Relative Efficacy of Some Novel Insecticides Against Sucking Pests of Black Gram [vigna Mungo (L.)]

Abstract

An investigation was carried out to study the relative efficacy of some novel insecticides against sucking pests of black gram [Vigna mungo (L.)] in randomized block design with three replications during Kharif, 2019 at Crop Research Centre of Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut. During the crop season, the whitefly population recorded first on third week of August and reached its peak (13.6 whiteflies/3 leaves) during second week of September, when the mean temperature, relative humidity and rainfall ranged from 29.8 to 30.0 0C, 83.1 to 85.9 per cent and 88.0 mm, respectively. The whitefly population showed positive correlation with temperature and relative humidity while rainfall was negatively correlated to whitefly population. The jassid population appeared first on fourth week of August and reached its peak (8.7 jassids/3 leaves) in fourth week of September. During this period the weather parameters like mean temperature, relative humidity and rainfall ranged from 28.4 to 29.9 0C, 78.0 to 85.9 per cent and 2.3 mm, respectively. The jassid population showed positive correlation with minimum temperature and relative humidity while maximum temperature and rainfall showed negative correlation. Efficacy of different insecticides viz. imidacloprid 17.8 SL, thiamethoxam 25 WG, acetamiprid 20 SP, oxydemeton-methyl 25 EC, spinosad 45 SC and emamectin benzoate 5 SG were evaluated against Bemisia tabaci and Empoasca kerri in black gram, revealed that all treatments were found significantly effective in reducing the population of both insects as compared to control. Imidacloprid 17.8.SL @ 100 ml/ha was found most effective treatment in reducing the population of B. tabaci and E. kerri followed by thiamethoxam 25 WG @ 100 g/ha. The emamectin benzoate 5 SG @ 200 g/ha was recorded least effective. The highest yield (10.24 q/ha) was obtained from imidacloprid whereas higher cost benefit ratio (1 : 9.78) was obtained from treatment thiamethoxam. The lowest yield (7.50 q/ha) and cost benefit ratio (1 : 2.02) were obtained from the treatment emamectin benzoate and spinosad, respectively.