Symptoms and Control Methods of Cotton Boll Red Rot

Symptoms After a cotton boll is infected, an irregularly shaped lesion initially appears. In wet weather or during continuous overcast and rainy days, the disease spreads rapidly, covering the entire boll, and in some cases reaching the cotton fibers, producing an even pink or light red mold layer. After rain, it easily sticks together, forming pink masses, causing the diseased boll to fail to crack open, and the cotton fibers to rot into stiff, matted locks. After seeds are infected, the germination rate declines.

The pathogen is the same as that of cotton seedling red rot.

Transmission route and disease conditions This fungus is a weak parasite and cannot directly infect cotton bolls; it mainly enters through wounds to cause disease. Lesions caused by cotton boll angular leaf spot, boll blight, boll anthracnose and others can all induce red rot. A large number of conidia are produced on diseased bolls and spread by wind and rain, causing multiple secondary infections.

For control methods, see cotton seedling red rot.