Insect, Mite and Nematode Pests of Forest Species and Plant Protection Methods in

Practice

ByGROUP NO:04

M.I Izzadeen PGIA/2015/042M.M.C.B Ehelamalpe PGIA/2015/182

PP 5260 Advances in Plant Protection Methods for Plantation Crops and Forest Species

Environmental, Ecological and Agronomic Conditions Required

Environmental conditions Temperature- Insects are cold-blooded

organisms( Ectothermic ).The temperature of their bodies is approximately the same as that of the environment. Therefore, temperature is probably the single most important environmental factor influencing insect behavior, distribution, development, survival, and reproduction.

Soil- A crop plant to resist or tolerate pests is tied to optimal physical, chemical and biological properties of soils. High nitrogen levels can enhance the incidence of stimulate outbreaks of Homopteran insects such as aphids and leafhoppers.

Humidity- Problems with nematode infestations are especially frequent in wet climates. Certain pathogenic species of lesion nematodes-effective pathogens in colder regions.

Ecological conditions

Monoculture- monocultures possess the necessary ecological conditions for out breaking pest populations.

Absence of Natural enemies. Poor/weak cultivars. Reduction of diversity. Lack of natural habitat for Natural enemies.

Agronomic conditions

Plant Population- Plant population per unit area influence crop microclimate. Dense population restricts wind movement within plant canopy leading to high humidity build up. This creates congenial condition for pest multiplication.

High Yielding Crop cultivars can provide improved conditions for pest colonization, spread and rapid growth.

Intensification- reduction of intervals between plantings of the same crop, or overlap of crops, which provides a continuous resource to pests.

Fertilization with high ‘N ‘contents. Use of low resistant Cultivar to pests. Pesticide usage -indirectly effect to Reduction of natural

enemies . Lack of rules ,regulations and standards for Imported seeds,

fertilizer, equipments Which imported with pests.

Insects pests1. Stem Borer (Zeuzera coffeae)2. Gold dust weevil (Hypomeces squamosus)3. Termite (Macrotermes natalensis)4. Southern Pine beetle (Dendroctonus

frontalis)5. Redheaded sawfly (Neodiprion lecontei)6. Grasshopper (Zonocerus elegans)7. Mole Cricket (Gryllotalpa africana)8. Longhorn Beetle (Phoracantha semipunctata)9. Snout Beetle (Gonipterus scutellatus)10. Emperor moth (Imbrasia cytherea)

Redheaded sawfly (Neodiprion lecontei)

DistributionNumerous sawfly species are found in North America. The redheaded pine sawfly is native to the United States and found primarily east of the Great Plains (Wilson 1978), north into Canada, and south into Florida.

HostsYoung, open-growing pine trees, under 4.6 m (15 ft) tall, are especially vulnerable. Although hard pines are preferred, larvae will feed on a variety of pine, cedar, and fir species if preferred food sources are exhausted.

Damage causedlarvae are gregarious feeders, capable of completely stripping small pine trees of foliage. Younger larvae eat the outer edges of pine needles leaving behind the central tissue, which wilts and dies, forming what looks like dried straw. Older larvae eat the entire needle, and complete defoliation occurs.

Control Biological Control.

◦ Natural enemies are numerous (58 different species are recorded) and disease, viruses, and predators regularly control populations.

◦ Larvae are also susceptible to harsh weather conditions such as extreme heat and cold.

Cultural/Mechanical Control. ◦ For small scale control, larvae can be mechanically or physically

removed. Hand picking can be an effective form of control for the homeowner and can be conducted by striking the branch sharply causing the larvae to fall off. The falling larvae can be caught with a bucket of soapy water held underneath the branch.

Chemical Control. ◦ Horticultural soaps and oils are effective for larval control, but the

application should target young larvae. ◦ Sprays may be ineffective on a small scale, as the insecticide may not

penetrate deep into the foliage and therefore not eliminate a majority of larvae.

◦ For commercial applications, young larvae should be targeted by more forceful spraying to thoroughly penetrate foliage. Spraying is only necessary if larval populations are reaching damaging thresholds.

Snout Beetle (Gonipterus scutellatus)Distribution

◦ native to Australia, now in S.Africa, S.America, Europe, S.E Asia

Species affected:◦ Most eucalyptus species mainly E. smithii, E.

dunnii,E. maideni and E. viminalis.

Damage caused◦ Adult beetles and the larvae feed on young leaves

(Photo 14.8), which may result in severe stunting or even death of the tree during long periods of heavy infestations.

Larval damage of eucalypt leaf

Adult beetle

Snout beetle larva with typical long black excrement filament.

Control: biological control –

In areas below 1,200m biological control is maintained by the introduced egg parasitoid, Anaphes nitens.

