Emergency Control Strategies for Hylurgops longipillus R. (Coleoptera, Scolytinae) Outbreaks: From Chemical Communication to Integrated Management.

Under climate warming, bark beetle outbreaks increasingly threaten forest health. Hylurgops longipillus, a native bark beetle in Northeast China, causes patchy mortality in Pinus koraiensis plantations. We developed an integrated emergency control system based on host selection chemical ecology. Damage characterization revealed that adults concentrated on trees with 10-50% crown needle yellowing, and infestations expanded as discrete patches radiating from multiple epicenters. Electrophysiological and behavioral assays of host volatiles and some of their isomers yielded a highly effective attractant (69.4 adults per five-trap set over 5 d, 1.8× control) and a repellent reducing ethanol-baited trap catches by 83.3%. Emergency control techniques consisted of integrated management combining removal and safe disposal of infested trees, chemical stump sealing, push-pull trapping, and tree vigor enhancement. Three-year monitoring showed ~94% decline in trap catches, no subsequent outbreaks, and stable control. This attractant-centered, chemical ecology-based system can rapidly suppress H. longipillus outbreaks and achieve long-term management, providing a scientific basis and operational framework for similar localized bark beetle emergencies under climate warming.