Tree-Killing Pest Found Near Sleeping Bear Dunes

Feb 19, 2021

Hemlock Woolly Adelgid
Credit Michigan Department of Natural Resources

A tree-killing pest has made its way into the Sleeping Bear Dunes National Lakeshore and its spread has state natural resources officials concerned.

The threat comes from the hemlock woolly adelgid, described as aphid-like creatures that are native to eastern Asia. They form small white masses on the underside of branches and make their way beneath the bark to feed off the sap.

“After a number of years of feeding on the hemlock tree, the hemlock woolly adelgid will kill the hemlock,” said Robert Miller, an invasive species specialist with the Michigan Department of Agriculture and Rural Development.

Miller said the hemlocks help protect the dunes from erosion, serve as homes and shelter for birds and deer, and they help keep inland trout streams cool and clear.

“We need our hemlocks here in the state because they help keep our sand dunes in place near our lakeshore and they keep our rivers cool and clean and they protect our wildlife habitat,” he said. “So, they’re an important resource.”

He said the hemlock woolly adelgid was already present in west Michigan lakeshore counties, and probably hitchhiked with campers into the dunes area.

Miller said, left unchecked, the pests are a menace to 170 million hemlocks across the state -- growing everywhere from wild forests to suburban landscapes. He said naturalists are particularly concerned people will unknowingly move the pest into the Upper Peninsula.