Screening and identification of potential Trichoderma sp. against soil borne pathogens of vanilla (Vanilla planifolia)

This study was conducted to evaluate the biocontrol potential of indigenous Trichoderma sp. against fungal pathogens of Vanilla. The pathogens causing wilt and rot diseases of vanilla Fusarium oxysporum, Rhizoctonia solani and Sclerotium rolfsii were isolated from naturally infected vanilla plants. Among the ten isolates, two species Trichoderma harzianum T2 and Trichoderma virens T5 which showed 80 to 90% inhibitions against the selected fungal pathogens were selected. The Trichoderma isolates were identified using Internal transcribed spacer (ITS) region amplification and sequencing. The sequences generated in this study were deposited in the NCBI gene bank and culture collection centre and got the accession number JN 863298 for the isolate Trichoderma virens and JN 000305 for the isolate Trichoderma harzianum.The compatibility of the bioagents with selected fungicides were also investigated under in vitro conditions. Bordeaux mixture was found to be inhibitory to Trichoderma at all given concentrations, whereas the bioagents found to be compatible with potassium phosphonate. Trichoderma harzianum inoculation gave 90–95% disease suppression under green house experiment and was superior than Trichoderma virens and the standard (MTCC 801). Application of biocontrol agents for crop protection is very significant as it has several advantages such as possibility of multiple pathogen suppression, low cost and promotion of soil fertility