LANSING, Mich. — The Michigan Department of Agriculture and Rural Development (MDARD) revised Michigan’s interior hemlock woolly adelgid quarantine. The quarantine was expanded to three additional Michigan counties.

The updated quarantine was announced on July 28 and now includes Benzie, Manistee, and Washtenaw counties. It regulates the movement of hemlock and tiger-tail spruce trees, forest products, and nursery stock. The quarantine goes into effect on August 1. 

The HWA are tiny aphid-like insects that secrete white wax as they feed on sap from hemlock shoots and branches, which can result in tree death.

“Our goal is to protect the 170 million hemlock trees that live in Michigan’s forests,” said Mike Philip, the director of MDARD’s Pesticide and Plant Pest Management Division. “According to the U.S. Department of Agriculture Forest Service, hemlock trees have a strong impact on streamside habitat conditions and stream health. Loss of hemlock could result in a rise in water temperatures in streams and an increase in soil erosion, something Michiganders certainly don’t need to further experience."

MDARD announced that trees infested with hemlock wooly adelgid should be reported as soon as possible. 

“If left unchecked, hemlock woolly adelgid could spread throughout Michigan’s hemlock trees, causing significant losses and affecting the timber and lumber industries, nursery and landscaping industries, the Christmas tree industry, and the tourist industry,” said Philip. “Hopefully, by expanding [the] quarantine area, we can keep the pest from moving to new areas in the state and slow the spread within the currently infested areas.”

For more information, visit www.Michigan.gov/Invasives.