Assessment of the low lethal effects of emamectin benzoate, chlorantraniliprole, and chlorfenapyr on life parameters and detoxification enzyme activity in <i>Helicoverpa armigera</i> (Lepidoptera: Noctuidae)

The cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), is a polyphagous global agricultural pest that brings serious losses to many kinds of crops. Emamectin benzoate, chlorantraniliprole, and chlorfenapyr are effective insecticides for their control in the field so far. Here, the low lethal effects of the 3 insecticides on H. armigera were evaluated. Exposure to the low lethal concentration (LC25) of these insecticides resulted in prolonged larval and adult developmental periods, with variations in pupal duration across in treatments. Specifically, emamectin benzoate and chlorantraniliprole extended pupal duration, whereas chlorfenapyr reduced it. All treatments exhibited lower pupal weight, emergence rate, and fecundity compared to the control. Additionally, life table parameters such as the net reproductive rate (R0), and intrinsic rate of increase (r) in treated groups were reduced, while the mean generation time (T) was extended in these treatments. Enzyme activity assays displayed that these insecticides caused different detoxification enzyme activities variations, indicating that CarE, MFO, and GST may play key roles in the detoxification of the tested insecticides in H. armigera, respectively. Collectively, the low lethal concentration of emamectin benzoate, chlorantraniliprole, and chlorfenapyr affect the biological traits and detoxification enzyme activities of H. armigera, and the rotation of these insecticides in the field may delay the development of resistance in the future.