Ophiostoma species were isolated from bark beetles and Abies mariesii, A. veitchii and A. homolepis attacked by the beetles in Nikko, Tochigi, central Honshu, Japan. One to two Ophiostoma species were frequently isolated from each species of bark beetle. Ophiostoma subalpinum was the most common associate of Cryphalus montanus. Ophiostoma sp. B as well as O. subalpinum was a common fungus associated with Polygraphus proximus. Ophiostoma europhioides was isolated from Dryocoetes hectographus and D. autographus as one of the common associates. Ophiostoma sp. J and Ophiostoma sp. S were frequently isolated from D. autographus and D. striatus, respectively. These fungi seem to have specific relationships with particular bark beetles. Ophiostoma sp. B, Ophiostoma sp. J and Ophiostoma sp. S have unique morphological characteristics and appear to be new species. Five trees of A. veitchii, approximately 43 years old, were inoculated with five Ophiostoma species to assess the relative virulence of the fungi. Ophiostoma subalpinum, Ophiostoma sp. B, and O. europhioides had relatively higher virulence than the other species studied.

Two ophiostomatoid fungi without conidiophores and conidia were isolated from bark beetles and bark beetle-infested Abies spp. The teleomorph characters were similar to species of Ophiostoma, but the absence of the conidial stage hampered their exact generic assignment. Detailed morphological observations and molecular analysis clarified their generic affiliation. Consequently, they were placed in the genus Ophiostoma , but their morphology and DNA sequences did not coincide with any other species of Ophiostoma. Here, we propose these two species as Ophiostoma aoshimae sp. nov. and Ophiostoma rectangulosporium sp. nov. The former species is characterized by perithecial necks ornamented with projections and ellipsoid to oblong ascospores, and the latter species is characterized by perithecial necks ornamented with rectangular ascospores and white colonies.

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Two species of Ophiostoma were isolated from four bark beetles (i.e., Cryphalus montatus, C. piceae, Dryocoetes hectographus, and Polygraphus proximus) infesting Abies veitchii and from their galleries in the waveregenerated forests in the central part of the main island (Honshu) of Japan. One of them is described here as a new species, Ophiostoma subalpinum, and the other is identified as O. davidsonii, newly reported in Japan. Ophiostoma subalpinum is characterized by short ostiolar hyphae, oblong or allantoid ascospores enclosed in a thin, hyaline sheath, and a Pesotum anamorph.