training module for seed treatment -...
TRANSCRIPT
2014
TRAINING MODULE FOR SEED TREATMENT Seed treatments provide protection to seeds and plants and improve the establishment of healthy crops.
Training on Seed management & treatment
Learning methods: Group discussion and field experimentation
Materials required: Marker pen, flip chart, note books, pen
Time allocation: 360 minutes
Session plan
Day Topic Duration Methodology
Day - Importance of seed treatment
in modern day agriculture
90 minutes Power point presentation
Day- Evaluation of Seed Treatment
and Integrated Pest
Management
90 minutes Power point presentation
& group discussion
Day- Seed Treatments methods &
techniques
90 minutes Power point presentation
Day- Advantages & precautions in
seed treatments
90 minutes Power point presentation
Seed Treatment
Seed treatments, in broad terms, are the application of
Biological,
Physical
Chemical agents
and techniques to seed that provide protection to seeds and plants and improve
the establishment of healthy crops. This brochure deals with the application of
chemical agents.
The Role of Seed Treatment:
Diseases and pests affecting crops can have devastating consequences in
agricultural and horticultural production if not properly managed.
Breeding is an excellent tool to build resistances against pests and diseases in the
plants.
However, breeding alone does not address all of the agronomic challenges,
therefore crop protection products are often needed and used for good crop
management.
These crop protection products can be applied during the growth of the crop but
can also be added to the seed as a seed treatment.
Seed treatments have played and are still playing a significant role in the history
of mankind, in staving off hunger and starvation by improving the establishment
of healthy crops
Today’s Modern Seed Treatments
Modern seed treatment products offer control of target pests and diseases and ensure
the establishment of healthy and vigorous plants. Their formulation and industrial
application also contribute to improvement in growers’ and workers’ safety and
stewardship of the environment.
Good Seed Treatment Practice
The seed industry and seed treatment applicators use an array of quality management
systems to optimise the application process. These quality systems define the treatment
process, handling of treated seed, worker protection, environmental stewardship and
provide the information required to facilitate the safe and legal treatment of seed and
the disposal of treated seed. Seed treatment requires adequate standards and good
application methods. These should be agreed upon between the involved parties on a
case-by-case basis to insure producer, applicator, seed and environmental safety in the
most cost efficient manner.
Evolution of Seed Treatments
Some of the first recorded seed treatments are the use of sap from onion (Allium spp)
and extract of cypress in the Egyptian and Roman periods. Salt water treatments have
been used since the mid-1600s and the first copper products were introduced in the
mid-1700s. Other key milestones were the introduction of arsenic, used from 1740
until 1808 and the introduction of mercury, used from 1915 until 1982. Until the
1960s seed treatments had been only surface disinfectants and protectants. The first
systemic fungicide product was launched in 1968. This systemic fungicide had not only
seed surface activity but also moved into the plants protecting the young seedlings from
airborne pathogens. Since the 1990s the crop protection and seed industries have
developed and adopted new classes of fungicide, insecticide, and nematicide chemistry,
expanding pest control while reducing user and environmental impact. The seed and
seed treatments industries have a long history of partnership and dedication in
providing growers with high quality seed. Today the seed must be as pest- and disease-
free as possible and the treatment must provide protection against pests and diseases
during germination, emergence and growth of the plant
Seed Treatment and Integrated Pest Management
The FAO International Code of Conduct on the Distribution and Use of Pesticides
(Revised version) adopted in 2002 defines Integrated Pest Management (IPM) as
meaning “the careful consideration of all available pest control techniques and
subsequent integration of appropriate measures that discourage the development of
pest populations and keep pesticides and other interventions to levels that are
economically justified and reduce or minimise risks to human health and the
environment. IPM emphasises the growth of a healthy crop with the least possible
disruption to agro-ecosystems and encourages natural pest control mechanisms”. Seed
treatments can be used as a primary tool in a successful Integrated Pest Management
Program for sustainable agriculture since they target the pests and diseases with
smaller amounts of active ingredients per hectare and are not introduced into the
atmosphere. In many cases, without the use of seed treatment, growers would have
great difficulty in controlling certain seed-borne and early season seedling pests and
diseases and would have to resort to more expensive and less environment-friendly
methods.
