hill

E. Flowering and after 1. Brown plant hopper 25 to 30 insects/hill 2. Climbing cutworm 4-5 larvae/m2 3. Rice bug 1 or 2 bugs/hill

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Unit – 7 INSECT PESTS OF MAJOR CROPS OF KERALA

A large number of major and minor pests are infesting our crop plants. Every year we are loosing major part of our agricultural products due to pest attacks. For increasing yield and to attain self-sufficiency in agriculture production, it is necessary to control these pests. For successful pest control thorough scientific understanding of pest, it’s destructive stage and suitable control measures are necessary.

1. PESTS OF RICE

Major Pests

1. Rice Stem borer or Yellow Stem Borer

Sc: Name : Scirpophaga incertulas (Lepidoptera)

Pest is the caterpillar of a yellowish moth. Adult female have a prominent black spot in the middle of the forewing. Forewing is orange yellow in colour. Hind wings are slightly brownish. Males are smaller in size than females. In males the spot is not very clear and there is a marginal row of spots on the fore wings. Nature of damage - Adult female lays eggs in masses of 15 to 80 on the upper leaf surface. Eggs are buff coloured and covered by hairs. One female lays up to 150 eggs. The hatched larvae carry on to rice plants by hanging on silken threads or move to other plants. They bore into the stem and feed on the internal contents of stem. So that translocation of food to the upper part is stopped. In the young stage the typical symptom caused is dead hearts. That is central leaf dies and turn yellow in colour. In the panicle initiation stage translocation of food to the panicle is stopped and grains turn to chaff and are white in colour called white ear head. Larvae pupate at the base of the stem. Total life cycle 5 to 6 weeks. It is a pest that occurs through out the season. Two to 3 generations are completed in one cropping season. Control measures

An integrated approach is necessary as it lives with in the plants. 1. Collection and destruction of adult moth by light traps. 2. Collection and destruction of egg masses in the nursery. That is clipping of leaf tip of rice

seedlings. 3. Removal and destruction of plants showing dead hearts during transplantation. 4. If infestation is endemic use some insecticide as spary. eg. Quinalphos, monocrotophos, fenthion. 5. After harvest fields are flooded or stubbles burnt to destroy remaining larvae. 6. Use of tolerant variety like IR-20 where ever possible. 7. Egg parasites used are Trichogramma and Telenomus. Sex pheromones are also tried.

2. Rice ear head bug or Rice bug.

Sc. Name : Leptocorisa acuta (Hemiptera) Also known as gundhi bug since it produce an offensive smell when disturbed. Adult bug is 1.8

cm long, olive brown above and green beneath. Nymphs are elongated greenish or yellowish green. Adults feed on milk of grains, as a result become chaffy. Chaffy grains become brown in colour and

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dry up. Nymphs feed on juice of stem and leaves. Pest infested crop show the presence of many chaffy grains and such infested ear heads stands erect unlike normal bend ones. Various types of grasses are alternate host for the rice bug. Control Measures

1. Clean the fields and bunds of grassy weeds 2. Since the insect is stage specific, avoid overlapping cultivation providing milky stage

continuously in an ela. 3. In small holdings bugs can be controlled by net sweeping. 4. When the bug is seen in large numbers apply one of the following insecticides, Malathion,

Carbaryl, Methyl Parathion. 5. Strict vigilance is necessary at milky stage, since the occurrence of bug coincides with

the flowering stage. Application of insecticide may be done either before 9 PM or after 3 PM so that fertilization of the flowers is not adversely affected.

Rice Stem borer Rice Bug 3. Brown Plant Hopper (B.P.H.)

Belongs to the order SC Name : Nilaparvata lugens (Hemiptera)

This is a sucking pest, very serious in Kuttanad and Kole area. Adults are greyish brown dorsally and deep brown ventrally. Eggs are pressed within leaf sheath and lamina. The larvae move to the base of plant and start feeding on plant sap. Usually summer crop is the most affected. All stages of rice crop is susceptible to this pest. As a result of sap sucking, plants turn yellow in colour and later dry up. Yellowish circular patches appear here and there in the field. The plants in these areas dry up very soon and yellowing and drying extend very rapidly. This symptom is called hopper burn symptom. Control measures

1. Use resistant or tolerant varieties such as Jyothi, Pavizham, Aiswaraya, Nila etc. 2. Apply one of the following insecticides soon as the yellowing symptom is observed, covering

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the infested patches and area surrounding the patches. While spraying and dusting care has to be taken to see that the insecticide reaches the base of the plant. Carbaryl, Quinalphos, Fenthion, Carbofuran, Monocrotophos etc.

3. Drain away water from the field and keep it in that condition until the pest population is decreased.

4. Predators of B.P.H. - Coccinella arcuata, Cyrtorrhinus lividipennis

4. Paddy Gall fly (Gall midge)

S.N. : Orseolia oryzae (Diptera)

Adult is a small fly with brown body and semitransparent wings. Eggs are laid at the base of each leaves, singly or in clusters. Larvae move towards growing point and start feeding there. As a result of continuous feeding and irritation caused by its feeding an oval chamber is formed surrounding the larvae. Gradually this chamber grows up as an elongated cylindrical gall. This is called silver shoot - presence of silver shoot in the place of centre leaf is the prominent symptom. The symptoms appear from the nursery to the flowering stage. In very young seedlings instead of silver shoot a swelling at the basal portion and excessive tillering are noticed. Maximum infestation is seen in rainy season. Control measures

1. Avoid late transplantation during 1st crop season. In areas where the pest is of regular occurrence apply Phorate or Carbofuran.

2. In gall midge endemic areas, roots of seedling may be dipped in 0.02% suspension of chlorpyriphos for 12 hours prior to transplanting.

3. In the main field apply any one of the following insecticide. Carbaryl, Quinalphos, Phorate, Carbofuran.

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5. Rice Case Worm

Sc. Name : Nymphula depunctalis (Lepidoptera) Paraponis stagnalis (New name)

This is the larva of a small delicate moth, snowy white with pale white markings. Insect is present in all rice tracts. Eggs are laid on surface of leaf and leaf sheath. Larvae move to tip of leaves and make cuts 1 to 2 cm from the tip and it folds. They make tubular cases and make it loose from the plant. By remaining in the cases larvae feed on green matter. Pest infestation is seen only in ill-drained fields because larvae require water for respiration. (Larvae are gill breathing). Dispersal of larva is by floating cases on water surfaces. Control measures

a) Drain away water from field. b) If infestation is severe apply carbaryl dust or spray.

6. Leaf Roller (Leaf Webber or Folder)

Sc. Name : Cnaphalocrocis medinalis (Lepidoptera)

Straw coloured moth with greyish brown border and two transverse marking. Eggs are laid on leaves. Caterpillar is causing damage. All stages of rice plant are attacked by this pest. In seedlings and young plants 3 to 4 leaves are webbed together to make a composite fold. In grown up plants larvae make folds on single leaves either longitudinally or transversely. Infested portion is white in colour due to scraping of green matter by the caterpillar. Attacked leaves dry up weakening the plant. Control measures

a) Open up the leaf folds with a thorny twig. b) Insecticide Quinalphos, Carbaryl, Methyl parathion, Fenthion etc can be sprayed. In the

initial stages restrict spraying to infested patches only. The field may be sprayed completely in case the infestation occurs uniformly.

7. Army Worm (Rice swarming caterpillar) Sc. Name : Spodoptera mauritia (Lepidoptera)

They are called army worm because they come in large numbers. That is in a sporadic nature. It is the caterpillar of a stout moth. Eggs are laid on tender leaves. Larvae feed by cutting bits of leaf blades. Occur sporadically in large swarms and eat away the whole crop. Then it moves to other fields. Plants are reduced to mere stumps which may die or if they revive they will not bear ear heads uniformly. Control measures 1. Spraying insecticide Carbaryl, Methyl parathion etc. 2. Ducks and other birds feed on caterpillar.

8. Rice Hispa

Sc. Name : Dicladispa armigera (Coleoptera)

Adult is a small beetle, steel blue to black in colour and body is spiny. Eggs are pressed singly with in leaf tissues towards leaf tip. The adults feed on green tissues of the leaves and feeding scars appear as short white lines on the leaf surface. The grubs mine the leaves causing formation of white blotches. Early stages of the crop are more susceptible to this pest.

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Control measures

1. Collecting and destruction by net sweeping 2. Clipping of leaf tip of seedlings during transplantation. 3. Spray any contact insecticides like Carbaryl

Rice Leaf roller Rice case worm

Rice swarming caterpillar Rice Hispa Minor pests of Rice

1. Rice thrips - The crop is highly susceptible in the nursery stage. The tips of leaves get rolled longitudinally into needle like out growth and turn whitish.

2. Whorl maggot - Serious in nursery, yellowing of leaves and deformed 3. Rice mealy bug - Weak yellowish stunted plants are seen in patches white waxy fluff is seen on leaf

sheaths. 4. Green leaf hoppers - General yellowing of plants, vectors of yellow dwarf virus 5. Grass hopper - Nymphs and adults feed on leaves and stem; cut the panicle during later stages. 6. Blue beetles - The adults feed on green tissues of the leaves, feeding scars appear as short white

lines on the leaf surface. The grubs mine the leaves causing formation of white blotches

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2. PESTS OF COCONUT

I. Rhinoceros Beetle

Sc.Name : Oryctes rhinoceros (Coleoptera) The adult is a large stout - built, brownish black beetle. Male is larger than female. The

beetles have a conspicuous upward curved blunt horn on its head. The horn is shorter in females. The beetles breed mainly in cattle dung or in other decaying organic materials. Nature of Damage - The food for the adult is the tender sweet tissues of the coconut shoot. The adult beetle bores into the central unopened spindle, spathe and leaf petioles. When the central spindle is attacked it breaks at the point of attack and the functional leaf area of the frond when fully opened shows characteristic triangular / geometrical cuts. Injury caused by the beetle may lead to secondary infestation by red palm weevil and other pathogenic microbes. Seedlings when attacked are killed outright. Control measures

1. Hook out the beetles from attacked palms by using beetle hooks . 2. Fill up topmost three leaf axils around the spindle with any of the following mixtures. (a)

Sevidol 25 gms + 200 grams fine sand. (b) 10.5gm of naphthalene balls covered with fine sand (3 balls). The leaf axil filling is to be done thrice in a year. In April - May, September - October and December - January as a prophylactic measure.

3. Treat manure pits and other possible breeding sites with Carbaryl 0.01%. This treatment has to be repeated every 3 months.

4. Adults and grubs of this major pest could effectively be controlled by using the virus, Baculovirus oryctes and grubs by the fungus Metarrhizium anisopliae

5. Using pheromone traps @ 1 trap per 4 ha.

II. Red Palm Weevil

Sc. Name : Rhynchophorus ferrugineus (Coleoptera)

The adult is a large sized brown weevil. The mother weevil scoops out small holes on healthy tender parts of young palms and lays eggs in these holes. In grown up trees eggs are laid in leaf axils and in wounds in the stem or leaf stalk. The plant sap oozing out of wounds and cuts attract weevils for oviposition. Injury caused by rhinoceros beetle or by disease also attract weevil for egg laying.

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The grub is the destructive stage of the pest. It tunnels into the tissues of the palm trunk and feed on the succulent tissues. The diagnostic symptoms of attack are presence of holes on the stem, oozing out of a viscous brown fluid and extrusion of chewed up fibres through the holes, longitudinal splitting of leaf base and wilting of central shoot. Some times the gnawing sound produced by the feeding grubs inside will also be audible. Symptoms of the pest infestation usually become clear at an advanced stage when the crown topples down. Control measures

1. Field sanitation should be given prime importance. 2. Avoid making steps or any other injury on the tree trunk to reduce the point of infestation. 3. Leaf axil filling as suggested under rhinoceros beetle will be useful against red palm weevil also. 4. When green leaves are cut from the palm, stumps of not less than 120 cm may be left on the

trees in order to prevent inward movement of grubs through the cut ends. 5. Inject attacked palms with pyrecone - E 2/20 or Carbaryl 1% concentration. Pyrecone 10 ml or

Carbaryl 50wp-20gm in 1 ltr. water per palm using a funnel. 6. Apply 1% DDVP or Aluminium phosphide tables (1-2 tablets per tree) as a curative measure. 7. When the pest infestation is through the crown, cleaan the crown and pours the insecticidal

suspension. 8. Coconut log traps with fermenting toddy and pine apple or sugarcane activated with yeast or

molasses can be set in coconut garden to attract and trap free floating populations of adult red palm weevil. Incorporate any of the insecticide to each trap to kill the weevils trapped.

Damaged palm III. Black headed Caterpillar

Sc Name = Opisina arinosella (Lepidoptera) The pest is a caterpillar of a moth. A female moth lays about 130 eggs in several groups on

the older palm leaves. The larva grows feeding on the surface tissue of the under surface of the leaflets. It makes elongated galleries of silk and frass on the underside of leaflets and remains within the galleries. It become full grown in about 40 days and pupates with in a tough silken tissues have larval gallery. The areas from which surface tissues has been eaten, turn brownish and dry up. Later the dried areas may break-up and drop away. The attack is generally confined to the lower leaves. The severity of attack will be marked during summer months from January-May. Control measures

1. As a prophylactic measure the first affected leaves may be cut and burnt during the beginning of summer season.

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2. Arrange for liberation of Braconid or Bethilid or Elasmid parasite as soon as infestation is noted. 3. When infestation is very severe and if the biocontrol is not likely to effect spray the under

surface of leaves with Dichlorvos 0.02% and Quinalphos 0.05%. After the application of insecticide follow up by liberation of larval and pupal parasite from the 21st day.

IV. Cockchafer beetle or Root grub

Sc.Name : Leucopholis coneophora (Coleoptera) The soil inhabiting white grubs cause damages to roots of coconut palm. The attacked palms

turn pale yellow, immature nuts shed and there will be considerable reduction in yield. Control measures 1. Plough or dig the infested soil coinciding with pre-monsoon showers. 2. Apply Thimet 100g / palm 3. Where ever possible light traps may be set up to attract and trap adult beetle.

V. Nut Crinkler (Coreid bug)

Sc:Name : Paradasynus rostratus (Hemiptera) The attacked buttons do not develop and tender nuts become barren. Feeding injury can be

seen on fallen nuts which show cracks and gummosis also.

Control measures

1. Apply Carbaryl 0.1% on the newly opened inflorescence after the receptive phase of the flowers and spray the entire crown excluding the leaves and the older bunches. The insecticides may be applied according to the severity of infestation in a need based manner.

2. Setting traps in coconut garden to trap adult bugs.

Root grub Nut Crinkler

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VI. Mealy bug

Sc. Name : Pseudococous longispinus (Hemiptera)

Mealy bugs infest unopened heart leaves and inflorescence, leaf become highly stunted, suppressed, deformed and present a crinkled appearance. The affected inflorescence is malformed and do not open. Even if they open they don't bear nuts. Control 1. Rogor 0.05%

VII. Coconut Scale

Sc. Name : Aspidiotus destructor (Hemiptera)

This is a circular hard scale insect. It is a dry season pest of coconut. The circular scales cluster on the underside of leaflets in large numbers feeding on the plant sap. The leaf lets as a result turn yellowish and in severe cases leaves may dry up. Control

1. Cutting and burning of infested leaf lets.

3. PESTS OF PEPPER 1. Pollu beetle

Sc. Name : Longitarsus nigripennis (Coleoptera)

The adult is a shiny flea beetle about 2.5 mm in length. The female beetle scoop out holes on berries and lays 1 or 2 eggs on the berries. Up to 100 eggs are laid by a female beetle. The grub bores in to the berries and feeds on its internal tissues. When the content of one berry is completed, it moves to another berry. 3 to 4 berries are fed up on by a single grub. The grub when full grown drops to soil and pupates in soil in an earthen cell. The injury caused to the pepper berries by the grub is often serious. Infested berries dry up and turn dark in colour. They are hollow and crumble when pressed. Such hollow berries are called pollu berries. The grub may sometimes eat into the spike stalks so that the entire spike beyond it dry up. The adults feed holes on tender leaves.

Control measures

1. Shade management 2. Raking soil around the plant to expose pupae 3. Spray Quinalphos or Monocrotopphos - 0.05 %

4. The sprayings are to be given at the time of spike emergence (June-July), at berry formation

(September-October) and once again at berry maturing stage if needed.

2. Marginal Gall Thrips

Sc. Name : Liothrips karnyi (Thysanoptera)

This is a black thrips about 2.8 mm in length. The infestation by the thrips on the leaves result in formation of marginal folded galls on them within which the insect lives in colonies comprising its all stages. The marginal gall is formed as a result of feeding activity of the thrips. The galled leaves are malformed also.

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Control measures

1. Spraying Monocrotophos 0.05% or Dimethoate 0.05% or Phosphamidon 0.05 %

Pollu beetle Marginal gall thrip 3. Pepper scale

Sc. Name : Lepidosaphes piperis (Hemiptera)

The mature scale is elongated and oval and dark grey in colour. It infest in large numbers on stems, leaves and petioles of pepper plant. The infested vines fade wither and dry up. The cuttings when affected cause severe damage. Soft scale infestation is seen on foliage and vines at higher elevations (Idukki, Waynad etc.) Control measures

1. Spray Quinalphos. Rogor etc. This treatment will be adequate for the control of mealy bug also.

4. Shoot Borer

Sc. Name : Laspeyresia hemidoxa (Lepidoptera)

It is the Caterpillar of a tiny moth. Caterpillar bores into terminal shoot of pepper plants killing shoot. The attacked shoot dies and dries up.

Control measures

1. Use any systemic insecticide.

5. Root grub

Damaging roots of live standards and teak poles can be controlled by application of Phorate at the rate of 2 g a.i. per standard in to the soil around the base of the plant through slanting holes.

4. PESTS OF BANANA

1. Pseudo Stem Weevil

Sc. Name : Odoiporous longicollis (Coleoptera) The weevil resembling the rhizome weevil of banana is becoming a serious pest in recent

days. Adult female weevil punctures and inserts eggs into the psuedostem. Grubs emerging out feed extensively on the pseudo stem and there by the entire plant droops. Control measure

1. Field sanitation is the most important factor in the prophylactic and curative control of this pest.

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2. Remove such plants along with rhizome in full and destroy them by burning the life stages of the insect using kerosene or by burying the material in deep pits in soil.

3. Destroy parts of rhizome and psuedostem of harvested plants in the field and destroy them as described above.

4. Remove the dry outer sheaths of psuedostem of all infested and un infested plants in endemic areas and spray any of the following insecticide.

Quinalphos 0.05 %, Carbaryl 0.2%, Chlorpyriphos 0.03% 5. Repeat the treatment after 3 weeks if infestation persists. Drenching all the leaf axils, rhizome

and surrounding soil and all round the entire psuedostem inserting the nozzle through the bore holes made by the larva and also within the outer sheaths by slightly raising the same at different spots is also effective.

2. Banana Rhizome weevil

Sc. Name : Cosmopolitus sordidus (Coleoptera) The attack by the pest is reported to be serious in all localities where banana is cultivated.

Female adults puncture healthy rhizomes and insert eggs through it. The adult is a small weevil dark brown in colour 1 to 2 cm length. Grubs tunnel within rhizomes and feeds resulting in stunting of rhizome development. If the infestation is to occur on a mature rhizome, symptoms appear as reduction in leaf number, reduction in bunch size and fruit number. The young suckers when attacked wither and die soon. The corms of attacked plants have extensive tunnels plugged with excreta, such a rhizome show black patches of rotten tissues resulting from the weevil attack. Roots are also damaged. Control measures

1. Adopt strict field sanitation 2. Select only healthy planting material 3. Deep plough the land so as to expose the inner soil layer to sun. 4. Cut and remove the outer layer of rhizome and sundry for 3 - 4 days after smearing it with

slurry of cow dung and wood ash. 5. Set traps using psuedostems of approximately half meter length which are split lengthwise

and laid in the field. Adult weevils attracted to it during nights may be collected and destroyed.

Psuedostem weevil Rhizome weevil

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3. Banana Aphid

Sc. Name : Pentalonia nigronervosa (Hemiptera)

This is not a direct pest and no symptoms of attack. The importance of this pest is that it acts as a vector for the transmission of the dreadful bunchy top disease of banana. The aphid lives in colonies at the base of the psuedostem and top region and leaf axils. Control measures

1. Apply 25g of Phorate 10G, 20 days after planting around the rhizomes in the soil.

2. Apply 12.5g Phorate in the leaf axils or 25g Phorate in soil 75 days after planting and 165 days after planting or Carbofuran 3G, 20gm / plant at the time of planting in soil, again 20g Carbofuran / plant for leaf axil filling 75 days after planting and 165 days after planting. When granules are applied around the base of the plant there should be sufficient soil moisture.

5. PESTS OF MANGO

1. Mango Hopper Sc. Name : Amritodus atkinsoni ( Hemiptera)

Idioscopus clipealis The adult is a wedge shaped hopper with broad head and tapering body. 30 to 4mm length,

greenish brown colour. Damage is caused by the adults and nymphs feeding on different plant parts. During flowering season population of hopper increases rapidly when the hoppers feed from shoots and flower stalks, flowers and buds dry up and drop. When the inflorescence is not available hoppers feed on leaves. Then leaves turn crinkled and undersized. Sooty mould develops on the plant parts of the hopper infested trees due to the honey dew secretion of hoppers. Control measures

1. Spray Carbaryl 0.1% or Malathion 0.1% at the time of flowering.

2. Leaf Hoppers Sc. Name : Amrasca splendens ( Hemiptera) Nymphs and adults cluster on lower side of leaves sucking sap from mid ribs or side-ribs. The

veins turn brown and leaves become stunted and curled. 3. Stem Borer

Sc. Name : Batocera rufomaculata (Coleoptera) Adult is a large longicorn beetle. Eggs are laid on slits in bark of tree. The grubs make zig-zag

burrows under the bark. The stem and branches dry and leaves shed. Bore holes with sap and frass coming out through them can be seen. The grubs become full fed in about 6 moths. Control measures

1. field sanitation 2. Apply paste made of crude carbolic acid 130 ml + soft soap 1 kg and hot water 3.7 ltrs to holes

in the bark and plug the holes Inject aluminium phosphide tablets into the burrows after chiseling the opening and widening the burrows with an auger.

