Effect of insecticides on natural enemies in Bt cotton

Abstract

Effect of various chemical insecticides on natural enemies in Bt cotton crop was evaluated as a state trial at cotton research station farm, Junagadh Agricultural University, Junagadh, Gujarat during Kharif 2016-17. The chemical insecticides used to spray on Bt cotton crop are Flonicamid 50% WG, Difenthiuron 50% WP, Buprofenzin (IGR) 25% SC, Thiamethoxam 25% WG, Fipronil 5% SC, Neemazal F 5% WSC, Carbosulfan 48% EC, Spiromesifen 22.9% SC, Clothianidin 50% WG, Acetamiprid 20% SP and Dinotefuran 20% SG. The difference in population of all predators (Coccinellids, Chrysoperla and spider) was significantly lower in all the insecticidal treatments than control. However, the treatments, Neemazal F 5 WSC (4.9 nos./plant), Buprofenzin 25 SC (4.8 nos./plant) and Acetamiprid 20 SP (4.8 nos./plant) had found somewhat safer for predators and recorded comparatively higher population of predators than rest of the treatments at 7 days after first, second and third spray.