Reduced Active Ingredient Loading into the Environment –
Seed treatment is sometimes the only delivery route for the control of certain
seed-borne pathogens.
Seed treatment can also deliver high levels of efficacy for the control of early
season pests and diseases at a much reduced usage rate compared to many
foliar or soil applied alternatives.
Using a seed treatment reduces the area in contact with a crop protection
product from 10,000 m for foliar application or 500 m for furrow application to
only 50 m.
As an example, for an insecticide in corn, at a plant rate of 100,000 seeds per ha,
the application rate is also reduced from 1,350 g active ingredient per hectare
(ai/ha) for foliar application or 600 g ai/ ha for furrow application to 50 g ai/ha
for a seed treatment.
This reduced active ingredient loading minimises the impact on the environment
significantly by decreasing the effect on non-target organisms and the movement
of the product in the environment.
How Seed Treatments are Applied
Seed treatment is a term that describes both products and processes.
Processes range from basic dressing to coating and pelleting.
In all cases, the basis of good application techniques is to deliver the product to
the seed at the correct dose and as uniformly as possible from seed to seed.
Seed Dressing: The most common method of seed treatment.
The seed is either dressed with a dry formulation or wet treated with a slurry or
liquid formulation.
Dressings are applied both on-farm or in specialised seed treatment facilities.
Seed Coating: A special binder is used with a formulation to enhance adherence to the
seed and begin to impact seed size and shape.
Coatings require advanced treatment application technology.
Seed Pelleting: The most sophisticated seed treatment technology,
resulting in changing the physical shape of a seed to enhance plantability and
handling.
Pelleting requires specialised application machinery and techniques and is the
most expensive of the applications.
PURPOSES OF SEED TREATMENT
Control of Seed borne Pathogens Seed borne, disease-causing pathogens may occur on
the surface of seed, hidden in cracks or crevices of seed, or as infections deep inside the
intact seed. These pathogens may be
important for three reasons. First, some
pathogens do not survive in soil or crop
residue and are dependent on the seed borne
phase for survival between crops. An
example is the fungus that causes loose smut
of wheat. Second, even if a pathogen can
survive in soil or residue, being seed borne may allow it to get a head start and, thus,
result in more severe disease. An example would be the fungus that causes Septoria leaf
blotch of wheat. Third, seed borne pathogens may hitch a ride to new localities in seed
shipments (such as the fungus that causes Karnal bunt of wheat or the bacterium that
causes black rot of crucifers).
Seed treatments can often be used to control pathogens that occur on or in the seed. The
choice of seed treatment may be dictated by whether the pathogen is borne externally
or internally. For example, both systemic and no systemic (contact) fungicides can
eliminate surface contamination of wheat seed by spores of the common bunt fungus.
However, the fungus causing loose smut of wheat is borne within the seed embryo and
cannot be controlled with a contact fungicide. In that case, a systemic fungicide is
required to control the internal pathogen.
Protection of Seeds and Seedlings
Seeds and seedlings are vulnerable to many soil borne and foliar pests. Insects and
pathogens can destroy germinating seeds and young plants, which are relatively tender
and lack food reserves to recover from injuries or to survive extended periods of stress.
Examples of stress include heavy rains, crusted soils, compactions, deep planting, cool
soil, very dry soils, and some post emergence herbicides. Under stressful conditions, a
number of aggressive or even fairly weak pathogens can become active and cause plant
population and yield losses. Seed treatments can protect the seed and seedling from
attack by certain insects and pathogens. No systemic fungicides or insecticides form a
chemical barrier over the surface of the germinating seed. This barrier protects the
germinating seed from chewing insects, such as wireworms, or soil borne pathogens,
such as pythium. Certain systemic seed treatments can protect aboveground parts from
sucking insects, such as aphids, or foliage diseases, such as rust. Systemic fungicides and
biological seed treatments can also protect young plants from root rot. Although the
duration of protection may be limited, a delay in infection can reduce the losses. For
chronic diseases, such as root rots, the earlier that the infection takes place, the greater
will be the damage. Typically, seed treatments will last only about 10 to 14 days beyond
planting, with pesticide breakdown being most rapid under warm, moist conditions.
