Biocontrol and growth enhancement potential of Trichoderma spp. against Rhizoctonia solani causing sheath blight disease in rice

Aim: The present study aimed to investigate the biocontrol and growth enhancement potentials of Trichoderma spp., against R. solani. Methodology: A total of 31 Trichoderma spp. were examined for their antagonistic potentials against R. solani in dual culture, effect of volatile and nonvolatile metabolites on the growth inhibition of test pathogen under in-vitro condition. The efficacy of Trichoderma spp. were further evaluated for controlling sheath blight and promoting rice growth under in-vivo conditions with different mode of applications. Results: The results of in-vitro confrontation assay revealed that among the different Trichoderma spp. tested, T. harzianum (SVPRT-THLi06) and T. atroviride (SVPP-4) exhibited excellent biocontrol efficacy with 90.9% and 72.0% mycelial growth inhibition, respectively. The culture filtrate of T. harzianum (SVPRT- THLi6) at 50% was highly effective in reducing R. solani mycelial growth up to 95.9% and in case of volatile metabolites, maximum inhibition (72.5%) in mycelia] growth of R. solani was recorded with T. harzianum isolate SVPP-8. A combined mode of application (soil treatment+ root dipping+ foliar spray) with T. harzianum (SVPRT-THLi06) was found most effective under greenhouse condition, which showed the least disease severity (12.4% vs control 49.6%) and disease incidence (27.1% vs control 96.4%). Interpretation: The present study revealed that T. harzianum (SVPRT-THLi06) has potential to control sheath blight disease as well as improve growth of rice crop. Therefore, in future it may be used as bio-based formulation for plant growth enhancement and managing sheath blight disease in rice cultivation and further may be applied in organic rice cultivation.