Insecticide Resistance Mechanisms in Indian Helicoverpa armigera
Mar 7, 2019
The cotton bollworm Helicoverpa armigera (Hübner), has developed resistance to almost all groups of insecticides used for its management in India. Studies using biochemical assays and synergists over the past five years on laboratory and field populations indicate that Helicoverpa displays a range of enzymes/isozymes, some of which are unique to the resistant strains. Neurophysiological studies indicate that nerve insensitivity contributes to resistance in individuals assayed in most field strains tested. Pyrethroid resistance was found to be mediated through increased activity of mixed function oxidases or esterases and also to some extent, by nerve insensitivity. Resistance to organophosphates was mainly due to high esterase activity, while preliminary evidence indicates that certain specific esterase isozymes also contribute to resistance against endosulfan.