马铃薯黑胫病初侵染来源的研究.

【Objective】To clarify potato blackleg disease source of infection in Ulanqab City,Inner Mongolia,and provide the basis for formulating effective prevention and control measures for potato blackleg disease.【Methods】The pathogen isolation,pathogenicity identification,molecular identification and soil survival tests of potato blackleg disease were carried out. Through pot experiment and field experiment,seven treatments were set up to investigate the occurrence of potato blackleg disease in the soil of continuous cropping land,seed potatoes of diseased land and diseased residues,and analyze and verify the differences in incidence rate of different treatments.【Results】The incidence rate of potato blackleg harvested in diseased areas and planted as seed potato over winter was 40.00%. Pectobacterium atrosepticum was isolated from the disease residue buried in soil after overwintering,and the incidence rate was 43.33% in the experiment of planting disease-free potato after the disease residue was planted in the disease-free soil. The incidence rate of disease-free potato was 6.67% in the previous diseased plots. The amount of pathogenic bacteria in unsterilized soil gradually decreased with the extension of time,and no longer survived after two months at normal temperature,and no longer survived after four months at -20 ℃. The results indicated that P. atrosepticum could survive the winter in the disease residual and become the primary infection source in the second year. The pathogenic bacteria in diseased soil were related to the occurrence of disease,but the bacteria free in cultivated soil could only survive for two months at natural temperature.【Conclusion】 The primary infection source of potato blackleg disease in Ulanqab City,Inner Mongolia is the infected seed potato and the disease residual after winter,and the amount of bacteria carried by the seed potato is an important factor affecting the occurrence of the disease. [ABSTRACT FROM AUTHOR]