Study of enzyme activity in Carbamate resistance and different compounds suppressing Carbamate resistance

Synergism of carbaryl methomyl and thiodicarb was tested by piperonyl butoxide (PBO) S.S.S-tributyl phosphorotrithioate (DEF) and diethyl maleate (DEM) to know the mechanism of carbamate resistance in Helicoverpa armigera. There was greater activity of enzyme Glutathione-S- transferase (GST) in carbaryl and thiodicarb resistance whereas less participation of Esterase and Monooxygenase enzymes. Esterase activity was found responsible for methomyl resistance, whereas GST and Monooxygenase enzymes were found to be less active. Bioassay also showed significant carbaryl resistance suppression by Citronella oil (75 mg/larva). Significant methomyl and thiodicarb resistance suppression was achieved by Sesamum oil (75 mg/larva) and Karanj oil (25 mg/larva).