First, cucumber downy mildew, resistance varies from place to place. It is suggested that one or two of dimethomorph, cymoxanil, propamocarb hydrochloride, metalaxyl manganese zinc, oxadiazole manganese zinc, flumorph manganese zinc, cyazofamid, difenoconazole and oxazolidone manganese zinc be used alternately (in severe cases).

(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 zhongshengmycin, thiamethoxam, kasugamycin, Pseudomonas fluorescens or zinc thiazole to control bacterial diseases.

Because the situation in the field is complicated, we can't just look at the symptoms of a few leaves, and bacterial diseases can't be ignored. We must nip in the bud.