Control Techniques of White Rust of Ipomoea aquatica

1. rotate with other vegetable varieties for 2 to 3 years. 2. Before sowing, seed dressing and sterilization are carried out according to the proportion of 300g and 35% metalaxyl of 100kg seeds; 3. 50% metalaxyl copper wettable powder 6000 - 7000 times solution is used at the initial stage of disease, or 72.2% Pulick aqueous solution 8000 times solution is sprayed, and once every 7 to 10 days can be used for prevention and control. reinfection. Rain and insects can also spread, and whether seeds can spread remains to be studied. Cold and wet night, warm day, heavy fog and wet soil conditions are conducive to the occurrence and epidemic of the disease. 3. Control method (1) Select disease-free seeds and seed treatment: select disease-free plots to keep seeds, soak newly bought seeds in warm water at 50℃ for 25 minutes, and sow after cooling. (II) Strengthen garden field management: select plots with high terrain, good drainage and ventilation for planting. Apply enough fertilizer and increase phosphorus and potassium fertilizer. Irrigate water reasonably, do not make onion land too wet. Discovered diseased plants, timely uproot buried. After harvesting, the diseased bodies are thoroughly removed, centralized treatment is carried out, and deep ploughing is carried out to reduce the bacterial source. (iii) Chemical control: At the early stage of disease, spraying once every 7-10 days, spraying 3-4 times continuously, commonly used pesticides are 1:1:240-300 times of bordeaux mixture, 200-300 times of 40% of ethyl phosphorus aluminum wettable powder, 500-1000 times of 25% of metalaxyl wettable powder, 500-600 times of 75% of chlorothalonil wettable powder, 500-700 times of 65% of zineb wettable powder, 500 times of 64% of alum, 500 times of M8 wettable powder and 700-1000 times of 66.5% of Prolik aqueous solution.