Sublethal and Transgenerational Toxicities of Chlorfenapyr on Biological Traits and Enzyme Activities of Paracoccus marginatus (Hemiptera: Pseudococcidae).

Abstract

Simple SummaryPapaya mealybug, Paracoccus marginatus, is an important invasive pest worldwide, which attacks more than 200 host plants. Chlorfenapyr has been demonstrated to have a significant control effect on P. marginatus. To evaluate the long-term sublethal effects of chlorfenapyr on P. marginatus, the sublethal and transgenerational effects of chlorfenapyr on the biological traits and changes of enzyme activities of P. marginatus were investigated. The results showed that chlorfenapyr had significant effects on the development of subsequent generations of P. marginatus, and chlorfenapyr also activated the activities of SOD of P. marginatus. The results demonstrated that chlorfenapyr-mediated sublethal effects occur in at least two successive generations of P. marginatus. Therefore, it is necessary to reapply the chlorfenapyr prior to emergence of the F3 generation to suppress the population and prevent outbreaks of P. marginatus.Papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae), is an economically important, invasive insect that is now distributed worldwide. Chlorfenapyr has been demonstrated to have a significant control effect on P. marginatus. In order to evaluate the sublethal and transgenerational effects of chlorfenapyr on P. marginatus, the life table data of three consecutive generations were collected and analyzed by the age stage, two-sex life table method, and the enzyme activities were assayed using a spectrophotometer. The results showed that exposure to the insecticide had significant effects on the biological traits of subsequent generations of P. marginatus, and a higher intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and a shorter mean generation time (T) were observed in the chlorfenapyr-treated F1 mealybugs. Enzyme activity assays showed that chlorfenapyr significantly inhibited the activities of catalase (CAT) and peroxidase (POD) while activating the activities of superoxide dismutase (SOD), which suggested that SOD, CAT, and POD may play an important role in the self-defense of P. marginatus against chlorfenapyr. These results conclusively demonstrated that exposure of P. marginatus to sublethal concentrations of chlorfenapyr induced hormetic effects on the F1 generation while having negative effects on the F0 and F3 generations.