Effect of sublethal concentration (LC20) of insecticides on the olfactory response of Scleroderma sichuanensis

Background This study investigates the sublethal effects of a sublethal concentration (LC 20 ) of three insecticides, thiacloprid, emamectin benzoate, and matrine, on the host-finding behavior of the parasitoid wasp Scleroderma sichuanensis Xiao. Results Behavioral assessments using a Y-tube olfactometer and the Ethovision 3.1 tracking system revealed that exposure to these insecticides, particularly thiacloprid and emamectin benzoate, significantly reduced the wasps’ ability to detect and respond to host-related cues, including a synthetic compound of Monochamus alternatus Hope, 1842, and host odors. The sublethal concentrations disrupted orientation, searching behavior, and overall activity, even without causing immediate mortality. Conclusion The results indicate that such behavioral disruptions may reduce the effectiveness of S. sichuanensis as a biological control agent, potentially threatening integrated pest management strategies. This study highlights the importance of behavioral changes induced by insecticides when assessing the combined use of chemical and biological control agents.