4. Mango Fruitfly Sc. Name : Dacus dorsalis (Diptera)

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Adult is a fly, brown to dark brown with hyaline wings. Eggs are laid in clusters under the skin of ripening fruits. The maggots grow feeding on the pulp and become full grown in about a week. Damage to the fruit is caused by both adult and maggots. The oviposition punctures made by adults serve as entry point for fermenting organisms. The maggot converts the pulp into a bad smelling semi-fluid mass unfit for use. Brown rotten patches appear on the attacked fruits and they drop.

Control measures

1. Collect and destroy attacked fruits that rot and drop down. 2. Spray trees with Malathion 0.1% emulsion containing 2% sugar. 3. pheromone traps

5. Stone weevil – Sternochaetus mangifera Coleoptera Adult weevils insert eggs under the rind of ripening fruit. On hatching, the grubs eat its way

through the pulp (making it tasteless and dirty) until it bores into the stone, where grubs pupates inside a cell. The wound heals up leaving no external sign of attack. The adult weevil on emergence acts its way through stone and pulp to come out before or after the fruit is eaten and thrown away.

Control • Collection and destruction of fallen fruits • Malathion 0.1% may be effective to control ovipositing weevils, sprayed 1 month after

fruit set.

6. Shoot Webber (Lepidoptera) It is the larva of a moth. Damage is caused by the larvae webbing together clusters of leaves

and feeding inside. The webbed up leaves dry. In severe cases of attack, the tree shows many webbed nests of leaves and tree shows a sickly appearance. Control measures

Spray any contact insecticide.

7. Shoot midge (Diptera) The adult is a minute yellowish midge. Terminal shoots show swelling and dry up. Young

plants when attacked are often prevented from growing due to continuous killing of new shoots. The damage is caused by the yellowish maggots tunneling with tender shoot, leaf petiole, flower buds etc. Grafted varieties of mango are more susceptible to the attack of midge. Control measures - 1. Carbaryl 0.1% or Dimethoate 0.05%

8. Leaf Cutting Weevil They cut down the tender leaves at base and make feeding holes on standing leaves. Young

plants often suffer much as all the tender leaves are cut down each time new flushes appear. Control measures

1. Carbaryl 0.1% at the time of appearance of new flushes.

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Leaf hopper Stem borer

Fruit fly Stone weevil

6. PESTS OF CUCURBITS

1. Fruit fly or melon fly

Sc. Name : Dacus cucurbitae (Diptera)

The adult is a reddish brown fruit fly. Eggs are laid in cavities, 2 to 4 mm deep and sealed with a gummy secretion. The maggots bore into the fruits and feeds on internal contents. The damage is caused by the larvae tunneling and feeding within fruits and such fruits rot and drop. Control measures

1. Apply Carbaryl 10% DP in pits before sowing of seeds. 2. Cover the fruits with polythene, cloth or paper bags. 3. Spray 0.2% Malathion or 0.2% suspension containing sugar @ 10gm / ltr at fortnightly

intervals after fruit set initiation. 4. Remove and destroy all decayed fruits. 5. Banana fruit traps may be prepared by applying Furadan granules at the cut end of ripe

banana fruits (Palayamkodan variety). These traps are kept in garden at 2m distance.

2. Epilachna beetle Adults and larva feed on leaves and defoliate leaves, leaves dry and fall.

Control measures Remove and destroy eggmass, grubs and adults occuring on leaves and spray carbaryl. 3. Pumpkin Beetle

3 species of pumpkin beetles are usually occurring on cucurbits - Red, blue and grey. Of these

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the Red pumpkin beetle is more commonly occurring one. Adults eat the leaves, make holes on foliage and cause damage on fruits and roots. The grubs bore into roots and fruits which lay on ground. Control measures Incorporate Carbaryl 10%DP in pits before sowing seeds to destroy grubs and pupae. 4. Snake gourd Caterpillar (Lepidoptera)

Hiding in a leaf fold caterpillar feeds on leaf blade. Large scale defoliation is caused by this caterpillar. Sometimes flowers and young fruits may also be eaten up. Control measures

Collection and destruction of Caterpillar and apply any contact insecticide.

5. American Serpentine Leaf Miner (Diptera)

This is a recently introduced polyphagous pest infesting crops like cucurbits, brinjal, bhindi, cowpea etc. Larvae mine the leaves and exhibit irregular serpentine like lines. As a result of attack leaves dry up and cause extensive damage.

Control measures

1. Spray neem oil emulsion.

Other pests of cucurbits include aphids, shield bug, pumpkin caterpillar, flower beetle etc.

Snake gourd caterpillar

Pumpkin Beetles Melon fly Epilachna Beetle

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7. PESTS OF COW PEA

1. Cow pea Aphid

Sc. Name : Aphis craccivora (Hemiptera) The adults and nymphs suck sap from the under side of leaves and terminal shoots of stem

and branches, flower stalks and pods. Infested leaves turn yellow, plants become stunted. Pods are malformed. Control Measures

1. Use of Psuedomonas flurescence as biocontrol agent 2. Spray Malathion 0.01% Quinalphos 0.03%

2. Flower and Pod Borer (Lepidoptera)

This is the caterpillar of a small moth. Eggs are laid at the base of the pods or on tender pods. The larvae bore into flower buds, flowers, pods and seeds, feeding on their internal contents. Several flowers may be webbed together. Control Measures - Spray Carbaryl 0.2%. Apply the insecticide after harvesting mature pods and pick the pods only 10 days after application of insecticide.

3. Pod bug Adults and nymphs suck juice from the seeds of pods. Attacked seeds shrivel up within the

pods and become discoloured. 4. American Serpentine Leaf Miner (Diptera)

This is a recently introduced polyphagous pest. Larvae mine the leaves and exhibit irregular serpentine like lines. As a result of attack leaves dry up and cause extensive damage. Control measures - Spray neem oil emulsion.

Aphid Pod Borer

Pod Bug Leaf Miner

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8. PESTS OF BHINDI 1. Fruit and Shoot borer

Sc. Name : Erias vitella (Lepidoptera)

Pest is the caterpillar of a moth. Larva bore into terminal shoot or into the fruit and feed on internal contents. The damaged shoots droop, wither and dry up. Infested fruits present a deformed appearance and holes on them plugged with excreta. Control Measures

1. Collection and destruction of affected plant parts. 2. Spray Carbaryl 0.15%

2. Leaf Hoppers (Hemiptera)

The adult is a greenish leaf hopper. Nymphs feed on leaf sap from the flower and leaf surface. Injury is caused by the saliva. Infested leaves crinkle, turn yellow and brick red in colour called hopper burn symptom. Control Measures

Spray Quinalphos or Fenthion at 0.05%

3. Aphids

Infest underside of leaves. Leaves become crinkled and plant stunted. Sooty mould develops on leaves. 4. Flower beetle - It feed on flowers. Shoot and fruit borer

9. PESTS OF BRINJAL

1. Shoot and fruit borer

Sc. Name : Leucinodes orbonalis (Lepidoptera)

Pest is the caterpillar of a moth. Eggs are laid on fruits and shoots. A female lays up to 250 eggs. The larvae bore into shoots and fruits. Attacked shoots droop, wither and dry up. Attacked fruits show holes on them plugged with excreta. Control Measures

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1. Collection and destruction of attacked fruits. 2. Spray Carbaryl 0.15 % at 15-20 days intervals.

2. Epilachna beetle

It is a small beetle, hemispherical in shape. Both adults and grubs cause damage to leaves by scraping the surface tissue. Damaged leaves dry up. Control Measures

1. Collection and destruction of adults and immature stages from plants. 2. In severe cases spray Carbaryl.

Other pests include green grass hoppers, aphids, mealy bugs, lacewing bugs, leaf webber, sphingid moth, leaf eating caterpillars etc.

Shoot and fruit borer Epilachna Beetle

10. PESTS OF RUBBER 1. Scale Insects - Hard scales and soft scales infest twigs and leaves of rubber tree. Severe infestation

causes dropping of leaves. Sooty mould appears on leaves when there is attack of soft scale. 2. Bark Caterpillar - Caterpillar of a small moth. It constructs galleries of silk on the bark surface of

rubber tree and feeds on surface tissue. Application of tar on the bark surface prevents the attack. The caterpillar can also be brushed away by using stiff brushes.

3. Root grub - The nursery plants are damaged and killed by the grub feeding on their roots. 4. Stem borer (Same as mango stem borer) - The grub bores into the branches of rubber occasionally

killing them. 5. Bark borer - The minute shot hole borer beetle bores into the bark and interferes with latex flow.

Termites, snails and rats are also causing damage to nursery plants.

11. PESTS OF CASHEW

1. Tea mosquito bug or cashew mirid Sc. Name : Helopeltis antonii (Hemiptera)

The adult bug is reddish brown with black head, red thorax and black and white abdomen. This is the most serious pest affecting cashew. The pest usually appears with the emergence of new flushes and panicles. Drying of the inflorescence and dieback symptom of the shoot is the result of

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attack. Injury is caused due to the saliva induced by the adults and nymphs. The area around the feeding point becomes necrotised. The insects feed from tender shoots, inflorescence, developing nuts and apples. The shoot show die back symptoms and the inflorescence show blossom blight (inflorescence blight). Loss in yield is as high as 30% Control Measures For control of tea mosquito spray

1. Carbaryl - 0.1 % 2. Quinalphos - 0.05 % 3. Phosphamidon - 0.03%. A rational rotation of insecticides would be desirable to counteract

the tendency of pest to develop field resistance. Spraying may be done thrice as follows. • 1st spraying - coinciding with the emergence of new vegetative flushes (Oct- Nov) • 2nd spraying - Coinciding with the commencement of panicle emergence (Dec-Jan) • 3rd spraying - At fruit set initiation or complete flowering (Jan-Feg.) Avoid spraying with

Phosphamidon at the time of flowering as it is highly toxic to honey bees.

2. Cashew Stem borer Sc. Name : Plocoderus ferugenius (Coleoptera)

The adult is a brown longicon beetle, size 2.5 to 4 cm. Eggs are deposited in the crevices on the trunk or exposed root. The grubs bore into the bark and sapwood making tunnels within them. Symptoms of attack include presence of bore holes with gum and frass emerging out of them at the collar region, yellowing and shedding of leaves, and drying up of twigs. As a result of large number of grubs tunneling within the stem and roots the tree completely dries up. Control Measures

1. Swab the tree trunk and exposed root with Carbaryl. 2. Remove the dried twigs and dead trees and burn them. 3. Prophylactic treatment by swabbing the tree trunk up to 1 meter height from the ground with

a suspension of Carbaryl 0.2% or coal tar and kerosene (1:2 ratio) can be given during March - April and Nov- Dec.

4. Injection of contact insecticide emulsion into the boreholes may also be done.

Other pests include brown aphid, Nut bug, Leaf and flower thrips, Shoot borer etc.

Tea mosquito bug Stem borer

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12. PESTS OF ARECANUT

1. Spindle bug Sc. Name : Carvalhoia arecae (Hemiptera) The adult is a red and black bug. 6 mm long. Eggs are thrust with in the tissues of tender

unopened spindle. Nymphs are greenish with reddish brown patches. They live in colony within the leaf axils close to the spindle. The adults and nymphs suck sap from the spindle and young fronds. The feeding scars appear as elongated brown lesions, which dry and drop leaving holes on the leaflets. In severe cases complete shredding and drying of leaves occur. Control Measures

1. Spray crown with Carbaryl 50% W.P. Spray should reach the leaf axils. 2. Repeat spraying after 30 days if pest incidence continues.

2. Inflorescence Caterpillar

The larva feeds on the floral parts of newly opened inflorescence. Control Measures

1. Force open the inflorescence out of the enclosing spathe and spray Malathion 50EC. 2. Control slugs which predispose inflorescence to the attack of caterpillar by using baits

of Metaldehide. 3. Root grub

The grubs feed on roots and damage them. The infested palm shows yellowing of leaves, tapering of stem and suppression in yield. Control Measures

1. Loosen soil around the base of palm to a depth of 10-15 cm and drench with Chlorpyriphos 0.04% or Phorate - 10G.

Termites are also damaging seedlings and young palms feeding at their base.

13. PESTS OF CARDAMOM

1. Cardamom Thrips

Sc. Name : Sciothrips cardamomi (Thysanoptera) The insect is a serious pest of cardamom. Thrips are seen in all concealed parts that is

beneath leaves or leaf sheath or floral parts. Damage is caused by lacerating and feeding on the exuding sap from the aerial parts. Infestation on the panicle and flower buds result in stunted growth

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of panicles, shedding of flower buds and warty growth on the surviving capsules. The infested capsules are light in weight, inferior in quality and fetch very low price in the market.

Control Measures For the control of this pest insecticide application is the only method. Since the pest

population is high during the dry moths during December to April pesticide application during this period is important. Four sprayings of insecticide is recommended during the period. During rainy months insecticide application is not necessary. During August to November 3 more sprayings are to be given. Any of the following insecticides can be used. E.C. Formulations - Quinalphos = 0.03%, Monocrotophos = 0.03%, Dimethoate = 0.05%, Fenthion = 0.03% Dust formulations - Carbaryl 10% D, Quinalphos 1.5% D, Each at 25 kg / ha 2. Leaf Eating Caterpillars - There are 10 sps. of caterpillars feeding on cardamom leaves. Out of this 7 spp. are hairy and appear in large numbers during certain season causing extensive defoliation. Control Measures - Mechanical collection and destruction spraying of any contact insecticide. 3. Rhizome Weevil - This is a serious pest in the secondary nursery especially where seedlings are raised continuously year after year. The grubs feed on the Rhizome and basal portion of the stem. This results in the drying of leaves and breaking of stem at the base. Control Measures 1. Drench the nursery beds with Chlorpyriphos 0.04% 4. Aphids - Pentalonia nigronervosa

These aphids are seen on cardamom plants. It is known to be the vector of the virus causing the major disease of cardamom called Katte disease. 5. Shoot Fly - Seen in the nursery during January to May. Dead hearts or decay of the central shoot is the external symptom. 6. Shoot Borer - The caterpillar bores in to the stem and feeds on the internal contents. This results in the decay of the central spindle and the production of dead hearts. Faecal matter of the caterpillar can be seen coming out through the holes.

14. PESTS OF GINGER 1. Rhizome Scale - The circular sales infest the rhizomes. Infested rhizomes when stored dry up.

Control Measures - Dip the rhizomes in Quinalphos before storage. (Seed purpose) 2. Shoot borer - The caterpillar bore into the shoot, as a result dead hearts are produced. 3. Rhizome maggots - This is seen associated with rhizome rot. Maggots of Calobata sp. bore into and feed within the rhizomes which as a result rot.

Control Measures 1. Organo-mercuric fungicide and Quinalphos

15. PESTS OF TAPIOCA 1. Tapioca Scales

This is a hard scale infesting the stem. The leaves of the attacked stem become discoloured and dry up. Gradually plants become stunted. The scales get distributed with the infested stem.

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Control Measures 1. Burn the infested stem. 2. Use pest free setts for planting. 3. Dimethoate 0.025 may be sprayed on setts before storing.

2. Red Spider Mites - Infest the under surface of leaf. Damage is severe during dry months. Infested region turn yellowish in colour and curl and dry up.

3. Termites - They damage planted setts. Control Measures

1. Sprinkle a little of Carbaryl 10% D.P or Chlorpyriphos in the mounts prior to planting.

16. PESTS OF SWEET POTATO

1. Sweet potato weevil (Coleoptera) The adult is a small weevil, black in colour. Eggs are laid on tuber or lower parts of stem. The

grub bore within tuber and vines making tunnels within them and feeding on the internal tissues. The attacked vines fade and gradually dry up. The infested tubers both in the field and in the store show dirty patches and holes on their surface. The weevil and its immature stages are seen within such tubers in large numbers. Control Measures

1. Remove and destroy crop residues of previous crop. 2. Use healthy and weevil free setts. 3. Drench with Endosulfan, Fenthion or Fenitrothion 0.05% (Repeat two or three times) 4. Trap adults using sweet potato cut tubers.

2. Tortoise beetles - Grubs and adults cause damage by feeding on leaves. Damage is often extensive and can be controlled by using a contact insecticide.

Other pests include hairy caterpillar, leaf caterpillar, sphingid caterpillar, leaf miner.

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17. PEST OF AMRANTHUS

1. Amaranthus Leaf Webber

Caterpillar webs together leaves of amaranthus and feeds from within skeletanising the leaves completely. Several larvae are seen within the webbed up leaves (The adult is a black moth) Control

1. Collection and destruction of larvae. 2. In severe cases spray Malathion 0.1% or Malathion dust 1%.

2. Amaranthus Weevil Weevils lay eggs on stem, petioles etc. The grub bores into the tissues making tunnels within

stunting and twisting of plant, swelling of branches and stem, suppression of shoot production are symptoms of attack. Control

1. Destruction of wild amaranthus host and affected plant parts.

18. PESTS OF CHILLY

1. Chilly thrips : Cirtothrips dorsalis ( Thysanoptera) Adults and nymph suck sap from leaves, stunting of leaves and plants

Control 1. apply contact insecticide

2. Aphid - Aphis gossippi (Hemiptera) - Greenish brown small insects, suck sap from under surface of plants, stunting of leaves and plants

19. PESTS OF ROSE

1. White flies - The nymphs and adults are seen on the leaves which become discoloured. 2. Red Scale - Infest leaves, shoots and buds. Attacked shoots fade and dry up. Spray systemic insecticides for control. 3. Leaf thrips and flower thrips - Leaf thrips colonies on leaves and become crinkled. Flower thrips infest on rose bud and flowers. As a result flowers become smaller and petals shrink showing feeding scars. The bud may even fail to blossom due to the thrips attack. Spray any systemic insecticide for its control. 4. Flower beetle - Feed on flowers and leaves.

5. Bees and wasp - Pith of pruned branches of rose is bored by certain nest making bees and wasp. The bored branches die and dry up.

Leaf caterpillars, leaf rollers and mites are also infesting leaves of rose.

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Scale Aphid thrips

20. PESTS OF ORCHIDS The common pests attacking orchids are thrips, aphids, spider mite, soft scale, mealy bugs,

orchid weevil, ants etc. Insecticides at suitable concentration can control all the insects. Other very serious pests of orchids are snails and slugs. They feed on the tender young shoots, roots and buds. Hand-picking is effective, if the number of plants is less. They move out during late night and hide before early morning. Damage is caused during this period. All the pests can be controlled by application of contact and systemic insecticides at appropriate concentration

21. PESTS OF ANTHURIUM

The major pests are scales and bugs, which are controlled by spraying Malathion @ 2 ml per litre of water. Snails also cause damage to young shoots and roots. Use of Metaldehyde can prevent the attack of snails.

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Unit – 8 NON-INSECT PESTS OF MAJOR CROPS

Considerable losses to the agricultural crops due to the attack of pest takes place every year. Besides the insect pest there are large numbers of non-insect pest attacking crop plants. This includes rats, mites, nematodes, snails & slugs, birds etc. In certain cases these pests seriously infect crop plants causing severe losses. It is very important to study the different non-insect pest attacking crop plants, their nature of damage and the measures adopted to control them.

1. RODENTS

Study of rodents is called rodentology. Rats belong to phylum Chordata, Subphylum vertibrata, class mammalia, order rodentia and family muridae. Rodents cause much damage to crops and stored products. Their high reproductive ability is notable. They attain puberty within 7 to 8 weeks. They can breed through out the year. Average gestation period is 21-30 days. They are very sensitive feelers. Many species are good swimmers also. Various rats sustain on a variety of food substance. They cause enormous loss of grains by direct feeding. They contaminate food by dropping their body hairs, urine, etc. They also cause damage to living crops. The rats can be brought under two different groups.

1. Domestic rats 2. Field rats

Domestic rats are found near human dwellings.

I. Domestic Rats

1. House Rats - Rattus rattus wroughtoni There are 2 sub-sps. one with white belly and the other with grey belly. (They are found in

houses and buildings). Tail length is more than the length of head and the body. They eat anything that man eats. They also cause qualitative damage due to deposits of faecal matter, urine and it hairs. It damages gunny bags, plastic containers, cloths, electric wires etc. The tender coconuts and cocoa pods are damaged by these rats in the fields. They also act as carriers of several animal and human diseases. Diseases like Bubonic plague and weil's diseases are which the country suffers on account of rats. Weil's disease is caused by contamination of food by urine of rats. 2. House Mouse - Mus musculus

Fur is short with out spines. Tail is almost naked and larger than head and the body. It is very active and found in houses and garden. It can climb up walls. It damages clothes, plastic containers and food materials. 3. Large Bandicoot Rat - Bandicota indica

This is the largest domestic rat. Fur is coarse. Tail length is almost equal to body length. Body weight ranges from 750 gm to 1 kg. It damages all tuber crops. It also damages even concrete buildings by making burrows under the basement. These rats are also seen in field. So they are considered as both domestic and field rats. II. Field Rats. 1. Large Bandicoot Rat - Bandicota indica 2. Lesser Bandicoot Rat - Bandicota bengalensis

It is a short tailed mole rat. Tail length is only 70% of the body length. Fur is short and coarse.

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It is seen making burrows in the paddy fields, bunds and also in areas where crops like tuber crops, vegetables, coconut, and young rubber plantations are cultivated. Their burrows are 1 to 1.5 meters deep, 4-5 openings are seen which are closed with loose excavated soil. Only one rat is found in a burrow. Grass, grains, tubers etc. are seen heaped up is burrow. They cause damage to rice crop.

3. Field rat / Norway rat - Rattus norvegicus

These rats are found in water logged areas. They damage paddy crop. House Rat Mouse Large bandicoot Integrated control of field Rats

Rats cause considerable damage to agricultural crops and other human possessions in addition to acting as carriers of diseases. It is necessary that all citizens understand the importance of rat control. An integrated approach to control rats involves the joint utilization of all feasible control measures in a complementary manner to maintain the rat population at a very low level. Integrated control of rats involves the following:-

1. Prevent their entry in to a region or building by putting up mechanical barriers or treating with repellents.

2. Encouraging predators such as snakes, cats, dogs, mongooses etc. 3. Causing death by a variety of methods

Different control measures include environmental control, mechanical control or trapping, biological control, chemical control or poisoning and integrated control methods. 1. Environmental Control

In this method rats are rendered into a hostile environment in which they cannot survive. In rice fields the height or thickness of the bunds should be just adequate. Otherwise they will pave way for nest building by rats. Mud walls in villages may be replaced by thorny hedges there by preventing the rats from making burrows. Proper sanitation should be maintained in houses by keeping food materials inaccessible to rats, in rat proof containers. The heap of garbage and sweepings in streets and towns should not be kept for a long period. Designing rat proof godowns and buildings is another step to ensure environmental control. 2. Biological Control

Both field and domestic rats are subjected to attack by a range of predators, parasites and pathogens. The predators include cats, dogs, snakes, owls, mongooses etc. The practice of rearing cats in house has been found to adversely affect rat density. 3. Trapping / Mechanical method

Trapping is the oldest method of controlling rodents. Almost any trap will catch some rats.

