Determination of fungicidal activities of six antagonistic actinomycetes in soil and their preliminary identification.

[Objective] The paper was to preliminarily identify the species of six actinomycetes strains,and to determine the fungicidal activities of their fermentation products.[Method] The species of six actinomycetes strains were identified by morphological method,and the fungicidal activities of the fermentation products of six actinomycetes strains were systematically determined by series of methods including mycelial growth rate inhibition method,spore germination method,potting and field test.[Result] Morphological identification results showed that six strains belonged to Streptomyces.Biological determination results indicated that the inhibition rates of the fermentation products of six actinomycetes strains with the concentration of 500 μg/ml against the mycelial growth of Fusarium oxysporum f.sp.Vasinfectum were all greater than 90%;the inhibition rates against the mycelial growth of Botrytis cinerea Pers.,Alternaria alternate and Fusarium oxysporum were also greater than 80%.The inhibition rates of the fermentation products of GZ-204 and GZ-331 strains against the spore germination of Bipolaris sorokiniana and Cercospora sorghi were 97.8%,98.2%,99.5% and 94.6%,respectively.Potting test showed that the protection effects of the fermentation products of GZ-204 and GZ-331 strains on wheat powdery mildew(Erysiphe graminis) were 78.8% and 87.1%,and their cure effects were 62.4% and 68.5%,respectively.Field test showed that the control effects of 200 times fermentation liquids of GZ-204 and GZ-331 strains on wheat powdery mildew were 50.5% and 69.2%,respectively.[Conclusion] The research provided the reference for the development of new pesticides with actinomycetes as the resource.