Sublethal Effects of Emamectin Benzoate on Development and Reproduction and RNAi of the Vitellogenin Gene in <i>Spodoptera frugiperda</i>
Yi Dai, Fanqin Yang, Jie Li, Huinan Fu, Xi Wang, Bin Wan, Meiting Cai, Tianrong Xin, Bin Xia, Ling Zhong, Zhiwen Zou
Abstract
Spodoptera frugiperda, one of the most destructive corn pests in the world, invaded China in December 2018. In this study, sublethal concentrations (LC 10 and LC 30 ) of emamectin benzoate (EB) were used to treat pesticide-free treatment (PFT) and EB treatment (ET) of S. frugiperda . In PFT, compared with the control (CK), the pupal weight, hatching rate, and pupation rate of LC 10 and LC 30 groups were significantly reduced. The fecundity and the expression of vitellogenin gene ( SfVg ) were decreased after LC 30 treatment, while the LC 10 treatment groups showed no significant difference from the control group. In ET, compared to CK, the fecundity was increased by 11.14 and 18.8%. The expression of SfVg was upregulated by 2.6 times after LC 30 treatment. Moreover, RNAi-mediated SfVg knockdown resulted in a nearly 70% reduction in oviposition. The result provided a theoretical basis for optimizing the application of EB and Vg-dsRNA in the control of S. frugiperda .