Pay attention to check and prevent Botrytis cinerea

Botrytis cinerea is the main disease of protected leek, which seriously affects the quality of leek on the market during the Spring Festival. the price of leek is generally the highest during the Spring Festival every year. once it gets sick, it will cause great economic losses to farmers. Therefore, the prevention and control of Botrytis cinerea is very important for the production of Chinese chives in protected areas. First, symptoms 1. White spot. There are small white or grayish brown spots on the front and back of the leaf, developing downward from the leaf tip. The lesion is fusiform or oval in shape and converges into patches in the later stage of the disease, resulting in half-leaf or whole-leaf scorch. two。 Dry tip. Rot downward from the cutting edge of the stubble, showing a water immersion at first, then light green, with brown wheel lines, the disease spot is mostly semicircular or "V" shaped after spread, and can be extended downward by 2 to 3 cm, showing yellowish brown, the surface is grayish brown or grayish green fluffy mildew. 3. Wet rot. When the humidity is high, the withered leaf surface is densely gray to green villous mildew, accompanied by mildew smell, and there are no white spots on the leaves. Second, prevention and control methods 1. Disease resistant varieties were selected. Such as Chinese leek No. 2, 791 snow leek, Zaofa leek No. 1 and so on. two。 Clean the countryside. After the leek is harvested, remove the diseased body in time, bury it deeply or burn it, to prevent the spread of germs. 3. Timely ventilation and dehumidification is the key to the prevention and treatment of the disease. Ventilation should be determined according to the growth of leeks. Freshly cut leeks or when the external temperature is low, ventilation should be small or delay ventilation, strictly guard against sweeping wind. 4. Cultivate strong seedlings and pay attention to stubble. Application of organic fertilizer, timely topdressing, watering, weeding, good stubble, improve plant disease resistance. Before planting, 50007000kg of mature farm manure, 15kg of diammonium phosphate and 50kg of plant ash were applied per mu, deeply into the soil, irrigated and irrigated in time after planting. Topdressing twice before frost, applying 15kg urea per mu each time, and watering in time after topdressing. 5. At the initial stage of the disease, 65% methyl thiocarbamate or 5% promethopril powder or 5% isobarbazide dust was sprayed with 1 kg per mu. In addition, it can also be sprayed with 1000 times of methyl thiocarbamate wettable powder or 1000 times of 25% prochloraz EC or 1200 times of 40% pyrimidine suspension, once every 10 days and 2 times in a row.