The invasive ambrosia beetle, Gnathotrichus materiarius (Coleoptera: Curculionidae), in Central Europe

Gnathotrichus materiarius Fitch, 1858 is an invasive bark beetle that colonizes conifers and has spread widely in Europe. The beetle was introduced from North America to Western Europe, where it was first detected in France in 1933. In countries of Western and Northern Europe, the first detections were found at ports or airports, which probably served as sources of further spread. Gnathotrichus materiarius spread eastward to the Czech Republic and other countries in Central Europe from Germany and Poland and spread northward from Italy to Slovenia. The presence of wilting spruces, outbreaks dominated by Ips typographus Linnaeus, 1758, and the subsequent transport of timber have probably accelerated the spread of G. materiarius. It is possible that G. materiarius was imported with timber to Austria, the Czech Republic, and Poland. Although G. materiarius has been present in Europe for almost 100 yr, and even though its host trees include Picea and Pinus spp., which are abundant in Central European forests, no significant damage caused by this beetle has been detected or reported. Gnathotrichus materiarius is a typical secondary pest in that it multiplies on decaying trees or trees already infested and killed by other bark beetle species. It has 2 generations a year in Central Europe. The beetles of G. materiarius occur the whole year, but the flight of adults starts in early May and the offspring beetles emerge in mid-July. The adults of F2 generation overwinter in wood. The best method for monitoring and detecting the presence of G. materiarius is the use of ethanol-baited traps.