Armillaria in the Northern Rockies: pathogenicity and host susceptibility on pristine and disturbed sites

Abstract

Over all plots, incidence of pathogenic Armillaria showed a strong tendency to decrease as habitat type productivity increased. This trend gave rise to a clear separation of plots by climax series. Within productivity groups, other patterns emerged. Disturbance appeared to be related to a dramatic increase in incidence of pathogenicity, but not occurrence, within the high-productivity grouping of communities. Also, the ability of disturbance to elicit pathogenicity seemed to decline as site productivity increased. Pristine plots within the low-productivity series exhibited high incidence of the pathogen in a pathogenic state. -from Authors