Mishra, A. K.Sankranti, Akshay2020-11-172020-11-172020M/PP/259/2018-19https://krishikosh.egranth.ac.in/handle/1/5810155129Elephant foot yam [Amorphophallus paeoniifolius (Dennst)] is commonly known as ‘king of tuber crops’ due to its higher biological efficiency, cultivated commercially in the districts of Muzaffarpur, Samastipur, Vaishali, Bagusarai and East Champaran of Agro-climatic Zone-1 of Bihar and regarded as money spinning crop. Among various diseases affecting elephant foot yam, collar rot disease caused by Sclerotium rolfsii causes significant yield loss to the tune of 20 to cent per cent. Considering seriousness of this disease, present investigation was carried out in experimental plot Tirhut College of Agriculture, Dholi, Muzaffarpur (Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar) during 2019-2020. Three broad objectives i.e., survey for prevalence of collar rot disease in elephant foot yam, germplasm screening against collar rot disease and management of collar rot disease through biocontrol agent and chemical fungicide were considered during study. Survey was conducted twice in crop growth period in Samastipur and Muzaffarpur district. Elephant foot yam grown in Samastipur district was found more prone to collar rot disease compared to Muzaffarpur district with increase in incidence of disease during August to September. Twenty number of germplasm were screened against disease including elephant foot yam variety, Gajendra (check) against collar rot disease. Among the screened germplasm, two germplasm viz., TCA EFY-16 and TCA EFY-13 emerged as a resistant germplasm with no disease incidence (0%) and high value of growth attributing characters and yield of 46.04 and 44.97 t/ha respectively. Field efficacy of biocontrol agent and chemical fungicide against collar rot disease was evaluated wherein corm treated with Trichoderma @5g/kg corm + soil application with Trichoderma grown in FYM @ 2.5 kg/pit + soil application twice with Trichoderma grown in FYM @250g/ plant (T6) resulted in minimum disease incidence at different fortnight interval i.e, 5.55% (75 DAP), 7.84% (90 DAP), 6.38% (105 DAP) and 4.52% (120 DAP) with overall 22.22% disease incidence with maximum disease reduction over control (52.94%) and highest yield (34.85 t/ha). Feasibility of treatment in economic terms was calculated by incremental cost benefit ratio (ICBR). The highest ICBR of 1: 2.57 with net profit over control was realized as Rs 134294/ha in treatment where corm were treated with Trichoderma @5g/kg corm + soil application twice with Trichoderma grown in FYM @250g/ plant (T2).EnglishThesis