Assessment of balsam woolly adelgid damage to eastern Washington and Oregon subalpine fir (Project WC-F-07-01)

Abstract

Balsam woolly adelgid (BWA) (Adelges piceae) is an exotic, aphid-like sucking insect originally from Europe that feeds only on Abies species. North American species are particularly susceptible, with the apparently most susceptible being subalpine (A. lasiocarpa), Frasier (A. fraseri), and balsam fir (A. balsamea) (Newton and Hain 2005). The BWA feeds directly through the bark on stems, branches, and buds, causing swelling at the buds and branch nodes (“gouting”), dieback, and tree death. During feeding, the insect injects a salivary substance into the host tree, causing branch calluses and abnormal wood formation. Heavy bole infestations usually kill the tree. Branch and twig infestations cause gouting, which progressively weakens the tree. Infestations can occur at any point in a tree. This results in topkill, top curl, dead branches in the middle, or random dead branches throughout the crown (fig. 12.1).

Parent Publication

• Forest Health Monitoring: national status, trends, and analysis 2010

Citation

Spiegel, Lia H.; Chadwick, Kristen; Mehmel, Connie. 2013. Assessment of balsam woolly adelgid damage to eastern Washington and Oregon subalpine fir (Project WC-F-07-01). In: Potter, Kevin M.; Conkling, Barbara L., eds. 2013. Forest Health Monitoring: national status, trends, and analysis 2010. Gen. Tech. Rep. SRS-GTR-176. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 129-134.