Abstract:In order to ensure the efficacy and its taxonomic status of actinomycete strain 11-3-1, agar block method and tissue culture method were used to test the antifungal activity. The results showed that the strain displayed a broad-spectrum inhibitory activity against 15 plant pathogenic fungi, especially to Sclerotinia sclerotiorum, the width of inhibition zones was up to 19.67 mm. Strain 11-3-1 induced alterations on hyphae morphology of S.sclerotiorum, such as distortion, cytoplasm exosmosis and deformation. Tissue culture method tests showed that the inhibitions rates of the fermentation broth was 96.91% to S.sclerotiorum, and fermentation broth had a better control effect than CK group and fungicide group. According to the morphological, physiological and biochemical characteristics, and 16S rDNA sequence, the strain 11-3-1 was identified as Streptomyces longisporoflavus.