Fungi associated with Cryphalus rhusi (Scolytinae; Coleoptera) infesting lacquer tree, Toxicodendron vernicifluum

We have examined the fungi associated with the scolytid bark beetle, Cryphalus rhusi, which infests the lacquer tree Toxicodendron vernicifluum. The fungi were also evaluated for pathogenicity in T. vernicifluum as a step toward clarifying the potential of the beetle for tree damage. Three fungal species, a Yamadazyma sp., a Fusarium sp., and Penicillium pinophilum were isolated from adult beetles that had emerged from branches. Of these, the Yamadazyma sp. appeared to be a close associate of the beetle, since it was isolated from all individuals used in the study, while the others were much less frequent. Pathogenicity tests revealed that the Fusarium sp. caused slightly larger lesions (by 2 mm) than the negative controls, whereas the Yamadazyma sp. did not cause any symptoms. We conclude that C. rhusi, with its associated fungi, is not likely to be a serious pest for T. vernicifluum.