Abstract
Spotted bollworm, Earias vittella Fabricius (Lepidoptera: Noctuidae) is a serious pest of cotton in South Asia, including Pakistan, and has developed resistance to most chemical classes of insecticides. The aim of this study was to determine the baseline susceptibility and stability of resistance to cypermethrin, deltamethrin and spinosad in a field collected population of E. vittella. The baseline susceptibility values of E. vittella to cypermethrin, deltamethrin and spinosad were 1.24, 0.94 and 0.16, respectively. Resistance to tested insecticides was unstable and spinosad was more toxic than cypermethrin and deltamethrin. The results suggest that deltamethrin, cypermethrin and spinosad can be included in a control program of E. vittella due to high reversion rates. These results have significant implications for the use of insecticides in E. vittella management.