Bursaphelenchus xylophilus, commonly known as pine wood nematode (PWN) and pathogen of pine wilt disease, is transmitted to new host trees through Monochamus spp.. In this study, five points were set 1 km apart placing the interface of the damaged area in the middle to measure density of the beetles and confirm the presence of PWN in Chungcheongbuk-do, Republic of Korea. The vectors collected from five traps on each point were sorted on weekly basis until the 12th week. We confirmed the presence of PWN in each collected vector by PCR with species-specific ITS primers.

Pine wood nematode (Bursaphelenchus xylophilus), the pathogen of pine wilt disease (PWD), is transmitted to new host trees through Monochamus spp., vector insects. In Korea, aerial application has been allowed conventionally to eliminate the vectors in their flying season. In this study, thiacloprid was applied to four-year-old Pinus densiflora, which were fed to adult M. alternatus emerged from PWD infected logs for 72 h in the condition of 1 DAT (Days after treatment of thiacloprid) and 15 DAT, respectively. We confirmed the presence of nematodes in each beetle applied to experiment by Baermann funnel method and PCR with species-specific ITS primers. After 72 h of 1 DAT and 15 DAT, thiacloprid residues in pine trees were 0.59-16.32 and 0.043-0.131 mg/kg and the mortalities of the beetle were 100 and 99.2%, respectively. Detection rate of B. xylophilus was 51.3%. The incidence rate of PWD in 1 DAT and 15 DAT showed no mortality and 5.55% compared with 55.5% of control, respectively.

Pine wilt disease (PWD) induced by the pinewood nematode (PWN), Bursaphelenchus xylophilus, is a great threat to pine forests in Europe and East Asia. Identification of interrelation between Monochamus spp., the major vectors of PWD and PWN is the key factor for effective control of PWD because PWN is trasmitted to healthy pine trees only by Monochamus vectors. In this study, direct injection system is designed to apply PWN artificially to M. alternatus just before emergence to adults. After injection of PWN (300~500 nematodes in 10 μl of 1X PBS) using adapted glass pipets, the survival rate of M. alternatus and detection rate of live PWN were 80.0% and 68.8% at 168 h respectively. As a result, we demonstrated the artificial injection methods of nematode to Monochamus vectors for further study of coeffect between vectors and specific stage of PWN including 3rd stage dispersal juvenile.