LC50 for Insecticides against Second Instar Larvae of Cotton bollworm Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) in Maharashtra

The present study deals with the efficacy of Spinter, Cypermethrin and Karate was assessed by larval dip bioassay against second instar larvae of cotton bollworm Helicoverpa armigera collected from the cotton fields at Aurangabad and reared in laboratory until F 1 generation second instar larvae are used to assess the toxicity of insecticide after 48 hours of insecticide treatments. The study result shows that toxicity of Karate was highest with LC 50 of 70.31ppm followed by Cypermethrin with LC 50 277.67ppm and Spinter 454.85ppm. The result showed the resistance increased in Helicoverpa armigera against Spinter in F 1 generation in laboratory conditions.