author(s)
Israrul Hoque Mondal and Kaushik Chakraborty

abstract
Experiment in field condition was carried out to assess the relative efficacy of three selected plant extracts i.e neem, tobacco, akando and two selected chemical insecticides i.e Dursban 20 EC and Fipronil against the incidence of yellow rice stem borer (YSB), Scirpophaga incertulas (Walk.) at Murshidabad, West Bengal, India, during three consecutive kharif crop seasons of 2013-2015. Grossly the experiment had six treatments that were replicated four times in each year in randomized complete Block Design (RCBD). Plant extracts significantly control S. incertulas population that is comparable with chemical insecticides. Fipronil showed the reduction of 56.28% dead hearts (DH) and 65.27% white head (WH) over control after 35 days of spraying. While the result for dursban was 30.01% DH and 40.27% WH. Neem extract reduced DH and WH by 38.33% and 48.14% respectively. The result from tobacco (22.18% DH and 24.30% WH), akando (15.33% DH and 16.89% WH) are appreciable. Fipronil and Dursban treated plot showed yield of 3.18 and 3.04 t/ha respectively. While in neem, tobacco and akando extracts treated plot the yield was 3.07, 2.86 and 2.68 t/ha respectively. The result indicates that out of the insecticides of plant origin, application of neem formulation effectively reduces S. incertulas infestation in consideration to chemical insecticides.