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The response varies with different species. The rats are easily caught in cage or box trap. But a rat trapped in such a trap will be exposed to other rats. So the rats develop trap shyness and they avoid such type of traps. The most effective rat traps are those which can completely conceal the rats trapped in it. Trapping is the preferred method of control in the houses and office building, because animals killed can be easily removed. Traps can be used profitably to deal with poison-shy and scattered survivors of poison campaign. Eg:- Moncompu trap, wonder trap etc. The rat traps can be grouped as follows.

1. Automatic traps - These are indented to catch more than one rat in a setting. When an animal enters this type of traps its weight makes it fall into a cage below. Eg: wonder trap.

2. Remote triggered trap - These work by upsetting a delicate balance when the bait stick is disturbed or when the bait is put on at treadle. eg: Box trap or Cage trap.

3. Pot traps - These traps are extensively used for catching rice field rats. This trap consists of a wooden plank, a mud pot of 10 inch diameter, a metal strip which carry bait and a ‘Y shaped wooden peg to which needle is tied. eg: Moncompu trap

4. Snap trap - These kill the rats instantly by snapping when the rat nibbles the bait placed in the middle of the open trap. These are variously called as "break back traps, 'spring traps' Saw toothed traps" and 'bamboo traps' depending up on the material used in making them.

5. Glues - A form of trapping in which a sticky substance entangles the animal

6. Kerosene tin trap - It is made by cutting the top of the tin and filling it with water up to 15 cm from the top. Chaff is floated on the water surface so that the rat cannot see water. Attractive and strong smelling bait like dry fish, fried coconut etc is pinned on to a piece of cork or lightwood and floated on the chaff. A plank is leaned against the side to enable the rat to climb to the top. Seeing no water and eager to get the bait the rat jumps on to the chaff and gets drowned.

Success or failure of trapping is dependent up on the following factors 1. Placement - Trap must be placed where rats visit frequently. 2. Concealment - New shining traps should not be used. To overcome shyness of trap cover the

trap by paper that does not interfere with the trigger action. 3. Size and Design - Traps should be neither too small nor too large. 4. Mechanical conditions - Putting out traps that are in poor working conditions is a waste of

time and effort. 5. Number of traps - Large number of traps relative to the expected size of the rodent

population should be used. 6. Bait used - Use fresh aromatic baits every time. Maintain the trap efficiently and operate

perfectly. Don't use any trap continuously. 4. Poisoning or Chemical Control

Three types of poisoning are usually employed to control rats. 1. Acute poisons - are those that can kill rats with a single dose. Eg. Zinc phosphide. 2. Multiple Dose or Chronic Poison - which require repeated ingestions over several successive

days. Eg.: Anti Coagulants like Warfarin, Rodafarin etc. 3. Fumigants - Are gases and are usually pumped or released from tablets put in through burrow

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entrances. Eg: Aluminium phosphide. 4. Repellants – neem products like neem oil, naphthalene

1. Acute Poisons Most popular acute poisons are used in solid form as fine powder. Eg: zinc phosphide. It is a

dark grey power and its toxic action is due to release of phosphine gas. When it is ingested phosphine gas is released causing injury to the kidneys, liver and lungs followed by death after a few hours. Dosage is 2%. Pre-baiting for 3-4 days in sequence is necessary to overcome bait shyness. For pre-baiting and baiting the same carrier material has to be used. Crushed wheat, maize, Bajra, puffed rice etc. when mixed with a little jaggery and oil will be excellent carriers. The stations may be selected in areas where rats are frequent, such as areas around kitchen, store and homestead. Expose baits in the evenings and collect them on the following morning. Conduct baiting for 3 successive days. Prawn powder is found as very effective bait for poisoning. Dry prawn available in the market is heated and powdered. Few drops of vegetable oil is added and zinc phosphide 1-2% is mixed with bait. Drawbacks - Rats develop bait shyness against acute poison. Some rodents take sub-lethal doses and are recovered after sometimes. 2. Chronic or Anticoagulant Poison

They interfere with the mechanism of blood clotting. Even in the absence of external wounding, animals which have ingested them develop internal bleeding and die from this cause. The anticoagulants are not very dangerous to man and domestic animals. Pre-baiting is not essential for anticoagulant. For preparing the poison bait, mix 90 gm of bait carrier with 3 gram of jaggery and 2 gm of groundnut oil. Add 5 gm of a 0.5% concentrate of warfarin or rodafarin to this mixture. Expose 25 gm of poison bait in each station continue for 3-4 days in succession.

2nd Generation Anti-Coagulants - They are used as single dose poison eg: Moosh - Moosh. Chemical Name: bromo diolone.

3. Fumigation It is practiced where baiting and poisoning are not practicable. Fumigants have been quite

widely used against rodents. The most effective fumigant is Aluminium phosphide which is available both as tablets and pellets as Celphos tablets or Aluminium phosphide tablets. Aluminium phosphide on contact with ambient moisture produces toxic vapour of phosphine. For fumigation, locate burrows which contain live rats. For this seal all burrow openings with mud in the evenings and examine the closed burrows next day. If the mud seal is open such burrows are marked as live ones. In such live burrows introduce Aluminium phosphide tablets at the rate of 1-2 tablets per burrow and seal the burrow opening immediately.

4. Repellents - Chemical repellents include Malathion and Cyclohexamide which are repellents to house rats.

Control of important species of rats - Lesser bandicoot rat attacking tuber crops can be easily controlled by poison baiting in rodent burrows. Firstly, locate the burrows in the field. Open the burrows to a length of 30 to 45 cm. The rats will come and close the burrows with soil within 30 minutes. Then it can be again opened and poison bait can be inserted into the burrow. Norway rat causes serious damage to paddy crop. The most effective method of control is using Moncompu trap.

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Firstly we have to locate fresh rat-damages in the field. These rats cut the paddy plants at the base above the water level in patches. The rats have a habit of coming to the same area on subsequent days. So the traps should be placed in such spots.

2. MITES

Study of mites and ticks is termed as Acarology. Mites belong to phylum Arthropoda calss - Arachnida. Important phytophagous mites belong to family tetranichidae and Eriophyidae. Mites are common and destructive pests of many plant species. They pierce the plant tissue with their sharp mouth parts sucking up the sap and destroying the chlorophyll. The injury on the foliage may result in grey brown mottling on the foliage or in the formation of galls.

Many species of mites are predatory or parasitic on insects and some are saprophytic. Body of mites is divided into anterior and posterior parts. Mites have four pairs of legs. Their mouth part is chelicerate, palps modified into grassing or piercing type. A continuous heavy infestation of mite usually results in plants becoming greatly stunted or killed out right. Mites live in colonies and usually prefer the under side of foliage. But may be found on both sides under conditions of heavy infestation. They flourish during warm dry weather and are not generally trouble some during cool wet seasons. Red Spider mite Eriopyid mite Important mite pests

1. Two spotted red spider mite - Family Tetranichidae. Attack rose, bhindi, citrus, tapioca etc. Usually seen on under surface of leaves. In case of heavy infestation can be seen all over leaf. They suck sap and as a result blotching of leaves occur and reduce photosynthetic efficiency.

2. Coconut calyx mites - Attack under surface of leaves, flower mites attack inside calyx region and cause button shedding.

3. Tapioca mites – Red spider mites infest under surface of leaves resulting in copper brown colour of leaves.

4. Arecanut mite - Infest under surface of leaves causing bronzing.

5. Calyx mite - Cause falling of tender nuts, they attack calyx when flower sets fruits.

6. Rose mites - Infest under side of leaves and flowers. Leaves turn yellowish and fall down.

7. Vegetable mite - infest crops crops like Bhindi, Brinjal tomato etc. leaves become dry up and fall off.

Eriophyid mites are minute, yellowish and worm like. They usually form galls and other malformations in plants.

8. Coconut Eriophyid mites – its become serious pest of coconut. They are very minute, microscopic in size and they spread through wind from one palm to another. They attack just set nuts and immature nuts up to 2 months. They live in colonies inside the calyx region of nut and suck sap. As

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a result of infestation surface of tender fruits show yellowing near the attacked region which extend later and cracking of surface also seen. Infested nuts fall prematurely. Even if they survive their shape will be deformed and weight of 'Corpa' will be less. Control

1. Spray neem oil garlic emulsion 2. Wettable Sulphur 80% WP 4gm in 1 ltr. water.

The spraying should cover all the immature bunches and inflorescence after fertilization. For this 1.5 litre Spray solution is sufficient.

Preparation of Neem oil bar soap garlic emulsion - Take 200 gm of garlic and made into a paste in 300 ml water. To this 200 ml neem oil is added. In another vessel 50 gm of ordinary bar soap is dissolved in 500 ml of water. Add the soap solution to the garlic neem oil mixture and stirred well. The prepared 1 litre of concentrated solution is diluted to 10 litres with water.

Acaricides - are used for controlling mites. Most of the insecticides we are using have acaricidal properties also. Eg. Dimethoate (Rogor), Phorate (Thimet), Quinalphose (Ecalux). The following are some of the specific acaricides.

1. Dicofol - Commercially available as kelthane, hexakel, dicofol 18.5% EC, this is a specific acaricide with outstandingly long residual action. It is effective against all stages of mites at the suggested application rate of 1 ml of 18.5 EC / litre

2. Tetradifon - This is available as Teedion 20% EC and 8% DP. It is effective against Tetranychid mites. For mite control in vegetables and other crops rate is 0.1% - 0.2%.

3. Chlorobenzilate - Available as Akar - 25% EC. This is effective against all stages or red spider mites infesting vegetable crops. Recommended dose is 0.05%. This chemical is safe to honeybees.

4. Sulphur - This is used either as fine dust or as wettable forms for the control of mites. Wettable sulphur preparations are recommended at the dose of 1 g per litre.

3. NEMATODES

Nematology is the study of thread worms, round worms or eel worms or commonly called as nemas. Plant parasitic nematodes belong to Phylum- Nemata, Class – Nematoda. Nematodes are small unsegmented invertebrate animals. Generally they are spindle shaped or cylindrical in nature. They are transparent in nature. They lack colour. Body is covered with a cuticular lining. Plant parasitic nematodes have sharp stylets which they use to penetrate tissues of their host. Some nematodes live completely inside the plant, others only half inside, on the plant surface or free in the soil. Wide spread damage is done by root knot nematode and burrowing nematode.

Those nematodes present in vertebrates are large in size and are visible to naked eyes. Those present in plants are microscopic in size. More than 90% plant parasitic nematodes are less than 1 mm in size. Nematodes are soil inhabiting organism and live in rhizosphere region in soil. It will be parasitic on roots or other parts. Those infecting foliar part is called foliar nematode. Nematodes are having world wide distribution. Because of their high multiplication rate and short life cycle (3-4 weeks) it is very difficult to eradicate them, once the soil is infested. Several disease complexes are made by them; other pathogens like fungi bacteria etc. are also exist with them and produce complex symptoms.

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Anatomy of a nematode Important Nematodes commonly seen in Kerala are, 1. Root Knot Nematode - Melodogyne Spp. About 32 sps. are reported. Mainly seen on tomato,

bhindi, brinjal etc. 2. Cyst Nematode - Heterodera spp. 3. Burrowing Nematode - Radopholus similes . It is a problem in banana and pepper. 4. Rice Root Nematode - Hirschmaniella oryzae

Other species are Lesion nematode, Stunt nematode, Wheat gall nematode, Spiral nematode, Reniform nematode etc.

Important Nematode pests and their control 1. Rice Root Nematode - Infest paddy roots and make them partially hollow. Feeding adversely affect absorption of water and nutrients. Plants show stunted growth in patches. Tiller production is affected. Control

1. Treat the nursery with Carbofuran @ 0.75% kg. ai/ha. 2. Dip the roots of seedling in 0.2% Dimethoate for 6 hours before transplanting in tracts

where nematode attack is detected.

2. Rice Cyst Nematode - Occurs in various proportions in certain areas of the state. Symptoms include leaf chlorosis, stunting and reduction in the number of leaves ear head length etc. In seriously affected patches yield is reduced substantially. Control

1. Soak paddy seeds in 0.02% solution of Carbofuran or Aldicarb for 6 hours 2. Dip paddy seedlings in the same solution for 6 hours before transplanting. These controls are

to be adopted in the areas where the nematodes occur at very heavy populations causing severe damage.

3. Nematodes Attacking Banana (Burrowing and Root knot nematodes) In cases of severe infestation there will be a high reduction in leaf number, total bunch weight

and number of fruits and plant health will be badly affected. Control

1. Dip the suckers in Carbofuran 0.1% suspension for 30 minutes before planting 2. Apply Carbofuran granules @ 1g. a.i./plant at planting time around the basins. 3. If infestation is severe apply neem cake @ 1 kg./ plant and Carbofuran 1 g ai/plant.

4. In pepper Burrowing nematode and Root knot nematode usually infest pepper and produce

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complex symptoms along with fungus. Symptoms are yellowing of leaves stunted growth and slow decline of vines. Control

1. Use nematode free rooted cuttings for raising new plantations. 2. For the infested vines apply Phorate or Carbofuran @ 1g a.i. / vine, twice in a year. The 1st

dose is to be given during May-June at the onset of monsoon and 2nd dose in last week of October or early November. The chemicals are to be applied around the vines in shallow basins and incorporated into the soil.

3. Root knot nematode can be effectively managed by the application of bacterial suspension of Bacillus macerans and Bacillus circulans prior to planting of vines or just before monsoon period in established plants.

5. Nematodes are infesting vegetables like brinjal, bhindi The root knot nematode of brinjal and bhindi can be managed by the application of Bacillus

macerans and Bacillus circulans in nursery beds two days before sowing. For controlling nematodes in bhindi apply neem leaves or Eupatorium leaves @ 250 gm/plant in the basin 1 week prior to planting and water daily. The effect of this treatment persists up to 75 days after sowing in summer season.

4. SLUGS AND SNAILS

These creatures belong to the group of shelled animals (Mollusca). Though the great majority of these shelled animals are aquatic forms, snails and slugs live on land are often found feeding on vegetation. Snails have an external spiral shell covering their soft body while slugs do not generally possess such a conspicuous shell. Though these are not regular pests, garden plants of different kinds are occasionally attacked by these creatures. Orchids and Anthuriums are often found attacked by snails and holes are found bored on the succulent leaves. These creatures are evident during wet weather and in damp areas and are generally active during the night. They can be controlled by metaldehyde bait. Eg – Giant African snail (Achatina fullica)

Slug Snail

5. BIRDS

Birds like parrot, sparrow, pigeons, etc cut and feed on cereal grains and pulses. Birds also cause damage to fruit crops like guava, papaya, mango, grapes, cherries etc. Fruits damaged by birds rot due to entry of fermenting micro-organisms through the point of attack. Birds are spreading a number of diseases of animals. Birds act as carriers of disease. But they don’t show symptoms. Birds causing damage to crops include sparrow, parrot, crow, pigeon, bee-eater etc. Bee eater eats honey

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bees from hives. Control

1. By trapping and enclosing 2. Destruction of roosting and nest 3. Use of non-toxic sticky materials 4. Use of toxic chemicals - seed dressing with Carbofuran 5 parts / 100 parts grain. 5. Use of resistant variety 6. Scaring birds using bird scares.

NON INSECT PESTS OF MAJOR CROPS OF KERALA a) Rice

1) Nematodes infesting paddy are,

i) Rice root nematode - Heishmaniella oryzae - infest paddy roots and make them partially hollow, adversely affects absorption of water and nutrients, show stunted growth in patches. Controlled by Carbofuran in nursery stage and Dimethoate in seedling stage. ii) Rice cyst nematode - Hetrodera oryzicola - Symptoms are leaf chlorosis, stunting, reduction in number of leaves, ear head length and yield. Controlled by Carbofuran

2) Rats infesting paddy are Large bandicoot rat, Lesser bandicoot rat, Field mouse, Norway rat, soft furred field rat, bush rat etc. Damage caused by cutting ear heads, making burrows in field, root damage, attack on booting stage etc. controlled by traps , Warfarin blocks, Aluminium phosphide, zinc phosphide etc.

3) Birds attacking paddy are Indian mina, pigeon, parrot etc. Damage to grains and tender leaves. Controlled by shiny tapes, crackers, birds scarers and traps.

b) Coconut 1) Eriophyid mite : Aceria guarraronis - Yellow triangular patches on tender nuts, button fall, distortion and stunting of nuts and reduction in copra yield. Controlled by neem oil garlic emulsion, dicofol, nutrient management.

2) Rodents - attack tender nuts, holes on nuts and shedding nuts. Controlled by warfarin blocks, baits

c) Tapioca 1) Rodents - attack tubers, holes on tuber and damage mounds. Controlled by warfarin

blocks, traps, poisoning 2) Red spider mite - crinkling of leaves, scrapping of leaf chlorophyll, holes on leaves

defoliation and reduction in yield. Controlled by Dimethoate, Dicofol, Wettable sulfur and water spray

d) Banana 1) Nematodes - reduction in number of leaves, bunch weight and fruit size. Controlled by the

application of neem cake 1 kg per plant and Carbofuran e) Vegetables

1) Mites - crinkling, scraping of leaf chlorophyll, bronzing, defoliation. Controlled by Dimethoate, Dicofol, Wettable sulfur and water spray.

2) Nematodes - yellowing in patches. Controlled by Carbofuran, Dimethoate.

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Unit – 9 PESTS OF STORED PRODUCTS

Considerable losses of food grains occur due to the attack of storage pests every year. Quite a large part of agriculture produce is lost in the field due to pest infestation. Over and above this a huge amount of produce in storage godowns are infested by different pest. The organisms responsible for losses in stored products are insect, mites, rodents etc. Under prevailing conditions the food grains have to be stored for a fairly long period. It is very important to take measures to reduce these losses. Grain storage problems - There are heavy losses during storage of grains by a number of agents, insects, rodents, mites, fungi, birds etc. The storage insects are one of the main causes which cause damage to grains. Nearly 17sp infest rice grains, larvae and adults feed inside or outside the grains. Losses may be quantitative and qualitative or losses to storage container. There are certain factors associated with storage pest.

1) Ambient relative humidity 2) Temperature 3) Grain moisture 4) Light 5) Types of storage container 6) Storage practices 7) Period of storage 8) Presence of storage fungi

Losses caused by insects are divided into following categories, 1) Quantitative losses or weight loss - Insects during storage mainly cause weight loss by direct

feeding on grains. This varies depending upon the type of containers, period of storage and local climatic conditions.

2) Qualitative loss - Sound and healthy grains with out visible pathogenic contamination fetch good prize. Storage insects are the main source of deterioration of grains. Quality is degraded by feeding on grain/kernels and destroying the germ and directly cause calory loss-chemical changes in the grain content.

3) Contamination with body products – body hairs, excreta, scales etc. contaminate grains. This will lead to loss of palatability and bad odour. When body parts are ingested along with food it may cause allergy in some people.

4) Contamination of grains by pathogenic and toxicogenic micro organisms - The insects infesting stored grains carry fungi and provide good ecological conditions for their development.

Important storage fungi - Aspergillus sp, Penicillium sp., Fusarium sp. Aflatoxin B1 is produced by Aspergillus flavus which is highly toxic to higher animals.

Tribolium sp. insects carry harmful bacteria in the gut eg. Salmonalla sp. which causes food poisoning. rtical movement of insects facilitate multiplication and also distribution of toxins. 5. Loss of seed viability - In paddy storage, seed viability is lost by storage insects, fungus and grain

moisture. Grains fed by insects fail to germinate. 6. Damage to storage container - Rodents, cockroaches and other insects damage containers.

Rhizopertha dominica, a pest capable of destroying wooden and polythene lined containers. It

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destroys all types of containers made of materials other than cement or iron. This enhances infestation by other insects.

PESTS OF STORED GRAINS The important group of insects affecting stored products is beetles and moths. Of these two,

beetles are of greater importance than moths. Beetles are more destructive because both the larvae and the adult insects attack the stored material, while among moths it is only the larvae or the caterpillar which cause the damage. The following are the important storage pests.

1. Rice Weevil - Sitophylus oryzae (Coleoptera) This insect is a small brownish black weevil, reddish or brown spot on elytra. This weevil is

seen in milled rice, unhusked rice, parboiled rice, maize etc. Both adult and grub not only feed on the stored products but breed and multiply rapidly in the store. The female weevil makes a small hole on the surface of the grain and deposit eggs. The grubs are white and fleshy and apodous. The grubs feed on starchy materials inside the grain. The grub period is 19-30 days. Pupation takes place inside the grains. Pupal period is on week, and the adult emerges out through the hole on the grain. 2) Lesser grain borer (paddy borer beetle) - Rhizhopertha dominica (Coleoptera)

The pest infest on rice, wheat, maize and dry fruits. Adult is small dark brown beetle around 4mm in length. It is the major pest of unhusked paddy (stored paddy). The adult beetles and grubs bore through the husk of the grain and feed on the internal contents and turn it into chaff. The attacked paddy grains show the round holes made by the pest. It is also sometimes found on other grains in company with other beetles. 3. Angumois Grain moth (paddy moth) (Lepidoptera)

It is yellowish white moth, pale forewing and grey hind wing pointed with fringes of hairs. Adult female moth lay eggs on the surface of the paddy. The larvae (caterpillar) feed on the internal content (endosperm). The attacked grains become chaff. Pupation inside the grain. It is a serious pest of unhusked paddy. It also attacks ripening grains of paddy, ragi, maize etc.

4) Rice moth (meal worm moths) - Corcyra cephalonica (Lepidoptera) Adult is very small shiny moth, found flying in numbers inside infested granaries and cause

considerable damage to paddy. Also feed on cocoa beans, wheat, barley, dry fruits, cashew nuts, ground nuts, biscuit, gingelly oil cake etc. Eggs are laid in the broken grain products. The emerging caterpillar is creamy white found remaining inside tubular granaries made up of the powdery matter and it result in formation of lumps. The lose grains are webbed together in a connected mass aggregate of grain.

