Geosmithia species (Hypocreales, Ascomycota) are associates of bark beetles and other arthropods. One species, Geosmithia morbida, is a virulent tree pathogen of Juglans nigra. To date, 10 Geosmithia spp. from conifer-infesting, and at least 23 species from hardwood associated bark beetles have been reported from Europe. The aim of this study was to survey Geosmithia spp. associated with 18 bark and ambrosia beetle species in hardwood ecosystems in Poland. In addition, we evaluated the pathogenicity of the six Geosmithia species by inoculating Acer, Fagus, Quercus, Tilia and Ulmus seedlings. Our surveys yielded a total of 1060 isolates from 2915 beetles and 1887 galleries. We identified isolates using morphology and ITS, β-tubulin and TEF1-α sequences. Altogether we identified 11 species including nine previously known and two new species described here as Geosmithia fagi sp. nov. and G. pazoutovae sp. nov. In addition, a sister species G. longistipitata sp. nov., associated with Picea trees, is described here. Bark beetles from hardwoods, with exeption of Dryocoetes alni, D. villosus, Scolytus ratzeburgi and ambrosia beetles, appear to be regular vectors of Geosmithia spp. Like in other parts of the world, most Geosmithia taxa exhibited a distinct level of vector/host specificity. None of Geosmithia isolates induced any disease symptoms under the conditions of our experiment. This study highlights the need for more intensive surveys across additional areas of Central and Northern Europe, insect vectors and host tree species in order to elucidate the Geosmithia species diversity in this region.

Geosmithia物种（Hypocreales，Ascomycota）是树皮甲虫和其他节肢动物的同伙。一个物种，Geosmithia morbida，是一个致命的病原体树黑核桃。迄今为止，10 Geosmithia spp。来自针叶树的侵扰，欧洲报道了至少 23 种来自硬木相关树皮甲虫的物种。本研究的目的是调查Geosmithia spp。与波兰硬木生态系统中的 18 种树皮和龙涎香甲虫有关。此外，我们通过接种Acer、Fagus、Quercus、Tilia和Ulmus评估了 6 个Geosmithia物种的致病性幼苗。我们的调查共从 2915 只甲虫和 1887 个画廊中获得了 1060 个分离株。我们使用形态学和 ITS、β-微管蛋白和TEF 1-α 序列鉴定了分离株。我们总共确定了 11 个物种，包括 9 个先前已知的物种和两个在此描述为Geosmithia fagi sp. 的新物种。十一月 和G. pazoutovae sp。十一月 此外，姊妹种G. longistipitata sp。11 月，与云杉树相关，描述在这里。来自硬木的树皮甲虫，除了 Dryocoetes alni、D. villosus、Scolytus ratzeburgi和 ambrosia 甲虫，似乎是Geosmithia 的常规载体属 与世界其他地区一样，大多数Geosmithia分类群表现出不同水平的载体/宿主特异性。在我们的实验条件下，没有任何Geosmithia分离株引起任何疾病症状。这项研究强调需要对中欧和北欧的其他地区、昆虫媒介和寄主树种进行更深入的调查，以阐明该地区的Geosmithia物种多样性。