Antifungal Activity and Control Effects of the Fermentation Products Produced by Two Soil Actinomycete Strains from Tarim Basin

In vitro and in vivo assays were performed to study the antifungal activity of the fermentation filtrate of actinomycete strains Y3 and Y5 against plant pathogens.Determination of mycelium growth rate showed that Y3 inhibited the growth of 13 of the 20 pathogenic fungi studied,especially the growth of Sclerotinia sclerotiorum,with an inhibition rate of 90%.Tissue culture test showed that the efficacy of Y3 against S.sclerotiorum was higher than 90%.In contrast,strain Y5 showed a more wide antimicrobial spectrum,in which 10 plant pathogens were considerably inhibited and the other 9 plant pathogens were weakly affected.Further study indicated the effects of strain Y5 on the mycelium growth and spore germination of Phytophthora capsici were obviously strong,being 98.7% and 90.3%,respectively.In a pot test the prevention and cure efficacy of Y3 and Y5 against P.capsici was 57.4% and 50.0%,respectively,thus indicating that the two actinomycete strains Y3 and Y5 were worth further studying and developing.