Remove the cotton crop and dispose of crop residues as soon as harvest is over; avoid stacking stalks in the field. Avoid ratoon and double cotton crops, and follow proper crop rotation. Grow one variety throughout the village as far as possible, and complete sowing in the village within 10–15 days. Avoid other malvaceous crops near cotton. Hand-pick and destroy egg masses, visible larvae and affected or dropped squares, flowers and bolls, and squash pink bollworm in rosette flowers. Intercropping with cowpea, green gram, black gram, soybean or maize reduces bollworm and sucking pests and supports natural enemies such as spiders and lady bird beetles.
Pending expert review
Source
Crop Production Guide – Agriculture 2020 (Directorate of Agriculture, Tamil Nadu & Tamil Nadu Agricultural University (TNAU)), Cotton – Pest management (general), pp. 271–272
Region
Tamil Nadu
Last updated
2026-11-04
Monitoring with traps
Use light traps (modified Robinson type, 125 W mercury lamp) to follow insect populations. Set up species-specific sex pheromone traps at 12 per hectare for pink bollworm, tobacco cutworm (Spodoptera litura) and American bollworm. Apply insecticides only where absolutely necessary, when the pest population or damage reaches the threshold level.
Economic threshold levels given for cotton: thrips – 50 nymphs or adults per 50 leaves; aphids – 15% of plants infested; leafhopper – 50 nymphs or adults per 50 leaves; mite – 10 per cm² of leaf; spotted and spiny bollworms – 10% of shoots, squares or bolls infested; pink bollworm – 10% of fruiting parts infested; Helicoverpa (American bollworm) – one egg or one larva per plant; whiteflies – 5–10 per leaf; stem weevil – 10% infestation; tobacco cutworm – 8 egg masses per 100 m row.
Pending expert review
Source
Crop Production Guide – Agriculture 2020 (Directorate of Agriculture, Tamil Nadu & Tamil Nadu Agricultural University (TNAU)), Cotton – Economic threshold levels, p. 272
Region
Tamil Nadu
Last updated
2026-11-04
Chemical pesticides: ask before you spray
The source lists many insecticides and fungicides for cotton pests and diseases. Many are hazardous, and some may be restricted. Choose a product only with your local Agriculture Officer, and spray only after the pest crosses the threshold level.
Follow the instructions on the product label. Consult your local Agriculture Officer before use.
Pending expert review
Source
Crop Production Guide – Agriculture 2020 (Directorate of Agriculture, Tamil Nadu & Tamil Nadu Agricultural University (TNAU)), Cotton – Pest & disease management, pp. 271–275
