Conductance distribution of emamectin benzoate nanocapsule particles within Pinus massoniana Lamb.

Emamectin benzoate-inclusive nanocapsule particles (EB-NC) were developed to improve the conductivity of emamectin benzoate (EB) within Pinus massoniana Lamb. and to enhance the efficacy of pine wood nematode disease control. The EB-NC granules (purified amount 22.57% EB) were prepared by emulsion polymerization method combined with freeze-drying technique. The appearance and particle size of EB-NC were analyzed by cryo-scanning electron microscopy and transmission electron microscopy, and the results showed that EN-NC was 100-200 nm and spherical. The slow-release performance of EB-NC particles was analyzed by dynamic analysis method, and the results showed that the cumulative EB release rates of EB-NC at 2, 4, 6, 12, and 24 h were 8.91%, 15.61%, 23.75%, 43.08%, and 77.55%. The average EB residues of EB-NC particles in pine trees were detected by HPLC method in spring and summer after trunk injection application to study the conduction distribution. The results showed that the average residues of EB in the lower, middle, and upper branches of the tree were 1.95, 3.44, and 7.64 mg/kg 90 d after the trunk injection application in spring to P. massoniana Lamb., and 0.67, 1.72, and 0.60 mg/kg 90 d after the trunk injection application in summer. The study showed that EB-NC particles with small particle size and large specific surface area could slowly release the active ingredients of the agent, and rapidly conduct in the ponytail pines after trunk injection application. This study provides a new idea and basis for the year-round control of pine wood nematode disease by trunk injection.