Pine bark beetle problem in Japan, referring to the discovery of the pine wood nematode, Bursaphelenchus lignicolus (Mamiya & Kiyohara)

Abstract

Heavy loss of pine trees has been occurring for several decades throughout central to southwestern districts of Japan. In spite of beetles abundantly found under bark of dead trees, entomologists were inclined to the assumption that some other agents had already infected healthy trees before beetle attack based on various findings. It has been proved recently that the causative agent was the pine wood nematode (Bursaphelenchus lignicolus) newly discovered by pathologists and its transmitter was the Japanese pine sawyer (Monochamus alternatus). Aerial application of insecticides against the sawyer is now employed as a tentative measure of control.