Study On Field Of Pharmaceutical Screening And Use Method Of Chinese Cabbage Clubroot In Taibai Mountain Area

Clubroot in Chinese cabbage is caused by infection of mastigomycotina plasmodiophora brassicae. It belongs to parasitic soil-borne diseases. In recent years, the incidence of the disease has been increasing year by year at Gaoshan vegetables production area, Taibai County, Shaanxi, and has threatened local vegetable safety production. In order to prevent the disease, the test performed field efficacy screening of different reagents on clubroot in Chinese cabbage on the one hand, and carried out systematic researches on application method and concentration of 10% cyazofamid suspending agent on control efficacy of clubroot in Chinese cabbage on the other hand. The following research results have been achieved:1. The results of drug screening trial indicate that:The overall control efficacy of 11 pesticide treatments is: 50% Fluazinam suspending agent > 50% Thiophanate-methyl > Bacillus subtilis 1 billion/g > 75% Dacotech > 40% Quintozene > Thiodiazole copper(20% Longkejun) > 50% Pu Jun Te > 50% dimethomorph > 50% Carbendazim > Dexon(95% Fenaminosulf) > 70% Mancozeb. Among them, the control efficacy and contrast difference of 50% dimethomorph, 70% Mancozeb and Dexon are not significantly different.2. Test results of 10% cyazofamid suspending agent on control efficacy of clubroot in Chinese cabbage:(1) For seedling transplanting fields with two crops in one year at low altitude areas, which indicate that: the optimal drug application method of 10% cyazofamid suspending agent for clubroot in Chinese cabbage control efficacy is root-irrigation. it is the most appropriate way to adopt twice root-irrigation, namely conducting root-irrigation with 2000 times diluents of 10% cyazofamid suspending agent on the current day of transplantation and day 10 after transplantation. In addition to root-irrigation, certain effects have been obtained on control efficacy of clubroot in Chinese cabbage by adopting two processing methods, namely pre-sowing immersing seeds in drug liquid, root-irrigation at plant transplanting, and pre-sowing mixing substrate with drug liquid, liquid spraying at land for growing field crops before plant transplanting.(2) For direct seeding fields with one crop in a year at high altitude areas, which indicate that the optimal drug application method for clubroot in Chinese cabbage at direct seeding fields is root-irrigation as well. It is more appropriate to perform root-irrigation with 1500~2000 times diluents of 10% cyazofamid suspending agent at day 15 after transplantation and day 23 after transplantation.3. Test results of drug local isolation indicate that:Set "Zhong Shu" as disease-resistant substrate. The disease index for application of 200 g solution per seed hole is the lowest. The average value is 10.58 and the control efficiency is the highest, with a mean value of 88.00%. The overall control effect of clubroot in Chinese cabbage on six drug local isolation methods is: "China vegetable seed" disease-resistant substrate > 50% Fluazinam suspending agent > BJKL suspending agent > 24% lime nitrogen powder > "Shu Bao" three prevention substrate mother dust > BJYT granules.4. Based on experiment and production investigation, proposed six prevention and treatment guidelines for comprehensive control on clubroot in Chinese cabbage at Gaoshan, Taibai. Concrete proposal: "rotating, planting, soil, fertilizing, management and prevention".