Occurrence Dynamics and Chemical Control of Mycterothrips glycines in Soybean Field in Northeast China

Mycterothrips glycines Okamoto (1911) (Thysanoptera: Thripidae) is rapidly increasing in fields, posing a new and potentially serious threat to soybean production in Northeast China. To clarify the population dynamics and screen effective insecticides against M. glycines, systematic monitoring and pesticide evaluation were conducted from 2024 to 2025. Occurrence dynamics were continuously monitored using yellow and blue sticky boards, while ten commonly used commercial insecticide formulations (thiamethoxam, clothianidin, sulfoxaflor, acetamiprid, imidacloprid, fenthion, pyridaben, abamectin, beta-cypermethrin, spinetoram) were hierarchically screened through laboratory bioassays, pot trials, and field spraying experiments. The results revealed a distinct ‘rise-and-fall’ occurrence pattern, with the initial, peak, and late occurrence periods occurring in mid-July, late July to early August, and mid-to-late August, respectively. Thiamethoxam and clothianidin exhibited the strongest toxicity against M. glycines (LC50 values of 12.87 mg/L and 13.46 mg/L, respectively), achieving field control efficacies exceeding 85%, which were significantly superior to conventional agents such as imidacloprid and abamectin. The study identified the soybean flowering stage as the critical window for control, recommending preventive interventions when sticky trap monitoring indicates the initial population peak (around mid-July). This research fills the technical gaps regarding the occurrence dynamics of M. glycines and the lack of registered control products in China, providing essential support for precision monitoring and management of soybean thrips.