Screening of two biocontrol strains of Bacillus subtilis against ginseng soil-borne disease and their antifungal activities.

[Objective] The paper was to obtain biocontrol strains with good control effects against ginseng soil-borne disease through screening. [Method] Dilution plate method and plate confrontation culture method were used to isolate and screen biocontrol bacteria from the rhizosphere soil of diseased ginseng. The strains were identified through morphology, physiological and biochemical characteristics and 16S rDNA. [Result] With Rhizoctonia solani, Fusarium oxysporum and Fusarium solani as the indicator strains, two biocontrol strains B59 and X1 with strong antagonistic effects were screened from the rhizosphere soil of diseased ginseng in Tieli farm of Heilongjiang Province, and they were identified to be Bacillus subtilis. The inhibition rates of two biocontrol strains against eight different fungi were all greater than 90%. The primary study indicated that B59 and X1 strains could secrete antifungal active substances. [Conclusion] Two biocontrol Bacillus subtilis strains B59 and X1 all had strong antagonistic effect against ginseng soil-borne disease, which had certain potential for development and utilization.