Studies On Antifungicidal Activity Of Secondary Metabolities Of One Actinomycete

This thesis studies on bio-activity of one actinomycetes isolated by institute of pesticide of NorthwestSci-tech University of Agriculture and Forestry. Agricultural antagonistic spectrum and action of modeand safety appraisement have been studied. The main results are as follows: By means of mycelium growth rate, the fermentation products of No.24 were tested against 20 kindsof fungi. The results showed that the fermentation products of No.24 have strong inhibition on variousfungi. At the concentration of 2000mg·L-1,the fermentation had an inhibition of rate more than70% .EC50 were 238.95 mg·L-1,146.87 mg·L-1,and 365.94 mg·L-1 respectively against Exserohilumturcicum,Macrophom kawatsukai and Botrytis.cintrea. The bioassay results of spore germination showedthat the fermentation had an inhibition against Exserohilum turcicum and Fusarium solani with an EC50 of129.33 mg·L-1 and 184.99 mg·L-1. At the concentration of 6000mg·L-1, the results of pot tests showd that the fermentation productshad a certain degree protective efficacy and therapeutic efficacy against Pseudoperonospora cubensis,Blumeria guaminis,Botrytis cintrea and TMV, The control efficiency were over 70%, and the protectiveefficacy was better than therapeutic efficacy.The field trails results indicated that thefermentation product of No.24 had a certain degree control effect against Pseudoperonospora cubensis,Blumeria guaminis and Botrytis.cintrea. The mode of action of No.24 secondary metabolize against disease fungi had been studied, the resultsshowd that the fermentation had a high degree inhibition on mycelium growth and spore germination. Themicroscope observation results showed that mycelium growed slowly and upward and formed umbrellastructure in the poisonous medium. Mycelium presented abnormal shap and crassitude. But It had noinfluence on producing spores and germinating. It had intensive inhibition on gemma elongation. Activity products of No.24 have strong conductibility, by means of local appling drugs, In pottest ,control effect against Blumeria guaminis is 47.54%; and it can persists 10d. Safety appraising had been studied on activity products of No.24, through appraising 14 agriculturalcrops, preliminarily judged that it was safe on agricultural crops.