Seeking the origin of the Japanese oak wilt from phylogeny of its vector insect and pathogen and from variation in virulence of the pathogen

在日本、台湾、泰国、越南和印度尼西亚等地采集到一株安氏甲虫、鸭嘴兽（Platypus quercivorus）和一种日本橡树枯萎病病原Raffaelea quercivora。通过DNA分析确定了它们的系统发育。病媒昆虫和病原菌在日本境外均有存在，未发生黄热病。日本以外的槲皮菌分离株对锯齿栎也具有致病性。毒力不受地区的影响。鸭嘴兽的侵染性尚需进一步研究，但其仅在日本发生的原因可能与寄主植物对日本的高易感性有关。

An ambrosia beetle, Platypus quercivorus, and Raffaelea quercivora, a pathogen of the Japanese oak wilt(JOW) were collected from Japan, Taiwan, Thailand, Vietnam, and Indonesia. Their phylogeny was determined by DNA analysis. Both the vector insect and the pathogen existed outside Japan without the JOW incidence. Raffaelea quercivora isolates outside Japan were also pathogenic to Quercus serrata. The virulence was not determined by regions. The reason why the JOW occurs only in Japan may be related to high susceptibility of host plant species in Japan though more studies will be needed for aggressiveness of Platypus quercivorus overseas.