COMPARATIVE EFFICACY OF TEN COMMERCIAL FUNGICIDES FOR THE CONTROL OF RHIZOCTONIA SOLANI, THE CAUSE OF BLACK SCURF DISEASE OF POTATO

Abstract

Black scurf disease of potato caused by Rhizoctonia solani is one of the major problems causing considerable yield losses throughout the world. The control of R. solani is mainly based on the application of fungicides. Therefore, in the present study, ten fungicides belonging to different groups were evaluated for their in vitro effectiveness against R. solani. Highly significant inhibitory effects of fungicides were recorded on mycelial growth, sclerotial production, and germination of sclerotia of R. solani. In the in vitro test, the sensitivity of R. solani was found to vary greatly with the fungicides and their concentrations. The mycelial growth of R. solani was found to be the most sensitive to Antracol, Benlate, Captan, Dithane M-45, and Ridomil while the least sensitive to Polyram Combi. An intermediate sensitivity of the fungus was noticed to Daconil, Brassicol, Bavistin, and Vitavex. Sclerotial production by the fungus was the most sensitive to Ridomil and Benlate. At 50 ppm concentration, Benlate and Ridomil completely inhibited the sclerotial production. Dithane M-45 and Captan reduced the production of sclerotia greater than Deconil, Brassicol, and Bavistin. The least effective fungicide in reducing sclerotial production was Polyram Combi. Similarly, the most effective fungicide in reducing sclerotial germination was Benlate. The fungicides, Ridomil and Dithane M-45 showed an intermediate effect on the germination of sclerotia while Daconil and Captan proved to be the least effective fungicides in sclerotial germination of R. solani.