K.S.NaikBasamma2016-10-272016-10-272008http://krishikosh.egranth.ac.in/handle/1/82615Potato (Solanum tuberosum L.) is one of the important vegetable crops of Karnataka. Sclerotium wilt of potato caused by Sclerotium rolfsii Sacc. is one of the most important soil borne diseases which is attaining the major status in potato in Karnataka. Potato plants were raised in an inoculated pots and after 6th week a pure culture of Sclerotium rolfsii was obtained from wilted plants and pathogenicity was proved successfully. Maximum dry mycelial weight was recorded on 10th day of inoculation. Among nonsynthetic media tested against Sclerotium rolfsii, potato dextrose agar, oat meal extract agar and Sabouroud’s agar supported maximum radial growth. Among synthetic media tested, Richards’s agar supported maximum growth. The temperature of 30°C, pH of 5.0 and 12 h light and 12 h darkness were found to be the best for fungal growth. Sucrose and potassium nitrate were found to be the best carbon and nitrogen sources respectively for the growth of the pathogen. Due to infection by S. rolfsii total phenol content was increased but reducing, non-reducing and total sugars were decreased. All the cultivars screened against S. rolfsii showed highly susceptible reaction. Soil solarization increased the soil temperature maximum by 9.9°C over nonsolarized. Reduction in soil microbial population i.e. fungi, bacteria, actinomycetes and S. rolfsii was noticed in solarized plot. Among non-systemic fungicides, thiram, emisan and mancozeb recorded cent per cent inhibition at 0.1, 0.2 and 0.3 per cent concentrations. Among systemic fungicides difenconazole, hexaconazole and carboxin at 0.05, 0.1 and 0.2 per cent concentrations recorded cent per cent inhibition of S.rolfsii. Among bioagents tested maximum inhibition of the pathogen was recorded in Trichoderma harzianum. Soil solarization in combination with carboxin + Trichoderma harzianum tuber treatment along with soil application of FYM and neem cake reduced the wilt incidence and increased yield of potato.Thesis