biological agents for pest control

Biological Agents For Pest Control: Crop Pest Control With insects


Biological pest control, also known as biopesticides, is the use of living organisms or natural substances to control pests. These agents are an alternative to traditional chemical pesticides, which can be harmful to the environment and non-target species. Biological pest control agents are derived from plants, microbes, or animals and work to control pests by disrupting their reproductive or digestive systems, acting as predators or parasites, or by other means. They are often preferred over chemical pesticides because they are more environmentally friendly and safer for humans and animals. In this blog, we will explore the various types of biological agents for pest control and how they are used to control pests in agriculture, forestry, and urban environments.

What is The Biological Agent?

There are some pests that feed on the eggs and larvae of other insects. And these insects are not harmful to normal crops. Rather, harmful insects that live by eating the leaves and stems of crops act as biological control agents by consuming the eggs and larvae. Many species of insects lay their eggs in the eggs or larvae of harmful insects. After the eggs hatch, the chicks grow by eating the eggs or larvae. Such insects are called bioagents.

Trichogramma Wasp: biological agents for pest control

Trichogramma Wasp.

Appropriate timing and routine of field release of biological agents for pest control should be known beforehand, otherwise, the desired pest control will not be achieved. Biological agents should be released immediately after the first sighting of harmful insects in the crop field. It must be remembered that it is wrong to expect immediate results in pest control with biological agents like pesticides. Moreover, biological agents will not work if the pest infestation is widespread. Moreover, it is important to know the number of biological agents released per acre of land.

Two biological agents are discussed below:

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Trichogramma Wasp: Biological Agents For Pest Control

Chilonis of Trichogramma Wasp: biological agents for pest control

Chilonis of Trichogramma Wasp. Image: Collected

The Trichogramma wasp is a small insect with small fringed wings belonging to the family Trichogrammatidae. A wasp that belongs to the Lepidoptera family (butterflies and moths) eats the eggs of enemy insects. Some species of these insects are parasites of water beetles, water bugs, and other insect eggs. Insects of this species can swim with their fins to find the eggs of host insects. In some cases, a particular species of Trichogramma wasp reproduce on different host species, and depending on hormones and other substances, their body color changes and other characteristics can be produced or changed.

The Trichogramma wasp lives inlays and grows within host insect eggs, preventing the host insect from hatching into larvae. Wasps hatch after 7 to 10 days in the host insect’s eggs. They are tiny insects, usually less than 1 millimeter long.

1 gram of host insect eggs contains about 50 thousand Trichogramma parasites, which can be used on 1 hectare of land.

Trichogramma Attack on Caterpillars

Trichogramma Attack on Caterpillars. Image: Collected.

The eggs of brinjal tip and fruit borers are uncoated, allowing Trichogramma wasps to easily parasitize them. From the beginning of the attack to the last harvest, this bolt should be removed after 10 to 15 days.

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Methods of Trichogramma Abolition: 

Things to pay special attention to for Trichogramma eradication:

    • Crop fields should be checked regularly for pest emergence. 
    • Parasitic Trichogramma eradication should be started as soon as eggs are seen on leaves/stems/flowers/buds/fruit buds or navels. 
    • In the case of brinjal, the process of removing the parasitic worm should be continued as per the rules throughout the season of attack of tip and fruit borers. 
    • Generally, it is best to deworm from 8 am to 10 am or 4.30 pm to 6 pm in the fall. Parasitized eggs or freshly hatched Trichogramma are transported to the field in vials. 
    • Old newspaper or other paper is usually cut into 6-7 cm squares and filled with 1 fold in the middle. Just like chocolate or candy paper is folded. A beam 22 cm long usually holds 120 to 130 pieces of paper. 
    • After placing 120 to 130 folded pieces of paper in a vessel 22 cm high or holding 3 liters of water, 1 gram of Trichogramma is released. Once the mature Trichogramma has entered the paper fold, it should be placed on the crop plant. 
    • In the case of brinjal, in the beginning, leaving 2 lines from the aisle, enter through a corner of the field. Then after 5-6 steps, a folded piece of paper should be placed in the fold of the tree branch. Before the end of the line, take a turn and skip 2 lines and walk along the line again. 
    • In this way, Trichogramma should be released in the whole land with the same rule. If Trichogramma is placed on the strip or card, then when it is finished, each strip card should be embedded in the groove of the leaves or branches of the tree or hung in the jungle (loft) from which more Trichogramma can come out and cause parasitism.