5) Red flour beetle - Tribolium sp. (Coleoptera) A small elongated flatish red beetle. It feeds on wide variety of flour and grain products. Oil

cakes, beans, dry fruits, nuts, biscuits etc. and also seen in milling machinery. Slender elongate white larvae are also found in infested material. Very bad pungent and nausative odour in the stored product resulting in quality loss and deterioration of the food material.

6. Pulse beetle - Callosobruchus chinensis (Coleoptera) The adult is a small active roundish beetle with brownish colour. Body is abruptly rounded. It

causes 20% damage to pulse crop. It is closely associated with pulses of all lands. Their eggs are laid on infested seeds and grubs bore into them by cutting a neat hole. Pulse beetle cause appreciable

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loss to stored pulses like cowpea, red gram, green gram etc. 7. Coffee Beetle - It is dark brown in colour. It is a pest of storage and field. It is also known as nutmeg beetle. It feed on coffee beans, stored spices, cured arecanut, processed tapioca chips etc. 8. Tapioca moth - It is minor pest of tapioca flour. The flour of tapioca is webbed together, make galleries and feed within it.

9. Drug store beetle - It is a minute brown beetle. It is found boring into all kinds of dry store like ginger, turmeric, coriander etc and vegetable, drugs of different kinds and practically all dry vegetable and animal matter.

10. Tamarind beetle - It is a dirty grey beetle belonging to same group. The grubs of this insect burrow into preserved tamarind fruit and spoil the same.

Rice Weevil Rice Moth

Pulse beetle Red flour beetle Lesser grain Borer

Damaged grains by storage pests

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INSECT PEST MANAGEMENT IN STORED FOOD GRAINS

Almost all the storage pest insects are more or less similar in their life habits. They breed and multiply so rapidly that all the different stages are found on the same food material. Once infested, the material is very badly damaged in a very short time. The pest gets dispersed very easily from one place to another with consignments of infested material in gunny bags and other containers. The measures to control storage pest are similar in the case of all the above insects since their general habits are more or less alike.

In the way of preventive measures there are three fundamental points to be remembered. 1) Proper condition of the storage container before the storage - Before consignment is stored in the store house or any vessel it should be made thoroughly clean and free from any traces of loose grains, chaff, bran etc. The corners and floor of the vessel and any cracks and crevices should be properly cleaned. 2) Proper condition of the product to be stored - The grains, pulses or other products should be thoroughly dried and made free from husk, chaff or any foreign matters. 3) Proper conditions of the material and container after storage - Once the material has been stored, the granaries, bins or vessels should be completely closed up and remain insect free. IMPORTANT CONTROL MEASURES

Various practices employed are, 1) Sanitation - Removing of dirt, debris, mud balls or any other foreign particles and insect living or

dead from healthy grains. This is a common method employed in grain markets. 2) Proper grain handling - Proper handling of grains and cleaning reduces losses. It is necessary to

disinfect all materials used for transport of grains. In FCI and CWC (Central Ware housing Corporation) mechanical devices are used to reduce spoilage of grains. These devices save time and labour.

3) Use of mechanical devices - In which infested grains are revolved at a speed range 3000-4000 RPM (revolution per minutes) which will destroy insects. This device is used in rice mills and flour mills.

4) Use of dryers - In which infested grains are to be dried. Paddy is harvested at 20-28% moisture content in grains. If grains contain more than 11-12% moisture, insect development will be faster. So it should be reduced. So grains are dried and moisture content is brought down either by sun drying or by using mechanical dryers can be done. Sun drying is followed at farmers’ level.

5) Use of improved storage structures - Storage structure is a container constructed in such a manner so as to prevent the entry of the elements detrimental to grains. In rural area structures made from locally available material are used. Eg. paddy straw, bamboo, mud bricks etc. Most of these structures do not meet the requirements of efficient storage structure. Grains are stored in bulk either below ground or above ground.

Above ground storage structures - Bins, silos, bags in godowns, jute bags or gunny bags are used. Gunny bags do not act as barrier for pest. Polythene lined bags are also used. Impregnation of insecticides on jute bags prevents insect entry. Bins - A number of bulk storage structures are used in India called bins eg. Aluminium bins, Nantha bins, pusa bins, silos etc. 6) Use of synthetic insecticides for controlling storage pests - Such insecticides are very few in

number. Because they should satisfy certain requirements such as, 1. Low mammalian toxicity

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2. Good persistency 3. Should not affect the viability of seeds 4. Economical 5. Should be easily available.

Insecticides used in storage are the following (a) Mixing grains with dust formulation - This is done for seeds meant for seed purpose, eg.

Malathion, Pyrithroids, Cerisan. Cerisan is a fungicide. (b) Treatment of grains with E.C. formulation of insecticide - Eg. DDVP, Fenetrothion. But when

taken in diet, health hazards occur. So direct treatment is not usually practiced. (c) Treatment of storage structures with insecticide - Eg. Fenitrothion, DDVP (d) Pre-harvest grain treatment with insecticides - It is done to check field infestation of the

grains in the ripening stage. eg. Malathion, Fenitrothion. 7) Use of fumigants in godowns - Fumigants are chemicals which at a given temperature and

pressure exist in gaseous state in sufficient concentration to be lethal to pest organisms. Fumigation is the process of subjecting insect infested material to the fumes of poisonous gas which will destroy all traces of insects in the material to be stored. They are more effective. They penetrate into the grains and cracks and crevices. This method is usually done in FCI and CWC. Eg. Carbon bisulphide, Carbon tetrachloride, chloropicrin, DDVP, EDB (Ethylene dibromide), Phosphine etc. This method requires trained personalities for doing the operation. Storage structure should have provisions to make it airtight.

8) Use of inert material for pest control - Aluminium oxide, Magnesium oxide, silica etc. can be mixed with grains. They puncture insect cuticle and parts of cuticle breaks. Insect dies due to moisture loss from body. Eg – ‘Dry die’

9) Use of plant products - Neem products such as neem leaf, neem oil, neem cake are found to possess insecticidal property. Kharanj, garlic etc are also used.

10) Use of radiant energy - Physical methods include manipulation of storage environment in such a way that it limits or destroys insect life in storage. Electrical energy, gamma rays, UV rays, X rays etc. are found to be best for pest control in storage. But the drawback is the high cost of installation of such units.

11) Use of sterility -Chemosterilants are used to reduce the inoculum potential of the pests. 12) Use of pheromone traps - Now days pheromone traps are also being used to control certain

storage pests like Indian rice meal moth, cocoa moth etc.

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Unit – 10 INTRODUCTION TO PLANT DISEASES

In the history of mankind plant diseases have been connected with a number of important events. The classic example is the late blight of potato which caused the notorious Irish famine. This incident paved the pathway for the scientific understanding of plant diseases and which helped in the development of plant pathology. The Irish Famine in 1845 and the Bengal famine in 1943 due to brown leaf spot of rice took a heavy toll on human lives.

Phytopathology is the study of the diseases of plants. It is the study of the nature, development and control of plant diseases. Disease is an interaction among the host, parasite and environment. Diseased plants are distinguished by changes in their morphological structures or physiological processes which are brought about by unfavourable environment or by parasitic agencies. Disease may be defined as a series of harmful physiological processes caused by continuous irritation of the plant by a primary agent. It is a harmful deviation from the normal functioning of physiological processes.

Disease – Any deviation from the normal physiological functioning in a plant. Pathogen – Any organism which cause disease. Plant Pathology – Study of plant diseases.

Classification of disease based on causal organism Disease is caused by biotic (living) factors and abiotic (Non-living) factors.

Biotic factors causing disease

When a parasitic micro-organism enters into the causal complex of a disease, it is commonly considered to be the cause of the disease. Sometimes a variation in the environment also makes a plant liable to infection. There are mainly four types of organisms are involved in plant diseases. They are fungi, bacteria, viruses, mycoplasma or phytoplasma and mycoplasma like organisms (MLOs) 1) Fungus - Attack plants and produce symptoms like rot, wilt, damping off, leaf spot, rust, blast,

blight and mildews. Fungi are thread like and propagated by spores. In favourable conditions, the spores germinate and produce infection on susceptible plants.

2) Bacteria - They are small single celled organisms. They gain entry into the plants through natural openings like stomata and wounds caused by insects, nematode and by man. They multiply inside the plant utilizing the nutrients from the plant and due to this activity symptoms are produced.

3) Virus - Virus consists of D.N.A or R.N.A often surrounded by a thin protein coat. Reproduction takes place inside the host plant. Usually viruses are transmitted by insects and these insects are called vectors. The common vectors are aphids and white flies.

Biotic factors

1. Bacteria 2. Fungi 3. Virus 4. Phytoplasma 5. Algae

Abiotic factors

1. Physiological disturbances 2. Nutrient deficiency 3. Environmental pollution 4. Lack of moisture 5. Stress

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4) Mycoplasma or Phytoplasma and MLOs - These are smaller than virus and contain both DNA and RNA. The symptoms are yellowing, greening, witches broom and stunting.

Classification of disease based on causal organism

Sl. No Disease causing agent Type of disease Examples

1 Bacteria Bacterial disease Bacterial Leaf Blight of paddy Bacterial leaf streak of paddy

2 Fungus Fungal disease Sheath blight of paddy, Blast of rice, Quick wilt of pepper, Blight of paddy, Bud rot of coconut, loose smut of wheat

3 Virus Viral disease Bunchy top of Banana, Cardamom Katte Cassava mosaic

4 Phytoplasma or MLO Phytoplasmal disease or Mycoplasmal disease

Root wilt of coconut, little leaf of Brinjal, Phyllody in snake guord.

Classification of disease based on mode of spread of pathogen

Sl. No Mode of spread Nature of spread Examples

1 Spread through air Air borne Rice blast

2 Spread through water Water borne Sheath blight of paddy Bacterial Leaf Blight of paddy

3 Spread through soil Soil borne Soft rot of ginger, Quick wilt of pepper, Damping off of seedlings

4 Spread through seed Seed borne Loose smut of wheat, Blast of rice, Blight of paddy

Symptoms of plant diseases Symptoms are external or internal reactions or alterations as a result of a disease Symptoms of plant diseases fall into 4 main groups, 1. Necrotic symptoms - In this drying of cells, tissues or organs is common. Symptoms in this group are hydrosis, wilt, blight, dieback, spot, rot, canker, damping off, scorch and bleeding. 2. Chlorotic symptoms - These are characterised by loss, suppression or reduction of the normal green colour in plants. Common symptoms in this group are chlorosis and yellowing. 3. Hypoplastic symptoms - In this the prominent character is underdevelopment or stopping of growth of cells, tissues and organs. Common symptoms in this group are suppression, etiolation, dwarfing or stunting and rosetting. 4. Hyperplastic symptoms - This is characterised by over development of cells, tissues and organs. The common symptoms in this group are abscission or defoliation, galls, curling or rolling, scab, fasciculation.

Some Common Necrotic Symptoms a) Hydrosis - A water soaked condition of tissues caused by water leaving the cells and filling up

the intercellular spaces. b) Wilting - The flaccid condition of leaves or shoots caused by a loss in turgidity. c) Blight - Similar to scorch but is usually applied to foliage or blossoms killed by a disease

organism. d) Die-Back - The dying backward from the tip of foliage, twigs or branches of plants.

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e) Spot - A term applied to more or less discoloured circular or angular lesions on foliage, fruit, or stems.

f) Rot - Dead tissue in a more or less advanced stage of decay. g) Scorch (firing) - The sudden death and browning of foliage or some times fruit. h) Canker- Localized, sharply demarked dead lesions, usually sunken or cracked, in the bark of

the trunk, stems and roots of trees and shrubs. i) Damping-Off - The rapid rotting of seeds or seedlings before they emerge from the ground or

the rapid rotting of the bases of seedlings so that they fall over. j) Bleeding - The continuous oozing of sap from wounds or injuries.

Some Chlorotic Symptoms a) Chlorosis - The partial failure of the development of green colour in organs that are normally

green. Chlorosis may be diffused or patterned. b) Yellowing - The yellowing of normally green tissue (usually foliage) is due to a breakdown of

chloroplasts or chlorophyll. Some Common Hypoplastic Symptoms

a) Suppression - The failure of certain organs such as flowers or seeds to develop at points where they normally develop.

b) Etiolation - Excessive spindliness accompanied by dwarfing of foliage and flowers and lack of natural chlorophyll development.

c) Dwarfing or Stunting - A symptom characterized by the abnormal size of the whole plant or of some of its organs.

d) Rosetting - The crowding of the foliage into a rosette formation caused by the shortening of the internodes of stems or of branches.

Some Hyperplastic Symptoms a) Abscission or Defoliation - The premature falling of leaves, flowers, or fruits caused by the

formation of the abscission layer at the bases of their petioles. b) Galls - Local swellings or tumour - like growths on any part of a plant. They may be large or

small, smooth or rough, and fleshy or woody. They may bear descriptive names such as warts, knots, tubercles, boils, blisters, and clubs.

c) Curling (Rolling) - The abnormal curling or bending of shoots or leaves because of tissue overgrowth on one side of the affected organ.

d) Scab - Definite, slightly raised and roughened lesions on fruits, tubers, leaves etc. e) Fasciculation - The abnormal development of twigs or roots about a common point. When

this occurs on the aerial parts of a plant, it is usually called a witches broom. General symptoms of plant diseases

1. Chlorosis / yellowing - leaves and other parts of the affected plants become pale green or yellow due to destruction of chlorophyll. eg: yellow dwarf of rice.

2. Mosaic - under development of chlorophyll, resulting in alternate light and green patches, eg: Cassava mosaic disease.

3. Little leaf - size of leaves are affected, affected plants get reduced in size. eg: Little leaf of brinjal.

4. Stunting - affected plants become under developed, internodal distance gets reduced. eg: Grassy stunt of rice.

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5. Galls and tumors - this refers to over growth and enlargement of plants, eg: Club root of crucifers.

6. Leaf curl, blistering and puckering - caused by fungi and virus, eg: blister blight of tea 7. Spots - death of tissue in a limited area. eg: brown leaf spot of rice. 8. Blight - necrotic area is extended to a large area eg: Bacterial leaf blight of rice. 9. Anthracnose - characterized by limited sunken black lesions. eg: anthracnose of bean 10. Witches broom - abnormal and excessive development of auxillary buds. eg: witches broom in

mango 11. Phyllody - floral parts transformed in to green leaf like structures, eg: phyllody in sesame 12. Damping off - collapse and death of young seedlings. eg: damping off of vegetables 13. Dry rot - rotting of plant parts such as fruits, bulbs, tubers etc, no oozing of liquid from

affected parts, affected parts become shrunk and produce a powdery mass black in colour, eg: dry rot of ground nut.

14. Wet rot - oozing out of liquid from affected parts. eg: soft rot of ginger. 15. Wilt - drying of entire plant, loose turgidity and droop, eg: fusarial wilt of cotton 16. Die back - twigs and young branches start drying from tip downwards. eg: die back of mango 17. Scab - on affected parts round or crust like lesions appear, eg: apple scab 18. Canker - localised death of cortical tissues of stem, leaves and fruits, eg: citrus canker 19. Rust - rusty appearance on plant parts, small pustules of spore break through host epidermis.

eg: black stem rust of wheat. 20. Smut - floral parts converted in to a black powdery mass. eg: loose smut of wheat. 21. Mildew - powdery or cottony growth on green plant parts, eg: downy mildew of grapes

KOCH'S POSTULATES

To prove whether a plant is affected with a particular disease, the plant pathologist usually applies Koch’s postulates. The postulates are,

1. The organism should be associated with all cases of a given disease. 2. The organism must be isolated from the diseased plant. 3. When the organism is subsequently inoculated into susceptible plant, it must reproduce the

disease. 4. The organism could be re-isolated from the experimentally infected plant.

Disease Epidemiology Epidemiology of disease is a study of the factors affecting the outbreak of an infectious

disease. Symptoms are external or internal reactions or alterations as a result of a disease. Inoculum is the infectious material that can cause disease and it is that portion of individual pathogens that is brought into contact with the host.

Etiology is the science of study of the cause of diseases. It includes the study of causal factors, their nature and their relations with the host.

Obligate Parasites - Parasites which are restricted to living tissues are called obligate parasites. eg Viruses

Facultative parasites - They are ordinarily sprophytic but under certain conditions they may become parasitic. Many damping off fungi such as Pythium and Rhizoctonia are good examples of this.

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Appearance of a disease in a large number of individuals over large areas in relatively short time is called an epidemic. In plants the epidemic is also known as epiphytotic. Epidemiology deals with outbreaks and spread of the disease in a plant population. Plant disease is the outcome of the interaction between the plant, the pathogen and the environment. In this disease triangle the environment favorably or unfavorably influences both the plant and the pathogen. When the favorable interactions between these three components of incidence of a disease continue for long, epidemics occur. These three factors form the most important components of a disease. These three components should be there for a long period of time for the development of a disease. Thus time becomes a fourth component of an epidemic. Often human activities interfere with epidemics through management practices and the epidemics may be encouraged or halted.

The study of epidemics helps to,

1. Understand the various factors involved in the development of an epidemic. 2. To understand the interaction of these factors in the development of the disease. 3. To predict a forthcoming infection to take timely control measures and to reduce losses.

Essential condition for the development of an epidemic / disease 1) Host related factors

(a) Level of genetic resistance of the plant. (b) Genetic uniformity of the population. (c) Abundance and distribution of susceptible host. (d) Presence of Collateral hosts.

2) Pathogen related factors (a) Presence of a virulent pathogen (b) High birth rate and low death rate of the pathogen (c) Easy and rapid dispersal of the pathogen (d) Adaptability of the pathogen

3) Environment related factors (Meteoropathology deals with the study of relationship between the weather and epiphytotics.)

(a) Temperature (b) Moisture (c) Cultural practices that modify temperature and moisture (d) Presence of antagonistic micro flora

4) Time related factors (a) Season of the year suitable for disease development (b) Time of planting (c) Duration of favourable conditions to develop the disease

5) Human activities

(a) Selection of field for cultivation (b) Selection of planting materials (c) Choosing the time of planting (d) Transportation of planting materials (e) Control measures taken to protect or manage the disease.

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Disease triangle

Plant disease forecasting Forecasting involves all the activity in ascertaining and notifying the growers of a community

that conditions are sufficiently favourable for certain diseases.

The ultimate aim of the science of plant pathology is to have a complete understanding of plant disease (host, pathogen, environment interactions) that enables us to control disease economically. The most economical way to control disease is usually to obtain a thorough knowledge of the disease epidemiology. We cannot effectively control certain diseases without some prior indication as to how they will behave in the coming period. Prior information will help to take preventive action. Unless we know where and when the sprays or dusts, etc. are to be applied we are likely to waste them. For certain diseases, no effective or practicable chemical control measures are available. Forecasting gives us an opportunity to revise our plans in order to avoid or reduce losses.

By watching the occurrence and severity of disease in areas with an earlier growing season and applying their own previous experience, together with the weather forecasts, the key pathologists are able to judge rather accurately whether or not the local crops are likely to be affected and if so, how soon and how seriously and can make their forecasts accordingly. The methods used in disease forecasting mostly fall into four main groups based on

1. Weather conditions during the intercrop months, particularly those affecting the survival of inoculum.

2. Weather conditions during the crop season. 3. The amount of propagules of the pathogen 4. The number of propagules of the pathogen in the air, soil or planting material.

Studies show that in the case of bacterial blight of paddy, it develops readily above 25 0C and symptoms may not appear below 20 0C. So a combination of rainy weather, strong winds and a temperature of 22 - 26 0C favour the outbreak of the disease. In India for forecasting rust epidemics, rain samples were collected and analyzed which gave precise data on the advent of the inoculum in a particular locality. The air-borne inoculum has been traced by wind trajectories and weather satellite - cloud images. With this information it was forecasted that if ground level conditions are favourable for infection, the early arrival of inoculum can lead to severe rust epidemics.

Virulent Pathogen

Disease or Epidemic

Favourable Environme

Susceptible Host

Human Activitie

Time

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Unit – 11 PLANT DISEASE CONTROL

Since plant diseases are a great threat to the cultivation of crops, disease should be controlled. In the control of plant disease, the main aim is to prevent or reduces the severity of the disease, so as to minimize the economic losses. To achieve a satisfactory control a combination of different control measures have to be adopted.

The control measures are divided in to two,

a) Prophylactic method - All the methods applied to prevent disease occurrence Eg: Prophylactic spraying of Bordeaux mixture before monsoon to prevent incidence of

quick wilt disease in pepper b) Curative methods - All the methods applied to cure a diseased plant.

Eg: Application of tridemorph for the control of stem bleeding in coconut

Different methods of control employed for the management of diseases are, 1. Physical methods 2. Cultural methods 3. Biological methods 4. Legal methods 5. Chemical methods 6. IDM – Integrated Disease Management

1. Physical methods – use physical energy for the control of diseases. eg: Hot water treatment of seeds against udbatta disease of rice.

2. Cultural methods - Cultural methods include avoidance of pathogen by proper selection of field, choice of time of sowing, by selecting disease escaping or resistant varieties and by modification of cultural practices, exclusion of inoculum by seed treatment etc.

Eg - Rouging of infected plants and plant parts, use of resistant varieties

3. Legal methods - Legal method involves seed certification to prevent spread of seed borne diseases, Quarantine regulations also restrict movement of agricultural commodities.

eg: Use of quarantine laws to control spread of plant disease

4. Biological control - Biological control implies control of a disease through some biological agency like living micro-organism or macro-organism.

eg - Trichoderma against quick wilt of pepper

Some common biocontrol agents used for the management of diseases are, a) Trichoderma - Biocontrol of soil borne plant pathogens involves mass introduction of

antagonistic microorganisms in the soil. Trichoderma spp. is a group of broad-spectrum antagonists subjected to detailed studies for their potential as biocontrol agents. They are effective against the quick wilt of pepper, rhizome rot of cardamom and ginger.

Application method - Dry neem cake and cow dung are to be powdered and mixed to get a coarse texture (at the ratio of 1:10 (w/w)) and then moistened by sprinkling water. Add the commercial preparation of Trichoderma spp. (available in polythene packets) @ 1-2 kg per 100 kg of neemcake-cowdung mixture. After thoroughly mixing, cover it with a perforated polythene sheet or

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ordinary newspaper and keep it in shade for 4-5 days for multiplication. Again mix well and keep for three more days for further multiplication. This preparation0is0ready0for0incorporation0in0the0soil.

b) Fluorescent Pseudomonas - These are a group of bacteria very effective against disease incited by species of Phytophthora, Pythium, Rhizoctonia, Fusarium, Ralstonia Colletotrichum and Xanthomonas in various crop plants in the nursery as well as in the main field.

