blue stain, caused by members of the ophiostomatales, is of concern to the forest industry because it can quickly devalue timber by penetrating deep into the sapwood and creating dark blue to black staining. these fungi depend on insect vectors, such as bark beetles (family scolytidae), for the dispersal of their spores. through a series of two field surveys, the objective of this thesis was to examine the diversity of ophiostomatoid fungi and their associated bark beetles in the thunder bay region, because of little research having been done on this topic in northwestern ontario.