Invasive Species Spotlight: Invasive Hemlock Woolly Adelgid

Americorps • February 8, 2023

A new location of invasive hemlock woolly adelgid has been found in Benzie County, 50 miles north of what was believed to be the northern edge of infestation in Mason County. The U.S. Department of Agriculture Animal and Plant Health Inspection Service confirmed that a sample taken from the site was positive for hemlock woolly adelgid on January 27, 2023. With funding from the Michigan Invasive Species Grant Program, the network is now undertaking a survey of the location and surrounding properties to determine the extent of the infestation and to mark trees for treatment this summer. Surveys will continue in other areas of the county and along the lakeshore through March.

Hemlock woolly adelgid is a small insect that uses a long, siphoning mouthpart to extract sap from hemlock trees. They can be easily spotted as they produce small sacks that look like balls of cotton and may appear alone or in clusters under hemlock branches.

This feeding weakens needles, shoots, and branches of hemlock trees. Over time, tree growth slows and trees take on a grayish-green appearance. Without treatment, infested trees die within four to 10 years. These insects have the potential to cause significant harm to Michigan’s hemlock population. 

Even though these tiny insects can’t move very far on their own, they can be blown by the wind or even “hitchhike” on animals, people, and potentially vehicles. Always remember when you’re leaving outdoor sites to clean-off and check your gear to make sure you don’t have any unwanted passengers such as the hemlock wooly adelgid. If you’re interested in helping remove invasives from Michigan’s public lands, join us at one of our On the Ground volunteer events. Visit mucc.org/on-the-ground/ to view our upcoming projects. 

photo credit: Connecticut Agricultural Experiment Station

Recent Posts

June 2025 NRC Recap

By Justin Tomei • June 12, 2025
The Natural Resources Commission met today in Bay City. There were no orders for information or action on the agenda. The big news was the commission brought back up the order to reinstate the year-round coyote season, and a vote will happen in August to satisfy posting and notice requirements. MUCC created the Coyote Coalition to put pressure on the NRC, and with today’s inaction, we know that it’s working. With the continued support of the coalition, we will continue fighting to protect proposal G. Consider joining the Coyote Coalition , and let the commission know that inaction is not acceptable, and to follow their legal charge and responsibility. Chair Becky Humphries announced new committee memberships. Wildlife Committee will be chaired by Commissioner John Walters, Governance, Finance and Policy will be chaired by Chair Humphries, Fisheries will be chaired by Commissioner Dave Anthony. There were no other orders for information or action. The next meeting returns to Lansing on July 10.

Conservation Cohort: Training Young Conservationists

By Olivia Triltsch • June 12, 2025
Last week on June 3rd and June 4th, Michigan United Conservation Clubs (MUCC) hosted a two-day training for young professionals.

PlayCleanGo Awareness Week: Taking Action on Invasive Species

By Katelyn Helsel • June 11, 2025
This week marks the annual PlayCleanGo Awareness Week , taking place from June 7-14. Hosted by the North American Invasive Species Management Association (NAISMA), this week encourages outdoor enthusiasts to help stop the spread of invasive species through simple actions. This year’s theme, “Partnering Together to Protect Our Favorite Places”, focuses on the importance of collaboration with Invasives Canada and CONABIO to illustrate how actions can create meaningful change across North America.
More Posts