Rashid A. Khan, M. Hamed, and Farhat Fatima Jamil

pp. 261 - 264

Abstract

The efficacy of Lorsban^TM, Alpha-cypermethrin^TM and Karate^TM was assessed by larval dip bioassay against third instar larvae of American bollworm, Helicoverpa armigera (Hub.) collected from a cotton field at Faisalabad and reared in the laboratory until F1 generation. Third instar larvae were used to assess the toxicity of insecticides after 48 hrs of insecticide treatments. Results showed that toxicity of Karate was above all with LC₅₀ of 71.31ppm followed by Alpha-cypermethrin with LC₅₀ 287.87 and Lorsban 464.85, respectively. These results showed the increased resistance of H. armigera against Lorsban in F1 generation
under laboratory conditions.