Occurrence And Prevention Of Cabbage Root Swelling In Anlong County

Chinese cabbage is a cruciferous vegetable and one of the main vegetables in China.It is planted all over the country.In recent years,the occurrence and harm of Chinese cabbage Clubroot is increasing in Anlong County.It has gradually become one of the main diseases of Chinese cabbage.The harm caused by this disease even makes it impossible to grow Chinese cabbage in some areas.Clubroot,caused by Plasmodiophora brassicae Woron is one of the soil-borne disease all over the world.It is harmful to the root of crops and the leaves of plants.Afterwards,the economic benefits of farmers will be reduced.This research paper is based on the investigation of Plasmodiophora brassicae in Qianxiang Township,Anlong County.It will mainly analyze the occurrence conditions and biological characteristics of root swelling disease,and carried out laboratory screening and field experiments to provide scientific basis for the prevention of Chinese cabbage root swelling disease in the karst area of Guizhou Province.The experimental results is presented below:1.The susceptibility of Chinese cabbage root swelling is affected by many factors.From the perspective growth season,due to the influence of temperature,the active degree of pathogenic bacteria is different,showing the disease is more serious in summer and autumn.A comparative experiments was conducted on seven Chinese cabbage varieties including Xingxing,and it was found that Xingxing and Cabbage King had strong disease resistance,and the disease rate was below 20%.Qianbai No.4,Chunxiao and Yunchunbai No.1 had moderate disease resistance,and the disease rate was about 40%.Qingza No.3 and Lufeng No.1 were more susceptible to diseases,with the disease rate reaching more than 50%.Besides,Soil types and soil acidity have significant effects on the occurrence of root swelling.The average incidence of rhizoma in yellow soil,lime soil and paddy soil was 27.60%,23.20%and74.40%.Acidic soil is beneficial to the disease,especially when the soil pH value is between 5.5 and 6.6.Comparing the incidence and disease index of Chinese cabbage root swollen disease by direct seeding and transplanting,it was found that the transplanting method was lower than that by direct seeding.2.Infection of Chinese Cabbage by Rhizobium spore suspension.By measuring the relative indexes of different concentration of Rhizobium spore suspension on different growth stages of Chinese cabbage,it was found that in the same period of time,with the increase of concentration,the incidence rate gradually increased,the average length,diameter,fresh weight and dry weight of root swelling gradually increased,and the fresh weight and dry weight of aboveground part gradually decreased;under the same concentration,with the increase of planting time,the incidence rate and average length of root swelling gradually increased.The diameter,fresh weight and dry weight increased gradually.Root swollen disease is affected by concentration and time,which can reduce the yield of edible parts of Chinese cabbage.3.Evaluation and Screening of Drugs for Cabbage Root Swollen Disease.In laboratory screening,the best control effect of Bacillus subtilis XF-1 with the experimental dose of 1×10~8 cfu/ml was 91.67%,and the worst control effect of lime milk was 36.13%.However,the control effect of Bacillus subtilis XF-1 with a concentration of 1×10~8 cfu/mL decreased to 75.66%.There was no significant difference between the control effect of cyperazole suspension,fluazidime suspension or their combination,while the control effect of lime milk and Thiophanate-methyl was relatively poor.