Abstract
Aqueous paraquat and ethephon solutions were injected into the trunks of Akamatsu, Japanese red pine, Pinus densiflora S. & Z. and Kuromatsu, Japanese black pine, P. thunbergii PARL. The parts of the trunks receiving chemicals secreted large quantities of oleoresin. At the same time Japanese pine sawyers, Monochamus alternatus HOPE, started laying eggs in these areas of the trunks. The number of egg-laying slits increased drastically, their density becoming more than 10 times than those on trunks of pines blighted by pine nematodes, Bursaphelenchus lignicolus M. & K. The secretion areas probably release powerful oviposition attractants for the Japanese pine sawyers.
