关键词: 玉米纹枯病, 枯草芽孢杆菌, 定殖力, 生物防治

Abstract: The soil bacteria Bacillus subtilis "515-126",which was isolated from maize soil rhizosphere,was an effective biological control of Rhizoctonia solani.In order to understand the prevention effects of the strain,the colonization ability of maize soil,maize root surface and maize sheath and its prevention effects on Rhizoctonia solani were determined respectively in this study.The results indicated that the colonization ability of the strain in both soil and root surface was good,but poor in maize sheath,and the colonization ability of the sterile soil was stronger than that of the raw soils.After being inoculated in soil,the population of strain "515-126" decreased by 92.8% in raw soils and increased by 15% in sterile soils after 60 days;the population of strain "515-126" on maize root surface in raw soils decreased by 68.9% and became 4.46 times of the initial strain in sterile soils after 45 days;the population of strain "515-126" in maize sheath decreased by 99.95% in raw soils and decreased by 99.91% in sterile soils after 40 days.The strain had some prevention effect on Rhizoctonia solani in the field,and the relative effect was up to 49.37%,which was lower than that of the validamycin (60.76%).The results of this experiment were of great significance to the improvement and stability of the strain's biologically controlling effect and the formulation of scientific prevention techniques.

Key words: Rhizoctonia solani, Bacillus subtilis, colonization, biological control