Ophiostomatoid fungi associated with bark beetles infesting broadleaved trees in Norway

The diversity of ophiostomatoid fungi associated with coniferous trees in Europe is quite well known. However, far less is known about the species associated with broadleaved trees. This study investigated the diversity of ophiostomatoid fungi associated with bark beetles infesting broadleaved trees in Norway. A total of 671 adult bark beetles were collected from six different tree genera. Ten bark beetle species were found; Anisandrus dispar, Dryocoetes alni, D. villosus, Hylesinus crenatus, H. varius, Scolytus intricatus S. laevis, S. ratzeburgi, Trypodendron domesticum and T. signatum. The mycobiota associated with these beetles is largely unknown. Approximately 2200 isolates were obtained from the sampled beetles and were identified using morphology and DNA-sequencing. This resulted in identification of eighteen species of ophiostomatoid fungi, seven of which are known species: Graphilbum fragrans, Grosmannia piceiperda, Ophiostoma karelicum, O. novo-ulmi, O. quercus, Sporothrix dentifunda and S. prolifera. The remaining eleven species are most likely undescribed. Four of these species are closely related to O. novo-ulmi, within the Ophiostoma ulmi complex. Two of the species belong to Sporothrix. Three species form part art of Leptographium sensu lato. The last two species could not be accurately placed within a species complex, but are likely to belong in Ophiostoma sensu lato. Most of the bark beetles were only associated with 1-3 species of ophiostomatoid fungi. However, the number of new species discovered underlie the need for more studies regarding ophiostomatoid fungi associated with broadleaved trees, both in Norway and other European countries.