Screening And Identification Of Biocontrol Actinomycetes

In order to find new actinomycetes with significant biocontrol effect and provide the effective source for biocontrol of plant pathogens, 54 strains of actinomycetes were isolated from seven soil samples collected from Shangluo, Zhouzhi counties of Shaanxi province, and Zhucheng county of Shandong province by the trapping and diluting methods. By antagonism in Petri-dish trial, 4 strains of actinomycetes were screened.The antagonistic spectrums of fermentation broth of four strains were tested then the preventing disease and growth-promoting effects of them were studied in greenhouse. The results showed that the fermentation broth of strain 06-6 have the best inhibiting effect on target pathogens. The significant growth-promoting on tomato plant and effective control effects to Botrytis cinerea on tomato were observed in greenhouse assay.The strain 06-6 was integrated with other four actinomycetes in different ratio to control Sphaerotheca fuliginea on cucumber in the greenhouse and the best combination 06-6+153+Am3 for the effective control effect was determined. Optimized conditions for fermentation of actinomycetes 06-6 were ascertained by the experiment of fermentation condition optimization. The result showed that the optimized medium for strain 06-6 was DBY, pH 7.5, the fittest culture time was 144h and the best content in 250mL flask was 50mL. The strain 06-6 was identified as Griseorubroviolaceu by the traditional and molecular biology methods.