Rice Sheath Rot: Targeted Approach for Studying the Efficacy of Fungicides and Biocontrol Agents Under Field Conditions of Northern India

Abstract

Sheath rot, caused by Sarocladium oryzae, has emerged as a potential threat in the rice-growing areas of northern India where commercially available rice varieties are susceptible to this disease. Various fungicides and Trichoderma spp. were evaluated in vitro and in vivo against S. oryzae to develop effective management tools to reduce yield losses from the disease. In a 2-year field trial, different combinations of seed treatments and two foliar sprays of fungicide and/or T. harzianum Th-II were evaluated in conditions of artificial inoculation with the pathogen. Based on combined data from the 2 years, the minimum percent disease index (PDI) (11.2%) and the highest mean grain yield (3.63 t/ha) with maximum net profit of INR ₹43,350/ha were recorded for seed treatment with azoxystrobin 11% + tebuconazole 13.8% SC followed by two foliar sprays of azoxystrobin + tebuconazole. The next best treatment consisted of seed treatment with azoxystrobin + tebuconazole followed by two foliar sprays of tebuconazole 25.9% EC; seed treatment with azoxystrobin + tebuconazole followed by two foliar sprays of tebuconazole 50% + trifloxystrobin 25% WG; and seed treatment with Th-II followed by two foliar sprays of azoxystrobin + tebuconazole, which resulted in PDI values of 12.7%, 14.1% and 14.4%; grain yields of 3.56, 3.47 and 3.44 t/ha; and net profits per ha of INR ₹41,087, ₹36,341 and ₹35,769, respectively.