ABSTRACT

The fungal disease, dry root rot of groundnut caused by Rhizoctonia bataticola leads to economic losses under both rainfed and irrigated situations. During survey, dry root rot incidence was observed in all the surveyed locations, ranging from 6.82 to 25.67 per cent. Among the three districts surveyed, the mean maximum disease incidence was noticed in Belagavi district (18.35 %) followed by Dharwad district (16.77 %) and Haveri district (16.71%). All the fifteen isolates collected from surveyed locations exhibited variability in their cultural and morphological characterestics. Among the five different fungicides evaluated under in vitro, Carboxin 37.5% + Thiram 37.5% DS and Thiophanate methyl 45% + Pyraclostrobin 5% FS were found to be most effective and significantly superior to all other fungicides. Among the different botanicals and bioagents evaluated under in vitro, crude neem oil at a concentration of 2.5 per cent and Trichoderma harzianum were found to be significantly superior. Seed treatment with Trichoderma harzianum @ 1 per cent, recorded highest germination percentage and seedling vigour index in paper towel method. Management of disease in field conditions revealed that, seed treatment with crude neem oil @ 10 ml kg-1 + seed treatment with (Carboxin 37.5% + Thiram 37.5 % DS) @ 2 g kg-1 + seed treatment with Trichoderma harzianum @ 10 g kg-1 and soil application of FYM based T. harzianum (2.5 kg + 250 kg FYM ha-1) result in lowest per cent disease incidence with highest yield. Four genotypes namely, ICGV-16690, ICGV-16668, Dh 245 and Dh 257 registered resistant reaction to dry root rot disease.