However, certain active ingredients can protect seedlings considerably longer when
applied at the highest labelled rate.
Alternatives or Supplements to Seed Treatment
Usually, seed treatments are not the only
available method to control a particular
pest.
Seed treatments should be compared to
alternative pest control measures for
cost, efficacy, safety, and so on.
Often, no single pest control method
provides sufficient control.
Seed treatments can often be supplemented with other control measures to
achieve satisfactory results.
Certified seed.
Certified seed is checked for the presence of certain seed borne diseases.
Therefore, treatments for seed borne pathogens may be unnecessary with
certified seed. Crop rotation.
Crop rotation reduces the populations of many insects and pathogens that
survive in soil or crop residue.
Seed treatments may be less necessary where crop rotation is practiced.
Fertility management.
Lack of micronutrients, such as chloride, and an excess of major nutrients, such as
nitrogen, can favor certain diseases. Maintaining appropriate soil fertility can reduce
disease pressure. Heat treatment. Hot water treatment can be used to rid seeds of
certain seedborne pathogens while leaving the seed viable. For example, the fungi that
cause black leg, downy mildew, and anthracnose of cabbage can be eradicated by
soaking seed at 122°F for 25 minutes.
This treatment will also eliminate the
bacteria that cause black rot.
Immediately after treatment, seed
must be cooled in cold water for
several minutes. Then seed must be
dried. Procedures must be carefully followed. If the water is too cool, the seedborne
pathogens will not be killed. If the water is too warm, the seed may be injured or killed.
Because it is difficult and impractical for some seed types, hot water treatment has
limited use.
Advantages of Seed Treatment
ï Seed borne pathogens are vulnerable. The seedborne phase is often the weak link in
the life cycle for many plant pathogens. Using seed treatments to control seedborne
pathogens is often very effective for disease control.
ï Precision targeting. Seed treatments are not subject to spray drift. Because chemicals
are applied directly to seeds, little is wasted on no target sites, such as bare soil.
ï Optimum timing. Seeds and seedlings are generally more vulnerable to diseases and
insects than mature plants. Applying treatments to seeds allows pesticides to be present
when needed most.
ï Low dose. Relatively small amounts of pesticides are used in seed treatments
compared to broadcast sprays. This reduces the cost and the potential environmental
impact. It also reduces the probability of chemical residues in harvested grain.
ï Easy to apply. Seed treatments are relatively easy and cheap to apply compared to
broadcast sprays.
Disadvantages of Seed Treatments
ï Accidental poisoning. Treated seed looks like food to some animals. Hungry livestock
Birds, such as pheasants or quail, may consume spilled treated seed. Even young
children may find and eat improperly stored treated seed.
ï Cropping restrictions. Just like other pesticides, some seed treatments may have
significant grazing or rotation crop restrictions.
ï Limited dose capacity. The amount of pesticide that can be applied is limited by how
much will actually stick to the seed. Seed coating technologies are helping to overcome
this limitation, but phytotoxicity may still be a problem.
ï Limited duration of protection. The duration of protection is often short due to the
relatively small amount of chemical applied to the seed, dilution of the chemical as the
plant grows, and breakdown of the chemical.
ï Limited shelf life of treated seed. Producing excess treated seed is undesirable
because the shelf life of treated seed may be limited. Surplus treated seed cannot be sold
for grain. This is a particularly serious limitation for seeds such as soybean, where seed
germination and vigor decline relatively quickly.
ï Phytotoxicity. Pesticide injury to plant tissues is called phytotoxicity. Since seed
treatments must exist in high concentrations on the tender tissues of germinating seeds
and seedlings, they generally have very low phytotoxicity. A few seed treatments are
partly phototoxic when applied at high rates. Lower germination and/or stunting may
occur if application rates are not carefully controlled. Cracked, sprouted, and scuffed
seeds may be particularly susceptible to toxic effects. A few seed treatments may reduce
the length of the sprout and, therefore, affect the choice of planting depth.
