Prevention and comprehensive treatment of downy mildew in spinach

The disease is caused by a fungus called spinach downy mildew. The main damage to the front of the leaf, disease spot yellowish, irregular shape, different sizes, diameter 3mur17mm, the edge is not obvious. After the disease spot enlarged, it connected with each other and became brown and withered in the later stage, and the gray-purple mildew layer was produced on the disease spot on the back of the leaf. The disease gradually developed from the outer leaves to the inner leaves and extended upward from the lower part of the plant. The diseased leaves withered and yellow during drought, rotted when the humidity was high, and the serious leaves of the whole plant turned yellow and died. The control methods are as follows: first, strengthen cultivation management: reasonable close planting, scientific irrigation, reduce field humidity. Second, select disease-resistant varieties: sharp-leaf varieties can be selected, or seeds can be collected on disease-free land or disease-free plants. Third, chemical seed dressing: seeds with bacteria, can be used before sowing with 50% Fumishuang wettable powder, the dosage is 0.4% of the seed weight. Fourth, pull out the diseased plant: if the diseased plant is found in the spinach field in early spring, it should be pulled out in time and burned out of the field. 5. Chemical prevention and treatment: at the initial stage of the disease, 40% ethyl phosphorus aluminum wettable powder 200 ml 250 times liquid, or 58% metalaxyl manganese zinc wettable powder 500 times liquid, or 72.2% Pulic water agent 800 times solution, sprayed once every 7 ml 10 days, 2 Mel 3 times in a row.