Seasonal incidence of major insect pests and predators of mustard in lower gangetic plains of West Bengal

Abstract

The present investigation was carried out during rabi, 2019-20 at Jaguli instructional farm of Bidhan Chandra Krishi Viswavidyalaya by using four varieties (ADV414, Bulet, TBM 204 and ADV 406) of rapeseed-mustard. Altogether two insects viz., mustard aphid (Lipaphis erysimi) and sawfly (Athalia lugens proxima) cause most of the damages at different crop growth stages. In the middle of January maximum intensity of sawfly was observed when the crop was flower bud formation stage. Maximum aphid population was noticed during 2nd week of February at silica formation stage of the crop irrespective of the varieties. The aphid population was very strongly correlated with the incidence of coccinellid population. The correlation study between sawfly population and weather parameters revealed that maximum and minimum temperature had significant negative correlation with the pest population. Among the weather parameters minimum relative humidity showed significant negative correlation with the aphid and coccinellid population. Regression studies indicated that temperature and relative humidity were the most influencing factors over the incidence of sawfly and aphid population respectively.