Invasive Bug That Kills Fir Trees​ Spotted In Northern MI: Officials

MISSAUKEE COUNTY, MI — An invasive bug that kills fir trees was found in northern Michigan, according to the Michigan Department of Agriculture and Rural Development.

A consulting forester found the balsam woolly adelgid (BWA) in trees at a residential property in Missaukee County, which is near Cadillac, while working with the landowner, state officials said.

The balsam woolly adelgid is a tiny, sap-feeding insect that attacks fir trees, including balsam, Fraser and white fir trees. An infestation of the bugs can weaken trees, kill branches and even kill them entirely. The bug is on the state's Invasive Species Watch List.

"We don’t know how balsam woolly adelgid was introduced to this site, but early detection is a fundamental component of successful response efforts," Director of the Department's Pesticide and Plant Pest Management Division Mike Philip said. "MDARD and its partner agencies have begun survey work to determine the extent of the infestation."

It is the second time officials detected the balsam woolly adelgid in Michigan. The pest was first found near Rockford in Kent County in 2021. Officials said the site was treated, they were still watching the site to ensure successful eradication.

Although Fraser and concolor fir trees are not native to Michigan, they are often planted in home landscapes. Balsam fir is native to the Upper Peninsula and Northern Lower Peninsula but also found throughout the state in residential and park settings.

Symptoms of balsam woolly adelgid infestation include:

• 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 and die.
• Tree crowns that become narrow and misshapen with few needles.

"This invasive insect is a significant threat to the nearly 1.9 billion balsam fir trees populating Michigan’s forests," Philip said. "And, as the third-largest Christmas tree-growing state in the country, Michigan produces nearly 13.5 million fir trees each year, which are susceptible to balsam woolly adelgid."

Anyone who suspects the pest is damaging fir trees, they should take photos, note the location and report it to the department at MDAInfo@michigan.gov or call 1-800-292-3939.