Diversity of fungi associated with the mountain pine beetle, Dendroctonus ponderosae and infested lodgepole pines in British Columbia

The mountain pine beetle (Dendroctonus ponderosae), one of the most destructive bark beetles, has damaged large areas of lodgepole pine forests in British Columbia (Canada). It has been suggested that the beetle has a mutually beneficial relationship with the fungi that it carries. In this work, the fungal associates of the mountain pine beetle were extensively investigated. Fungi were isolated from the beetles, galleries and sapwood of infested lodgepole pines (Pinus contorta var. latifolia) at six epidemic sites in British Columbia. The isolated fungal species were more diverse than previously reported. We identified a total of 1042 isolates that belong to nine species. Among these, Ophiostoma clavigerum, an Ophiostoma minutum-like species, and Ophiostoma montium were frequently isolated. Unexpectedly, the Ophiostoma minutum-like species was found at high frequency on the mountain pine beetle. Leptographium longiclavatum, Entomocorticium dendroctoni and an unidentified species of Entomocorticium also appeared to be specifically associated with the mountain pine beetle.