Monitoring of insecticide resistance in Cotton leafhoppers, Amrasca bigutulla bigutulla (Ishida)

Insecticide resistance monitoring study against, Amrasca biguttula biguttula revealed moderate to high level of resistance against the neonicotinoids tested, viz., imidacloprid and acetamiprid as compared to dimethoate which was found to be the most effective insecticides amongst the tested chemicals. The resistance ratio for imidacloprid, acetamiprid and dimethoate was 23.41, 19.08 and 5.21-fold, respectively when compared to the susceptible strain of cotton leaf hoppers. Relatively more glutathion-S-transferase values corresponding to the higher LD₅₀ values of neonicotinoids indicated the role of GSTs in imparting resistance in cotton leaf hoppers against the imidacloprid and acetamiprid.