Bio‐control potential of Trichoderma spp., against Fusarium spp., the incitants of Pokkah boeng disease of sugarcane under in‐vitro conditions

Fifty one Trichoderma isolates were isolated from sugarcane rhizosphere soil using selective culture media and characterized for their cultural and morphological characteristics. Trichoderma isolates were evaluated in-vitro conditions for their bio-control activity against Fusarium spp., the causal agent of Pokkah boeng disease of sugarcaneby dual culture method, an assay for production of volatile inhibitory metabolites and mycoparasitism. Morphological and genetic characterization was carried out. There was not much variability in colony characters and growth rate among fifty-one isolates of Trichoderma spp. Among the Trichoderma isolates, twenty promising Trichoderma isolates were molecularly identified as T. harzianum, T. afroharzianum, T. atrobrunneum, T. aureoviride, and T. asperellum. It can be concluded that predominantly Trichoderma harzianum and other allied spp., are abundant in the sugarcane rhizospheric ecosystem. In dual culture assay, twenty isolates showed > 70% linear growth inhibition against F. fujikuroi and F. proliferatum. Twenty promising isolates were further screened for the production of inhibitory volatile metabolites. Among them, nine isolates showed growth inhibition > 7% against both Fusarium spp. Mycoparasitism was observed in eleven isolates, among them four isolates viz., T28, T38, T49, and T41 showed parallel mycoparasitism against F. fujikuroi while seven isolates (T9, T17, T26, T28, T41, T49, and T40) showed coiling around F. proliferatum hyphae. Thus, the four most promising strains viz. T28, T38, T41, and T49 were identified as potential Trichoderma spp., and need to screen further for disease management in field conditions. On the basis of the antagonistic study, it can be concluded that T. harzianum strain T28, T. aureoviride strainT38, T. harzianum strain T41, and T. harzianum strain T49 are potential candidates for being explored further as biocontrol agents for the management of Pokkah boeng disease.