Management of Sap-Sucking Insects and Pink Bollworms in Cotton Crops

Cotton crops are primarily affected by sap-sucking insects such as aphids, jassids, and thrips during the initial growth period. Bollworm infestations typically begin in dry-season cotton crops from the second week of July, with other bollworms emerging by the last week of July, and pink bollworms appearing in the first week of August. The pink bollworm infestation manifests as caterpillars in August. All these pests can significantly damage the cotton crop, but early management can greatly reduce their impact. The following measures are recommended for effective pest control:

Integrated Pest Management (IPM)

Management of Sap-Sucking Insects:

1. Seed Treatment: Bt cotton seeds are usually treated with insecticides such as imidacloprid or thiamethoxam. This provides protection against sap-sucking insects for 2 to 3 weeks, so no additional insecticide spraying is needed during this period.
2. Crop Hygiene: Infested branches, leaves, and other plant debris should be regularly collected and destroyed along with the insects.
3. Monitoring: Approximately 8 to 10 days after germination, place 25 yellow sticky traps per hectare to monitor whitefly infestations regularly.
4. Intercropping: Intercropping cowpeas with cotton can attract natural enemies of cotton pests, such as bollworms, which feed on the cowpea crop.
5. Weed Management: Keeping the crop weed-free through timely intercropping will eliminate alternative food sources for insects. Additionally, alternative host plants like flax and okra should be removed.
6. Fertilization: Fertilizer application should be based on soil tests to avoid excessive growth, which can make the crop dense and more susceptible to pests.
7. Natural Predators: If natural predators of sap-sucking insects, such as lady beetles, lacewings, or parasitic wasps, are present in sufficient numbers, avoid using chemical pesticides.
8. Field Survey: Regularly survey the cotton crop for sap-sucking insects. If the average number exceeds thresholds (e.g., 10 mites per leaf, 2-3 caterpillars per leaf, or 10 aphids per leaf), chemical control may be necessary. Use insecticides such as Buprofezin 25% (20 ml), Fipronil 5% (30 ml), or Imidacloprid 17.8% (2.5 ml) mixed with 10 liters of water for spraying.

Management of Pink Bollworm:

1. Pheromone Traps: Begin using pheromone traps 40 to 45 days after crop emergence. Place traps at least one foot above the crop to disperse the pheromones effectively. Install two traps per acre or five traps per hectare. If 8 to 10 moths are caught in these traps for three consecutive days, take measures for pink bollworm management. Additionally, install 15 to 20 pheromone traps per hectare for mass trapping.
2. Odor Traps: Place 15 to 20 odor traps at each cotton collection center and ginning factory weekly to capture moths.
3. Caterpillar Control: Regularly inspect the crop for caterpillars and destroy them to prevent future generations.
4. Neem Extract Spray: After 35 to 40 days of crop emergence, spray with 5% neem seed extract or azadirachtin 3000 ppm (40 ml per 10 liters of water) every fortnight.
5. Parasitic Insect Release: After 55 to 60 days of crop emergence, release Trichogramma toidiabacterium or Trichogramma chilonis parasitic insect cards (1.5 lakh eggs per hectare) four times at intervals of 12 to 15 days.
6. Weekly Inspection: Select 20 representative trees per acre and count the number of flowers, leaves, and bolls on each. Determine the percentage of infestation by pink bollworm, and if more than 5% is infested, apply chemical insecticides. Recommended insecticides include Profenophos 50% (30 ml), Chlorantraniliprole 18.5% SC (3 ml), Thiodicarb 75% (20 g), Fipronil 5% SC (30 ml), or Lambda-cyhalothrin 5% EC (12 ml), mixed with 10 liters of water.