Cytospora Canker of Conifers

by Paige Thrush, Nancy J. Taylor  & Francesca Peduto Hand

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Cytospora canker is a stem and branch disease, causing dieback on hundreds of different species of trees and shrubs. The disease is especially destructive to spruces and other conifers in the Midwest and eastern U.S., most often damaging species that are stressed and/or planted outside of their native ranges. Colorado blue, Norway, Engelmann, white, black, red, and Oriental spruce are common hosts. Picea pungens, the Colorado blue spruce, sustains the greatest damage when it is planted in the landscape east of its natural range in the Rocky Mountains. Other susceptible conifers include balsam fir, Fraser fir, Douglas-fir, eastern larch, European larch, Japanese larch, eastern white pine, red pine, jack pine, Himalayan white pine, western red cedar and eastern hemlock.