Symptom

• The fungus infects the seedlings and produces small reddish circular spots on the cotyledons and primary leaves.
• The lesions develop on the collar region, stem may be girdled, causing seedling to wilt and die.
• In mature plants, the fungus attacks the stem, leading to stem splitting and shredding of bark.
• The most common symptom is boll spotting with small water soaked, circular, reddish brown depressed spots on the bolls.
• The lint is stained to yellow or brown, becomes a solid brittle mass of fibre.

Reddish brown depressed spots

Survival and Mode of Spread

• The pathogen survives as dormant mycelium in the seed or as conidia on the surface of seed .
• It also perpetuates on the rotten bolls and other plant debris in the soil.
• Primary spread is through infested seed and soil.
• Secondary spread is through air-borne conidia.

Favourable Conditions

• Prolonged rainfall at the time of boll formation and close planting.

Management

• Remove and burn the infected plant debris and bolls in the soil.
• Rogue out the reservoir weed hosts.
• Treat the acid-delinted seeds with Chlorothalonil at 4 g/kg of seed .
• Spray Copper oxychloride @ 500 g / acre, at boll formation stage

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