Abstract
On 17 tree species, which included five pine species, the effect of wood tissues on the molting rate of the dauerlarvae (a dispersal 4th stage) of Bursaphelenchus xylophilus was studied using three methods. The active substance which induced the dauerlarvae to molt exuded from the wood tissues and infiltrated the agar plates (agar plate method). This substance can be extracted by acetone (acetone extact method). Differences in the molting rate of dauerlarvae directly invading wood tissues were observed among tree species (direct method). Throughout the experiments based on each of the three methods, species of Pinus and Larix leptolepis showed the highest molting rate. Abies firma and Cedrus deodara followed them. In every tree species some effect on the molting rate was demonstrated. Since there was no significant difference in the molting effect among pines, which consisted of species both resistant and susceptible to B. xylophilus, we concluded that variability of molting could not be a factor of resistance of pine trees to pine wilt disease. Jpn. J. Nematol. 13:6-13(1983)
