Toxicity of Insecticides against Helicoverpa armigera on Cotton in Maharashtra

Bioassay of five insecticides viz., fenvalerate, cypermethrin, quinalphos, carbaryl and endosulfan were undertaken in laboratory against populations of Helicoverpa armigera collected from known pesticide usage locations in Maharashtra. The log dose probit assays indicated that H. armigera population from Amalner with heavy pesticide usage area recorded higher LD₅₀ values compared to Madha population representing low pesticide usage area. Irrespective of locations, fenvalerate was most toxic to H. armigera followed by cypermethrin, Endosulfan was least toxic to H. armigera.