Toxicological Studies of Imidacloprid &; Bifenthrin : Toxicological studies of imidacloprid and bifenthrin against mustard aphid, Lipaphis erisimi (Kalt.) on Brassica rapa L.

"Toxicological studies of imidacloprid and bifenthrin against mustard aphid,Lipaphis erisimi (Kalt.) on Brassica rapa L. subsp. Oleifera (toria)" revealed that all the incecticidal treatments viz., imidacloprid 20, 40, 60 g a.i./ha, bifenthrin 60, 80, 100 g a.i./ha and deltamethrin 15 g a.i./ha were found to be significantly superior over control (untreated). The highest population reduction of the aphid was obtained with imidacloprid at 60 g a.i./ha (81.59 and 86.01%) after one and seven days of spraying in both the years. The highest mean yield was obtained from imidacloprid 60 g a.i./ha (6.97 q/ha)which was not significantly different from imidacloprid 20 g a.i./ha . The LC50 values of imidacloprid was 0.00017.Based on population reduction, yield,cost : benefit ratio, relative toxicity, residual toxicity and residues dissipation pattern imidacloprid 20 g a.i./ha can be considered sufficient to control the L. erysimipopulation and to optimize the yield of rapeseed.