This tiny bug could mean big trouble for Michigan trees

Photo Courtesy of Manuel Will via Unsplash.

By Lucas Henkel

November 8, 2023

If you’re ready to start scoping out the perfect Christmas tree, be sure to keep an eye out for an invasive species that could put a damper on the holiday season.

The balsam woolly adelgid is a sap-feeding insect that attacks true fir trees, including balsam and fraser fir. The tiny bug has been identified across Michigan—specifically in Kent, Missaukee, and Oceana counties—and could put nearly 2 billion balsam fir trees in the state’s forests at risk.

Balsam woolly adelgids are super small—they’re only one-to-two millimeters long—and form white, waxy “wool” that covers twigs, branches, and stems of infested balsam fir trees. Infected trees can be identified by swollen and distorted twigs—commonly called “gout”—and by narrow, misshapen tops with few needles. Over time, an infestation can disrupt the tree’s ability to absorb nutrients and often results in its death within 2-3 years.

Tiny white, cottony tufts on the trunk of an infested tree. Photo Courtesy of Jerald E. Dewey, USDA Forest Service, Bugwood.org via Michigan DNR Website.

As the third-largest Christmas tree-growing state in the country, it’s important that Michiganders do their part in identifying these bugs. Balsam woolly adelgids can travel quickly around the state by attaching themselves to firewood, logs, and vehicles. If you notice white, waxy material on twigs, branches, or stems, or twig gouting on fir trees, don’t move them! Instead, take photos of the infestation, note the location, and report it to state officials.

Swollen tissue in tree twigs, called gouting, is a sign of balsam woolly adelgid infestation. Photo Courtesy of David McComb, USDA Forest Service, Bugwood.org via Michigan DNR Website.

For more information on balsam woolly adelgid and how to report them, visit: michigan.gov/invasives/id-report.