Rai, BimlaRavali, Somshetty2020-10-292020-10-292020M/PP/261/2018-19https://krishikosh.egranth.ac.in/handle/1/5810153940Rice is the second vastly essential cereal crop in India and nearly two-third of humankind depending on it for their food needs. Rice outcomes are inflicted by so many components; they might be biotic components or abiotic components. Sheath blight disease of rice caused by Rhizoctonia solani Kuhn is led to severe economic losses if weather variables are favourable for it. Disease symptoms were in round or elliptical or irregular shape, greenish grey, varying from 1-2 cm in length, later gradually enlarged and became greyish white centre with brown margin. Lateral stages infection was spread to upper parts like leaf blade, flag leaf, glum, and grains. In the current investigation seven rhizospheric mycoflora i.e. Trichoderma harzianum, Trichoderma viride, Penicillium sp., three Aspergillus species and one unknown isolated from rhizophere soil. T. harzianum and T. viride produced 55.56% and 48.70% of growth inhibition respectively. Four rhizobacteria were isolated from rhizospheric soil, among these RB1 (Pseudomonas fluorescence) and RB2 have shown growth inhibition as 20.86% and 9.30% respectively. Aqueous and ethanol extracts of seven botanicals (Aloe vera, Calotropis, Kanel, Neem, Datura, Bhang and Beal), seven essential oils (Citronella oil, Eucalyptus oil, Cedarwood oil, Nirgundi oil, Lemongrass oil, Clove oil and Neem oil), and eight new chemicals were tested contrary to R. solani. Botanicals were evaluated at 20%, 30% and 40% of concentrations. In the case of aqueous extracts at 20%, 30 % and 40 % of concentration Datura has shown maximum growth inhibition per cent as 85.37 %, 90.56 % and 92.04 % respectively than other extracts and it was followed by Bhang and Calotropis. In the case of ethanol extracts of botanicals at 20% of concentration Calatropis, Datura and Beal have exhibited 100% growth inhibition, at 30% of concentration Neem and 40% of concentration Kanel all so showed 100% of growth inhibition. Essential oils were evaluated at concentrations of 100ppm, 200ppm and 300ppm. At 100ppm Neem essential oil showed maximum growth inhibition per cent (51.48%). At 200ppm Cedarwood oil showed maximum growth inhibition per cent (69.26%). At 300ppm Cedarwood oil and Lemongrass oil showed maximum growth inhibition per cent (82.96%) followed by Clove oil (65.56%). Under new chemicals at 50ppm concentration Flusilazole 12.5% + Carbendazim 25%, Trifloxystrobin 25% + Tebuconazole 50% w/w WG and Carbendazim 25% + Mancozeb 50% WS were showed 100% growth inhibition. Essential oils and chemicals were evaluated at suggested doses in field climate (in vivo) contrary to blight disease. In the case of essential oils, Cedarwood oil @1.0 ml/L has produced 57.38% of disease control and has given 48.24% higher yield than control check, it is followed by Lemon grass oil and Neem oil. In case of new chemicals, Trifloxystrobin 25% + Tebuconazole 50% w/w WG (75% WG) @1.0 ml/L has produced 86.41% disease control and has given 53.11% higher yield than control check. In the current assessment among 146 germplasm/varieties, 2 were not conference with the disease, has represented with 0 ratings, 81 germplasm have 1 to 3 rating resistant reaction. Disease severity significantly correlated with maximum and minimum temperature, minimum temperature, evening relative humidity, and evaporation. It revealed that high temperatures (30 – 32 0C) and high relative humidity (above 90%) were responsible for the establishment of sheath blight of disease in rice.EnglishThesis