ENDOGENOUS PINE WOOD NEMATOCIDAL SUBSTANCES IN PINES, PINUS-MASSONIANA, PINUS-STROBUS AND P-PALUSTRIS

The presence of the repellents and nematicides to the pine wood nemato de, Bursaphelenchus xylophilus, was found in the heartwood and bark of Pinus massoniana, P. strobus and P. palustris, which have a resistanc e to the pine wood nematode. The heartwood of P. massoniana contained a repellent, alpha-humulene and two nematicidal substances, pinosylvin monomethylether (PSM) and (-)-nortrachelogenin for the nematode. The bark of the pine contained two nematicides, methyl ferulate and (+)-pi noresinol. PSM, which showed the highest nematicidal activity (LD50 wa s 4 ppm), was also contained in the heartwood of P. strobus and the he artwood and bark of P. palustris. The resistance of these pines to the pine wood nematode is considered to be attributed to the presence of these endogenously defending substances. Further, the relationship bet ween the structure and the nematicidal activity was elucidated for PSM and methyl ferulate. Moreover, PSM showed little anti-acetylcholinest erase activity.