Geographic distribution of false smut disease of rice in India and efficacy of selected fungicides for its management

Abstract

False smut disease of rice caused by the fungus Ustilaginoidea virens, has become a serious production constraint in various rice-growing regions of India. Analysis of rice false smut disease survey data of last 24 years revealed significant changes in the intensity of the disease in various rice-growing regions of India over the years. We evaluated three fungicide formulations viz., trifloxystrobin-tebuconazole (TT) combination (0.04%), kresoxim methyl (KM) (0.1%) and propiconazole (PC) (0.1%) for their effectiveness against false smut disease of rice. Under in vitro condition, TT and PC completely inhibited the fungal growth while KM inhibited the growth by 80%. We evaluated the efficacy of these chemicals in a multi-location trial in 3 hot spot locations, consecutively for three years. A single fungicide spray was given in 3 different crop stages (booting, 50% panicle emergence and 100% panicle emergence). The results indicated that all the treatments significantly reduced the percentage of both infected panicles and spikelets in all the three locations. Both TT and PC were most effective in reducing the disease intensity and increasing the yield when applied either in booting or in 50% panicle emergence stage.