【Abstract】 The objective of this study was to determine the pathogenicity of Bursapelenchus xylophilus isolates from China, Japan and Canada to 4-year black pine (Pinus thunbergii) and masson pine (Pinus massoniana) seedling. The results showed that their pathogenicity diferentiated distinctly. The mortality of black pine ranged from 0 to 87.5%, and the RHS index ranged from 0 to 110. The pathogenicity of Chinese nematode populations was greater than that of Japan and Canada. The pathogenicity of BxCN3, BxCSC and BxCZD was stronger, with mortality 87.5% and the RHS index exceeding 90. In the 6 isolates whose dead rates were 87.5%, the population of BxCN3 from Nanjing had the shortest death time, 38 days. In all of the tested populatios, the dead process of population BxCZD from Zhejiang was shortest, 14 days in black pine. The results of detrermination in P. massoniana indicated that 4-year seedlings resisted P. xylophilus, with only two seedlings died in this experiment. In this study, incubating carrier with non-symptom was found in P. thunbergii seedlings inoculated with pine wood nematode. It is important for incubaton of nematodes of the spread of the nematode.更多还原