Control of Botrytis cinerea of leek in greenhouse

When the humidity in the greenhouse leek shed is large, gray mold is easy to occur. After the disease, the leaves gradually produce pale brown to white spots from the tip down, both sides have, after expansion, oval or fusiform spots, and merge into large dead spots. Air humidity above 85%, temperature at 15℃~20℃, warm and humid conditions conducive to the occurrence of this disease. Control measures: 1. Select disease-resistant varieties. Broad-leaf resistant varieties such as Xuejiu, 791, Jiaxingbaigen, etc.; narrow-leaf cold-resistant varieties such as Gong, Huangmiao, Zhongjiu No. 2, etc. 2. Strengthen field management. Frequent irrigation with small amount of water helps to raise ground temperature. After each harvest, 2~3 times of shallow tillage and soil cultivation are carried out to reduce the humidity in the shed. Timely ventilation and moisture removal. Master harvest time, harvest in low humidity and no dew conditions, dry roots and cultivate soil after harvest. Remove the residual leaves of diseased plants in time, increase fertilizer application, and enhance the disease resistance of leek. 3. Chemical control. 250g of 10% Sukeling smoke agent is used for fumigation per mu, or 1000g of 10% meilin powder is used for spraying per mu, or 1000 - 1500 times of 50% Sukeling WP, 500 times of 50% thiophane methyl WP and 500 times of 70% mancozeb WP can be used for spraying control. Control the disease once every 7 days until the disease is under control.