Armillaria mellea and Decline of Red Spruce. A. C. Carey, Yale School of Forestry and Environmental Studies, New Haven, CT. E. A. Miller, and G. T. Geballe, Yale School of Forestry and Environmental Studies, New Haven, CT; P. M. Wargo, U.S. Forest Service, Northeastern Forest Experiment Station, Hamden, CT; and W. H. Smith and T. G. Siccama, Yale School of Forestry and Environmental Studies, New Haven, CT. Plant Dis. 68:794-795. Accepted for publication 15 March 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-794.

Roots of 288 red spruce trees (Picea rubens) in mixed hardwood, transitional, and montane boreal forest in New England and New York were excavated and examined for colonization by Armillaria mellea. The fungus was associated with declining and dead spruce in all locations. The percentage of roots colonized by the fungus increased with increasing severity of decline symptoms but decreased with increasing elevation. In high-elevation boreal forests, where the decline has been documented to be most intense, 75% of the recently dead and severely declining trees were not colonized by A. mellea. Although A. mellea is involved in red spruce decline, it is not the major cause of the current regional episode of spruce decline and mortality.