Method of application - The talc-based formulation at 1-2% level may be used for soil drenching and spraying. Seedlings/cuttings are treated with Pseudomonas culture by dipping the root/tip of cuttings in slurry of Pseudomonas (250 g in 750 ml for 20 minutes). For seed treatment in paddy use 10 g talc-based Pseudomonas culture for 1 kg of seed; suspend Pseudomonas in water used for sprouting. This helps in the control of fungal and bacterial0diseases.

For all the crops, the time of application and the frequency of application may vary depending on the incidence and intensity of the infection. A combined application of Trichoderma and Pseudomonas fluorescens may be resorted to at the time of planting in the nursery and/or main field for the control of diseases of pepper, cardamom and ginger. The application may be repeated based on the intensity of disease incidence. Chemical fertilizers and plant protection chemicals should not be used along with biocontrol agents.

5. Chemical control - Involved use of fungicides and antibiotics. A fungicide is an agent that kills or inhibits the development of the fungus spore or mycelium. The fungicides used on plants may be classified as protectants, eradicants and therapeutants on the basis of their uptake by and mobility within plant tissues.

Antibiotics - Antibiotics are substances which are produced by micro-organisms and which act against other micro-organisms. Most antibiotics known are products of actinomycetes and some are from fungi and bacteria. The important antibiotics for the control of plant diseases are Streptocyclin (antibacterial), Aureofungin (antifungal) etc. Fungicides are divided in to two,

1. Inorganic – contains no carbon eg; Bordeaux mixture, Bordeaux paste, cheshunt compound, Sulphur, copper oxychloride etc.

2. Organic compounds – contains carbon. eg synthetic organic fungicides like Carbendazim, Ziram, Mancozeb etc.

FUNGICIDES

Generic names Formulations

Required concentration in spray formulation

required per ha for rice (R) or other crops (OC)

Remarks

1 2 3 4 Copper based products Copper oxychloride Blitox 50 W

0.3-0.4 % For foliar spray Fytolan 50 W

Sulphur based products Sulphur Thiovit 80 WP 0.2-0.5 %

For foliar spray against powdery mildew. Also effective against mites.

Carbamates and others Ziram Cuman-Z 27%

0.2-0.4% Residual acting protective fungicide for foliar JK Ziram

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application Zineb Dithane Z-78 0.2-0.4 % (

Thiram Thiride 75 WP 0.2-0.3 % For foliar spray, soil and seed treatment

Mancozeb Dithame M-45 0.2-0.4 Foliar fungicide

Indofil M-45 Organophosphorus compounds Ediphenphos

Hinosan 50% EC

0.1% of the formulated products

For control of blast and sheath blight, high volume spray recommended.

Chlorinated nitrobenzene Dinocap Karathane 25% WP

Karathane 48% EC 0.05% spray of 48 EC or 300 g/ha of

25 WP

For foliar spray for powdery mildew control of

cucurbits and rose Heterocyclic nitrogen compounds

Captan Captan 75% WP 0.1% For seed treatment at 1.5

g per kg seed Hexacap 75% WP Systemic fungicides

Carbendazim

Bavistin 50%WP

500 g/ha

Effective against powdery mildew diseases in

ornamental plants; and blast, sheath blight and

sheath rot of rice.

Benomyl Benlate 50% WP 1-2 g/litre (R) Foliar fungicide for blast control in rice.

Caboxin Vitavax 80% WP 500 g of the

formulated product / ha (R)

For seed treatment and for foliar application Vitavax 75%

Kitazin Kitazin-P 48 EC 1 ml/litre (500 ml/ha) (R)

For foliar spray against rice blast

Pyroquilon Fongorene 50 WP 2 g/kg seed For seed treatment Tricyclazole Beam 75 WP 2 g/kg seed For seed treatment

Hexaconazole Contaf 5 EC 750 ml/ha For foliar spray against sheath blight

Propeconazole Tilt 25 EC 0.5 to 0.75 ml For foliar spray against sheath blight

Potassium phosphonate Akomin 40% 0.3 %

Effective against Phytophthora foot rot of pepper

Tridemorph Calixin 80% EC Coconut stem bleeding Antibiotics Antifungal materials Aureofungin sol 50 g/ha (R) For foliar spray

Antibacterial material

Agrimycin-100 750 g in 500 l water

(R, OC) For foliar spray

Plantomycin Paushamycin

Streptocycline 15 g in 300 l water (R, OC)

Validacin 3 L Validamycin A 3% 2 m/l Control of sheath blight

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FUNGICIDE CALCULATIONS

Quantity Commercial formulation =

1. Calculate the quantity of Bavistin 50 WP require to prepare 10 L of 0.3% spray solution.

Q= 10 L X 0.3/100 = 10 X 1000 X 0.3/100 = 30 g

2. Calculate the quantity of Hinosan 50 EC required to prepare 500 l of 0.1% concentrated spray solution

Q = 500 l x 0.1% = 500000 x 0.1/100 = 500 ml

PREPARATION OF SOME COMMON INORGANIC FUNGICIDE 1. Bordeaux mixture (1%) - Dissolve 1 kg of powdered copper sulphate crystals in 50 litres of

water. In another 50 litres of water, prepare milk of lime with 1 kg of quick lime. Pour the copper sulphate solution into the milk of lime slowly stirring the mixture all the while. Test the mixture before use for the presence of free copper, which is harmful to the plants, by dipping a polished knife in it. If the blade shows a reddish colour due to the deposits of copper, add more lime till the blade is not stained on dipping. Always use wooden, earthen or copper vessels for the preparation of Bordeaux mixture

2.0Bordeaux0paste0(10%) - Dissolve 100 g of copper sulphate and 100 g of quick lime each in 500 ml of water separately. Mix together to make one litre of the paste.

3.0Cheshunt0compound - Weigh 60 g copper sulphate and 330 g of ammonium carbonate. These two are well powdered and thoroughly mixed. The dry mixture is stored in an airtight glass container for 24 hours before use. About 25 g of this mixture is dissolved in a little hot water and solution is made up to 8 litres with cold water and used for soil drenching.

Name of fungicide Use 1. Bordeaux mixture Foliar application 2. Cheshunt compound Soil Drenching 3 .Bordeaux Paste Wound Dressing

IDM- Integrated Disease Management confined use of all the different methods of plant disease control SOIL SOLARIZATION

Soil solarization is a method of hydrothermal disinfection of soil. This is dome by covering the moist soil with transparent polythene sheet and expose to direct sunlight during the hottest period of the year. Methods of solarization

1. Nursery Bed - The nursery bed for raising the seedlings is to be leveled and the pebbles are removed from the surface. Incorporate sufficient quantity of organic manure and sprinkle water at the rate of 5L/m2. Cover the area with 100-150 gauge transparent polythene sheets. Seal the ends of the sheet with soil to keep it in position and to maintain temperature and moisture inside. Adequate care is to be taken to see that the polythene sheet is in close contact with soil to avoid air pockets.

Volume of spray fluid X Recommended Conc. of spay fluid in %

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Keep the sheets in this position for 20-30 days. Protect it from stray animals and birds. After the period of solarization remove the sheets and the bed is now ready for sowing or transplanting.

2. Potting mixture - Potting mixture is prepared as per the recommended practice. Spread the potting mixture on a level surface to a height of 15-20 cm. Sprinkle water using rose can and cover the soil with polythene sheet of 100-150 gauge thickness. Solarize for 20-30 days. This method is effective for the preparation of disease free pepper cuttings. Hints for solarization

1. Solarization should be done in open field without any shade. 2. Transparent polythene sheet of 100-150 gauge thickness should be used as it is cheap and is

more effective in conduction of heat. 3. Summer months are more suitable for solarization. 4. Soil should be moist during solarization. This increases the sensitivity of resting structures of

pathogens in soil and weed seeds. 5. Solarization may be extended to more than a month to effect disinfection to deeper layers of soil. 6. Excess seepage of water into the solarizing bed should be avoided. But summer showers

won’t affect the process. 7. Potting mixture should never be heaped for solarization. It should be spread to a height of 15-

20cm and moistened before solarization. 8. Soil should have good tilth and should be in good contact with the polythene sheet.

Benefits of solarization

1. It controls fungal pathogens like Pythium, Phytophthora, Rhizoctonia, Fusarium etc. 2. Solarization controls plant parasitic nematodes like root knot nematode. 3. Solarization controls weeds like Cynadon, Cyperus etc. 4. Improves plant growth expressed as increased plant height, number of leaves, better root

formation etc.

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Unit – 12 DISEASES OF MAJOR CROPS OF KERALA

In Kerala our crop plants are severely affected by many diseases; which causes a major loss of about 20% reduction in Yield. To reduce the disease incidence and to increase the yield, control of diseases is very essential.

1. DISEASES OF RICE Fungal diseases 1. Blast - Causal organism - Pyricularia oryzae Symptoms - The fungus produces spindle shaped spots with grey centre and brown margin or lesions on leaf blades, nodes and grains. As the disease advances the spots will coalesce and leaves are killed or dried up. Nodes turn black in colour and break easily. The grains will turn black in colour and shed. Control

1. Avoid excess nitrogenous fertilizers 2. It can be controlled by spraying Hinosan 1 ml in 1 litre of water or kitzazin 1.5 ml in 1 litre

water. 2. Blight (Brown Leaf Spot) casual organism - Helminthosporium oryzae Symptoms - The fungus will produce oval shaped dark brown coloured spots on the leaf blade and leaf sheath. In the later stage, spots will coalesce together and leaves killed or dried up.

Control - Spray Hinosan or Kitazin

3. Narrow brown leaf spot casual organism - Cercospora oryzae Symptoms - Oval shaped narrow spots are found on leaf blade.

4. Sheath blight casual organism - Rhizoctonia solani

Symptoms - On the leaf sheath greenish grey irregular spots are found. In the advanced stage this will coalesce together and sheath will dry up.

Control 1. Destroy the stubbles after harvest 2. Avoid nitrogenous fertilizers, use fungicide hinosan or bavistin 3. The fungus is soil borne so drench the soil with 0.1% Dithane M-45 (Mancozeb)

5. Sheath rot casual organism - Sarocladium oryzae Symptoms - Oval shaped spots appear on sheaths. Panicles partially emerge. Whitish powdery fungal growth seen inside rotten sheath. Control - Spraying Hinosan or Kitazin.

6. Udbatta disease casual organism - Ephelis oryzae Symptoms - The panicle emerges from leaf sheath as a straight, dirty coloured, hard cylindrical spike, reduced in size resembling an agarbathi or Udbatta. No grains are found on the affected ear heads. It is seen in hilly areas, not a serious disease

BACTERIAL DISEASES 1. Bacterial Leaf Blight (B.L.B.) casual organism - Xanthomonas oryzae Symptoms - The earliest symptom is the appearance of pale yellow or dull green spots on the leave towards the tip and margins. It leads to drying from tip through both the margins down wards. When

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the affected leaves are cut and immersed in clear water in a test tube a turbid ooze of bacteria can be observed. This will confirm the disease. Later stage marked with severe blight termed as cresek stage. Control

1. The disease is seed borne. So the seeds are soaked in Agrimycin or streptocyclin solution for 8 hours followed by hot water treatment for 30 mins.

2. application of cow dung slurry through irrigation water 3. Bleaching powder is also effective.

2. Bacterial Leaf Streak casual organism - Xanthomonas oryzicola Symptoms - Leaves with fine narrow yellow translucent intervienal line joining to form dark dirty white patches.

VIRAL DISEASES 1. Tungro Virus Symptoms - Plants are stunted in all parts and the leaf turn yellow or orange in colour and the yellowing begins from the tip. Tillering will be reduced. Control - Virus is controlled by controlling the vectors. The vector of Tungro virus is green leaf hoppers. It can be controlled by spraying ecalux-0.2%. 2. Grassy Stunt

Symptoms - Severe stunting with excessive tillering, erect growth habit resembling a grass bunch. Vector is BPH. It can be controlled by spraying ekalux.

Other viral diseases are Yellow dwarf and ragged stunt.

Blast Sheath rot

Bacterial blight

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2. DISEASES OF COCONUT

1. Bud rot: Causal organism - Fungus - Phytophthora palmivora Symptoms - The earliest symptom is the yellowing of 1 or 2 younger leaves surrounding the spindle. The spindle withers and droops down. The tender leaf base and soft tissues of the crown rot into a slimy mass of decayed material emitting a foul smell. The disease proves to be fatal if not checked at the early stages. Palms of all ages are liable to be attacked by the fungus but normally young palms are more susceptible particularly during monsoon when the temperature is low and humidity is high. Control

1. In early stages of diseases (when the heart leaves start withering) cut and remove all affected tissues of the crown and apply Bordeaux paste and protect it from rain till normal shoot emerges. Protect the bud (cover it with polythene cover or mud pot).

2. Burn all disease affected tissue removed from the palm. 3. Spray 1% Bordeaux mixture on spindle leaves and crown of the diseases affected as well as

neighboring palms as a prophylactic measure.

2. Grey Blight Causal organism - Fungus - Pestalotia palmarum Symptoms - symptoms appear in the mature leaves of the outer whorls as yellow specks encircles by a greyish band which later become greyish white. The spots coalesce into irregular necrotic patches causing extensive leaf blight. In advanced stages tips and margins of leaflets dry and shrivel giving a burnt appearance. Control

1. Remove older disease affected leaves. 2. Spray leaves with Bordeaux mixture.

3. Leaf Rot Causal organism - Fungus Symptoms - blackening and shriveling up of distal ends of the leaflets in the central spindle and younger leaves. Later the affected portions break-off in bits and carried away by wind. The tree gradually weakens and the yield is reduced. Control - Spray crown and leaves with 1% Bordeaux mixture or 0.4% Mancozeb in January, May and

September.

4. Stem Bleeding Causal organism - Fungus - Theilaviopsis paradoxa Symptoms - Exudation of reddish brown liquid through the growth cracks at about 5-10 cm above the ground level and bleeding patches higher up in the trunk are characteristic symptoms. The tissues beneath the bleeding points decay and become yellowish. The general vigour of the palm is reduced and yield declines. Fatal instances are not uncommon. Control

1. Remove completely affected tissues by chiseling and there after dress the wounds with hot coal tar or Bordeaux paste.

2. Avoid any mechanical injury to the stem. 3. Improve general condition of the palm through proper manuring and other cultural practices. 4. Application of Calyxin 25ml/25 litres of water as soil drenching once in four months.

5. Thanjavoor Wilt Causal organism – Fungus - Ganoderma Symptoms - Characteristic symptom of the disease is rotting of the basal portion of stem. The bark

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turns brittle and often gets peeled off in flakes leaving open cracks and crevices. The internal tissues are discoloured and disintegrated emitting a bad smell. Mild bleeding occurs at the basal region. The tissues on the bleeding sprouts are soft to touch. Damage of root system following root rotting has been observed. Ultimately the palm dies off Management

1. Apply organic manure 50 kg/palm and neem cake 5 kg/palm 2. Isolate the affected palm from healthy one by digging a trench around the palm. 3. Avoid flood irrigation to prevent the possible spread of pathogen. 4. Drench the basins with 40 liters of 1% Bordeaux mixture.

6. Root Wilt diseases Etiology is unknown

Symptoms - Characteristic symptom is the flaccidity of leaflets, General chlorosis, wilting of leaves, decay of root system are also seen. Leaflets curve inwardly so that the whole frond develops a cup like appearance. Abnormal shedding of buttons and immature nut fall is noticed. Management

This is a non-lethal disease and the affected palm survives for a long period giving a reasonably good yield. The root wilt affected palms are susceptible to diseases like leaf rot and pests like rhinoceros beetle and red palm weevil. Efficient management of palm affected with root wilt help in suppression of the disease.

1. Apply fertilizers at the dose of 0.34% kg N and 0.17 kg P2O5 and 0.68 kg. K2O 2. Apply 50 kg cattle manure or green manure and 1 kg lime/palm/year and 500 gm MgO

/palm/year. 3. Grow green manure crops like cowpea, sesbania etc in the basins. 4. Follow strictly all the prophylactic methods against leaf rot disease, rhinoceros and red palm

weevil etc. 5. Destroy coconut palms which are severely affected and produce less than10 nuts per year. 6. For replanting DXT seedlings is preferred.

7. Mahali (fruit rot and nut fall) Causal organism – Fungus - Phytophthora

Symptoms - Shedding of female flowers and immature nuts are the symptoms. Lesions appear on young fruits or buttons near the stalk end which later develop into decay of underlying tissues.

Control - Spray Bordeaux mixture 1% 8. Button shedding - The shedding of buttons in coconut is due to the following reasons.

1. Pathological conditions 2. Attack of insect pests 3. Nutritional deficiencies 4. Soil variations 5. Climatic variations 6. Genetic factors like limited capacity to bear 7. Water shortage 8. Physiological disorders

The causes of button shedding may be identified and appropriate control measures should be adopted.

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Bud Rot Stem bleeding Bud rot Root wilt

3. DISEASES OF BANANA

1. Bunchy top Causal organism – Virus transmitted by Aphid Symptoms - Affected plant produces short narrow leaves which are chlorotic and exhibit mosaic symptoms. Leaves arise in clusters giving a rosette appearance. They are brittle with numerous dark green sports. The plants do not usually grow taller than 2-3 feet height. They fail to produce any fruit. Sometimes bunches develop partially with a crinkled appearance and burst through the sides of pseudo stem. Control

1. Eradicate all the disease affected plants by burning 2. Use disease free suckers for planting. 3. Karpooravally, kanchikela, koombillakannan, njalipoovan are less susceptible varieties. 4. Use insecticidal treatments recommended for control of vector.

2. Panama Wilt (Banana wilt) Causal organism - Fungus - Fusarium oxysporum Symptoms - Sudden wilting of plant or individual leaves even if there is sufficient supply of water. Leaves turn yellow and chlorotic. Petioles longitudinally break and leaf blade hangs down. Entire foliage may wilt within 2-3 days and finally psuedostem breaks up longitudinally into two halves.

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Control 1. Drench the soil around the affected clumps with bavistin solution.

2. Remove and destory all affected clumps along with corms

3. Apply lime at the rate of 1kg/ pit.

4. Varieties such as Palayamkodan, Robusta and Nendran are resistant to the disease

5. Dip suckers in carbentazim 0.1-0.2% solution before planting.

3. Sigatoka Leaf Spot Causal organism - Fungus - Mycosphaerella sp.

Symptoms - Small narrow chlorotic streaks 1 cm long are present on leaves. The streaks spread, later the leaves may become necrotic, particularly towards leaf margins giving a characteristic scorch appearance. As a result bunch size and quality is affected.

Control

1. Cut and burn all the severely affected leaves 2. Spray 1% Bordeaux mixture or Captafol 0.3% or Kavach 0.3% or spray with 1% oil emulsion.

4. Kokkan disease Causal organism – Banana bract mosaic virus 1st reported from Thrissur district in Kerala. Nendran is highly susceptible.

Symptoms - During young stage of banana (2 months old) pinkish and reddish streaks can be seen on the psuedostem. Later the streaks turn to dark black. Symptoms appear on all aerial parts of affected plant except on lamina. The affected plant produces only a small bunch. The fingers are small, curved and with pale green to ashy green colour as compared to healthy. Control

1. Suckers should not be taken from affected plants which show necrotic streaks or abnormal

colour of the psuedostem.

2. When the young plants show pinkish streaks, uprooted and destroy.

5. Infectious chlorosis (Cucumber mosaic virus disease)

Symptoms -The most characteristic symptoms are the loss of leaf colour in patches. appearance of parallel chlorotic streaks on the younger leaves, giving a striped appearance on the leaves. As the disease progresses, leaves emerge distorted, margins become irregularly wavy, often with blotches of necrotic tissues and the leaf lamina is reduced in width. In severe cases, rotted areas are found throughout the leaf sheath and psuedostem. The affected plants produce only small bunches. This is a virus disease transmitted by aphids

Control 1. Use disease free suckers for plan

2. Eradicate disease affected plants.

3. Use insecticides recommended for insect vector contro

4. Avoid growing leguminous and cucurbitaceous vegetables as intercrop in banana.

Other diseases include Cordana leaf spot, Freckle leaf spot

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Bunchy top Kokkan

Sigatoka leaf spot Panama wilt

4. DISEASES OF PEPPER

1. Quick wilt Causal organism - Fungus - Phytophthora palmivora Symptoms - 1st symptom is present on the leaves as rotting from the distal end. The rotting will advance within few days and leaves turn dark in colour. The leaves along with petiole wither and fall down. The lateral branches will also be broken into bits and falls down. At the same time roots will also rot. Basal region of main stem (collar region) will also rot and plant will die within few days. The fungus is present in the soil which wills germinate with south west monsoon and gain entry into the root system. At the same time fungus present on the surface of the soil will be splashed due to the action of raindrops and will get entry at the collar region. And this will spread to the whole plant.

Control 1. Prophylactic measures are important to control this disease 2. All infected or dead wines along with root system are to be removed and burned. 3. Effective drainage should be ensured in the field. 4. Before onset of south west monsoon spray vines with 1% Bordeaux mixture or 0.2% copper

oxychloride. 5. The basal 50 cm of main stem from the ground level should be pasted with Bordeaux paste. 6. Soil around the pepper plant at the radius of 50cm should be drenched with BM 1% or copper

oxychloride 0.2% @ 10 1trs / plant. 7. These measures should be repeated when there is a gap in monsoon season

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2. Fungal pollu (Anthracnose) Causal organism - Fungus – Colletotrichum sp. Symptoms - The fungus will attack on the berries present on the spike, as a result berries will become hollow with a black colour. The entire spike may be attacked leaving behind only 1 or 2 berries. Disease is present during August at the berry formation stage. Control

1. Minimise shade in the garden. 2. Spray with B.M.1% or Captafol 1% once before flowering and then at berry formation stage.

3. Damping off Causal organism - Fungus - Pythium sp. This is present in nursery stage. The seedlings rot just above the ground level and damping off

will take place. Control

1. Potting mixture should be treated with Bordeaux mixture or solarise. 2. For seedlings spray with BM 1% at weekly intervals.

