Screening and Identification of the Antagonistic Microbe to Rhizoctonia solani and its Physiological Characteristics

Using dual culture,3 strains of actinomycete and 5 strains of bacterium which inhibition zone width against Rhizoctonia solani above 10 mm,were screened from 67 soil samples of Hanyuan county,Pingshan county of Sichuan and Sidonggou region of Guizhou.The strain B1 and strain B4 were found having most antagonistic effects on Rhizoctonia solani among these screened microbes.According to their colony features and physio-biochemical reactions,strain B1 had been identified as Bacillus circulans,while strain B4 as Bacillus polymyxa.Meanwhile,it was found that the optimum growth temperature of strain B1 was 34~38℃,of strain B4 was 28~32℃ respectively,the optimum growth pH of strain B1 was 6.5,of strain B4 was 7 respectively,strain B1 and B4 could tolerate the salinity as high as 5% and 3% respectively in this study.