EFFECT OF MONOCHAMUS-CAROLINENSIS ON THE LIFE-HISTORY OF THE PINEWOODNEMATODE, BURSAPHELENCHUS-XYLOPHILUS

The development of Bursaphelenchus xylophilus in pine wood infested wi th and free of Monochamus carolinensis was investigated. Formation of third-stage dispersal juveniles occurred in the presence and absence o f pine sawyer beetles. The proportion of third-stage dispersal juvenil es in the total nematode population was negatively correlated with moi sture content of the wood. Formation of nematode dauer juveniles was d ependent on the presence of the pine sawyer beetle. Dauer juveniles we re present in 3 of 315 wood samples taken from non-beetle-infested Sco ts pine bolts and 81 of 311 samples taken from beetle-infested bolts. Nematode densities were greater in wood samples taken adjacent to inse ct larvae, pupae, and teneral adults compared with samples taken from areas void of insect activity. Nematodes recovered from beetle larvae, pupae, and teneral adults were mostly fourth-stage dauer juveniles, a lthough some third-stage dispersal juveniles were also recovered. Daue r juvenile density was highest on teneral adult beetles.