Cotton leaves are vulnerable to diseases that, left unchecked, weaken the plant, cause early yellowing and leaf drop, and cut into how well it can fill its bolls. Spotting the signs early and spraying the right fungicide in time is what keeps the crop safe.
1. Grey Mildew
How to Spot It
Look for small, angular, yellowish spots on the upper surface of older leaves, with a greyish, powdery fungal growth developing on the underside directly beneath each spot. As the disease progresses, spots merge and leaves turn yellow, dry up, and drop prematurely, sometimes defoliating a large part of the plant.
Solutions to Control It
Azoxystrobin 18.2% + Difenoconazole 11.4% w/w SC - Combines a strobilurin with a triazole, giving both protective and curative action against the fungus, with the systemic triazole component moving through the plant to reach new growth.
Product Recommendation
- Syngenta Amistar Top Fungicide
- Katyayani Azodharma Fungicide
- JU Agri Azole Fungicide
- EBS Azolex Fungicide
- Dhanuka Godiwa Super Fungicide
2. Alternaria Leaf Spot
How to Spot It
Look for small, circular to irregular brown spots on the leaves, often with visible concentric rings inside each spot and a yellow halo around it. Badly affected leaves turn yellow and drop early, and in severe cases the disease can also show up on bolls as dark, sunken lesions.
Solutions to Control It
Carbendazim 12% + Mancozeb 63% WP - Pairs a systemic fungicide that moves within the plant with a protective contact fungicide on the leaf surface, giving control both inside the plant and against new infection.
Product Recommendation
3. Leaf Spot
How to Spot It
Look for scattered, roughly circular spots on the leaf surface that can range from pale brown to dark brown depending on the stage of infection. Spots tend to appear first on the lower, older leaves and move upward as the disease spreads through the canopy.
Solutions to Control It
Carbendazim 50% WP - A systemic fungicide absorbed into the plant tissue, disrupting the fungus's cell division and stopping the spread of existing infection while protecting new growth.
Product Recommendation
Cultural Practices to Keep Disease Pressure Down
- Rotate cotton with a non-host crop where any of these diseases have appeared in previous seasons
- Maintain balanced fertilization, especially adequate potassium, to keep plants resilient
- Avoid overly dense planting so the canopy gets enough airflow and sunlight
- Remove and destroy infected plant debris after harvest rather than leaving it in the field
- Monitor the crop regularly from the vegetative stage onward, especially after rain
Disclaimer: Always confirm current label registration, approved dosage, water volume, and pre-harvest interval (PHI) for your state before using any product, since labels are periodically revised by regulatory authorities.
This guide is a general advisory. Do your own research and verification before using any product. Always confirm suitability for your crop stage, region, and field conditions before making any purchase, spray, or crop-management decision.
