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Pathogenicity and delimitation of a novel Corinectria sp. infecting Picea rubens
Cameron Stauder - West Virginia University. Matthew Kasson- West Virginia University, Division of Plant and Soil Sciences

Red spruce (Picea rubens) has been a primary target for restoration in the Appalachian Mountains over the last few decades following more than a century of decline attributed to forest fragmentation and degradation. Additional threats, especially from introduced pathogens and insect pests, could further destabilize these already fragile ecosystems. An undescribed, pathogenic fungus was recently discovered on stressed red spruce in Virginia and West Virginia. Infections were observed as depressed areas along the stems with red perithecia on the surface of the bark, from which the fungus was isolated. Phylogenetic analyses of beta-tubulin and EF1-? DNA sequences indicated the putative pathogen is closely related to but distinct from the former Neonectria fuckeliana, now Corinectria fuckeliana. The failure of previous surveys to uncover this Corinectria sp., even as a secondary pathogen contributing to red spruce decline, raises concerns that this fungus may represent an emerging pathogen. Broad host range studies are warranted as the closely related C. fuckeliana is a known pathogen of Abies, Picea, and Pinus. Excised stem assays have confirmed pathogenicity of this Corinectria sp. on red spruce as fungus treated wounds had significantly larger (p < 0.001) canker areas (5.5 cm ± 0.17 SE) compared to negative controls (1.3 cm ± 0.13 SE). Additional pathogenicity tests are underway. Given this may represent an emerging pathogen, the pathogenicity of this Corinectria sp. is of great concern to identify potential threats to red spruce management and restoration efforts.