Training module for seed treatment - lavsodisha.orglavsodisha.org/downloads/training_module/Seed_Treatment.pdf · The Role of Seed Treatment: Diseases and pests affecting crops can

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.