ï Worker exposure. In the course of treating and handling large volumes of seed,
workers may be exposed to seed treatment chemicals as aerosols. Inhalation of aerosols
and skin contact with seed treatments must be prevented in the seed treatment process.
SEED TREATMENT TECHNIQUES FOR PADDY
Seed Treatment for Improved Germination
Dry seeds in bright sun light (between 12.00 • p.m. to 1.00 p.m.) for half an hour
before sowing to improve the germination and seedling vigour.
Soak the paddy seeds along with a gunny bag in water for 12 hours and then
soak in biogas slurry for 12 hours before sowing.
Soak paddy seeds in Panchagavya (35 ml per litre of water) for 30 hours before
sowing.
Soak paddy seeds tied in khada cloth in sweet flag extract (500 gms of sweet flag
rhizome powder in 2.5 litres of water) for 30 minutes and shade dry before
sowing.
Soaking the seeds in cow dung extract enhances the germination capacity. Take
½ kg of fresh cow dung and 2 litres of cow’s urine and dilute with 5 litres of
water.
Soak 10 - 15 kg of seeds that are previously soaked in water for 10 - 12 hours, in
this cow dung extract for 5 - 6 hours.
Dry the seeds in shade before sowing in the nursery.
Fill the paddy seeds in a closely-knit bamboo basket lined with Salvadora persica
leaves at the bottom and pour about 10 to 12 litres of water over the basket.
Cover the basket with Salvadora leaves and place a weight over it.
Leave the setup undisturbed for 24 hours before sowing. This will help in early
and vigorous germination.
Mix biofertilizers like Azospirillum / Phosphobacteria / Pseudomonas (@ 1.25
kg / 60 – 70 kg of seeds) in one litre of cooled rice gruel and mix it with sprouted
seeds and shade dry for 30 minutes before sowing. Seed Treatment for Healthy
Seedlings Take the paddy seeds in a tightly closed gunny bag and soak it in the
biogas slurry for 24 hours before sowing to get green and healthy seedlings with
well developed root system. These seedlings will get established well soon after
the transplantation.
Collect cow’s urine in a mud pot and keep it for 48 hours. Soak paddy seeds in
10% of this cow’s urine (100 ml cow’s urine in 1 litre of water) before sowing for
healthy crop. Seeds should be shade dried for half an hour before sowing.
Mix Vi tex, Tulsi and Pongam leaves extract (pound 3 kgs of each leaves and
extract) with fresh cow dung solution and soak 25 kg of paddy seeds tied in a
gunny bag in this solution for 12 hours.
Seeds should be shade dried for half an hour before sowing. This will produce
healthy and disease resistant seedlings.
Seed Treatment for the Prevention of Pest and Disease Attack-
Soak seeds in water for 12 hours and then mix it with 10% cow’s urine (10 ml
cow’s urine + 90 ml water) or 5% prosophis kashaayam (5 ml kashaayam +
95 ml water) and dry it for 30 minutes.
Use the seeds for sowing within 24 hours. This will enhance the resistance of
the paddy against bacterial leaf blight disease.
Soak paddy seeds tied into small bundles using kada cloth in cow’s urine
solution (500 ml of cow’s urine with 2.5 litres of water) for 30 minutes and
shade dry before sowing.
This method of seed treatment prevents the crop from seed borne fungal and
bacterial diseases.
Soak paddy seeds in 20% mint (Mentha sativa) leaf extract (200 ml of leaf
extract mixed with 800 ml of water) for 12 hours before sowing.
This will increase the germination rate and vigour of seedlings. This will also
help in the control of Helminthosporium leaf spot disease in paddy.
Soak the sprouted seeds of paddy tied in small bags in sweet flag solution
(500 gms of sweet flag rhizome powder in 2.5 litres of water) for 30 minutes
and shade dry before sowing.
This will improve the resistance of the seedlings against Seed borne bacterial
and fungal diseases.
Seed Treatment for Protection and Nutrition •
Mix paddy seeds with cow dung before sowing. The cow dung covering the seeds will
protect them from birds and other insects in the nursery and also acts as manure for
seeds. This practice increases the drought resistance and acts as a seed hardening
measure. It is generally preferred for dry land paddy cultivation.