Residue Dynamic of Emamectin Benzoate In Pinus taiwanensis after Trunk Injection

Pinus taiwanensis stand in Kuocang Mountain of Zhejiang province were selected on January 31st, 2020 for experiment of trunk injection of Emamectin benzoate (EB) to control against pine wilt disease (PWD) caused by Bursaphelenchus xylophilus. In October 2020 and 2021, investigation was made on death rate of pine and EB residue after trunk injection. The result demonstrated that stand treated by injection in 2020 and 2021 had no death of trees, while the control (no injection) had death rate of 5.42% and 9.25%. Analysis on residues of EB in trunk, branch and needle of P. taiwanensis after 1 year of trunk injection resulted that the highest residue of EB in the trunk was 29.95 mg/kg, resudual in needle was 8.46 mg/kg. In 2021, EB residues decreased, but remained over 1.00 mg/kg the trunk, branch and needle.