Fruits and vegetables are attacked by several pests and diseases from harvesting to storage. Amongst different strategies present for the control of disease and pests here we are going to discuss the best way to control which is to use Biological control agents (BCAs).
What is biocontrol:
Biocontrol or biological control method means using biological organisms to control pests and diseases in plants. Few organisms have the ability to control pests in crops by eating the pests or by infecting them.
How to use a biocontrol agent:
- Sticky traps: Sticky traps are cards and traps which contain BCAs (Trichogramma wasp, Praying mantis) on them. It is installed in fields at different locations, it contains sticky glue-like substances that help trap the disease-causing organism, and BCAs help to kill them.
- Soil treatment: Some commercially prepared bio-control agents come in powder form which can be mixed with the soil used for growing vegetables and fruits. The ideal quantity used for soil treatment may be 5% of the total media (if we are using 1kg of soil for planting then, 50gm of powder will be sufficient).
- Seed treatment: Inoculants of BCAs are available in markets which can be applied on the seeds before planting. 200 gms of inoculants is mixed with 200ml of jaggery solution. Required amount of seed is dipped into the slurry (jaggery solution with BCAs inoculants) and mixed evenly then dried in the shade for 30 minutes. The treated seed should be used within 24 hrs. 200g of inoculants is sufficient for 10 kgs of the seed.
- Foliar application: Commercially prepared bio-control agents come in both powder and liquid forms which are mixed with water and then sprayed directly on the standing crops (just like we apply pesticides or herbicides).
- Direct release: Some biocontrol agents (mainly adult wasps and insects eg.Trichogramma wasp, praying mantis, ladybugs etc) are released directly into the fields and allowed to attack the pests.
Merits of Biocontrol Agents
(1) Biological control is cheaper than any other method.
(2) Biocontrol agents give protection to the crop till they are harvested.
(3) They do not cause toxicity to the plants.
(4) Application of biocontrol agents is safer to the environment and to the person who applies them.
(5) They do not interfere with the natural growth of fruits and vegetables.
(6) They multiply easily in the soil and leave no residual problem.
(7) Biocontrol agents not only control the disease but also enhance the root and plant growth by way of encouraging the beneficial soil microflora (micro organisms which helps in nutrient uptake).
(8) Biocontrol agents can be combined with bio-fertilizers.
(9) They can be used in Integrated Pest management and Organic farming as well.
(10) Leaching of harmful substances to ground water does not happen when we use BCAs.
Bio control agents available in markets:
|BCAs||Used in crops||Disease/pests controlled|
|Trichogramma wasp||Almost all vegetables are attacked by Lepidoptera (caterpillars)||Caterpillars|
|Trichoderma virens||Ornamental plants, Vegetables, Fruits (citrus)||Root rot (Pythium, rhizoctonia)|
|Trichoderma harzianum||Tomato, cucurbits(pumpkin, bitter gourd, cucumbers, ivy gourd,watermelon, etc) leafy vegetables, flowers, Cole crops (cauliflowers, cabbage) tuber crops (potato, sugar beets) fruits (Citrus,pine, pomegranate,fig , litchi)||Fusarium (wilt, crown rot, head blight, scab) Pythium, (root rot) rhizoctonia (root rot, collar rot, damping off)|
|Trichoderma viride||Tomato, cucurbits(pumpkin, bitter gourd, cucumbers, ivy gourd, watermelon, etc) leafy vegetables, flowers, Cole crops(cauliflowers, cabbage) tuber crops (potato, sugar beets) fruits (pomegranate, fig, guava, citrus, etc)||Root rot,|
Green mould in citrus
|Beauveria bassiana||Tomato||damping-off (Rhizoctonia)|
|Pseudomonas spp||Vegetables(Okra, Tomato, chilly, brinjal, leafy vegetables, etc ) fruits(Pomegranate, guava, apple, fig, mulberry, papaya, strawberry, etc)||Soil born fungal pathogens|
|Bacillus spp||Vegetables(Approx all vegetables) and fruits||Soil born fungal pathogens|
|Verticillium lecanii||Potato, Cucurbits||Aphid|
|Baculoviridae (virus)||Mostly all vegetables and fruits|
Tobacco , cotton
|Caterpillars , bugs, sucking pastes|
Use of biocontrol agents in kitchen gardens:
Biocontrol agents are easy to apply and can be used in our kitchen gardens effectively. Vegetables like tomato, chilly and leafy vegetables in our kitchen gardens are prone to aphids, sucking pests, and caterpillars which can be easily controlled by using natural enemies (biocontrol Agents) like ladybugs, Trichogramma, entomopathogenic fungus(fungi which cause disease in insects), etc. Commercially prepared BCAs are easily available in markets at very affordable prices with user guides.
Use of biocontrol agents in hydroponics:
Hydroponics is a method of growing crops without soil. Control of pathogens and growing disease-free crops is of prime importance in hydroponics. The use of biocontrol agents is also applicable to soil-less plant culture. Pseudomonas and Bacillus are found to be highly effective for the control of pathogens (eg: Rhizoctonia, Fusarium, Pythium, etc.) in hydroponics. Especially in case of hydroponically grown tomatoes.
Biological control agents are highly useful for the control of pests and diseases in fruits and vegetables and are eco friendly with no toxic effects like chemicals used for the control of pests. It gives us healthy and tasty vegetables without any health hazards. BCAs require a longer time to show effects which is the only problem associated with them.
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