Evaluation of Biocontrol Efficacy of Trichoderma Isolates and Methods of its Application against Wilt of Chilli ( Capsicum annuum L.) Caused by Fusarium solani (Mart) Sacc

Seven isolates of Trichoderma spp. were evaluated as bio-agents against chilli wilt caused by Fusarium solani in the laboratory as well as pot culture experiments. Among the Trichoderma isolates, T. viride PDBCTV I0 recorded 100.00 per cent inhibition of linear growth of F. solani under dual culture on potato dextrose agar regardless of whether the Trichoderma spp. were seeded at all same time, one day prior, or two days prior inoculation (DPI) with the pathogen. T. harzianum PDBCTH I0 recorded 100.00 percent inhibition only in the 2 DPI treatments. The antagonists were applied in three different ways with or without carrier for optimization of delivery system. Seven days prior application (DPA) of bio agents favored maximum proliferation of propagules of antagonist in the soil followed by simultaneous application of antagonist and test pathogen and 1east number of propagu1es of antagonists were recorded in application through seed treatment. Under pot conditions, T. harzianum PDBCTH 10 and T. viride (Indigenous) recorded maximum number of propagules in soil. Further, it reduced F. solani propagules up to 100.00 per cent at 60 days after application (DAA), indicating number of test pathogen came down to essentially '0'. However, T. viride PDBCTV I0, T. viride PDBCTC 23, T. viride PDBCTV 24, Trieco (T. viride) and T. harzianum PDBCTH 8 also reduced F. solani population from 10.61 x 103 cfu g^-1 of soil to less than 2 x 10³ cfu g^-1 in 7 DPA treatment at 60 DAA.