In about 1900, a tiny insect called balsam woolly adelgid (Adelges piceae), a European native, appeared in North America on balsam firs (Abies balsamea) in New England and Canada. In 1928 it was found for the first time in a western state, on ornamental firs near San Francisco. It can now be found in in eastern North America from Newfoundland to North Carolina. In the West it is found in British Columbia, Washington, Oregon, Idaho and California.
Any true fir can be host for balsam woolly adelgid, though some are more susceptible than others. In Mt. Rainier and North Cascades National Parks, infestations have been found on subalpine fir (Abies lasiocarpa) and Pacific silver fir (Abies amabilis), but subalpine fir is more heavily damaged.