Study On Fermentation And Action Mechanism Of Trichoderma Against Rhizoctonia Solani

Inhibition effects of Trichoderma longbrachitum ACCC30150, T. citrinoviride ACCC30152, T. viride A and T. harzianum B were tested against thirteen plant pathogens by dual culture on potato dextrose agar Petri plates. The results showed that these four strains had wide inhibiting spectrums and stronger inhibition abilities against other 12 kinds of pathogens except for Curvularia lunata. T. longbrachitum ACCC30150 had the strongest inhibition capacity with a rate of 95% against Rhizoctonia solani Kulhn. It was found that Trichoderma possessed food and space more quickly than pathogens. Moreover, the four Trichoderma strains had different characteristics against different plant pathogens.Mycoparasitic activities of these four Trichoderma strains were studied against R. solani. By light microscopy, the investigation showed that T. longbrachitum ACCC30150 and T. citrinoviride ACCC30152 could inhibit pathogen by mycoparasitism, with evidence of either by parallel growth with its hyphae, or by penetrating hyphal cells of pathogen by forming appressoria, which invariably lead to hyphal cell cytoplasm leak and disruption. However, mycoparasitism of T. viride A and T. harzianum B against R. solani had not been found. So far, the hypothesis of "Snap Mechanism" had not been reported.The characteristics of fermentation liquids of the four biocontrol strains were studied. Results showed that the fermentation liquids were neuter or acid at the end of the fermentation, of which pH value were 6.0, and the colors were various. The crude extracts of mycelium and fermentation liquids were assessed for antimicrobial activity. The results showed that only ACCC30150 had antimicrobial activity, and the active component was in the fermentation liquid which could be solute with ethyl acetate.In this experiment Rhizoctonia solani Kulhn was selected as a test pathogen for the next study about the effects of the four biocontrol isolates.Biocontrol effects of Cucumber Rhizoctonia Rot caused by R. solani with Trichoderma were studied under greenhouse condition. An experiment was preformed to evaluate the effects of different biocontrol strain, different component and different time of inculation. The greenhouse experiment showed that effects were various between the four...