Rice (Oryza sativa
L.) is second most important cereal and the staple food for more than half of the world’s population. It provides 20% of the worlds dietary energy supply followed by Maize and Wheat. Sheath blight is one major biotic constraints that affects rice production in India and is considered economically important disease of rice in the world The disease is caused by Rhizoctonia solani
Kuhn (teleomorph: Thanetophorus cucumeris
(Frank) Donk), a fungal pathogen of both rice and soyabeans. The yield loss due to this disease is reported to range from 5.2-50 per cent depending on the environmental conditions, crop stages at which the disease occurs, cultivation practices and cultivars used. The disease has been named as “sheath blight” because of primary infection on leaf sheath. The fungus attack the crop from tillering to heading stage and leaf blade symptoms also observed. Initial symptoms are noticed on leaf sheath near water level. As the spot enlarge, the centre become grayish with irregular brown blackish border. The fungus Rhizoctonia solani
produced usually long cells of septate mycelium which are hyaline within young, yellowish brown. It produced large number of globose sclerotia which initially turn white, late turn brown to purplish brown. Sclerotia as a major source of primary inoculum. An experiment was conducted in vitro
condition during 2017-18 at experimental field of IGKV, Raipur to management the sheath blight disease of rice by application of different botanical plants were evaluated for their antifungal activity against R. solani.
The six botanical plants product and extract namely, Neem oil + Teepol, Neem powder, Karanj oil, Karanj powder + Teepol, Chili + Garlic + Teepol, Chli + Teepol + sarf. Poisoned food technique was employed for the evaluation of botanical plant product and extracts in the laboratory. The all treatments significantly reduced the mycelial growth of Rhizoctonia solani
over untreated treatment. Hexaconaxole was recorded with zero mm mycelial growth (100% growth inhibition) is followed by Neem oil treatment with 10.33 mm mycelial growth and 88.52% growth inhibition, Chili+Garlic 15.33 mm mycelial growth and 82.92% growth inhibition, Karanj oil 16.33 mm mycelial growth and 81.85% growth inhibition and Chili treatment was recorded 80.55 mm mycelial growth and 80.55% growth inhibition over control treatment. The maximum mycelial growth was recorded under control treatment (90.00 mm).
Nirmal Prasad, Nohar Singh, Avinash P and Pradeep Kumar Tiwari. Efficacy of botanical plant product and extracts against Rhizoctonia solani Kuhn causing sheath blight disease of rice under in-vitro Condition. J Pharmacogn Phytochem 2020;9(3):312-315.