Relative Susceptibility of Helicoverpa armigera from two Locations to Certain Insecticides

Differences in susceptibility of Padappai and Guntur populations of Helicoverpa armigera Hb. to deltamethrin, cyper-methrin, fenvalerate and chloropyriphos were low. It is suggested that low effectiveness of insecticides in controlling bollworms in Guntur may be because of killing of natural enemies due to over usage of synthetic pyrethroids. In the absence of baseline data on susceptibility of Helicoverpa to insecticides, it may be difficult to attribute the failure of insecticides to control the bollworms due to development of insecticide resistance.