This study proposes a novel "pesticide-pest mutual management" strategy, transforming the traditional unidirectional impact of pesticides on pests into a sustainable and interactive process. Using the Asian longhorned beetle (Anoplophora glabripennis, ALB) as a precursor, a series of nitrogen-rich biochars (ALB-BC) was synthesized to remove and detect insecticides used in ALB control from water. Among them, acid-modified ALB-BC (HBC 400) exhibited an exceptional adsorption capacity for thiacloprid, reaching 1591.06 mg g-1. Mechanistic studies revealed that Lewis acid-base interactions serve as the primary adsorption mechanism, underpinning ALB-BC's high affinity for thiacloprid. Additional mechanisms, including hydrogen bonding, π-π interactions, and pore filling, further enhanced adsorption performance. These interactions were attributed to the high concentrations of carbonyl and hydroxyl groups, as well as nitrogen species (e.g., pyridinic-N, pyrrolic-N) in ALB-BC, derived from the abundant peptide bonds and polysaccharide structures in ALB. Furthermore, ALB-BC effectively extracted and detected poorly water-soluble insecticides (e.g., cyhalothrin, cypermethrin, and fenitrothion) used in ALB control, alongside thiacloprid, achieving recoveries of 84 %-96 % and detection limits of 0.04-0.09 μg L-1. This study highlights the potential of utilizing forestry pest resources for sustainable applications and demonstrates promising prospects in environmental monitoring and pollution mitigation.