Bio efficacy of fungicides against rice sheath blight caused by Rhizoctonia solani under in vitro condition

Abstract

Sheath blight caused by Rhizoctonia solani Kuhn [Thanatephorus cucumeris (Frank)\rDonk], occurs throughout the temperate and tropical rice growing regions. Rice sheath\rblight was considered as a minor disease in earlier days, but now it is regarded as an\rinternationally important disease second only to rice blast. Use of fungicides with a\rbroad spectrum of activity against more than one disease is common in rice. The foliar\rspray of fungicides is the single most effective method for the management of sheath\rblight disease. The bio efficacy of various fungicides like Carbendazim 50 per cent\rWP, Mancozeb 50 per cent WP, Benomyl 50 per cent WP, Copper oxychloride 50 per\rcent WP, Edifenphos 50 per cent EC, Iprobenphos 50 per cent EC and Hexaconazole 5\rEC were used to test against the R. solani by Poisoned food technique and Mycelial\rdry weight is analyzed. All the tested fungicides registered appreciable inhibition in\rcolony growth and mycelia dry weight. Among the eight fungicides, Hexaconazole 200\rppm and 400 ppm were completely inhibiting the mycelial growth of R. solani. Among\rthe fungicides, Hexaconazole showed the highest level of inhibition and recorded 49.3\rmg mean of mycelial dry weight. The result of the experiment revealed the superiority\rof Hexaconazole in the control of R. solani, hence the same was used for further\rstudies.