Abstract
To control pine wood nematodes (Bursaphelenchus xylophilus), chemical absorption, translocation and distribution of pesticides in the pine tree were studied. The treatment of Japanese pine with trunk injection of mesulfenfos (O, O-dimethyl O-4-methylsulphinyl-m-tolyl phosphorothioate) or soil incorporation of disulfoton (O, O-diethyl S-2-ethylthioethyl phosphorodithioate) was confirmed to be the most stable in effectiveness for the control of wilting disease caused by nematodes without phytotoxicity. Amounts of pesticides absorbed in the pine tree were determined by gas liquid chromatography (FPD). Both mesulfenfos and disulfoton were distributed vertically into the trunk and branch portions. Mesulfenfos was mainly found in the xylem and disulfoton was detected from xylem and phloem. The degree of control of pine wood nematodes was correlated with the concentration of pesticides in the pine tree. Detected compounds from the treated trees after trunk injection of mesulfenfos were mainly parent mesulfenfos. In the case of soil incorporation of disulfoton, oxidative products which are the sulfoxide and sulfone derivatives of disulfoton were found in the pine tree.
