Sharma, RoopaliSapna2020-11-042020-11-042020-10https://krishikosh.egranth.ac.in/handle/1/5810154428Rice is one of the important and staple food crop for 70% of world population. India shares about 21% of global rice production. Sheath blight of rice caused by Rhizoctonia solani causes heavy losses ranges between 4-50%. To overcome the problem different management strategies are applied. Among all strategies chemical control still performs better in disease reduction although, due to indiscriminate use of fungicides it upset the biodiversity, environment and soil health. The biological control has emerged as an effective approach for reduction of rice sheath blight because BCA’s have property of growth promotion, induced systemic resistance, hyperparasitism against the Rhizoctonia solani. Due to the inefficiency of working of biocontrol agents in adverse environment and different mode of action of biocontrol agents in one formulation, the present investigation has carried out to study the combining effect of fungal and bacterial biocontrol agents consortium for reduction of rice sheath blight disease as well as for growth promotion of rice plant. During the investigation 11 treatments were used, Two are the potential Trichoderma asperellum isolates (Th17, Th14), two potential Pseudomonas fluorescens isolates (Psf173, Psf2), four are the consortium of potential Trichoderma asperellum and Pseudomonas fluorescens isolates (Th17+Psf173, Th17+Psf2, Th14+Psf2, Th14+Th17), one is standard check PBAT3 (Th14+Psf173), one is fungicide carbendazim and one is control (which is untreated). The pathogen Rhizoctonia solani was identified from collected diseased samples by means or morphological and cultural characteristics. Formation of sclerotia and mycelium in Petri Plates and right angle (90º) branching under microscope proved that the pathogen is Rhizoctonia solani. In case of glass house experiment seed treatment, soil treatment and foliar sprays of biocontrol agents consortium on seed germination percentage, root-shoot length, dry weight and fresh weight of rice plant reveals that the consortium PBAT3, followed by consortium of TH17+Psf173 found be effective as comparison to the carbendazim and control. In field condition, seed treatment, soil treatment, seedling treatment and foliar sprays of biocontrol agents consortium shows that the consortium were found effective in every aspect. Such as plant length, tillers/hill, yield q/ha and test weight was found maximum in consortium of PBAT3 followed by consortium of TH17+Psf173 which was far better than carbendazim and control. Experiment in field condition also reveal that the minimum disease severity were found in carbendazim followed by PBAT3 but overall results shows that the consortium is almost effective as carbendazim in sheath blight disease reduction. Beside this, the biocontrol agents are most effective when applied from initial stages of crop growth and the investigation also proved that the seed treatment, soil treatment and foliar spray of biocontrol agents consortium showed the best results in disease reduction percentage as well as in yield attributes. Therefore, it can be recommended that PBAT3 and Th17+Psf173 consortium against sheath blight disease can be practiced in farmer’s field successfully.EnglishThesis