Sublethal effects of emamectin benzoate on biological characteristics and the expression of vitellogenin (SgVg) and its receptor in Sclerodermus guani

Abstract

Emamectin benzoate (EMB) is a commonly used insecticide for controlling agricultural and forest pests. To facilitate its rational use in integrated pest management (IPM), the sublethal effects of EMB on the development and reproduction of Scleroderma guani were evaluated. Sublethal doses of EMB (LD₁₀ and LD₃₀) significantly reduced the longevity and fecundity of F₀ females. In the F₁ generation, sublethal doses significantly reduced larval development duration and male longevity but significantly extended female longevity. Additionally, the LD₃₀ treatment significantly decreased the number of laid eggs in F₁ females by 20.72% compared with the control group. The net reproductive rate (R₀) was significantly declined by the LD₃₀ treatment compared with the control group (CK). Furthermore, the mean generation time (T) was significantly extended in both LD₁₀ and LD₃₀ treatment groups. Compared to the control group, the expression of SgVg and SgVgR genes in the LD₁₀ and LD₃₀ groups was significantly lower, which may be a crucial factor for the reduced fecundity of the females. These results indicate that sublethal doses of EMB significantly reduced adult longevity and fecundity of S. guani. The findings are practical for developing IPM strategies for forestry pests using S. guani and EMB.