Sublethal effects of the cis-nitromethylene neonicotinoid insecticide cycloxaprid on the white-backed planthopper, Sogatella furcifera (Hemiptera: Delphacidae)

Abstract

Cycloxaprid is a novel cis-nitromethylene neonicotinoid insecticide which shows high insecticidal activity against a wide range of sap-feeding insect pests. Studies were carried out to investigate the sublethal effects of cycloxaprid on the white-backed planthopper, Sogatella furcifera (Horváth) (Hemiptera: Delphacidae). When the third-instar nymphs were treated with LC25 of cycloxaprid, the female adult longevity and fecundity were significantly decreased in both the F0 and F1 generations. Moreover, the oviposition days and egg hatchability in the F1 generation were decreased. However, no significant differences were observed for the adult preoviposition period (APOP), total preoviposition period (TPOP), intrinsic rate of increase (ri), finite rate of increase (λ), net reproductive rate (R0) and mean generation time (T) of the F1 individuals. Additionally, the P450 activity and the mRNA expression levels of CYP4CE3, CYP417A4, CYP439A3, CYP6FJ3, CYPSF01 and CYP4FD2 were significantly induced by LC25 of cycloxaprid exposure in the third-instar nymphs. In contrast, the expression level of vitellogenin (Vg) in the female adults was significantly decreased after being treated with cycloxaprid at their nymph stage. These results indicate that cycloxaprid has potential as a good alternative insecticide for the sustainable control of S. furcifera field populations.