The reason of disease of Chinese cabbage
1, the relationship between climate and disease
Rainy conditions, water cabbage leaf base to the lack of oxygen, so the wound to heal, soft rot bacteria from wound invasive disease easily;High temperature and drought prone to virus disease, drought is helpful for aphids breeding and activity, is not conducive to growth of Chinese cabbage, less resistance to aphids and the spread of the virus disease mainly medium;High temperature and high humidity to downy mildew sporangium production, germination and invasion.
2, different growth period and the relationship of the disease
Seedlings before 7 leaf stage the temperature is high, the high incidence of aphids, easy cause virus invasion of bacteria from the wound, lead to cannot bear the ball, harm seriously;Cabbage stage Indus to core prone to downy mildew;Cabbage package after heart period, poor wound healing force, prone to soft rot [3-4].Saline-alkali land, excessive use of ammonium sulfate or uneven application of root cause burn, restrain the growth of seedlings, time is too long, soil, water and so on are easy cause tipburn.
Chinese cabbage disease control measures
1, select disease-resistant varieties, reasonable arrangement of crop
Should choose high quality resistant white dragon 7, Zheng Bai, Beijing new no. 3, 4, such as abundant resistance of 70 varieties.General green varieties to downy mildew, good resistance to soft rot disease, virus disease, suitable for old Chinese cabbage heavy plot planting area.With the gramineous crops, reasonable arrangement of stubbles or green, garlic crop rotation, to avoid cruciferae, melons and solanaceous fruit vegetable continuous cropping [5], which can effectively reduce the common disease in Chinese cabbage.
2, agricultural
Weeding extermination, eliminate the bacteria source.And quick lime, 750 kg/hm2 prevention and control of Chinese cabbage soft rot.Increasing phosphorus, potassium, and calcium, manganese element, return to have rotten organic fertilizer.
3, chemical control
Is a viral disease.Viral disease transmitted by aphids, should be timely prevention and control of aphids, commonly used agents have 2.5% deltamethrin 3 000 times liquid, 2.5% effort was 4 ~ 5 000 000 times liquid, 21% neutralising the dead 4 000 times liquid, 40% dimethoate 1 000 times liquid.On this basis, the disease early spraying 1.5% plant disease spirit Ⅱ emulsion 1 000 times liquid, 20% virus A wettable powder 500 times liquid, spray once every 10 d 1, 2 ~ 3 times.The second is downy mildew.Indus to regiment period, spraying protective agents such as 80% mancozeb wettable powder 000 times liquid, and 1 strain after spraying 50% armor frost spirit or mancozeb wettable powder 500 times liquid [6].Third, the soft rot.Num often watered;Well after the rain drainage, reduce cabbage wound is produced or promote wound healing, prevention and control of early onset with new plant toxin.Seedling stage to the Indus spraying 72% streptomycin sulphate wettable powder 000 3 ~ 4 000 times liquid, 53.8% can kill 2 000 times liquid, 47% plus farmers wettable powder 800 times liquid, and prevention and control of every 10 d 1, row 2 ~ 3 times;Use FengLing 2.25 ~ 3.75 kg/hm2 pouring the FengLing root or spraying of water 1.5 t 1.50 ~ 2.25 kg/hm2, 750 kg of water prevention and control.Four is tipburn.Spray water in time and 1% calcium superphosphate solution, or rootone 2 000 times liquid, and 0.7% calcium oxide mixture, or 0.7% manganese sulfate solution, prevention and control of 5 ~ 7 d, even three times.
4, comprehensive prevention and control of
Single measures of prevention and control technology for Chinese cabbage disease control effects are not very ideal, 100% control effect is difficult to achieve, so should adopt comprehensive prevention and cure [8].1 year, 2 years the disease-resistant varieties should be replaced, and take preventive pesticide applying early, and according to the climatic conditions to predict the possibility of disease, and spraying pesticide has corresponding prevention, can effectively control the disease occurs, and thus enhanced the quality and yield of Chinese cabbage.
