Xylosandrus germanus (Blandford) (= Xyleborus germanus) is an ambrosia beetle that is found in Japan, Korea, the KurU Islands, Vietnam, China, Taiwan, central Europe, and the Cnited States (Nobuchi 1981). It attacks apparently healthy plants and those that are dying or recently dead (Weber 1982). Kaneko (1967) reported X. germanus to be a serious pest on tea (Thea sp.) plants in Japan, and Heidenreich (1%0) reported it on oak (Quercus sp.) trees in Gennany. This beetle seems to be increasing in economic importance on black walnut (Juglans nigra L.) and other hardwood species in the U.S. (Weber 1982).
Weber, B. C. and McPherson, J. E.
"Annotated Bibliography of the Ambrosia Beetle Xylosandrus Germanus (Coleoptera: Scolytidae),"
The Great Lakes Entomologist, vol 15
Available at: https://scholar.valpo.edu/tgle/vol15/iss3/7