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Ecology and Epidemiology

Dissemination of Hymenomycetes by Dendroctonus pseudotsugae (Coleoptera: Scolytidae). T. C. Harrington, Former graduate research assistant, Department of Plant Pathology, Washington State University, Pullman 99164, Present address of senior author: Department of Plant Pathology, University of California, Berkeley 94720; M. M. Furniss(2), and Charles Gardner Shaw(3). (2)Principal entomologist, U.S. Forest Service, Intermountain Forest and Range Experiment Station, Moscow, ID Pullman 99164; (3)Professor, Department of Plant Pathology, Washington State University, Pullman 99164. Phytopathology 71:551-554. Accepted for publication 10 November 1980. Copyright 1981 The American Phytopathological Society. DOI: 10.1094/Phyto-71-551.

Isolations of Hymenomycetes on semiselective media were attempted from preflight, in-flight, and postflight Douglas-fir beetles (DFB), Dendroctonus pseudotsugae. Eighty adult DFB either removed or allowed to emerge from Douglas-fir bolts (preflight) yielded no Hymenomycete. In contrast, 178 of 222 DFB collected in flight yielded at least one Hymenomycete: Fomitopsis pinicola from 169; Cryptoporus volvatus (often obscured by the faster growing F. pinicola) from five; and other Hymenomycetes (less important in sapwood decay) from 31. Basidiospores acquired during the flight period, rather than dikaryotic mycelial fragments, are hypothesized to have been the propagules disseminated, since most of these isolates were without clamps (monokaryotic). Of 122 postflight adults removed from egg-laying galleries, F. pinicola was isolated from five and C. volvatus from one. We suggest that many of the propagules were detached in moist phloem during tunneling. These DFB-vectored propagules may be significant in the enhanced sapwood decay noted in trees attacked by DFB.

Additional keywords: bark beetles, dead tree deterioration, Aleurodiscus lividocoeruleus, Coriolus versicolor, Phlebia subserialis, Oedocephalum sp.