Exploration and Interaction of Trichoderma species and their Metabolites by Confrontation assay against Pythium aphanidermatum

Four species of Trichoderma when screened against Pythium aphanidermatum by dual culture technique had varied antagonistic effects against the pathogen. The efficacy of Trichoderma culture filtrates was also determined. Since mycoparasitism plays an important role in antagonistic mechanism of Trichoderma species, extracellular enzymatic activity of the strains was assayed. Damping off of Chilli caused by Pythium aphanidermatum is a major disease in vegetables. In vitro experiments evaluated the effect of four isolates of Trichoderma species viz. Trichoderma harzianum (Th Azad), Trichoderma viride (01PP), Trichoderma asperellum (Tasp/CSAU) and Trichoderma longibrachiatum (21PP) were tested against Pythium aphanidermatum (both grown on PDA). T. harzianum (Th Azad) recorded maximum growth inhibition (60.38%) against P. aphanidermatum and produced more amounts of volatile and non-volatile metabolites. The culture filtrate of Trichoderma harzianum recorded complete inhibition on the mycelial growth of pathogen. The experimental results of different seed treatments in chilli revealed significant responses against all the seven seed quality attributes viz. germination, shoot length, root length, seedling length, seedling dry weight, vigour index I and vigour index II. T1 treatment (T. harzianum (Th Azad) was found to be significantly superior and effective in increasing 8.39 per cent more germination of chilli from control.