What agents are used to control tomato leaf mildew?

Leaf mildew is a common disease in tomato. Although it does not directly infect the fruit, it will lead to the decrease of leaf function and affect the yield and quality. In production, some farmers often report that it is difficult to control leaf mold, and the effect is not obvious after spraying. The reason for the poor control effect is mainly due to improper prevention and control methods, and the following four points should be paid attention to when applying pesticide. There are many drugs for the control of tomato leaf mold, including preventive chlorothalonil, therapeutic carbendazim, flusilazole, difenoconazole and so on. Early prevention and early treatment of tomato leaf mildew is an airborne disease. Once the pathogen infects and produces disease spots, as long as there is enough humidity in the greenhouse, the disease will spread quickly. To prevent tomato leaf mildew, preventive medicine should be sprayed every 10 days from the seedling stage, and should be sprayed every 7 days during the first to second panicle flower setting period of tomato. After the appearance of disease spots in the lower leaves, therapeutic agents should be sprayed as soon as possible. Tomato leaf mildew at the spraying site usually starts from the lower leaves of the plant, and the plant located at the corner of the south shed is usually the first to occur. Therefore, the focus of spraying prevention is on the lower leaves of the plant and the plants in the south of the greenhouse. Focus on spraying to protect the middle and upper functional leaves. Many azole fungicides have high control effect on tomato leaf mold, but these fungicides (except difenoconazole) usually inhibit the growth of tomato. Therefore, the tomato fruit expansion period can not continuously spray a large number of azole fungicides, so as not to inhibit the fruit expansion.