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Invasive Species: Balsam Woolly Adelgid

Balsam Woolly Adelgid

(Adelges piceae)
*Detected in Michigan*



  • Tiny one-to-two-millimeter white woolly tufts on the lower trunk of the tree and possibly on large branches in the spring and summer.
  • Swelling and distortion of the twigs, commonly called "gout".
  • Flagging - a branch or branches that turn brick-red.
  • Tree crowns that become narrow and misshapen with few needles.

Balsam woolly adelgid looks like a white, waxy substance on the bark of a balsam tree.

Tiny white, cottony tufts on the trunk of an infested tree. Photo courtesy of Jerald E. Dewey, USDA Forest Service,

balsam woolly adelgid
Swollen tissue in tree twigs, called gouting, is a sign of balsam woolly adelgid infestation. Photo courtesy of David McComb, USDA Forest Service,


If you notice white, waxy material on twigs, branches or stems, or twig gouting on fir trees, do not move them! Take photos, note the location and report it to:


Habitat: Balsam woolly adelgid can infest true fir trees, including balsam, Fraser and concolor (white) fir in forests and landscapes in Michigan. Balsam fir can be found in conifer and mixed hardwood/conifer forests of Michigan's Upper and Northern Lower peninsulas.

Native Range: Central Europe.

U.S. Distribution: Balsam woolly adelgid arrived in North America around 1900 in areas of New England and Canada. In 1928 it was discovered near San Francisco. Today, balsam woolly adelgid is found on the West Coast in California, Oregon, Washington and Idaho; throughout New England; and in areas of North Carolina, Virginia, West Virginia, Tennessee and Michigan.

Michigan Distribution: Infestations have been confirmed in Kent, Missaukee, and Oceana Counties.

Michigan Status: Balsam woolly adelgid is on Michigan's watch list.

Local Concern: Balsam woolly adelgid is a sap-feeding insect that attacks true fir trees, including balsam, concolor (white) and Fraser fir. Repeated attacks weaken trees, cause twig gouting, kills branches and, over the course of several years, cause trees to die. There are nearly 1.9 billion balsam fir trees in Michigan's forests. As the third largest Christmas tree-growing state in the country, Michigan produces nearly 13.5 million fir trees each year, grown on over 11,500 acres. True fir trees, including forest, landscape and Christmas trees, are susceptible.

Means of Introduction or Spread: Balsam woolly adelgid can be introduced on infested

nursery stock, Christmas trees, firewood or tree products. Though the insects don't move far on their own, they can be carried by wind, wildlife or vehicles to new locations.

Quarantine Information: A Michigan Department of Agriculture and Rural Development quarantine regulating the movement of potentially infested nursery stock from areas in North America with known infestations has been in effect since 2014.