Downy mildew can occur from the seedlings of lettuce to various stages of harvest, and the adult plants suffer more. The main damage leaves, from the base to the upper leaf development. At the onset of the disease, light yellowish near-circular to polygonal lesions form on the leaf surface, and when the air is wet, a layer of moldy mildew forms on the back of the leaf, sometimes spreading to the foliage. The late lesions were dead and yellowish-brown. When severe, all outer leaves died of yellow. Control methods: Select disease resistant varieties. From the appearance point of view, mosaic and leaf-type varieties are more resistant to disease. At present, the domestic planting of Mengma, the emperor, chicken lettuce, red lettuce, Guangdong lettuce and other varieties more resistant. After harvesting and before planting, remove the fallen leaves of the diseased body and concentrate it properly. The manure must be sterilized by high-temperature fermentation. The use of high ridge, high ridge or plastic film covering cultivation, appropriate sparse, pouring small water, flood irrigation is strictly prohibited, timely drainage after rain, protection of rainy days to pay attention to leak, the use of drip irrigation in areas with good conditions can better control the disease. In the initial stage of disease prevention and treatment, it is possible to use 25% thiobacillus suspension 1500 times, or 69% enoyl morpholine-manganese zinc wettable powder 800-1000 times, or 72% WP wettable powder 600-800 times. , Or 72.2% Precic liquid 600 times, or 72% clenbuterol wettable powder 600-800 times, when spraying should be sprayed as far as possible to the base of the leaves, the protection of the ground should be preferred to use dust or smoke Agent control. At the beginning or early stage of disease, chlorothalonil dust 1 kg/mu can be sprayed, or 45% chlorothalonil aerosol 0.5 kg/mu smoke can be used for prevention and treatment. Canned Pear In Syrup Half,Pear In Syrup Half Canned,Pear In Syrup Tin,Pear In Syrup Canned ZHANGZHOU TAN CO. LTD. , https://www.zztancan.com