author(s)
Asad Yar, M Ahsan Khan, M Ali Mujtaba, Kamran Ghani and Imran Ali

abstract
Research was conducted to evaluate the toxicity of different conventional insecticides against the field strain of Amrasca devastans (Distant). A. devastans is the pest of economically important crops belongs to the family solanaceous and malvaceous which includes cotton, okra and brinjal and has the potential to become the major pest of these crops, that’s why different insecticides (Bifenthrin, Deltamethrin, Dimethoate and Acephate) were being utilized to suppress this pest. The immoderate utilization of insecticides become the cause of developing resistance in jassid. To monitor the LC₅₀ in A. devastans against these insecticides laboratory trials were conducted and adults of A. devastants were released in leaves immersed with recommended dose of insecticide concentration. Results revealed that the population of A. devastans showed lowest LC₅₀ against dimethoate (2.48 ppm) and highest LC₅₀ against deltamethrin (60.61 ppm). Highest LC₅₀ against deltamethrin showed that A. devastans have developed resistance against this particular insecticide. LC₅₀ of Acephate is (16.48 ppm) followed by Bifenthrin with (5.57 ppm) and Diamethoate with (2.485 ppm). Lowest LC₅₀ in case of Bifenthrin and Diamethoate showed that there are still chances of developing resistance in these insecticides against jassid. Judicious utilization of conventional insecticides which have various mode of action may help farmer to remain the jassid population underneath the Economic Threshold Level.