4. Slow decline This is a complex disease, fungi, bacteria and nematodes are responsible.

Symptom - wilting of leaves, rotting of few leaves and shedding of leaves here and there. These symptoms will continue foe a longtime and the plant will die slowly with a slow reduction in yield. Control - achieved by a combination of chemicals like fungicide, antibiotics and ematicides. 5. Phyllody Causal organism - Phytoplasma

In certain pockets, instead of normal spike with berries, leaf-like structures are produced. Such vines, if noticed, must be uprooted and destroyed. Planting material should not be collected from such vines.

6. Stunted disease Causal organism - virus.

The symptoms due to this disease include shortening of internode and narrowing of leaves with mottling. Such leaves also become leathery and deformed. Since the disease is systemic and transmitted through planting materials, extreme care should be taken to avoid collecting planting materials from such vines. Once it is noticed, it is better to uproot the vines even at the cost of losing some yield to avoid further spread.

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5. DISEASES OF RUBBER 1. Abnormal leaf fall Causal organism - fungus - Phytophthora sp.

Symptom - During south - west monsoon season the fruits rot, later infected leaves fall in large numbers prematurely either green or after turning coppery red, with a drop of latex often coagulated in the centre of a black lesion on the petiole. Control - Prophylactic spray of foliage prior to the onset of monsoon with 1% BM or oil based copper oxychloride. 2. Powdery mildew Causal organism - fungus - Oidium heveae Symptoms - noticed on newly formed tender flush during the refoliation period of January to March. Tender leaves with ashy coating curl, crinkle, edges roll inwards leaving the petioles attached to the twigs giving a broomstick appearance. In later stages, on older leaves white patches appear. Infected flowers and fruits shed. Control

1. Dusting with sulphur 3-5 rounds at weekly or fortnightly intervals. 2. Surphur mixed with an inert material like talc (70:30 mixture) could also be used.

3. Pink disease Causal organism – fungus - Corticium salmonicolor Symptoms - Trees in the age group of 3-12 years are highly susceptible. The seat of infection is usually at the fork region. White or pink coloured cob-web like mycelial growth form on bark surface with streaks of latex oozing out from lesions. Later rotting, cracking of bark, exudation of latex and finally drying up of twigs and branches is noticed. Control

1. Regular inspection of trees during July - September for detecting the disease. 2. In early stages of infection apply Bordeaux paste up to 30 cm above and below the affected region. 3. In severe cases prune off and burn the dried up branches.

4. Bark rot Causal organism – fungus - Phytophthora spp. Symptoms - During rainy season, when trees are tapped, depressions are formed in the tapping panel due to localized rotting and drying bark. Black vertical lines running downward into the tapping bark and upwards into the renewed bark are noticed. The bark when0renewed0becomes0highly0uneven. Control

1. The tapping cut and nearby bark should be washed with mancozeb (0.375%) or phosphorous acid (0.08%) at weekly intervals.

2. The rotten bark may be scraped off and applied with fungicide and then covered with petroleum wound-dressing compound.

Other diseases are Corynespora leaf disease, patch canker, dry rot,bird's eyespot, brown root etc.

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6. DISEASES OF GINGER

1. Soft rot / Rhizome rot Caused by fungus - Pythium and Phytophthora Symptoms – The 1st visible symptom is found at the basal region of plant which become watery and rots. The leaves become slightly pale in colour and their tips turn yellow and yellowing spread downwards. At the same time rhizomes get rotten and are converted into a slimy mass emitting a foul smell. The plant will die soon. Control

1. Water logging in ginger garden should be avoided 2. Before the onset of monsoon spray with 1%. B.M. or Mancozeb 0.2% and drench the soil with

1% B.M. or Cheshunt compound. 3. When the disease is present in the field, spraying and drenching should be done as above and

channels should be made around the infected area to isolate it from healthy plants. 2. Leaf Spot Caused by fungus

Presence of irregular brown spot on the leaf lamina and later drying up of leaves. Controlled by Spraying 1% B.M. or 0.2% Mancozeb.

7. DISEASES OF MANGO

1. Anthracnose Causal organism – fungus - Colletotrichum gleosporioides Symptoms - seen on the leaves, flowers, fruits, stem etc. On the leaf, numerous sunken spots appear. Later it becomes necrotic and leaves crinkled. The leaves will dry-up, on green twigs, dark brown lesions are produced and twigs dry up showing die back symptoms. Flowers when infected wither and shed and no fruiting will take place. On the tender fruits spots appear and they turn black. Finally drying of the whole tree and reduction in yield occur. Neelam and its hybrids are highly susceptible. Control

1. Crowding in orchards should be avoided. 2. Affected twigs should be pruned and apply Bordeaux paste. 3. Spray with BM 1% or Zineb or Ziram 0.2% or Captan 0.3%.

2. Pink disease Causal organism – fungus - Corticium

Symptoms - Trees in the age group of 3-12 years are highly susceptible. The seat of infection is usually at the fork region. White or pink coloured cob-web like mycelial growth form on bark surface. Later rotting, cracking of bark, exudation of fluid and finally drying up of twigs and branches is noticed. Control

1. Regular inspection of trees during July - September for detecting the disease. 2. In early stages of infection apply Bordeaux paste up to 30 cm above and below the affected region. 3. In severe cases prune off and burn the dried up branches.

3. Grey blight Causal organism – fungus - Pestalotiopsis mangiferae

Symptom and control same as in coconut 4. Sooty mould Fungal disease caused by Meliola mangiferae

Symptoms - Black sooty mould growth can be seen in stem, leaf etc. If the whole leaves are covered with sooty mould, photo synthesis will be reduced and so yield is reduced. When the insects attack

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on fruits there will be a honey dew secretion and that will in turn enhances the attack of sooty mould. Control

1. Control of insects properly 2. Spraying with dilute starch solution

5. Red Rust Caused by algae - Cephaleuros parasiticus

Symptoms - Algal growth can be seen on stems and twigs as star like growth. The tissues are penetrated and damaged by the absorption of food from inside. On the upper surface clusters of orange red hairy growth and be seen.

Control - Spray B.M. 1% 6. Mango malformation

This is a complex disease or disorder. Caused by Fungus, mites, virus and physiological reasons. Symptoms -

a) Vegetative malformation - It is more severe in young seedlings and grafted plants. Affected plants develop excessive vegetative growth, producing bunches of dwarf branch giving a broom stick or bunchy top appearance.

b) Floral malformation - Flowers on affected plants are abnormal and develop monstrosities. The abnormal shape is due to thick fleshy and profusely branched peduncle. The flowers bear scanty pollen and fertilization will not be effective. Later they dry up giving no yield. Root system also may be affected. The tap root is twisted and become necrotic.

Anthracnose on fruits Anthracnose on stem Sooty mould Malformation

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8. DISEASES OF ARECANUT

1. Mahali (fruit rot or Koleroga disease) Causal organism – fungus - Phytophthora Symptoms - The fungus will attack distal end of immature nuts and rotting will result. The rotting will proceed to the stalk end, nuts will fall down. The fallen nuts and stalk end will be rotten forming a slimy mass. If it is not controlled, all nuts fall down and yield will be completely lost. Control

1. Spray with BM 1% before onset of south west monsoon. 2. Repeat the spraying when there is a dry spell during the monsoon and again after the

ceasation of south west monsoon just before the onset on north-east monsoon. 2. Bud rot - Same as in coconut

3. Foot rot or Anabe disease Caused by fungus Phythium The collar region of seedlings will be affected by the fungus, as result collar region will rot and

seedlings will topple down, roots will also be rotten. For control drench the soil around the palm with BM 1% or Captan 0.3 % 4. Yellow leaf disease Etiology is unknown Symptoms - All the leaves in the crown of palm show general chlorosis. As a result yield is reduced. The disease can be managed by adopting recommended manurial application, cultural, plant protection and other management practices. Improve drainage conditions in the garden. 5. Sun scorch

The south-west of the palms will be scorched by the rays of sun leading to the drying of seedlings. It can be protected by pasting with 'China clay' or lime or by wrapping with areca spathe or even with plastic film.

9. DISEASES OF CASHEW

1. Anthracnose Caused by fungus - Colletotrichum gleosporioides. Symptoms - Fungus attack leaves, twigs, inflorescence, cashew apple and cashew nut. Reddish brown water soaked sunken lesions followed by exudation of resin from the affected parts. Later twigs will be dried up, nuts and apple decay and fall off. Yield is very much reduced. Control - Spray B.M. 1% or Mancozeb. 2. Pink Disease - Same as in rubber and mango 3. Root rot Caused by fungus - Pythium spp

Rotting of roots. During of the twigs followed by yellowing of leaves and stunted growth of plants. Soil drenching with cheshnut compound can be practiced. 4. Decline - Affects all ages of tree. Usually in the lateritic soil. Defoliation and drying of twigs during summer and death of the tree occur with in 2-3 years. Provide good management pactices. 5. Gummosis Caused by fungus - Ceratocystis paradoxa

Reddish brown gummy exudation from the affected region. Later the affected region or twigs dry up. For control chisel out the infected area and apply hot coal tar or Bordeaux paste. 6. Seedling blight - Wilting and withering of seedlings and rotting of underground portions of stem and seedling will dry up. Spray with B.M. and drench with Mancozeb 0.3% (Dithane M45). 7. Inflorescence blight Caused by fungus - Colletotrichum gloeosporioides

The inflorescence will be affected with sunken spots and later dry up. Spray Mancozeb 0.3%

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10. DISEASES OF CARDAMOM 1. Katte diseases (Mosaic) Caused by Virus and Vector is banana aphid. Symptoms - discontinuous stripes of light green colour running almost parallel to each other from the mid rib to the margin of the leaves, which form a mosaic pattern. On young shoots such stripes are seen on leaf sheath also. Infected clumps will be smaller in size with fewer tillers. Control

1. Destroy infected plants by burning 2. Control vector by spraying insecticide 3. Remove all alternate hosts of the virus.

2. Azhukal or Capsule rot Caused by fungus - Phytophthora spp. Symptoms are present during south - west monsoon season. The fungus affect leaves, shoot, panicles and capsules. On the infected leaves water soaked lesions appear first and rotting and shedding of leaves occur thereafter. Infected capsule become dull greenish brown and decay. This emits a foul smell and subsequently sheds. Control

1. Remove and destroy all infected clumps 2. Spray with B M 1% before the onset of south - west monsoon and again in the dry spell during

the monsoon or after ceasation of monsoon. 3. Drench with 1% BM @ 3 1titre / plant covering the panicle

3. Clump rot Caused by fungus - Phythium sp. Affected shoots becomes brittle and easily break of from the rhizome at the bulbous base.

Control 1. Drench with B.M. or cheshunt compound 2. Application of ammonium phosphate or super phosphate 100gm / plant during the last week

of may check the spread of this disease. 4. Leaf blotch Caused by fungus. This disease is characterized by the appearance of large blotches of irregular lesions with alternating shades of light and dark brown necrotic tissues. Spray mancozeb 0.3% 5. Chenthal disease This is a bacterial disease caused by Corynebacterium. Symptoms - Appearance of rectangular linear reddish brown lesions mainly on the lower surface of leaves. Lesions are clearly visible even on dried leaves. The incidence of this disease appears to be more severe in areas which do not have proper shade. Control - Provide adequate shade in the garden. 6. Damping off Caused by Fungus - Pythium spp.

Infection is observed at the collar region and seedlings topple down. Drenching with BM 1% or cheshunt compound will help to reduce infestation.

11. DISEASE OF VEGETABLES Diseases of cowpea 1. Anthracnose Caused by fungus

Irregular spots on leaves and branches and dry up. 2. Powdery mildew Caused by fungus

Powdery growth on the leaf surface and later blight occur

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3. Downy mildew It is a fungal disease - Pseudopernospora

Serious during high humid periods, mycelial growth seen under the leaves, later dry up. Application of mancozeb 0.3% Diseases of cucurbits

1. Downy mildew - It is severe during rainy season. This can be checked by spraying mancozeb 0.2% (waiting period of mancozeb is three days).

2. Powdery mildew - Can be controlled by spraying nitrophenol 0.05%.

3. Mosaic - Control the vectors by spraying Dimethoate 0.05%. Uprooting and destruction of affected plants and collateral hosts should be done.

4. Bacterial wilt Caused by bacteria Xanthomonous spp. The plants will wilt suddenly even when there is sufficient supply of water, leaves drop down

and fruits fall off. Ooze test should be conducted to diagnose this disease. Apply antibiotics.

5. Fruit rot Caused by fungus - Pythium affanidermatum A watery soft rot develops especially in the fruits touching the soil surface. The disease is

common in the field during and after rain. It also spreads among fruits during storage and transport. Control

1. Efforts should be made to keep the fruits away from the soil surface by having some mulch below the fruits.

2. Soil drenching with cheshunt compound Diseases of chilly 1. Anthracnose 2. Bacterial wilt - The plants will wilt suddenly even when there is sufficient supply of water, leaves drop down and fruits fall off. Ooze test should be conducted to diagnose this disease. Apply antibiotics. 3. Fruit rot and dieback of chillies Caused by fungus Collectotrichum capsisi

The sign of infection is the appearance of small black circular spots and these spots will join together and the fruit lose their normal red colour and turn straw coloured or pale white. Dieback symptoms - The infection begin from the growing point of the flower buds and twigs of branches. Later branches and twigs turn brown. The plants dieback and attack spreads. Spraying Zineb 0.25% for control 4. Little leaf viral disease

By the attack of virus, the growth of the plant is stunted and leaves become small having a miniature shape. Eradicate infected plants and the vector white fly is controlled by Rogor 0.03%

For avoiding damping off of the seedlings in the nursery, sow the seeds as thin as possible in raised beds prepared in the open area during summer months. Spray nursery and main field with 1% Bordeaux mixture at monthly intervals during rainy season. Uproot and destroy the plants affected by bacterial wilt and mosaic. Cultivate resistant varieties like Manjari, Ujwala and Anugraha in bacterial wilt prone areas. Diseases of bhindi

1. Yellow vein mosaic disease (YVM) Viral disease, vector white fly - Bemisia tabaci Symptoms - The symptom is the yellowing of veins followed by veinal chlorosis. The yellow network

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of veins and veinlets become thick. In severe cases the chlorosis may extend to inerveinal areas and result in the complete yellowing of leaves. Fruits are dwarf, malformed and yellowish green in colour.

Control 1. Eradication of affected plants. 2. Controlling the vector by spraying Rogor 0.03%. 3. Use of resistant varieties like Arka Anamika, Arka Abhay and Susthira 4. destruction of host weeds

2. Anthracnose

3. Bacterial wilt

Diseases of amaranthus

1. Damping off of seedlings 2. Leaf spot disease 3. Bacterial wilt Diseases of brinjal 1. Damping off of seedlings 2. Anthracnose 3. Bacterial wilt 4. Little leaf of brinjal - Causal organism; Mycoplasma

For avoiding damping off of the seedlings in the nursery, sow the seeds as thin as possible in the raised beds prepared in the open area during summer months. Follow mechanical removal and destruction of disease affected portions for control of Phomopsis fruit rot. Uproot plants affected by little leaf and spray insecticides for further control. Cultivate resistant varieties like Surya, Swetha and Haritha and the hybrid Neelima in bacterial wilt prone areas.

12. DISEASES OF TAPIOCA

1. Cassava mosaic (topioca mosaic) caused by virus. Transmitted by white fly Bemissia sp. Symptoms - It is present on leaves as mosaic pattern as yellow, light green and dark green patches intermingling each other resembling a mosaic pattern. Later leaves will be crinkled, rolled longitudinally and perpendicularly and yield will be reduced. Control

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1. Disease affected plants should be isolated and destroyed by burning 2. Setts should not be taken from disease affected plants for planting. 3. Tolerant varieties like H-97 can be planted 4. Vector white flies can be controlled by spraying Ekalux 0.2%

2. Leaf Spot Causal organism - fungus - Cercospora

Presence of brown irregular spots with dark margin on leaves.Spray 0.2% Ziram or Zineb or 1% B.M for control. 3. Bacterial blight Causal organism - Bacteria - Xanthomonas spp.

Blight is present on the margins of leaves. Later the margin rolls inward and dries up. Yield is reduced. Chemical control using antibiotics is not effective. So resistant varieties like H-97, H-226, H-1687 and H-2304 can be planted.

13. DISEASES OF SWEET POTATO 1. Damping off Cause by Fungus - Pythium sp.

Collar region is affected and vines rot and dry up. Drench with BM 1% or cheshunt compound

2. Cercospora leaf spot Caused by fungus - Cercospora

Presence of irregular brown coloured spots with necrotic tisues on leaves. The spot coalesce and leaf dry up. Spray BM 1% or Mancozeb.

14. DISEASES OF ROSE

1. Leaf spot Caused by fungus - Colletotrichum and Cercospora. Necrotic spots of different colour, shape and size appear on leaves which may extend to

branches and later dry up. Spray with Bordeaux mixture. 2. Blight - Sports appear on leaves and later leaves are killed suddenly giving a burnt appearance. Spray B.M. 3. Powdery mildew Caused by fungus - Oidium rosae

Appearance of white powdery mass on the upper surface of leaves. Leaves fall prematurely or become yellowish and dry up. Dusting with sulphur will help to control the disease 4. Damping off - Seedlings are affected particularly after the onset of south - west monsoon. Collar region is rot and seedlings fall down. Drenching with cheshunt compound help to reduce infestation

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15. DISEASES OF ANTHURIUM

1. Bacterial blight - Blackening of the stem and decay of leaf axils are the symptoms of bacterial blight. 2. Anthracnose - Tiny circular black spots appear on leaf and spadix in case of anthracnose. Spraying

mancozeb 0.3% or carbendazim 0.1% can control the disease. 3. Root rot caused by fungus Pythium and Phytophthora .

Can be controlled by the application of potassium phosphonate 0.3%.

16. DISEASES OF ORCHID

The important fungal diseases are

1. Leaf spot (Colletotrichum and Gloeosporium) 2. Leaf blight (Pythium) 3. Collar blotch (Penicillium thimmi) 4. Collar rot (Sclerotium) 5. Orchid wilt (Sclerotium rolfsii)

These can be controlled by application of mancozeb, carbendazim etc. at the recommended dose. Spraying should be done prior to the commencement of monsoon and at fortnightly intervals during heavy monsoon.

6. Mosaic viral disease 7. Ring spot viral disease

Destroying the affected plants can control spread of these diseases.

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Unit – 13

WEEDS

Weeds have been a problem ever since man started cultivating crops. They successfully compete with cultivated crops by thriving adverse conditions and are known as silent killers of crop plants. They create difficulties in agricultural operations, increase labour cost, and create health hazards and difficulties in aquatic systems. About 45% of total crop losses in India are reported due to weeds. This indicates the importance of weeds and weed management in crop production.

“Weed is a plant grown in a place where it is not required. Weed is a plant out of place”. Weed is an unwanted and uncultivated plant, they reduces crop yield and contaminate the produce and act as alternate host of many pest and disease

CHARACTERISTICS OF WEEDS 1. Weeds require less amount of nutrients - The total nutrient requirement of a weed is very

less when compared with cultivated crop. So weeds can grow in any soil. 2. Weeds require less amount of moisture - The water requirement of weeds is very low. And

they have the advantage of drought tolerance to a greater extent. So they can survive in adverse conditions.

3. It flowers profusely and produce large number ob seeds - If at all some seeds are not germinated the remaining seeds will help the wed plant for successful establishment of generation.

4. Germination percentage of weed seeds is very high - So it will result in the formation of large number of individuals during the next generation.

5. The longevity of weed seed is very high - The period during which a seed remain viable is called longevity. The longevity of weed seeds is high; it can thrive over unfavourable conditions for a long period and come to germinate, whenever conditions become favourable.

6. Possibility of vegetative propagation - Weeds are having the capacity of vegetative propagation in addition to seed propagation. So even though the sexual propagation is failure the weeds can survive by the vegetative propagation.

7. Weed seeds are provided with hairy and spiny appendages – help in seed dispersal more effectively.

8. Weeds have short life span - As the weeds have short lifespan, it can complete its life cycle within a short period and hence they can survive in adverse condition. Similarly more number of germination is possible because of shorter life cycle.

9. Evasiveness - Many weeds are capable or escaping from animal and man due to their bitter taste, presence of spine, causing Allergies etc. eg: Mimosa, Parthenium

CLASSIFICATION OF WEEDS

Weeds can be classified based on the following aspects,

1. Number of cotyledons (Dicot or monocot) 2. Lifespan 3. Habitat

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1. Classification of weeds based on number of cotyledons

a) Monocotyledons (Monocot) b) Dicotyledons (Dicots)

a) Monocots - are narrow (leaves with parallel venation) leaved weeds. Grasses and sedges belong to this group. Monocots are coming under the family Graminae and Cyperaceae, eg. Cynadon dactylon; Cyperus rotendus.

b) Dicots - are broad leaved weeds and with tow cotyledons and leaf with reticulate venation. eg: Eupatorium odoratum, Lantana camara

2. Classification of weeds based on life span a) Annuals b) Biennials c) Perennials

a) Annuals - They complete their life cycle in a season or in a year. After producing seeds they die. eg. Vernonia cineria, Emilia sonchitolia.

If the life cycle is very short it is called Ephemeral. eg. Phyllanthus niruri. b) Biennials - They have life span of two years or two seasons. In 1st year or 1st season the plant grow vegetatively and the 2nd season they produce more seeds and they die. eg. Wild carrot, chicory. c) Perennials - They live more than two years and they require more than 2 years for completing their life cycle. They are again classified into two based on the herbaceousness of stem. Hard wood perennial and woody perennials. Perennial weeds are again classified into shallow rooted perennials and deep rooted perennials. Shallow rooted perennials - eg. Cynadon dactylon, deep rooted perennials - eg. Lantana camara 3. Classification of weeds based on habitat

1. Dryland (Terrestrial, Upland) 2. Aquatic (Wet land, Low land) 3. Semiaquatic

1. Dryland weeds - All weeds found on the land surface or uplands are called terrestrial weeds. eg: Lantana camara, Eupatorium, Mimosa

2. Wetland weeds - Weeds which are grown in aquatic environment like water or marshy places are called wet land weeds. eg. Salvinia molesta.

