Transgenerational suppression of Aphis gossypii Glover (Hemiptera: Aphididae) population resurgence by mepiquat chloride in combination with sublethal insecticides.

Abstract

Aphis gossypii Glover (Hemiptera: Aphididae) is a globally significant agricultural pest that has developed varying degrees of resistance to numerous classes of insecticides. Studies on the plant growth regulator mepiquat chloride (DPC) indicate that direct exposure inhibits development and reduces the reproductive capacity of A. gossypii. However, the effects of combining DPC with insecticides on the development and population dynamics of A. gossypii remain unclear. Therefore, this study investigated the effects of DPC in conjunction with sublethal doses of imidacloprid (IMI-LC₃₀) and sulfoxaflor (SUL-LC₃₀) on the toxicity and sublethal effects of A. gossypii, using life table parameters and qPCR analysis. The results showed that the combination of DPC with IMI or SUL did not enhance the toxicity of either IMI or SUL. Compared to treatments with IMI-LC₃₀ or SUL-LC₃₀ alone, the combination treatments showed no significant differences in longevity, fecundity, and population parameters of the F₀ generation. However, the fecundity of the F₁ generation was significantly reduced, and population parameters also exhibited a decreasing trend. Moreover, exposure of A. gossypii to IMI-LC₃₀ or SUL-LC₃₀ resulted in the upregulation of reproduction-related genes Vg and VgR in the F₁ generation. This effect was suppressed when either IMI-LC₃₀ or SUL-LC₃₀ was co-applied with DPC. These findings demonstrate that combining DPC, in combination with IMI or SUL, can suppress the population resurgence of A. gossypii induced by sublethal exposure to these insecticides on their own. This research provides insights for the effective use of DPC and insecticides.