1 , prevention and treatment of viral diseases

　　 1 Choose resistant varieties or hybrids. 2 Clean the garden to prevent the pathogen infection of weeds or other cruciferous vegetables. 3 sowing in a timely manner, avoiding the high temperature and locust season. 4 Avoid continuous cropping with cruciferous crops. 5 Grasp the prevention and control work: prevent and control the mites in the seedling stage, 50% 蚜 蚜 可 wettable powder 2000-3000 times liquid or 10% imidacloprid WP 2000 times liquid spray anti-mite; spray the anti-toxicity 300 times in the early stage of the disease No. 1 oil emulsion fluid or virus times 500 times or 20% or 5% A5000 virus bacterial and viral agents with water 500 times, every 7-10 days, spray, even spray 2-3 times.

　　 2 , prevention and control of downy mildew

　　 Control method: Spraying at the beginning of the disease. Green Heng 2 wettable powder 600 times liquid, spray 50 kg per acre ; 75% chlorothalonil wettable powder 500 times liquid, spray 50 kg per acre ; 70% mancozeb 500 times liquid, each 50 kg per mu .

When the Chinese cabbage disease mixture occurs, a mixed drug can be used to play a multi-effect effect. When mixed with the black spot downy mildew, mu selected Green Hang 40 gram 2 Wettable powders 70% mancozeb wettable powder mixing 100 grams of water was added 40-50 kg of spray, spray once 5-7 days , even spray 2-3 times; when soft rot or black rot and downy mildew mixed, each green selection of green heng No. 6 wettable powder 40 grams plus agricultural streptomycin soluble powder 30 grams of water 40-50 kg spray 5-7 days, and even spray 2-3 times; when soft rot, black rot and black spot fat mix, the choice of green Hang mu 6 40 gram of 70% wettable powders of mancozeb WP 50 grams of soluble powder 30 g streptomycin mixed with water spray 40-50 kg, 5-7 days, rotating spraying better. 　

3 , prevention and control of soft rot

　　 1Select disease-resistant varieties: use straight-type and green-type varieties.

　　 2 Agricultural control measures: take sorghum cultivation; remove the diseased plants in time, dissolve the lime in the diseased hole; increase the application of decomposed organic fertilizer; timely cultivate the sedge, keep the soil a certain humidity, and promote the seedlings. In addition, cover the mulch before sowing to increase the ground temperature, improve soil ecological conditions, and avoid planting on low-lying and clay plots.

　　 3 chemical control: timely medication before the onset or early onset to prevent the spread of disease. The medication should focus on the lightly diseased plant and the surrounding plants, paying attention to the petiole and stem base close to the surface. Soil treatment at the beginning of the disease: 150 g of quicklime and sulphur ( 50 : 1 ) mixed powder per square meter for soil disinfection. Commonly used agents are agricultural streptomycin, 47% galene WP 700-750 times solution, neomycin, Feng Guardian, 70% dikesone 500-1000 times solution, DT bactericide 500 times solution, " Fengling" (enhanced vegetable Fengning) and so on. "Fengling" seed dressing method is to mix 15-20 grams of medicament per 50 grams of seeds ; "Fengling" rooting method is 100-150 grams of medicament per acre plus 50 kilograms of water; "Fengling" spray The method is to spray 150-200 grams of medicament per acre plus 100 kilograms of water. The rooting and spraying should be carried out in the evening or on cloudy days. It can also be mixed with vegetable Fengning or Nongkang 751 .