Abstract
It has been cleared that pine damage in Japan was caused by the participation of pine wilt disease whose pathogen is pine wood nematode, Bursaphelenchus xylophilus. Its main vector is Monochamus alternatus. However, Okauma et al. (1999) indicated that pines are not damaged by the pine wilt disease, from the result of their outdoor experiment releasing M. alternatus with B. xylophilus to Japanese red pine trees. Then, we did another experiment in almost same condition as that of Okauma et al. (1999). But, we use adult of M. alternatus in which the number of pine wood nematode were estimeted individually. As a result, maturation feeding quantity was no different from experiment of Okauma et al. (1999), and dying occurred only in the release plot. Thus we thought that the participation of Japanese pine sawyer with pine wood nematode was the cause of dying in our experiment.
