Michigan DNR Needs Winter Hikers Help Identifying Wooly Adelgid Infected Hemlock Trees

The Michigan DNR needs hikers help protecting the state’s more than 170 million hemlock trees. An invasive species called, wooly adelgids, has been confirmed in infected eastern hemlock trees in five counties along Lake Michigan’s shoreline. Winter hikers are key to the state department’s fight against the invasive species. Wooly adelgid affected trees are easier to spot in cold temperatures, by checking the underside of hemlock branches for white and round ovisacs near the base of needles. Up close the ovisacs of wooly adelgid infected hemlocks, can appear alone or in clusters, of what look like tiny cotton balls. The eastern hemlock is a very popular tree found in front yards, and parks. And typically found in moist soil along streams, rivers and Michigan’s coastal dunes. Without treatment for wooly adelgid, hemlock trees can die within 4 to 10 years of becoming infected. Michigan’s coastal dunes, a common home for the eastern hemlock, are primarily found along the Lower Peninsula’s shore with Lake Michigan, and the Upper Peninsula’s Grand Sable Dunes, near Pictured Rocks National Lakeshore.

Reporting possible Wooly Adelgid information:

Report infested hemlock trees by using the Midwest Invasive Species Information Network, available online at MISIN.MSU.edu or as a downloadable smartphone app. The MISIN smartphone app will take a GPS location point if a report is made at the site; it also will allow you to upload photos with a report.

Reports also can be made by email to MDA-Info@Michigan.gov or by phone to MDARD’s Customer Service Center at 800-292-3939.

Identify the location of infested trees and, whenever possible, take one or two pictures of infested branches to help confirm identification. To avoid spreading the insect, do not collect sample branches or twigs.

To find out more about the effort to inventory and treat infested hemlock trees in Michigan, view a recording of the January 2021 NotMISpecies webinar, “Hemlock Rescue,” available at Michigan.gov/EGLE/Outreach/Not-MI-Species-Webinar-Series.