M.G.PalakshappaPraveenkumar.N.2016-11-022016-11-022009http://krishikosh.egranth.ac.in/handle/1/83381Sesame is one of the important oilseed crops of Karnataka. Sesame suffers from several diseases. Among them collar rot caused by Sclerotium rolfsii is the most destructive one causing 10-15 per cent loss. Hence, detailed studies on this pathogen including isolation, pathogensity test, standardization of inoculum level, survey of the disease in sesame growing areas of northern Karnataka, in vitro evaluation of botanicals, bioagents, biorationals, organic amendments and integrated disease management had been carried out. Rhizosphere population of microorganisms was estimated in different intervals in the treatments of integrated management of collar rot of sesame. A pure culture of S. rolfsii was obtained from sesame plants showing typical collar rot symptoms and its pathogensity to sesame was proved. Maximum incidence (5.9%) was recorded in MARS, UAS, Dharwad and minimum incidence (1.0%) in MARS, UAS, Raichur and Kanyadoddi village in Raichur taluka. Nimbicidin at 5 and 10 per cent, T. harzianum and cowurine + vermiwash at 2 and 6 per cent and cowurine + butter milk at 4 and 6 per cent were found effective in inhibiting mycelial growth and sclerotial formation of S. rolfsii. Vermicompost recorded least disease incidence (30.30%) followed by neem cake (33.33%). Rhizosphere microbial population increased in all integrated treatments tested. At 30 DAS the maximum population of fungi, bacteria and actinomycetes were noticed in T1 (FYM + seed treatment with T. harzianum), T2 (FYM + seed treatment with P. fluorescens) and T5 (FYM + drenching with jeevamrutha), respectively. The same trend was also noticed at 45 DAS. In the integrated management of sesame collar rot, the treatment T7 (FYM + seed treatment with carboxin) was found to be the most effective in reducing the disease and it recorded the least per cent disease incidence (33.33%).Thesis