【Objective】This study aimed to evaluate the conduction residues and disease prevention efficacy of different chemicals in pine trees following trunk injection and identify trunk injections with strong persistence and effective control, providing a theoretical basis for the use of trunk injections to prevent pine wood nematode (Bursaphelenchus xylophilus).【Method】The insecticidal efficacy of 5% emamectin benzoate soluble liquid, 5% avermectin emulsifiable concentrate, and 1% emamectin benzoate-9% imidacloprid soluble liquid on B. xylophilus was assessed using the dipping method. The sublethal concentration (LC₂₀) of each pesticide was applied to Botrytis cinerea and inoculated with B. xylophilus to assess their effects on nematode feeding and reproduction. Subsequently, these pesticides were injected into the trunks of Pinus massoniana in the forest, and the translocation of residues within the trees was analyzed one year and 660 days after injection. In June of the second year (2022), P. massoniana was artificially inoculated with B. xylophilus, and the disease prevention effect was observed and statistically analyzed one year after the injection.【Result】After 24 hours of treatment, the LC₅₀ values for the three agents were determined to be 10.879 8 mg/L, 57.008 7 mg/L, and 93.693 9 mg/L, respectively. When B. cinerea was inoculated with nematodes and treated with sublethal concentrations (LC₂₀) of these pesticides, all three significantly inhibited nematode feeding rates and reduced nematode populations (333, 466, and 500 nematodes, respectively, compared to 47 766 nematodes/dish in the control). One year after injection, the pesticides were found to translocate upward from the injection sites in P. massoniana. Residual amounts were detected in the upper branches, except for the 5% avermectin emulsifiable concentrate. Among the treatments, the 5% emamectin benzoate soluble liquid exhibited the lowest residual concentration at 0.006 3 mg/kg, while the mixed formulation showed the highest residual concentrations of imidacloprid (0.213 0 mg/kg) and emamectin benzoate (0.082 3 mg/kg). These compounds accumulated at higher levels in areas 2.0 m and 0.5 m from the injection points, with concentrations of 12.863 6 mg/kg and 128.395 2 mg/kg, respectively. After 660 days, residual concentrations of all formulations decreased, although residues remained detectable in the upper branches. The highest residual compound concentration was 0.125 1 mg/kg, followed by 5% emamectin benzoate soluble liquid at 0.074 1 mg/kg, and 5% avermectin emulsifiable concentrate at 0.012 4 mg/kg. Unlike the results after one year, where certain areas exhibited the highest residual concentrations for the 5% emamectin benzoate soluble liquid and the mixed formulation, the residual concentrations decreased with height over time. Pine trees inoculated with B. xylophilus 450 days post-injection and analyzed 75 days after inoculation showed a 100% disease prevention rate with all three pesticides. Continuous observation revealed that 5% avermectin emulsifiable concentrate had a significantly better preventive effect.【Conclusion】The three agents-5% emamectin benzoate soluble liquid, 5% avermectin emulsifiable concentrate, and 1% emamectin benzoate-9% imidacloprid soluble liquid—not only exhibit strong toxicity to B. xylophilus but also demonstrate good translocation and persistence in P. massoniana following trunk injection. Additionally, these injections maintain a strong preventive effect against pine wood nematode infection even into the second year. Among the agents tested, 5% avermectin emulsifiable concentrate shows the best overall control efficacy and should be considered for large-scale application in forest management.