Exploiting the biocontrol potential of indigenous Trichoderma sp. against major phytopathogens of Vanilla (Vanilla planifolia)

Abstract

This study was conducted to evaluate the biocontrol potential of indigenous Trichoderma sp. against fungal pathogens of Vanilla. The pathogens namely Fusarium oxysporum, Rhizoctonia solani and Sclerotium rolfsii caus-ing wilt and rot diseases of vanilla were isolated from naturally infected va-nilla plants. Among the ten isolates mainly two species Trichoderma harzi-anum T2 and Trichoderma virens T5 which showed 80 to 90% inhibitions against the selected fungal pathogens were selected. The Trichoderma iso-lates were identified using internal transcribed spacer (ITS) region amplifica-tion and sequencing. The sequences generated in this study were deposited in the NCBI GenBank under the accession number JN 863298 for the isolate T. virens and JN 000305 for the isolate T. harzianum.The compatibility of the bioagents with selected fungicides was also investigated under in vitro con-ditions. Bordeaux mixture was found to be inhibitory to Trichoderma at all given concentrations whereas it was found to be compatible with Potassium phosphonate. T. harzianum inoculation resulted into 90-95 % disease sup-pression under green house experiment and was superior than the inocula-tion of T. virens and the standard T. harzianum (MTCC 801). Application of biocontrol agents for crop protection is very significant as it has several ad-vantages such as possibility of multiple pathogen suppression, low cost and promotion of soil fertility.