Overturning disease is the main disease of the melon seedlings. It spreads rapidly and harms fiercely. The disease mainly manifests as the base or middle part of the embryonic stem, ie, the seedlings appear water-soaked at or above the junction of the soil surface, and then turn brownish and brownish. The cotyledons often have not yet wilted and cause cataplexy, sometimes germination of the young buds and cotyledon Has browned and rotted. When the humidity of the seedbed is high, a white floc develops from the residue of the diseased seedlings and the nearby soil surface. The occurrence of damping-off disease is related to loose soil disinfection, low temperature and high humidity, poor ventilation, lack of light, and tall plantlets. It must be prevented by comprehensive prevention and control measures. 1, seedbed selection and disinfection. Seedbed should be selected for high dryness, well-drained, uncultivated land for melon crops, bedrock or nutrient soil 2-3 weeks in advance with formalin, or 40% for each soil before mixing. Chloronitrobenzene 125 grams disinfected. For each 5 kg cover soil, add 9 g pentachloronitrobenzene and 70% mancozeb 1 g cover 1 m2 seedbed. 2. Strengthen seedbed management to prevent tall seedlings. Seedbed water was soaked once before sowing, and the first true leaves of the melon seedlings were not watered in principle before the unfolding; the temperature control followed the principle of “high-low-highâ€, that is, the bed temperature was kept at about 30°C before the melon seedling was unearthed. Melon seedling unearthed 70% to the first true leaf flat development to reduce the bed temperature to 20-25 °C; the first true leaf is expanded again to raise the bed temperature to about 28 °C. After the first leaves of the melon seedlings were unearthed, they were protected from the emergence of tall plantlets by removing the flat film and opening the ventilation at both ends of the arch shelter. Once the tall plantlets are produced, they must be converted by means of cooling, dehumidification, increased ventilation, and increased light. In short, the implementation of fitness nursery, improve the quality of melon seedlings. 3, chemical control. Differences in different cases were sprayed and pharmacy methods used for chemical control. If the seedbed is dry and the weather is fine, use 400 times copper ammonium complex (2 parts of copper sulfate, 11 parts of ammonium bicarbonate, 1 part of sealed powder for 1 day to dissolve 400 parts of water), or 64% antimony wettability Powder 800 times liquid spray bed. Spraying should be carried out in the morning to facilitate the removal of excess moisture after spraying. If you suffer from continuous rain at the time of onset, you should not use spray treatment. Otherwise, the condition will be aggravated. Herbal soil should be used to root the roots. The formula for medicinal soil is: 1 square meter of seedbed, 50% carbendazim WP 5 g and 70% thiophanate-methyl WP 5 g. Or simply use 50% of 64% anti-virus WP and mix with 5-10 kg dry fine soil. Pesticide method is very effective. Rongcheng Jingyi Oceanic Technology Company Limited , https://www.jingyifoods.cn