Primary Study On The Biocontrol Of Rapeseed Sclerotinia Stem Rot With Trichoderma Spp. And Gliocladium Spp.

171 fungal strains were isolated from the surface and inside of sclerotia buried in the soil of rapeseed field to study the fungal varieties and their quantity variation at the different time from Jone to December .2002.The fungi were identified as Gliochadium spp., Trichoderma spp., Fusarium spp., Penicillium spp., Mucor spp., Rhizopus spp., Aspergillus spp.and Pythium spp. Gliocladium spp. were 47.68%and Trichoderma spp. 32.42% respectively which were dominat at the different time of sampling .There were among 55 Trichoderma spp. isolates, 17 isolates of T. koningii, 16 isolates of T. harzianum, 9 isolates of T.aureoviride and7 isolates of T. viride ,others belonged to T. pseudokoningii, T. hamatum, T. longibrachiatum. As the buried time of sclerotia become longer, the species of Trichoderma spp. change very much. T. harzianum and T. koningii appeared earliest J.viride and T.aureoviride later,and T. pseudokoningii, T. hamatum, T. longibrachiatum latest. The strains T3 ,T8,G4,G8 that possed stronger potential ability to biocontrol were selected through dual culture on PDA plates ,effects of metabolites and the trails of detached leave in vitro.The results of solid state fermentation showed that the condition of sporulation of T3 ,T8,G4 and G8 was different,but not much great. It could make the great sporulation when wheat bran and husk media was used,temperature 25 C, oxygen supplyed 7/10 and cultured for 196h.The non volatile substances of T3,T8,G4 and G8 had obvious inhibitions to hyphal growth.of S. sclerotiorum,the inhibitory rate was more than 80%. The non volatile substances of the T3 was stable,the inhibitory rate of which was more than 77% even it was heated at 12rC.The inhibitions to the infection of S. sclerotiorum of cell-free culture filtrates of selected fungis and their serial dilution was obvious on the leave in vitro ,and the efficiencies of inhibition was in 74.14%-89.66%.But They could not stop infecting of S. sclerotiorum completely. The different concentration of conidia of selected fungis had inhibitory effects against S. sclerotiorum, when the conidia was more than 107cfu/mL, the efficiency ofinhibition was more than 94%.The result in fidld test showed that the disease index of each management of selected fungis was obviously less than contrast.but much higher than dimethachlon. The relative control effects of fermentative liquid and conidia of T8 were 62.96% and 58.84% respectively, and which were 84.5% and 75% of the relative control effect of dimethachlon;And the cell-free culture filtrates of T3 ,G4 could also effectively prevent rape Sclerotinia stem rot.their relative control effects were over 80% of dimethachlon; and those of cell-free culture filtrates of G8 were more than 75% of dimethachlon.