Cotton: controlling sucking pests and pink bollworm

Cotton losses in Maharashtra come mainly from sucking pests in the first 60 days and from pink bollworm later in the season. The key is to monitor weekly and spray only when a pest crosses its economic threshold level (ETL). Calendar spraying wastes money and kills the natural enemies that keep pests in check.

Doses in this guide are taken from the product labels. Always read the label and leaflet before use, respect the pre-harvest interval, and check with your nearest Biostadt retailer or agronomist for advice specific to your field.

Weed control in the first 45 days

• Pre-emergence: Hitbac (pendimethalin 38.7% CS) 1500–1750 ml per hectare, sprayed within 1–2 days of sowing on moist soil.
• Post-emergence broadleaf weeds: Nanchaku (pyrithiobac sodium 10% EC) 625 ml per hectare, or Nanchaku Power 1000 ml per hectare, at the 2–4 leaf stage of weeds.
• Follow up with one intercultivation or hand weeding around 30–35 days.

Sucking pests (0–60 days)

Pest	What you see	Spray when (ETL)
Jassids	Leaf edges curl down and turn yellow then red ("hopper burn")	2–3 nymphs per leaf
Whitefly	Clouds of tiny white insects, sticky leaves, black sooty mould	8–10 adults per leaf
Aphids	Colonies under young leaves, crinkled leaves	10% of plants infested
Thrips	Silvery, brittle leaves that curl upward	10 thrips per leaf

Products labelled for these pests include Ultimo Super, Evident, EDAN and Wapkil. Bioclaim Pro is labelled for whitefly, jassids, thrips, aphids and pink bollworm together. Use the dose on the product page, and rotate between products rather than repeating the same one. Seed treated with Evident Flo (10 ml per kg seed) protects the crop from sucking pests for the first few weeks.

Pink bollworm (60 days onwards)

• Install 5 pheromone traps per hectare from 45 days after sowing and count moths every few days.
• Spray when you catch 8 moths per trap per night for 3 nights in a row, or find 10% rosette flowers or damaged green bolls.
• Pick and destroy rosette (partly opened, twisted) flowers by hand every week.
• Labelled products: Bioclaim (emamectin benzoate 5% SG), Ulka, Tremor and Janbaaz Sc.
• After the last picking, graze or shred the stalks and do not store unginned cotton near the field. This breaks the pest cycle for next season.

Diseases

For leaf spot and grey mildew, spray Decimer 500 ml per hectare at the first symptoms and repeat after 15 days if the weather stays humid.

Spray safely

• Wear gloves, a mask, full sleeves and eye protection while mixing and spraying.
• Spray in the early morning or late evening, never against the wind or before expected rain.
• Use clean water and the full recommended water volume. Poor coverage is the most common reason a spray "does not work".
• Do not mix products unless the label allows it. If unsure, do a jar test first.
• Keep children and animals away, and never reuse empty containers. Rinse them three times, puncture them and dispose of them safely.