Integrated Management Strategies For American Bollworm In Cotton Crops

Are you concerned about the impact of American bollworm on your valuable cotton crops? Uncover vital information and proven strategies to combat this persistent pest by exploring the insights provided in this article!  

Helicoverpa armigera, commonly known as the American bollworm, poses a significant challenge to agricultural productivity particularly in the cultivation of cotton crops. It is one of the destructive pests in agriculture. This voracious insect pest is notorious for its wide range of host plants and ability to cause substantial yield losses if left unmanaged. In cotton, their population normally peaks during boll development stage, which results in high yield loss.  

Type of Infestation

American bollworm infests the cotton crop by feeding on all parts of the plant and leading to reduced yield.  

Scientific Name: Helicoverpa armigera 

Most Affected States

Helicoverpa armigera is found throughout the country, but the most affected states are Andhra Pradesh, Maharashtra, Karnataka, Gujarat and Tamil Nadu. 

Symptoms of American Bollworm in Cotton

• The larva of American bollworm feeds on all parts of plants including leaves, squares, flowers and small bolls.
• In the early stage, larva feeds on the tender leaves.
• Whereas in the later stage, they feed on the internal content of squares or bolls by thrusting their head inside while leaving the rest of the body outside.
• The presence of bore holes with frass material excreted by larva can be seen on the infested bolls.
• As a result of damage, the affected squares and bolls fall off from the plants.

Control Measures

A combination of different control measures is often required to effectively manage American bollworm infestations in cotton crops. The following are some common IPM practices used to control American bollworms.  

Cultural Measures

• Cultivate Helicoverpa resistant cotton varieties like L1245, LD135, Sujata, LK861 and Abadhita etc.
• Deep summer ploughing exposes the hibernating insects to the sun and predatory birds.
• Avoid the practice of repeatedly cultivating cotton in the same area during both winter and summer seasons.
• Grow intercrops like greengram, blackgram, soyabean, castor, sorghum etc., with cotton to reduce the bollworm infestation.
• Erect bird perches to encourage predatory birds.
• Proper nutrition management, including balanced fertilization and irrigation can also help to reduce the susceptibility of cotton plants to American bollworm attacks.

Physical Measures

• Light Traps play a major role in trapping adult American bollworm insects. Install Farmoguard Solar Light Trap in the fields at the rate of one per acre.

Mechanical Measures

• Hand picking and destroying the caterpillar is an effective way to reduce American bollworm population.
• Remove and destroy the crop residues to prevent the carry-over of pests to the next season.
• Tapas Helico Cotton Bollworm Lure can be used to attract and trap American bollworm. Install Funnel Trap with Helic-O-Lure at the rate of 6 per acre for effective trapping.

Biological Measures

• Encourage bio control agents like an egg parasitoid, Trichogramma sp., at 2.5cc per acre at 15 days interval 3 times from 45 days after sowing.
• We can also release an egg larval parasitoid Chelonus blackburnii and the predator Chrysoperla to keep the American bollworm population in check.
• Vedagna Nobor Bio Insecticide is a combination of biological inputs containing natural plant extracts which imparts resistance against American bollworm. The recommended dosage is 2.5-3 ml per liter of water.
• Delfin Bio Insecticide contains Bacillus thuringiensis var kurstaki which when sprayed at the rate of 1 gm per liter of water can effectively control Helicoverpa in cotton.
• Farmroot HeraNPV is a viral insecticide based on Polyhedral Occluded Bodies of Nuclear Polyhedrosis Virus of Helicoverpa armigera. When sprayed, caterpillars get infected by virus and eventually die. For better results, spray HeraNPV at 0.5 to 1 ml per liter of water in the early morning or late evening hours.

Chemical Measures

In case of severe infestation, chemical management may be necessary. Some of the commercial chemicals used for controlling American bollworms are mentioned in the table below, 

Product Name	Technical Content	Dosage
Delegate insecticide	Spinetoram 11.7% SC	0.9 – 1 ml/lit water
Plethora Insecticide	Novaluron 5.25% + Indoxacarb 4.5% SC	2 ml/lit water
Rimon Insecticide	Novaluron 10 % EC	2 ml/lit water
Fluton Insecticide	Flubendiamide 20% WG	0.5 gm/lit water
Vesticor Insecticide	Chlorantraniliprole 18.5 % SC	0.3 ml/lit water
Coragen Insecticide
Tracer Insecticide	Spinosad 44.03% SC	0.3-0.4 ml/lit of water
Cigna Insecticide	Lufenuron 5.4 % EC	2 ml/lit water
Starclaim Insecticide	Emamectin benzoate 5% SG	0.5 gm/lit water