Chemical control of white rust of hollow cabbage

First, rotation with other vegetable varieties for 2 to 3 years. Second, before sowing, seed sterilization should be carried out according to the proportion of 100kg seeds with 300g metalaxyl; third, at the initial stage of the disease, 6000 to 7000 times solution of 50% nail cream copper wettable powder, or 8000 times solution of 72.2% Prik water agent, can be sprayed once every 7 to 10 days. To infect again. Rain Water and insects can also spread, but whether seeds can be spread remains to be studied. Cool and wet at night, warm during the day, heavy fog, and the condition of sticky and wet soil is conducive to the occurrence and prevalence of the disease. 3. Control methods (1) choose disease-free seeds and seed treatment: select disease-free land to keep seeds, soak the newly bought seeds in 50 ℃ warm water for 25 minutes, cool and sow. (2) to strengthen the management of garden fields: select plots with high terrain, good drainage and ventilation for planting. Apply enough fertilizer and increase the application of phosphorus and potassium fertilizer. Irrigate properly so as not to make the green onion floor too wet. If you find a diseased plant, remove it and bury it in time. After harvest, the disease and residue were thoroughly removed, concentrated treatment, and deep ploughing was carried out to reduce the source of bacteria. (3) Chemical control: spray at the initial stage of the disease, once every 7-10 days, 3-4 times in succession. The commonly used agents are 1240,300 Bordeaux solution, 40% aluminum ethyl phosphate wettable powder 200300 times, 25% metalaxyl wettable powder 1000 times, 75% chlorothalonil wettable powder 500,600 times, 65% Dysen zinc wettable powder 500700 times, 64% poison alum, M8 wettable powder 500x. 66.5% Pulic water agent 700-1000 times.