Chemical Control- No insecticides are registered against this pest.

biological control - Anaphes nitens lays its eggs in the eggs of the eucalyptus snout beetle.

Species affected:The main trees affected are Pinus patula and Pinus radiata.

Damage caused:The caterpillars feed on the foliage of pine trees and large populations may completely defoliate the trees.

Control:The use of the biological insecticide Bacillus thuringiensis var. kurstaki is recommended.

Emperor moth (Imbrasia cytherea)

Caterpillar of the pine emperor moth. Emperor moth

Damage

Longhorn Beetle (Phoracantha semipunctata)

Species affected:All commercially grown eucalyptus spp.

Distribution: native of Australia, now spread Africa, Asia, America

Damage caused:Trees that are dead, dying or under stress from drought, fire or poor site conditions are attacked and ring barked by the larvae. The larvae initially feed on the cambium and phloem layers, but later bore into the xylem as well. As they feed and tunnel they leave tightly packed frass behind in tunnels that indent into both the inner side of the bark and the outer side of the timber.

Control:To avoid high beetle populations it is advised not to leave any dead or felled timber with bark on for any length of time. Remove the breeding sites and remove the pest.

Adult Longhorn beetle.

Damage

Termite (Macrotermes natalensis)

These well-known and easily recognised small white subterranean ant-like insects are indigenous to South Africa. Most damage is caused by Macrotermes natalensis. Distribution Most of the countries in the world.

Species affected:E. grandis and E. fraxinoides are most susceptible, with E. nitens, E. paniculata and E. camaldulensis being moderately susceptible and E. smithii, E. macarthurii, E. dunnii and E. fastigata being the most tolerant species.

Damage caused:Roots are eaten away to form a point below the root collar (Photo 14.4), or the plant is ring-barked.

Roots eaten away to form a point below the root collar in seedlings.

Control:Before establishing trees in Field , the presence of

termites should be established and if necessary a drenching of Chlordane 60% EC (1ml mixed with 1-2ℓ water per plant) should be applied at planting. Alternatively, during planting 10g of Carbosulfan 10% CG per plant can be mixed with the soil around the root plug.

On Stem

Grasshopper (Zonocerus elegans)

There are many species of these easily recognised jumping and flying insects. One of the more common grasshopper pests is the elegant grasshopper, Zonocerus elegans.

Species affected:All commercially planted Eucalyptus, Acacia and Pinus

spp.

Damage caused:By stripping off seedling bark at lower levels and

feeding on the underlying tissue, grasshoppers can cause serious damage and can even chew through thin stems and branches. Both adult and young hoppers cause damage. Being diurnal, grasshoppers are easily spotted.

Control:As there are several insecticides registered for the control of grasshoppers (Carbaryl 85% WP).

Grasshopper (Zonocerus elegans)

Mite pests

1. Spider Mite (Oligonychus coniferarum)2. Ash Flower Gall Mite (Aceria fraxiniflora)3. Maple bladdergall mite (Vasates

quadripedes)4. Pearleaf Blister Mite (Eriophyes pyri)5. Maple spindlegall mite (Vasatesaceris-

crummena)6. Crimson erineum mite (Eriophyes regulus)

Spider Mite (Oligonychus coniferarum)

The spider mites are the primary mite pests in forest nurseries.

Species affected:Pine, hemlock, spruce, juniper, fir, and white-

cedar are often heavily attacked.

Damage caused:Heavy infestations of spider mites cause

reduced seedling growth, along with foliage yellowing or browning ,Although most spider mite attacks do not cause seedling mortality, they may predispose trees to attack by insects and fungi or to damage by adverse environmental conditions.

Washed-out appearance of conifer needles infested with spider mites.

Webbing made by spider mites on infested plant.

Adult spider mite.

Control

Biological -Release lady beetles or encourage their propagation by reducing the use of insecticides and establishing a variety of plants in nursery borders. Predatory mites, an anthrocorid bug, and predaceous thrips also afford some natural biological control of spider mites.

lady beetles

Cultural - During the growing season spray the foliage with water under pressure to dislodge mites and eggs. Proper irrigation will also stimulate seedling growth and reduce mite damage.Use a variety of tree species in windbreaks. Avoid planting host species such as pine adjacent to windbreaks of the same species.

Chemical - Dicofol or an equivalent, such as propargite, demeton, or oxydemeton-methyl, can be applied. Use a hydraulic sprayer to wet the entire plant.Spider mites can tolerate most insecticides. Most miticides do not kill spider mite eggs.

