First, downy mildew is the main disease, and the resistance varies from place to place. It is suggested to select one or two components such as dimethomorph, cymoxanil, propamocarb hydrochloride, metalaxyl manganese zinc, oxaprozin manganese zinc, flumorph manganese zinc, cyazofamid, fipronamide, etc. Should be mixed (serious) alternately used.

(If it is a protective greenhouse, pay attention to humidity control. It is recommended to use chlorothalonil aerosol to control the disease in rainy days. )

Prevention first, comprehensive prevention (disease prevention, dose reduction by one). Use pesticide ingredients alternately, and don't use the same pesticide ingredients continuously. This is the principle of plant protection.

Secondly, it is suggested that it is best to use bacterial pesticides such as streptomycin, zhongshengmycin, thiamethoxam, kasugamycin or zinc thiazole to prevent and control bacterial diseases.

Because the situation in the field is complicated, we can't just look at the symptoms of a few leaves. Be sure to nip in the bud.