William J . Otrosina

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I Garbelotto. M., Ratcliff, A., Bruns, T. D.. Cobb, E W.. and Otrosina, W. stumps or trees were S; isolates from pine stumps were 80% S and 20% J. 1996. Use of taxon-specific competitive-priming PCR to study host P; isolates from pine, incense cedar, and western juniper trees were 23% specificity, hybridization, and intergroup gene flow in intersterility(More)
The genus Heterobasidion includes some of the most important pathogens of conifers in the world, and as such it is one of the most intensely studied genera of fungi. Because of the remarkable paucity of distinguishing morphological traits, the taxonomy of species within this genus has always been problematic. A partial resolution of the taxonomic issues(More)
Fungi in the basidiomycete species complex Heterobasidion annosum are significant root-rot pathogens of conifers throughout the northern hemisphere. We utilize a multilocus phylogenetic approach to examine hypotheses regarding the evolution and divergence of two Heterobasidion taxa associated with pines: the Eurasian H. annosum sensu stricto and the North(More)
Otrosina, W. J., Chase. T. E.. and Cobb, F. W., Jr. 1992. Allozyme differentiation of intersterility groups of Hererobasidion isolated from conifers in the western United States. Phytopathology 82:540-545. Allozyme analysis was conducted on 64 isolates from basidiocarps of Heterobusidion unnosum. The isolates belonged lo the “S” and “P” intersterility(More)
A randomized complete block experiment was performed to measure the effect of prescribed, dormant-season burns of three different levels of severity (measured as fuel consumption and soil surface heating) on subsequent insect infestation and mortality of mature longleaf pine (Pinus palustris Mill.). Multiple-funnel traps baited with a low release rate of(More)
A natural first generation hybrid fungus shows interspecific heterozygosity. The nuclear condition of a rare natural hybrid between two taxa of the Heterobasidion complex is investigated. Heterobasidion species are known to be either homokaryotic (haploid) or heterokaryotic (n+n), but heterokaryons are made up of both homokaryotic and heterokaryotic(More)
ABSTRACT The structure of Heterobasidion annosum populations was studied in 15 mixed-conifer sites in central and northern California. Study sites displayed mortality of white fir trees in enlarging discrete patches (mortality centers). At each site, fungal genotypes were defined by somatic compatibility tests. In two sites, further genetic and molecular(More)
Black-stain root disease is a threat to conifer forests in western North America. The disease is caused by the ophiostomatoid fungus Leptographium wageneri (W.B. Kendr.) M.J. Wingf., which is associated with a number of bark beetle (Coleoptera: Scolytidae) and weevil species (Coleoptera: Curculionidae). We developed a polymerase chain reaction test to(More)
A 35-year-old longleaf pine stand exhibited trees in various stages of decline. A study was conducted to determine root-infecting fungi and other abnormalities associated with varying degrees of crown symptoms. A four-class crown symptom rating system was devised according to ascending symptom severity. Leptographium procerum and L. terebrantis were(More)