3. Semi-aquatic weeds - Weeds which grow in both water and land are called semi aquatic weeds. eg. Cyperus iria, Ludwigia

Common weeds of Kerala

Sl. No Common Name Scientific Name Group Habitat

1. Nut grass Cyperus rotundus Monocot Upland

2. Bermuda grass Cynodon dactylon Monocot Upland

3. Crow foot grass Dactylocteniun aegyptium Monocot Upland

4. Ischaemum Ischaemum indicum Monocot Upland

5. Siam weed Chromolaena odorata Dicot Upland

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6. Sweet brown weed Scoparia dulcis Dicot Upland

7. Phyllanthus Phyllanthus niruri Dicot Upland

8. Indian penny - wort Centella asiatica Dicot Upland

9. Touch-me-not Mimosa pudica Dicot Upland

10. Biophytum Biophytum sensitivum Dicot Upland

11. Vernonia Vernonia cineria Dicot Upland

12. Wild sage Lantana camara Dicot Upland

13. Mile-a-minute Mikania micrantha Dicot Upland

14. Barnyard grass Echinocloa crusgalli Grass Low land

15. Water hyacinth Eichhornia crassipes Dicot Aquatic

16. Salvinia Salvinia molesta Fern Aquatic

17. Ludwigia Ludwigia perrinis Dicot Semi -aquatic

WEED MANAGEMENT The important aspects of weed management are prevention and control. Weed control

methods can be classified in to two, 1. Prophylactic or preventive methods - This is the method adopted to control weeds in an area

before the establishment of weeds. Weed laws prevent transport of contaminated crop seeds. 2. Control or Curative methods - This is the method adopted to control weeds in an area after the

establishment of weeds. Eradication - All the weeds are destroyed in this method. If the weed is extended in a large area it is not economic eradication is important only if the weed is a newly introduced one and spread over only a limited area.

IMPORTANT PREVENTIVE METHODS 1. Use of weed free crop seeds - Some crop seeds may be contaminated with weed seeds.

Before sowing make it sure that the seed lot do not contain any weed seeds. 2. Use of weed free manures - Farmyard manure and cow dung manure may be contaminated

with weed seeds. So as far as possible use only dry cow dung and F.Y.M. after the removal of weed seeds.

3. Use of clean agriculture implements - Sometimes some weed seeds may adhere to agriculture implements. So use only clean implements and remove weed seeds from agriculture implements like plough, spade.

4. Use of irrigation water free from weeds – Some times weed seeds and other plant parts may contaminate the irrigation water. This can be avoided by providing screening devices at diversion point.

5. Take appropriate measures during harvesting, threshing and storing - Care should be taken to avoid contamination of crop seeds during harvesting, threshing, storing etc.

6. Seed certification - As far as possible use only certified seeds for sowing. 7. Legal measures - Quarantine laws to prevent movement of plant parts from one place to

another or one country to another should be enforced to prevent the spread of weed seeds.

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CONTROL METHODS The main control measures with respect to weeds can be divided into four,

1) Mechanical 2) cultural (Cropping and competition method) 3) Biological 4) Legal 5) Chemical 6) Integrated weed management

1. Mechanical method a) Hand Weeding - This is the oldest method of control of weeds. It is done by pulling out of

weeds from field by hand. This is very successful against annual weeds. It is widely practiced in rice fields.

b) Hand hoeing - It is an appropriate method to eliminate weeds between row of crops. Using a hoe weeds are to be removed. It is effective against annuals, biennials and shallow rooted perennials. It also increses soil aeration to a small extent.

c) Digging - It is effective method to control perennial weeds. It helps to remove the underground portion of the weeds from the soil. Digging followed by collection and removal of weeds is commonly practiced. Digging also helps to improve the aeration of soil. It is more effective than hand weeding and hand hoeing.

d) Sickling - It is the removal of aerial parts of weeds by means of sickle. When the top portion of the weed is removed, it will check the seed production. Sickling can be practiced in sloppy area because the root system of weeds is not damaged. So it will not result in soil erosion.

e) Tillage - In this method, using ploughs, cultivators and harrow etc. weeds are incorporated to the soil. Objective is to reduce the weeds. This can be done for annuals, biennials or perennials. But depth of the tillage is according to the crop. Tillage operation is given after sowing but before germination.

f) Burning or flame cultivation - It help to control undesirable weeds on road sides, fallow lands etc. It has an added advantage of control of pest and diseases also. Flame cultivation is a method coming under burning. Flame cultivation meaning selective control of weeds by burning in between rows of crops. This is practiced in cotton in western countries by means of a flame thrower.

g) Flooding - In wet land areas for controlling weeds, flood the field by water and the weeds can be allowed to get decayed. So this has an added advantage of increasing the organic matter content of the soil.

h) Grazing - To allow for grazing by animals like cattle will result in weed control. It can be practiced only in uncultivated area.

i) Mowing - In this method we remove the aerial parts of the weeds to improve the unsightly appearance of weeds. Weeds are got removed from lawns etc. by using the implements called mowers. This is having same effect as Sickling.

2. Cultural methods a) Crop rotation - Growing different crops (belongs to different group) in same field in

rotation is called crop rotation. This help in reduction of weed growth because some weeds are crop specific in nature. This is effective when weeds are associated with a

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certain crop. If we are changing the cultivated crop it will result in the control of such weeds to some extent.

b) Mulching - It means covering the soil with different plant parts. Paddy husk, plant residue, green leaves, thatched coconut leaves or polythene sheets can be used for mulching. These check growth of weeds and there by result in the weed control.

c) Close planting - It means planting crops with close spacing. This will result in the control of weeds because weeds will get only less space, sunlight etc. for their growth.

d) Crop combination - This is the cheapest method of weed control. In areas where there are severe weed problem we are growing certain crops which have the capacity to compete with cultivated crops to some extent. Here the crop seeds germinate and grow and produce some yield. Seeds of such crops have good germinating capacity. Here the crop withstands the weed growth to a greater extent. eg. Calapagonium, cowpea.

e) Minimum tillage or zero tillage - In this method we reduce the tillage operation. It is practiced in light soils which are more erodable and crops like Maize and Sorghum. They remove the weeds by herbicide application and sow the seeds of crops with out any tillage.

f) Inter cropping - Fast growing short duration inter crops reduce weed growth. g) Summer Fallowing - Just give a rough tillage and soil is in a cloddy condition. The soil is

desiccated and dry up. h) Good crop stand - By adjusting time of sowing, depth of sowing etc. we can control the

weed growth. i) Smother Crops - Mimosa invisa, Calapagonium, Centrocema etc can smother weeds,

especially used in rubber plantation. 3. Biological control

In this method natural enemies of the weeds are used to control weeds. Natural enemies like insect pest, predators, pathogens, fishes, plants (competitive plants) etc. can be used for this purpose. These organisms shouldn't be harmful to the cultivated crops.

The natural enemies (oranisms) used for biological control is called bioagent. A bioagent should have certain characteristic for successful control of weeds. They are the following:- 1. Host specificity - The bioagent should be host specific that means it should not attack any crops

and it should feed only on the particular weed which should be controlled. Starvation test is performed to know the host specificity.

2. Easiness in multiplication - The bioagent should be able to multiply in large numbers within a small period. Then only there will be effective weed control.

3. Feeding habit of the insect - The bioagent should be a feeder that means the bioagent should feed the weed plants in large quantities within a small period of time. It should preferably feed on flowers, seeds or bore into the plants rather than attacking leaves.

4. Bio-agent hardiness - The bioagent should be able to survive in new locality. Important achievements

• The first attempt on biological control of weeds was made in Hawaiian Islands in 1920 to control Lantana camara using Crocidosema lantana (moth) and Agromyza lantanae (seed fly)

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• African payal is a serous problem in Kerala. The control of Salvinia by the release of Cyrtobagous salvinia weevil is gaining popularity in Kerala

• Eichornia is another problematic aquatic weed in Kerala. It was biologically controlled by Neochaetina weevils in association with a mite Orthogalumna sp. A fungus named Cercospora is also used for its bio control.

• Another important dry land weed in Kerala is Eupatorium. Experiment using larva of Parachaetus pseudoinsulatus (moth) were found effective against Eupatorium

• Zygogramma bicolorata a fly found effective against the noxious weeds Parthenium.

Sl No Name of weed

Bio control agent

1. Lantana camara Crocidosema lantana (Moth) Agromyza lantanae (seed fly)

2. Salvinia Cyrtobagous salviniae (Weevil)

3. Eichornia Neochaetina (Weevil) Orthogalumna sp (Mite) Cercospora (Fungus)

4. Eupatorium Parachaetus pseudoinsulatus ( larvae of a moth)

5. Parthenium Zygogramma bicolorata (Beetle)

6. Opuntia Cactoblastis cactorum ( larvae of a moth)

Neochaetina Cyrtobagous

Control of Salvinia - It is controlled by a weevil called Cyrtobagus salviniae. In areas where Salvinia is a problem the weevils are released. Even a pair of weevil is sufficient for establishment in an area but generally 50-100 weevils are recommended in an area. If collection of weevil is not possible, 1 kg of infested Salvinia can be used. Weevils are released to tender Salvinia for easy establishment. Within a period of 1-1.5 years complete destruction of Salvinia is obtained. 4. Chemical control

In this method we are using chemicals for controlling weeds. These chemicals are known as weedicides or herbicides. These chemicals kill or inhibit the growth of the weeds. Advantage of chemical control

1. It kills the weed in the near vicinity of the crops, which cannot be controlled by intercultural operations.

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2. It kills weeds which are noxious to man and hence cannot be controlled by manual weeding. 3. It is easy less time consuming and more profitable, more effective and labour saving. 4. Effect of herbicide is longer lasting than physical methods. 5. When spiny weeds are there chemicals are used. For sloppy lands tillage is difficult, since

chances of soil erosion occur. Then herbicides are more useful. 6. Weeds which have mimic nature can only be destroyed herbicides. 7. It is better to use herbicide when hand weeding is impossible due to rainfall. 8. When the labour is not sufficient for hand weeding, then use of herbicide is good.

Disadvantages 1. Farmers should be educated. He should have knowledge about herbicides so that it should

not be misused. 2. Depending on crops, farmer has to stock different herbicides. 3. Residue problem- It is another problem. It may remain for many years. 4. Farmer has to use special applicators and sprayers.

i) Classification of herbicide based on point of application. 1. Soil herbicides 2. Foliar herbicides 3. Aquatic herbicides.

ii) Classification of herbicide based on mode of action 1. Contact / non-systemic 2. Systemic / Translocated

1. Contact herbicides - It does not move beyond the point of contact. Only plant parts which come in contact with the herbicide are killed. The underground roots, rhizomes etc. may not be damaged by the contact or herbicide. Hence these plant parts may regenerate. eg. Paraquat, propanil

2. Systemic herbicides - These herbicides enter a plant and move within the plant and kill the tissues at a distance from the point of entry (application). They enter the plant usually through leaves, stems, root etc. These systemic herbicides are effective in destroying roots of perennial weeds. The systemic herbicides move through the vascular system to the growing point of roots and shoots.

eg: 2,4 –D, Glyphosat, Dalapon iii) Classification of herbicide based on time application

1. Pre-plant herbicides - These are applied to the soil before the crop is planted. Herbicides which are likely to produce a toxic effect on emerging crop seedling can be applied before the crop is planted. These chemicals should be incorporated into the soil before planting. eg : Calcium cynamide

2. Pre-emergent herbicide - These are applied after sowing, but before the actual emergence of the crops or weeds. Eg. Butachlor

3. Post-emergent herbicide - These are chemicals which are applied after the emergence of the weeds. eg. Paraguat, Glyphosate

iv) Classification of herbicide based on selectivity 1. Selective herbicide - They are selective in action and kill plants of only certain species while

plants of all other species survive. eg. 2,4-D (effective on broad leaved plants)

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2. Non-selective herbicide - They are effective against all plant weeds. eg. Paraquat

HERBICIDES Common names Commercial

formulations and concentration

Recommen-ded dose, kg ai/ha

Product per ha

Crops recommended

Hints on time and method of application

a. Selective herbicides 2,4-D sodium salt Fernoxone 80%

WSP 0.8-1.0 1.0-1.2 kg

Rice - for control of broad leaved weeds and sedges

Apply at 20-25 DAS / DAT

Thiobencarb Saturn 50% EC 2 4.01 Rice – dry sown and transplanted

Pre-emergent spray at 0-6 DAS or at 6 DAT

Butachlor Machete 5% G Rice - wet sown and transplanted

Broadcast evenly on soil surface at 7 DAS or at 4-8 DAT

Oxyfluorfen Goal 23.5% EC 0.15 0.641 Rice – dry sown Banana

0-3 DAS Pre-emergent spray

Cyhalofop butyl Clincher 10% EC 0.08 800 ml Rice - for control of Echinochloa sp.

Spray 18-20 DAS

Diuron Klass 80% WP 1.50 -3.00 1.9 -3.8 kg

Banana Pineapple

Pre-emergence spray or directed spray when tank-mix with paraquat

Atrazine Atrazine 50% WP 2.00 4.0 kg Sugarcane Pre-emergence spray at 3 DAP

b. Non–selective herbicides

Paraquat Gramoxone 20% EC 0.4-0.8 2.0-4.01

Rice - land preparation, Plantation crops, pineapple and banana

For clearing weeds before land preparation. Directed application in inter-row areas.

Glyphosate Roundup 41%SL Glycel 41% SL Weed All 41%SL

0.8 2.01 Do Do

Calculation of Weedicides

Quantity of herbicide required = Rate of application in kg ai / ha x Area in ha Strength of commercial product

1. Calculate the quantity of Fernoxone 80% WSP required to control broad leaved weeds in 2 ha of rice field at a recommended rate of 1kg ai/ha

Q = 1x2 x 100 = 2.5 kg 80

COMMON WEEDS FOUND IN RICE FIELDS Grasses

1. Echinocloa colonum - Kavada 2. Oryza rufipogen - wild rice 3. Echinocloa crusgalli - Barn - yard grass.

X 100

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Sedges 1. Cyperus iria - Muthanga 2. Cyperus deformis - Muthanga 3. Fimbristylism mileacea - Mangu

Broad leaved weeds

1. Eichornia crassipes - Kulavazha 2. Monochoria vaginalis

Ferns 1. Salvinia molesta 2. Marsilea quadrifolia 3. Azolla pinnata

Algae

1. Spirogyra spp

WEED MANGEMENT IN RICE FIELDS

Keep rice fields free from weeds up to 45 days either by hand weeding or by use of herbicides. The recommendation for use of herbicides in different systems of rice culture is given below:- A. Dry Seeded rice

Pre-emergent spray of thiobencarb at the rate of 1.5 kg ai/ha or butuchlor 1.25 kg. ai/ha in 300 ltrs of water on the same day of seeding or with in 6 days of seeding effectively control weeds up o panicle initiation stage. Application of pendimethelin at the rate of 1.5 kg. ai/hector as pre-emergent weedicide. Applications on the same day or within 6 days after sowing.

B. Wet seeded rice. (Direct seeding with sprouted seeds under puddles condition)

Bulachlor at the rate of 1.25 kg. ai / ha or thiobencarb at the rate of 1.00 kg. a.i / hactor - is recommended to be applied on 6-9 days after sowing. Then apply 2, 4-D at the rate of 0.5 kg. ai/ha 20 days after planting (sowing).

C. Transplanted rice

Thiobencarb EC - 2 kg. a.i./ha, Pendimethalin granules or E.C. 1.5 kg. a.i. / ha or butachlor 1.25 kg. a.i./ha may be applied on 6th day after transplanting. Where broad leaved weeds are predominant apply 2,4-D at the rate of 1.0 Kg a.i. /ha in 400 litres of water 25 days after transplanting.

Control of Salvinia

Trampling of african payal in situ in the wetlands a week or prior to transplantation will control the weed and add to soil fertility. This method is also effective to prevent vegetative regeneration of Salvinia. For control of Salvinia occuring in channels and other water bodies Paraquate at the rate of 0.75 kg. ai/ha in 500 lts of water may be sprayed. Chemical control measures should be applied only in areas where protected drinking water supply is assured and with caution.

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Unit – 14 PLANT PROTECTION EQUIPMENTS

Effective pest control depends on many factors such as proper selection of the pesticide, its application at the correct dose and at the proper time and the selection of the most efficient equipment for securing a uniform deposit of the pesticide on the target substrate with out any wastage of material in the least time and with minimum labour. Pesticides may be applied as sprays, mists, aerosols, fogs, smokes, vapour, dust or granules. Out of these the important methods are spraying and dusting. Spraying

The spray fluid may be a solution, an emulsion or a suspension of the toxicant. The liquid phase is usually water. However water is not a good carrier for pesticide because of the hydrophobic nature of the target surface. Pesticides may break down by hydrolysis in water and evaporate from the target surface. Making the pesticide particle light and hence drift. The toxicant has to be well distributed in order to achieve effective control of pest. The spray fluid is to be broken down to fine droplets to have a well distribution of the toxicant. The droplet size varies from 30 to 400 micron in different types of sprays. The atomization of the spray fluid under pressure which may be hydraulic or pneumatic, through a nozzle or by emitting a jet of spray-fluid into a high velocity air stream. Spraying can be classified on the basis of volume of the fluid used per unit area.

1. High Volume Spraying (Full Cover Spraying) - In conventional spraying the pesticide is diluted with water and spray droplets are large enough to acquire momentum required to reach the target surface. The large droplets coalesce on the foliage and much of the pesticide accumulates on the edges and tips of leaves or is lost due to runoff. High volume spraying requires 50-1000 1tr / ha of spray fluid in the case of field crops and 1500 - 2000 1tr / ha in the case of orchard crops.

A reduction in the amount of water in the spray fluid or total elimination of water would lower the cost of application. This has lead to L.V and U.L.V sprayings.

2. Low Volume Spraying (Concentrate Spraying) - In this case concentration of the pesticide is 8-25 times than that in the high volume spraying. There is a corresponding reduction in the quantity of spray fluid applied per unit area. The volume of spray fluid ranges from 12 - 125 litres / ha. Droplet size 70 microns - 150 microns.

3. Semi - concentrate spraying (Semi - low volume) - Here the concentration of the pesticide is 2-4 times of that in the H.V. spraying.

4. Ultra Low Volume Spraying (U.L.V Spraying) - The pesticide is applied undiluted in small quantities, usually at the rate of 0.5 litre - 5 litres /ha in a highly concentrated form. (U.L.V concentrate). In concentrated spraying air is the carrier of the toxicant and not water. Droplet size varies from 30-150 microns. The pesticide liquid is fed in to air stream flowing at high velocity. The atomization is more with release in air volume pesticide is atomized into extremely fine droplets. Spray deposits from U.L.V formulations persist longer than that from emulsions. Advantages of ULV Application

1. The reduction in the volume of spray fluid decreases the time spend in traveling to recharge the sprayer, in fetching water, in mixing the pesticide and in filling the spray fluid in the tank.

2. The infested area can be sprayed quickly as compared to the H.V. spraying. In a day of 8 hours 8 hectare can be sprayed in the case of ULV spraying 3 ha in the case of LV spraying

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using motorised knap-sack sprayer. And 0.5 to 1ha in the case of H.V spraying employing manually operated sprayer.

3. The mixing tanks are not needed since the pesticide is directly transferred from the container into the tank of the sprayer.

4. Many hazards while mixing solution, preparing dilutions or transferring from mixing tanks can be eliminated since no mixing is required.

5. Since the use of water as carrier is completely eliminated the ULV spraying holds out of a great promise for use places where the water supply is short.

Sl. No Type of sprayer Volume of Spray

fluid per Ha. Particle size

(Microns) 1 High Volume Sprayers 500-100 lit. 300-500

2 Low Volume Sprayers 50-200 lit 100-300

3 Ultra Low Volume Sprayers < 5 lit. 60-100

4 Controlled Droplet Application (CDA) Sprayers

Formulation like aerosols are use as such

Fogging machine-1-15

Sl. No Type of sprayer Examples

1 High Volume Sprayers Knapsack, Rocker, Hand Sprayers

2 Low Volume Sprayers Power Sprayers

3 Ultra Low Volume Sprayers ULV Sprayers

4 Controlled Droplet Application (CDA) Sprayers Fogging machines, Smoke generators

1. PARTS OF A SPRAYER The important parts of a sprayer are tank, pump, agitator, power source, pressure gauge,

valves, filter, pressure chamber, hose, spray lance, cut-off device, booms and nozzles. 1. Tank - the sprayer may have built-in tank as in the case of knapsack sprayer or there may be a

separate container as in the case of peddle pump for holding the spray fluid. The capacity of tank varies from less than 1 ltr to over 2000 ltr. in large sprayers. The tank should be made of a non corrosive metal or thick polyethylene.

2. Pump - A pump is necessary for the atomization of the spray fluid. Pump is the most vital and expensive component of a sprayer. There are 2 types of pump.

a) Air pump or Pneumatic pump - These are used in compressive sprayers. They force the air in to the air tight spray tank and do not pump the liquid directly. The air compressed in the tank exerts pressure on the spray fluid which is then pushed into the discharge tube.

b) Positive displacement pump - These pumps take in a definite volume of the liquid from the inlet and transfer into the outlet.

3. Agitator - The pesticide formulations are rarely soluble in water. The wettable powders even if thoroughly mixed with water are susceptible to separation and may cause plugging or uneven distribution. Most of the sprayers are provided with agitators for keeping the pesticide uniformly dispersed in the spray fluid.

4. Filter - A strainer made of wire gauze should be fitted beneath the tank filler cap to filter the spray

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fluid as the tank is being filled. Dirt in the fluid may cause abrasion, interfere with the function of valves and may cause blocking of nozzles.

5. Power Source - Petrol engines coupled with the equipment or any separate engine provides power to the power operated sprayers.

6. Pressure gauge - It is fixed on the discharge line to adjust the pressure required for spraying 7. Valves - Are important in a sprayer because they maintain the direction of flow of the spray fluid. 8. Hose - Hose is used to conduct the spray fluid from the spray tank to the lance. 9. Spray lance - It is a detachable brass tube usually 90cm long. The nozzle will be screwed on to its end. 10. Spray cut - off device (trigger) - A device in the lance to shut off the flow of the liquid. 11. Nozzle - It is an important component as it breaks up the liquid released from the equipment into

droplets and spread them as a spray. The size of the droplet varies with the design of the sprayer and of the nozzle. Spray pattern varies with nozzle. Nozzle is attached to the lance or boom. Hollow cone nozzles are used in weed control. Nozzles are different types according to the form of energy used for breaking the spray fluid. There are hydrolic energy nozzles, gaseous energy nozzles, centrifugal energy nozzles etc. Most of the field sprayers rely up on the principle of hydraulic atomization. The nozzle breaks up the stream of liquid and spreads it out into a spray. The hydraulic energy nozzle consists of a small chamber with a device inside it to atomize the liquid before it comes out of the orifice. The components of nozzle are body, Cap, orifice plates, swirl plate and seal and spacers.