Anthrocorid bug

Ash Flower Gall Mite (Aceria fraxiniflora)

Species affected:Ash species

Damage caused:Feeding on male flowers by ASH FLOWER GALL MITES causes irregularly-branched, gall-like growths to form. These aborted male flowers may turn black and persist through winter.

Control:Although the galls caused by these mites detract from the appearance of ornamental trees, infestations do little actual damage to their health. Control measures are not usually necessary.

Ash Flower Gall Mite

Ash Flower Galls

Maple bladdergall mite (Vasates quadripedes)

Species affected:silver and red maples

Damage caused:adults feed on developing buds.

Control:hough these mites and midge cause galls that may be aesthetically undesirable, they are not a serious threat to the host tree. Handpicking infested leaves, which tend to be most common on lower branches, can help reduce populations. Systemic insecticides can be applied in spring or early summer to kill mites.

Nematodes pests

1. root-knot nematodes (Meloidogyne spp)

2. pine cystoid nematodes (Meloidodera spp)

3. lance nematodes (Hoplolaimus spp)4. lesion nematodes (Pratylenchus spp)5. stunt nematodes (Tylenchorhynchus

spp)6. stubby-root nematodes (Trichodorus

spp)7. dagger nematodes (Xiphinema spp)

Nematodes and their Host

Distribution◦ Plant-parasitic nematodes occur in forest

nurseries. ◦ Cool temperatures are unfavorable to most

species. ◦ Certain pathogenic species of lesion

nematodes-effective pathogens in colder regions-are rarely found in southern nurseries in the world.

Damage

◦Nematodes seldom kill seedlings outright.

◦Severely debilitate the plant through partial destruction of the root system.

◦ Wounds caused by nematode attack may serve as points of entrance for root pathogens.

◦The resulting disease complex may then cause significant mortality.

Symptoms

◦ Nematode diseases ordinarily cannot be diagnosed solely by their symptoms.

◦ Poorly functioning root system.◦ Diseased seedlings are stunted and their foliage is

reduced in size and becomes chlorotic◦ Root-knot nematodes may cause galls on the roots

and, roots near the galls.◦ Dagger nematodes cause galls and bending of lateral

roots.◦ lance nematode- damaging cortical tissue and causes

extensive internal cell destruction.◦ Stunt, stubby-root, and dagger nematodes cause

discoloration and surface lesions.

(a) Acacia- Root galls caused by Meloidogyne sp (b) Ficus -Root galls caused by Meloidogyne sp (c) Leaf chlorosis and necrosis -caused by Subanguina chilensis,(d) Wilting of needles of pine tree -caused by Bursaphelenchus xylophilus

Diseased seedlings are stunted and their foliage is reduced in size and becomes chlorotic

Pine seedling on right was severely stunted by nematode attacks.

Control

Cultural - Crop rotation controls certain nematodes. In the rotation sequence, favor crops that are not susceptible.

Chemical - Fumigate the soil before seeding to control nematodes in forest nurseries. Methyl bromide is one of the most effective soil fumigants and provides excellent control in most nurseries.

Dip roots of infected hardwoods in chemical solutions to control root-knot nematodes. A 15-minute dip in fensulfothion. Immersing bare roots in hot water at 126 0F for 2 minutes has controlled lesion nematodes infecting.

Integrated Pest Management

Defined as the harmonious use of multiple tactics to control pests to a tolerable level

Knowledge and understanding the life history and mating habits of the pest is essential.

IPM Methods◦ Pest free planting◦ Crop rotation◦ Physical barriers◦ Natural predators◦ Trapping◦ Genetically modified plants◦ Chemical control

Monitoring

Mapping with GIS

Chemical Spraying also a Challenge..

Pheromones Traps

Pheromones -Highly volatile, unstable chemicals used by insects for communications.

Over 100 commercially available for use in IPMs There are two types of pheromones (sex and aggregation) Sex - These are wide spread, well documented and are

designed to increase the probability of successful mating. Well known in the order Lepidoptera (moths and butterflies)

Aggregation - Found in a number of insects. Most common is order Coleoptera (beetles). Used for mate selection, finding hosts and for defense

How will climate change affect pests

Physiological changes in the host plant,

Direct effects on the development and survival of the pests and pathogens,

Indirectly through impacts on natural enemies, competitors and vectors, and

Enhancing the suitability of our climate for non-native pests and pathogens.

Future challenges in Pest management

Release of control organisms could attack non-targeted species

Genetically modified genes can poison non-targeted insects

Surface and groundwater can be contaminated (pesticides)

Harmful residues may remain on the plants (pesticides)Loss of resistance and effectiveness may occurTreated foods may pose health risks (genetically

modified or treated with insecticides)Genes may transfer to other plants with negative

effects (genetically modified)Release of natural predators could attack other plants

and animals creating more problems.

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