Braconid Wasp: Biological Agents For Pest Control

Braconid wasp

Braconid wasp.

Braconid is a parasitic insect belonging to the Braconidae family. This medium-sized wasp can parasitize many insect pests. Both males and females can be winged or wingless. Their abdomen is hairless or sparsely hairy. Pests A single worm caterpillar (caterpillar) can have many caterpillars. The pupa grows in the white, yellow-colored silk cocoon of the worm’s body. Some species of enemy insects live within the caterpillars and pupae.

Bracken worm is a very invasive ectoparasites. The female braconid first injects poison into the body of the host insect worm, paralyzing the worm. A female Braconid can parasitize 500 to 1,000 host insect worms. Parasitized worms become weak and can no longer survive. The female bracken lays eggs on the parasitized worm and then feeds and grows inside the worm’s body. As a result, the insect is destroyed.

biological agents for pest control

Attack of Braconid Wasp on Harmful insect Larvae

Adults of this species are kept in glass/plastic containers/exercises and supplied to the field through this. This Baiyam is called Banker. A bunker can hold 800 to 1,000 live adult bracken. Male and female insects should be released in a ratio of 60:40 in the bunker or in the field. Full-grown bracken should be released 5-6 times at 10 to 15 days intervals in a cropping season.


Braconid Release Method in The Field: 

In the case of brinjal, from the beginning of the attack of the tip and fruit borer insects, the full-grown insects should be removed after 10 to 15 days from the beginning of the attack to the final harvest. Things to pay special attention to when weaning adult bracken:

    1. The emergence of brinjal tip and fruit borer or national crop fly should be confirmed through regular surveys. 
    2. Parasitic braconid should be removed as soon as host insect larvae are seen in the tip or fruit and the procedure of parasitic braconid should be continued as per rules throughout the season of attack. 
    3. Generally, it is best to exterminate the parasite between 8 am and 10 am or 4.30 pm and 6 pm in the fall. Parasitized eggs or newly hatched broilers are transported to the field in crates or bankers. 
    4. Typically a 22cm tank or bunker holds 800 to 1,000 full-grown bracken. At the beginning of the release of this insect, after leaving 2 lines from the side of the aisle and going in through one of the fields, after going 5-6 steps, open the lid of the mouth of the bunker a little and take out a few brackets. In this way, if you finish in one line, skip 2 lines or 6-7 steps and walk straight again in the next line and leave the insect after 5-6 steps. 
    5. In this way, the whole land should be freed from the area of ​​the banker after the braconid is cleared. The next day, when the adult bracken hatches, it should be released again and this process should be continued until the bracken hatches. 
    6. Finally, the strips/cards should be tied to the branches of trees or bushes so that later more bracken can emerge and parasitize.

Artificial Feeding of Trichogramma And Braconid: 

If it is impossible to release Trichogramma and Braconid in the field due to strong sun or heavy rain, honey or sugar syrup should be provided for them. A small piece of clean cotton soaked in honey or sweet syrup or syrup should be placed on the mouth cloth of the vial or bunker. Care should be taken that honey or syrup does not drip or drip into the vials or bunkers and in any way prevent ant infestation. Once the cotton piece is dry, it should be soaked again with honey or syrup. Trichogramma and braconid wamps should not be released during hot sun or rain. If for some reason they cannot be released, they should be kept in such a way that the ants cannot catch them. For this, a water container can be placed under the table or the foot of the stool. Vials should be stored in a well-ventilated area.

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