12. Booms - A number of nozzles can be arranged in a horizontal tube called the boom or spray bar. It is normally coupled with power sprayers. Booms are used for treating row crops.

TYPE OF SPRAYERS A) Pneumatic Sprayers (Sprayers with air pump)

These are called pneumatic sprayers or compression sprayers because air pressure is employed for forcing the liquid through nozzle for atomization. The tank of these sprayers should not be filled completely with the spray fluid. Usually 3/4 of the tank is filled so that adequate air pressure can be developed over the spray fluid in the tank. They don’t have agitators and hence are not used for spraying materials which settle down quickly.

1. Compression Hand Sprayer - It has a container of 0.5 - 3.5 ltr capacity. The tank is filled to about 3/4

th of it and the pump is worked to force air into the space to build sufficient pressure up on the spray fluid. The air pressure forces the liquid up the outlet and through the nozzle in the form of fine continuous spray.

2. Compression Knapsack Sprayer - These are similar to the compression hand sprayers but are adapted for spraying large quantities of spray fluid. It consists of a tank for holding spray fluid with compressed air, a vertical air pump with handle, a filling hole with a strainer, a spray lance with a nozzle and cut - off device. It is fitted with a plastic skirt that provides a rest with the back of the operator and has shoulder straps for carrying. Used in gardens and farms.

3. Air atomizer (mist blower) - It is a small and simple hand sprayer. It consists of a pump barrel fitted with a plunger which is moved back and forth to produce a blast of air. It works on the principle of air blast breaking up the spray droplets and carrying them to the target. Used for spot treatment and in house hold spraying against flies and mosquitoes.

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a) Hand sprayer: These are the smallest types of sprayers. Used for pest control in houses and small kitchen gardens. They comprise of a tank (1-2 L capacity) and an air pump to develop pressure and are provided with an air check valve at one end a delivery tube connected out side to nozzle through a trigger control valve. The pressure developed by the pump forces the liquid to rise in the delivery tube and then go out through the nozzle the flow being regulated by the trigger control valve.

Parts of Pneumatic hand sprayer

b) Knapsack sprayer: It consist of a strongly built bras cylindrical tank, a vertical air pump passing through the top and tightly fixed to it and a delivery tube with a spray lance. Water is filled to 2/3 rd of the tank capacity and air is pumped into the tank moving the plunger rod up and down inside the pump barrel. Compressed air creates pressure on the surface of the liquid. The liquid moves up the nozzle and get broken up into fine droplets.

1. Piston Handle

2. Trigger

3. Handle

4. Pump Barrel

5. Tank

6. Piston rod

7. Piston

8. Air check valve

9. Delivery tube

10. Spray lance

11. Nozzle

Parts of a Knapsack sprayer

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B) Hydraulic Sprayers

1. Hand Syringe - It consists of a cylinder and a plunger or piston. Spray fluid is contained in a separate tank.

2. Hand Sprayer - It is a small light and compact unit capacity varies from 0.5 - 1 ltr. Used in kitchen gardens.

3. Bucket sprayer - It consists of a brass pump a foot-rest, a hose, a lance and a nozzle. The pump is lowered into the liquid in a bucket and held in position during operation by placing a foot on the rest.

4. Knap-Sack Sprayer - This can be fitted comfortably on the back of the operator like a knap-sack. It has a flat or lean shaped tank with a capacity of 10-30 ltrs, made of galvanised iron, brass, stainless steel or plastic. It is operated by a leaver handle. It is provided with a built- in double barrel pump of the piston type with a leaver for operating it. This sprayer is used for spraying low crops like vegetables, rice etc.

5. Rocker sprayer: It consist of a pump assembly, a rocking lever, pressure chamber, suction hose with a strainer, delivery hose and spray lance with nozzle and a trigger cut off devise. By rocking movement of the lever, pressure will be built in the pressure chamber and this helps to force the liquid to come out through nozzle. There is no tank and the spray liquid is kept in bucket. The rocking movement of the lever causes the piston to move to and fro in the barrel. First few strokes create a vacuum and the liquid is sucked in through the suction hose and build up the required pressure in the pressure chamber. A continuous rocking movement is required to maintain steady pressure. The pressure chamber acts as a reservoir of liquid and gives constant delivery under pressure. It is used for spraying tall trees like coconut, cashew, pepper, mango etc.

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Nozzle

Pump

Spray lance

Lever

Stand

Cut off device

Holder

Parts of a Knapsack sprayer

Tank

Filter hole

Parts of Rocker Sprayer C) Power sprayer: Suitable for spraying large area of field crops. Consists of a spray tank (10-12 l capacity), a two stroke petrol engine, fuel tank, blower assembly, pleated hose, delivery tube etc. The fan in the blower is connected with the two stroke engine. A liquid delivery pipe from the tank provides the liquid at the end of pleated hose. Another hose from the blower is connected to the tank in such a way that a small portion of air enters the tank on the surface of the liquid. This air provides some agitation and creates constant pressure on the top of the liquid pushing the liquid to the end of the hose. The air blast is created by the blower and divides the liquid as micronised droplets.

Power Sprayer

Delivery tube

Tank

Petrol engine

74

Lever

Cutoff device Pump assembly

Suction hose with Strainer

Nozzle

Spray lance

Pressure chamber

Wooden Platform

Hose

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Bucket Sprayer

There are different types with hydraulic pumps and air pump. 1. Stretcher sprayer - The sprayer is fixed on a stretcher type frame with a pair of handles on

each end. 2. Wheel Barrow Sprayers - These sprayers are too heavy to be carried by the operator and

hence are mounted over wheel barrows. 3. Traction Sprayers (Tractor mounted) - It is attached to a tractor as a single unit and is

completely carried on the tractor all the time. The power to operate the pump is obtained from the wheels during traction. Once the wheels stop the power gets cut off.

Sl. No Crops Type of sprayer

1 Potted plants, house hold pest control Hand Sprayers

2 Rice, Vegetables Knap sack sprayer

3 Arecanut, Mango Rocker sprayer

4 Rubber, cashew plantations Aerial Spraying

2. DUSTERS a) Manually Operated Dusters

1. Package duster - It consists of a container provided with a rubber or plastic part which when squeezed with fingers provides a puff of air that eject a quantity of dust. The capacity varies up to 500gm of dust. Plastic bottles similar to ones available for applying toiler power are also used.

2. Bellow dusters - This types of duster has a pair of bellows made of leather, rubber or plastic. The bellow can be worked with a handle just like a black smith does. The dust is placed either in the bellows or in a separate container made of wood, metal or plastic attached to the end of bellows. The air current produced runs through the container and draws the dust out through the opening.

3. Rotary – dusters - They are also called crank dusters and fan type dusters. They vary considerably in design and may be shoulder, mounted back, or belly mounted. Basically a rotary duster consists of a blower complete with gear box and a hopper with a capacity of about 4 – 5 kg of dust. The duster is operated by rotating a crank and the motion is transmitted though the gear to the blower. Generally an agitator is connected to one of the gears. An adjustable feeding mechanism is also provided. The air current produced by the blower draws the dust from the hopper and discharges out through the delivery tube which may have one or two nozzles.

Rotary Duster

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Bellow Duster

b) Power duster: Operating principle is similar to that of power sprayer, the only difference

being the delivery tube is replaced with a dust outlet pipe.

Maintenance of plant protection equipments

Points to be taken care while handling plant protection equipments

1. Follow the instructions of manufacturers for maintenance of equipment.

2. Clean the equipments properly and store in a dry place.

3. Drain the tank of a sprayer and flush it with clean water, wash the pump, nozzles, strainers,

lances, hoses, etc, with clean water.

4. Empty the hopper and clean with a cloth in case of dusters.

5. Replace the worn out parts, grease and oil the moving parts, eg. Cylinder, piston, plungers,

washers, valves, etc. when not in use.

6. Do not bend rubber hoses at angles

7. At end of season clean sprayer thoroughly, drain all water from engine, pump and tank,

disconnect hose and run lubricating oil through pump. Drain oil from engine and pump and

replace with new oil.

8. Do not through the nozzles and delivery tubes of dusters on bare ground

9. Always keep sufficient stocks of spare parts and tool kits

10. Drain the spray solution to avoid clogging of nozzle

Power Duster

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Field problems and remedies for plant protection equipments 1. Knapsack sprayer

Sl. No Problem Rectification 1 Nozzle block • Follow procedure for cleaning blocked nozzles

2 Pressure drops quickly • Check that the filler cap or lid gasket is in good

condition and the cap is properly secured. • Ensure that all connections and washes are proper.

3 Trigger cut- off valve is leaking • Dismantle the trigger cut off valve and check the ring washer. If damaged replace.

2. Rocker Sprayer

Sl. No Problem Rectification

1 No spray • Nozzle block, follow procedure for cleaning blocked nozzles

2 Suction do not result • If suction valve stuck, clear it

3 Leakage through plunger rod • Either piston worn out or it is loose. Check the piston if it is loose lighten the screw

4 Liquid not entering in to the delivery tube • Delivery valve gets stuck clear it.

3. Dusters

Sl. No Problem Rectification

1 Dust not coming out • Check whether the hopper is empty • Check whether the valve is open

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Unit – 15 COMPATIBILITY OF PLANT PROTECTION CHEMICALS & FERTILIZERS

In the plant protection schedule, very often it becomes necessary to combine the application of different agrochemicals such as fungicides, insecticides, herbicides and fertilizers. In doing so, we can save the cost of labour and time too.

Compatibility – it is the ability where different plant protection chemicals and fertilizers when mixed together will not react with each other and not lose their individual properties.

Two agro chemical are said to be compatible if their mixing together for combined application will not result in chemical reaction leading to loss of their individual pesticidal properties or physical properties or their mixing will not result in formation of other phytotoxic compounds. Compatible chemicals can be mixed together and combined spraying can be done. Two or more insecticides, fungicides or herbicides can be mixed together and can be sprayed if they are compatible. So in this combined spraying farmer can save labour charges and save time also. Before mixing the chemicals we must know the compatibility of selected chemicals.

Different types of fertilizers are also mixed together and applied. Some times fertilizer may be mixed with herbicides or pesticides. In this case also only compatible fertilizers should be mixed together. Mixing incompatible fertilizers result in loss of nutrients in the form of gases or convert soluble nutrients in to insoluble one or induces caking,

2,4–D is a herbicide which is compatible with Quinalphos(Ekalux), Phosphamidon, and

Dimethoate (Rogor). So theses can be mixed and applied if a joint application of herbicide and insecticide is warranted. 2,4–D can be mixed with urea and applied in rice. Bordeaux mixture is not compatible with most of the most of the insecticides and fungicides. But it is compatible with urea, Quinalphos, 2,4-D and wettable sulphur.

In the case of mixing fertilizers for combined application, never mix nitrogenous fertilizers and organic manures with lime. Lime should be applied first, only after 2-4 weeks organic manures like cowdung or compost or other nitrogenous fertilizers may be applied.

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Compatibility chart for combination sprays

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Brodeaux mixture 1 N Q N C N N N N N N N C N N N N N N Q N C C N Q C C C C C

Captan 2 N Q C C Q Q C C C Q C C C Q N Q C C C C Q C C C N C C C Copper fixed 3 Q Q N C C C C C C N C Q C N C C C C C C C C C C N C C Carbaryl 4 N C N C C C C N N C C C C N C C C C C C C C C N C C Carbophenothion 5 C C C C C C C C C N C C Q C Q C C C C C C C C C Demeton 6 N Q C C C C C Q Q C C C C N C C C C C C C C C N C Demeton-methyl 7 N Q C C C C C C Q C C C C N C C C C C C C C C N C Dicofol 8 N C C C C C C C C C C C C C N C C C C C C N C C N C Dichlorvos 9 N C C N C C C C C C C C C C N C C C C C C C C C N C Dicrotophos group 10 N C C N C C C C C C C C C C N C C C C C C C C C N C

Dinocap 11 N Q N C N Q C C C C C Q C C N Q C C C C C C C Dimethoate 12 N C C C C C Q C C C C C C C N C Q C C C C C C N C Dithiocarbamates 13 C C Q C C C C C C C Q C C C N C C C C C C C C C C N C Endosulfan 14 N C Q C C C C C C C C C N C C C C C C C C Q Fenitrothion 15 N Q C C C C C C C C C C C C N C C C C C C C C C N C Lime sulphur 16 N N N N Q N N N N N N N N N N N N N Q N C C N N C C C Malathion group 17 N Q C C C C C C C C Q C C C C N C C C C C C C C N C C Q Oxydemeton methyl 18 N C C C C C C C C C C C C N C C C C C C

Phosphamidon 19 N C C C C C C C C C C Q C C C N C C Q C C C C Phosalone 20 Q C C C C C C C C C C C C C C Q C C Q Q C C C Q Pyrethrine 21 N C C C C C C C C C C C C C C N C C C Q C C N N N Quinalphos 22 C C C Sulphur wettable 23 C Q C C C C C C C C C C C C C C C C C C C C C C C C Streptomycin 24 N C C C C C C N C C C C C C C C C C C C Toxaphene 25 Q C C C C C C C C C C C Q C C N C C C C C C C C N C Urea 26 C C C C C C C C C C C C N C N C C C C Zinc sulphate + lime 27 C N C N C N N N N N N N N C N N C N C C

2,4-D 28 C C N C C C C C C C C C C Q C N C C C C Lead arsenate 29 C C C C C C C Dinitro compounds 30 C C C Q C Q C Q C C

C = Compatible, N = Not compatible and Q = Questionable. Compatibility may vary with solvents or emulsifying agents used

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VOCATIONAL HIGHER SECONDARY EDUCATION

Model Examination

AGRICULTURE (PLANT PROTECTION – II)

(For Continuous Evaluation and Grading Scheme)

VHSE II Total score: 80

Register No:………………….. Time: Time : 2¾ hrs

Instructions:

1. Read questions carefully before answering

2. Maximum time allowed is 2 hours, 45 minutes including cool off time.

3. First 15 minutes is cool off time during which you should not answer the questions. This time is meant for reading the questions carefully.

4. Answer all the questions

1. Choose correct answer from the following (1)

A pest which causes 13% damage can be included in which class?

(Minor Pest, Non-insect Pest, Sporadic pest, Major pest)

2. Find the odd one out and justify your answer? (1)

(Nicotine, Pyrethrin, Thuricide, Azadiractin, Rotenone)

3. Find the missing pair (2)

a) Carbofuran : Systemic poison , Carbaryl : ……………….. b) Beetles: ……………, Flies : maggots

4. Suggest the best formulation suitable for the following situations and justify your answer (2)

a. To protect natural enemies.

b. Water available in plenty.

5. Using the relationship given find out the missing ones (4)

Beetles Biting and chewing

1) Honey bees ……………………

2) …..………… Sponging type

3) Thrips ……………………

4) …..………… Siphoning type

6. Write whether the following statements are true or false. Justify your answers. (3)

a) Bucket sprayer is an example for pneumatic sprayer.

b) Bordeaux mixture is used for the control of rice blast disease

c) In a rice field, frog feeds on insect pests. This is an example for biological control.

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7. Drying of inflorescence and die back of shoots are observed in cashew trees of your plantation.

identify the pest and suggest suitable control measures. (3)

8. Mention the name of plant protection method involved in each of the following (4)

a) Trap Cropping

b) Pheromone Traps

c) Covering of bitter gourd fruits with paper bags

d) Trichogramma egg cards

9. A farmer cultivating coconut approaches you with immature nuts showing triangular yellowish

patches below the perianth region and asks for your help. As an agricultural student identify the

pest, its nature of damage and suggest suitable control measures. (3)

10. Match the following (4)

A B C a) Eight legs Insects House rats b) Six legs Nematodes Red spider mite c) Four legs Arachnids Parrot d) No legs Rodents Beetles

Birds Slugs Root knot

11. A pond in your locality is heavily infested with Salvinia. Analyse the suitability of the different

management methods you have studied. (3)

12. Complete the following (3)

Crop Symptom of attack Pest Rice Hopper Burn ………………… Coconut …………………… Red palm weevil Pepper Hollow berries …………………. Mango ………………….. Fruit flies Brinjal ………………….. Shoot and fruit borer Banana Holes on psuedostem ………………….

13. On the eve of environmental day you are invited to school to present a talk on pest out breaks

and its major reasons. As an agricultural assistant prepare a short write up for the talk. (3)

14. Recent studies reveal that bacterial leaf blight is a serious problem in paddy growing areas.

Suggest a method to find out the infection caused by bacteria in field condition. List out

important steps to control the disease. (3)

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15. Classify the following diseases based on the casual organism? (4)

(Blast of Rice, Bunchy top of Banana, Quick wilt of Pepper, Mahali of Arecanut ,

Katte disease of Cardamom, Little leaf of Brinjal, Bud rot of Coconut, Cassava Mosaic)

Fungal Diseases Bacterial Diseases Viral Diseases Mycoplasmal Diseases 1……… 2………

16. A farmer in your locality is complaining about high labour cost for application of plant

protection chemicals and fertilizers. As an agricultural student advise him a method to reduce

the cost of application of these chemicals and discuss its merits and problems. (3)

17. A farmer complaints about storage pest incidence in his farm house storing paddy. Your teacher

asked you to prepare an investigatory project regarding the incidence. Prepare a write up

including possible pests that may cause damage to the stored paddy and precautions to be taken

to avoid such incidence in future. (4)

18. Identify the sprayer given below and name the parts indicated. (4)

19. A farmer asked your help to Calculate the Quantity of Quinalphose 25EC required to spray

vegetables cultivated in an area of 175 cents at a concentration of 0.05% using high volume

spray @ 500lts/Ha. As an agricultural student help the farmer to calculate the quantity of

chemical. (4)

20 A farmer approaches you for the effective management of rice stem borer. As an agricultural

assistant suggest the IPM methods for the control of rice stem borer. (5)

1

2

4

6

5 3

121

21. Complete the following diagram and write a paper article on ‘Metamorphosis in insects’. (5)

a) b)

22. In an agro-clinic seminar conducted by Krishibhavan you are asked to present a class on plant

diseases. Discuss about the essential condition required for the development of disease

(epidemic) and importance of disease forecasting to minimize losses caused by pathogens. (6)

23. You are posted as an assistant manager in agricultural firm manufacturing insecticides. The

firm is planning to produce a new insecticide with highly toxic chemical for field application.

Prepare a label for the product and prepare a leaflet showing precautions to be taken while

handling pesticides. (6)

Answers Qn. No

Scoring Indicators

Score details

Total score

1 Major pest 1 1 2 Thuricide, it’s a biopesticide 1 1

3 a) Contact b) Grubs

1 1

2

4 a) Granules b) EC,WP Similar ones

1 1 2

5

1) Chewing &lapping 2) Diptera 3) Rasping &sucking 4) Lepidoptera

1 1 1 1

4

6 a) False, its hydraulic sprayer b) No, BM is phytotoxic in rice c) False, its natural control

1/2 + 1/2 1/2 + 1/2 1/2 + 1/2

3

7

Tea mosquito bug, Field surveillance, removal off egg masses,

spraying of chemicals at flushing, flowering and seed set

1 1 1

3

8 a) Cultural Control b) Modern method c) Mechanical

1 1 1

4

?

?

Bug

?

122

d) Biological 1

9

Attack of coconut eriophyid mite Use of neemoil garlic emulsion Use of dicofol as chemical method Similar points

1 1 1 3

10

Eight legs- mite –red spider mite Six legs- insects – rice stem borer Four legs- rodents – house rats No legs-nematodes – root knot

1 1 1 1

4

11 Mechanical – trampling, composting Biological - Cyrtobagous Chemical - Paraquat

1 1 1

3

12

1) BPH 2) Brown ooze from stem, holes 3) Pollu beetle 4) Decayed fruits, maggots inside 5) Holes on fruits, wilting of stem 6) Psuedostem weeevil

1/2 1/2 1/2 1/2 1/2 1/2

3

13

Uncontrolled growth of insects in a short period Deforestation Intensive agriculture Mutation Resurgence Similar points any four

1 1/2 1/2 1/2 1/2

3

14

1. Ooze test 2. Cow dung supernatant 3. Use of bleaching powder 4. Similar points

1 1 1 3

15

1. Blast of rice- fungus 2. Bunchy top – virus 3. Quikwilt – fungus 4. Mahali – Fungus 5. Katte – virus 6. Little leaf- mycoplasma/MLO 7. Bud rot of coconut- Fungus 8. CMV- virus

1/2 1/2 1/2 1/2 1/2 1/2 1/2 1/2

4

16

• Mixing and use of two compatible chemicals • Time and labour saving reduction in cost of

cultivation • Phototoxic effects is incompatible mixed

1 1 1

3

17

Rice weevil 1/2

4

Rice moths 1/2 Large grain borer 1/2 Angumoise grain moth 1/2

Management Sanitation

1/2

Storage yard should be insect proof 1/2 Proper drying 1/2 Fumigation with chemicals Similar points

1/2

18 Rocker sprayer 1 4

1 Nozzle 1/2

123

2 Spray lance 1/2 3 Cutoff device 1/2 4 Pressure chamber 1/2 5 Pump assembly 1/2 6 Suction hose with strainer 1/2

19

Quantity = Qty of spray fluid X Concentration -------------------------------------------- Conc. Of formulation

1 4

Calculation 1 Answer- 700ml 1 Unit 1

20

IPM for Rice stem borer IPM concept with diagram Cultural –Resistant variety IR-20 Mechanical – Egg mass removal Biological – Tricho cards Modern – Pheremon traps Legal – enforcement of law Chemical – carbaryl Similar points

2

1/2 1/2 1/2 1/2 1/2 1/2

5

21

a) 1 larva/Caterpillar 2 Pupa b) Nymph Ametabola – silver fish details Incomplete metamorphosis -details with example Complete metamorphosis- details with examples

1/2 1/2 1/2 1/2 1 2

5

22

Factors Host related

1

6

Pathogen Related 1 Weather factores 1 Time related 1/2 Humen activities 1/2 Disease forecasting and Prophylactic steps will prevent the spread of diseases with examples Drizzle with cloudy condition – late blight of potato

2

23

Label Symbol – Yellow colour- warning statement-1, Poison, Name of Chemical, Formulation similar points, pictures etc

3

6

Precautions Reading label before application 1/2 Storing in original container 1/2 Washing after application 1/2 Protective clothing 1/2 Avoid drinking and smoking while appln. 1/2 Regular medical check ups 1/2 Similar points any six

124