The Toxicity Response of Coccinella septempunctata L. (Coleoptera: Coccinellidae) after Exposure to Sublethal Concentrations of Acetamiprid

Coccinella septempunctata is a nontarget beneficial arthropod and an important aphid predator in agricultural crops. In this study, the toxic effects of the neonicotinoid acetamiprid on C. septempunctata were investigated to determine its applicability and efficacy against the aphid predator. The results of the toxicity test showed that the second instar larvae of C. septempunctata were the most sensitive to acetamiprid. The LC50 values of the 1st, 2nd, 3rd, and 4th instar larvae were 15.767, 9.412, 18.850, and 25.278 mg a.i. L−1, respectively. Compared with that of the control, the predation ability of different larval instars was inhibited by sublethal concentrations of acetamiprid. The results of the predatory function test showed that sublethal concentrations of acetamiprid could reduce the consumption of aphids by fourth instar C. septempunctata larvae over a short duration and significantly inhibited the predatory ability of ladybird larvae. The results of the developmental test showed that sublethal concentration of acetamiprid shortened the growth duration of C. septempunctata larvae. Acetamiprid had considerable adverse effects on the different developmental stages of C. septempunctata. Together, our results provide information for implementation in biological and chemical control strategies for the integrated management of aphids.