William J. Otrosina

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for help in performing the isozyme analysis. 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 groups S and 77% l? The recovery(More)
R oot diseases are somewhat mysterious. Operating as they do within the soil, it is difficult to actually view root pathogens or follow their progress in causing disease. The signs and symptoms that they produce can be quite subtle and variable. Just identifying which pathogen occurs in a specific situation is often challenging. Nevertheless, in the past(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)
and F intersterility groups were subjected to isozyme analysis. European S, P, and F groups had more variability than the North American S and P groups in expected hterozygosity, number of alleles per locus, and percent polymorphic loci. In contrast with the North American S and P groups, the European intersterility groups could not be distinguished from(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)
We determined the effects of subsoiling on woody lateral roots and enzyme activities involved in stem carbon metabolism of 90-to loo-year-old Jeffrey pine (Pinusjefreyi Grev. and Balf.) growing on the eastern side of the California Sierra Nevada Range. Twelve 1 .O-ha plots were established on each of two sites. Four site treatments-thinning and subsoil-ing(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)
A 35year-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)
The fact that endemic root disease causing pathogens have evolved with forest ecosystems does not necessarily mean they are inconsequential. A pathogen such as the P group of Heterobasidion annosum has become an intractable problem in many Sierra east side pine stands in California because the fungus is adapted to colonization of freshly cut stump surfaces.(More)