The distribution of pinewood nematode, Bursaphelenchus xylophilus and its vector, Monochamus saltuarius in pine wilt disease infected Korean white pine, Pinus koraiensis in South Korea

After pine wilt disease (PWD) at Korean white pine, Pinus koraiensis has been first reported in the middle area of South Korea in 2006, it spread rapidly to the nearest area. However, it is difficult to predict the spread of damage and set up the proper control strategy specific to P. koreaiensis because the pathology and the biology of PWD in P. koraiensis are not the same with PWD in P. densiflora distributed in middle southern area. So, we selected 14 of dead P. koraiensis in PWD damaged area and analyzed the inner-tree distribution of pinewood nematode, Bursaphelenchus xylophilus and the entrance holes of its insect vector, Monochamus saltuarius. There was no statistical significance between height or direction of wood extracted and the distribution of B. xylophilus among 12 dead pines. The entrance holes of M. saltuarius were concentrated on 5 dead pines without leaves and the maximum number of entrance holes in individual tree was 543. It indicates that the event of spawning of M. saltuarius adult and entrance of hatched M. saltuarius larvae to wood may be dependent on the time of death of host. The entrance holes were frequently found in a southward direction. These result shows that M. salutuarius larvae prefer relatively weak woody parts to enter easily. However, the relation between the thickness of bark of P. koraiensis and the frequencies of entrance holes of M. saltuarius was not observed.