author(s)
Soumya Patil, D Sridevi, T Ramesh Babu and B Pushpavathi

abstract
Laboratory bioassay of seven selected insecticides namely imidacloprid, acetamiprid, thiamethoxam, diafenthiuron, spiromesifen and chlorfenapyr and dimethoate was evaluated against cowpea aphid A. craccivora, during October to December, 2014 in Department of Entomology, College of Agriculture, Rajendranagar, PJTSAU. Relative efficacy based on LC₅₀ values was found using two bioassay methods viz., leaf dip and direct spray method. Relative efficacy of imidacloprid (8.022) was highest in leaf dip method followed by thiamethoxam (2.419) while in direct spray method spiromesifen (1.948) showed highest efficacy followed by thiamethoxam (1.617). Results of this study indicated that out of selected seven insecticides, neonicotinoid insecticides were highly effective against cowpea aphid.