Sublethal Effects of Abamectin and Acetamiprid on the Longevity, Fecundity and Detoxification Enzyme Activity of Rhopalosiphum padi.

Abstract

The bird cherry-oat aphid Rhopalosiphum padi (L.) poses a significant threat to wheat production, resulting in substantial yield reductions. Abamectin and acetamiprid are frequently utilized for management. This study assessed the sublethal effects of abamectin and acetamiprid on R. padi through life table analysis and enzyme activity assays. At 24 h, the LC₁₀ and LC₃₀ values for abamectin to R. padi were 0.063 mg/L and 0.252 mg/L, respectively, while, for acetamiprid, the corresponding values were 0.065 and 0.293 mg/L. The results indicated that exposure to sublethal concentrations of abamectin (AB-LC₁₀) extended the longevity of R. padi F₀ generation, while acetamiprid (AC-LC₁₀ and AC-LC₃₀) decreased it. Furthermore, the fecundity of the F₀ generation was significantly reduced following exposure to AB-LC₃₀, AC-LC₁₀ and AC-LC₃₀. In the F₁ generation, exposure to sublethal concentrations of acetamiprid negatively impacted on R. padi, as evidenced by a significant reduction in longevity; fecundity and population parameters (R₀, r, λ, s_xj, l_x, l_xm_x, v_xj and e_xj). Conversely, sublethal concentrations of abamectin did not significantly affect these parameters. Additionally, population projections revealed a significantly smaller total population size of R. padi in the acetamiprid-exposed group compared to both the abamectin-exposed and control groups. Except these population-level effects, the activities of detoxification enzymes, including cytochrome P450 monooxygenases (P450), glutathione S-transferases (GST) and carboxylesterases (CarE), changed differently after treatments. These results suggest that sublethal concentrations of acetamiprid, but not abamectin, significantly inhibit the population growth of R. padi. These insights are crucial for R. padi control and facilitate the development of effective control strategies that take into account these sublethal effects in integrated pest management strategies targeting R. padi.