Effects of sublethal concentrations of cyantraniliprole on the biology and metabolic enzyme activities of Laodelphax striatellus (Fallen)

Cyantraniliprole has been widely used in China for controlling many pests, including the small brown planthopper (SBPH) Laodelphax striatellus (Fallen), which is a major pest of rice. Sublethal effects of cyantraniliprole on SBPH have not yet been examined. In this study, 3rd instar nymphs of SBPH were exposed to the LC10, LC20, and LC30 (3.17, 6.07, and 9.70 mg/L) of cyantraniliprole, which led to reductions in survival rate and hatchability of the F-0 generation. Compared with the control, sublethal concentrations of cyantraniliprole significantly prolonged the development time of the 4th and 5th instar nymphs of the F-1 generation. In the LC10, LC20, and LC30 treatment groups, the nymphal duration was prolonged by 1.98, 0.99, and 2.54 d, respectively. In addition, the sublethal concentrations of cyantraniliprole shortened the adult preoviposition period. The activities of cytochrome P450 monooxygenases and carboxylesterase in SBPH were promoted after treatment with sublethal concentrations of cyantraniliprole. The increase in insecticide resistance may be due to the increase in the activity of detoxification enzymes. Therefore, this research can provide a theoretical reference for the treatment of resistant SBPH.

Automated summary

This study found that exposure to sublethal concentrations of cyantraniliprole led to reduced survival rate and hatchability of the small brown planthopper (SBPH). It also prolonged the nymphal duration and shortened the adult preoviposition period. The increase in detoxification enzyme activity may contribute to the development of insecticide resistance. This research provides valuable insights for managing resistant SBPH populations.