Studies On Ecology And Biological Control Of Antagonistic Trichoderma Spp. Against Phytophthora Capsici In Ya'an

Fifty-eight Trichoderma spp. strains were isolated from the capsicum soil in the different depth 5cm and 10cm in ya'an suburb.they were indentified as following species:Tharzianum, T. pseudokoningii, T. citrinoviride, T. atroviride, T. longibrachiatum, T. hamatum, T. koningii,, T. aureoviride.The two Trichoderma isolates were selected and used according to the antagonistic test against Phytophthora capsici .The dominant strains were T. harzianum, T. pseudokoningii, T. koningii.The deeper of the soil located and the higher the soil temperature,the less distribution of Trichoderma spp. were during the capsicum growth.The antagonistic test showed that T.harzianum, T. pseudokoningii* T. koningii had the better antagonistic effects .The inhabition of metabolites against Phytophthora capsici were 69.1%% 67.2%, and 63.6% repectively.The interaction between T.harzianum and hypha of Phytophthora capsici showed that T.harzianum made hypha of Phytophthora capsici dissolved % twisted and distorted. In the end,it led to collapse of hypha.The colonization experiment in potted capsicum soil showed that the colonization of Trichoderma spp. in the soil which were mixed with T. harzianum and triadimefon. quicker than that in the soil only applied T.harzianum. The possible reason is some microorganism in soil was inhabited by pesticide to make T. harzianum colonize quickly.The biological control against Phytophthora capsici with T. harzianum showed that T. harzianum had strongly biological effect on phytophthora capsici .The biological control effect of the treatment of which were mixed with triadimefon and T. harzianum was the same with the treament of which only was used T. harzianum,botii are 100%.But The biological control effect of the treatment in which was only used triadimefon was 93%. At the same time T. harzianum also promoted capsicum growth obvisouly.T. koningii * T. pseudokoningii and The strains which came from Aemerica kangnaier had obvisouly advantage in capsicum growth.But the biological control effect of kangnaier isolate was superiorer than others two.