Toxicity of neonicotinoid insecticides on key non-target natural predator the larvae of Coccinella septempunctata in environmental

To evaluate the neonicotinoid insecticide tolerance in larvae of Coccinella septempunctata, which is a crucial focus of integrated pest management (IPM) programs, we used lethal and median lethal doses (LR50) of such insecticides and monitored insect mortality and development using a direct-contact method. The mortality tests show that neonicotinoid insecticides are highly toxic to larvae. The LR50 of pre-imaginal stage larvae are ranked as follows: 0.06% clothianidin GR > 0.06% dinotefuran GR > 5% acetamiprid EC > 2% thiamethoxam LDL > 70% imidacloprid WP > 350g/L imidacloprid SC. The mortality rates tended to stabilize after 72 h, even until the pre-imaginal stage. Hazard quotient (HQ) values indicate high potential risks of neonicotinoid insecticides on C. septempunctata in and off farmland. The LR50 dose affects the developmental duration, fourth-instar larvae weight, pupal weight, and weight increment of treated C. septempunctata. These results emphasize the importance of assessing side effects of chemical treatments on natural predator species serving as biological control agents for IPM strategies in agriculture. (C) 2021 Elsevier B.V. All rights reserved.