The pathogen overwinters on the diseased body with ascospore shell. In the next year, the ascospore is released from the ascospore shell for initial infection, and then the diseased part produces conidia for reinfection.
Warm and dry or shade between plants is easy to occur.
Excessive application of nitrogenous fertilizer resulted in severe dry wet alternation.
It mainly damages leaves and sometimes stems and flowers. The disease spots on the leaves are white dots at the beginning, and then expand to white powder spots. In the later stage, the whole leaf is covered with white powder layer, and when it is serious, the leaves are yellow and deformed or even fallen leaves; the disease spots on the stems are brown, irregular and rectangular, with white powder on them; the flowers are twisted, and when it is serious, they fall off.
1. Select disease resistant varieties according to local conditions.
2. Strengthen cultivation management, reasonably close planting, pay attention to ventilation and ventilation; apply fertilizer scientifically, increase P and K fertilizer, improve plant disease resistance; irrigate timely, drain water timely after rain to avoid moisture retention.
3. In the early stage of the disease, spray 50% colloidal sulfur 100 g with water 20 kg or 15% keto wettable powder 2000 times.
