Dysplasia, also known as blight, is the most common and most serious disease occurring in nurseries. It endangers a variety of seedling flowers, which mostly occur in March to June when it is cloudy and rainy, and the air humidity is high. In severe cases, the seedling roots rot and die, affecting the survival rate of seedlings. Phytophthorasis is mainly caused by Rhizoctonia, Pythium, and Fusarium in fungi. Nursery, low humidity, soil viscosity, compaction, poor drainage of the old nursery and previous crops are tomatoes, potatoes, cotton, vegetables, and alkaline soil or excessive Nitrogen Fertilizer, are prone to damping off. And it can be spread by soil, rain, irrigation and seeds. The prevention and control of damping-off disease should be carried out from the soil, and prevention should be the main method and integrated prevention and treatment. First, improve the level of nursery technology. Select high-quality, dry, well-drained plots. For poorly-drained low-lying land, ditches should be dug around for the implementation of needle and broad-leaved tree rotations. Nursery made a high bed, flat bed. Appropriate early sowing, cover soil after sowing, uniform thickness. For cutting propagation of flowers, the cuttings should be allowed to dry until slightly dry and then cut to facilitate wound healing. Sowing should not be too dense, and time seedlings, keep good ventilation. In combination with site preparation, decomposed organic fertilizers are used to improve soil quality and inhibit germs, and seedlings, lands, fertilization, and nitrogen, phosphorus and potassium are properly matched to enhance seedling resistance and create a better seedling growth. Good environment. Second, the seeds and soil disinfection. Bacterial damping-off pathogens can survive in the soil for a long period of time. Therefore, direct elimination of pathogens in the soil is extremely important for controlling disease. Seedbed soil can be used 50% carbendazim or 50% thiram, or 40% chloronitrobenzene, or 40% of the seed dressing cream, 6 grams to 8 grams per square meter. The drug is weighed first, then mixed with appropriate amount of fine sandy soil and then mixed with ready-made medicinal soil. Some of the medicinal soil is sprinkled in the sowing line before sowing, and the remaining part covers seeds after sowing. Prior to sowing, the seeds were sterilized with a pair of seed dressings, such as Enkeson and Formosa. Third, timely control of pesticide application. Before the onset of disease, when the seedlings are tender, the lime powder and the ash can be mixed in a ratio of 1:4, and 100 kg to 150 kg can be applied per acre seedbed. The disease prevention effect is good. Can also begin in the emergence period, every 7 days to 10 days, per acre nursery with Bordeaux mixture spraying seedlings, seedlings to form a protective film on the surface to prevent the invasion of bacteria. Seedlings can be used during the onset of the enemy 500 times to 800 times the liquid, or Fumei cream 400 times to 500 times sterilization seedlings. Pay attention to spraying seedling shoots and central diseased plants and the surrounding soil, spraying once every 7 days to 10 days, and spraying 2 to 3 times.
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