The invasive insect hemlock woolly adelgid was found in Leelanau County in July, officials confirmed on Thursday. It has been spreading north in Michigan for a few years, after devastating hemlock populations on the East Coast decades ago by attaching itself to the trees and feeding on their sap.
Members of the Northwestern Michigan Invasive Species Network identified it on a private property, after a concerned landowner left them a voicemail.
Leelanau County is now one of eight counties in Michigan with active populations of hemlock woolly adelgid – it’s also been found in Allegan, Antrim, Benzie, Ottawa, Muskegon, Oceana, and Mason counties, according to the DNR, and in Huron-Manistee National Forests this spring.
Zach Seguin is the Invasive Species Specialist with the Northwest Michigan Invasive Species Network. He was on-site with the team that sampled trees at the property in Leelanau.
The discovery there is troubling, but, he said Leelanau’s geography, surrounded by Lake Michigan, makes it easier to contain invasive spread.
The county “tapers down into a point,” he said, “and so from there, there’s not a whole lot of other places it could go once it gets to the end of Leelanau County.”
He says Antrim County, where hemlock woolly adelgid was found in late March, concerns him much more, since the insect could spread into more of northern Michigan from there.
Seguin recommends checking underneath hemlock needles for the telltale spots that look like cotton balls, and reporting them to the Invasive Species Network.
Hemlock woolly adelgid spreads in various ways, like by hitching a ride on birds, cars, or people’s clothes. Hemlocks that have the bug can be treated with pesticides, which are usually effective if used early enough.
Susie Iott, an invasive species specialist with the Michigan Department of Agriculture and Rural Development, says Leelanau County will now be added to the state’s interior quarantine, which restricts movement of untreated hemlocks from nurseries.
“For a concerned citizen,” she said, “a way to be helpful is by cleaning clothing or vehicles if you go or camp near places with hemlock wooly adelgid.”
She also added, when buying firewood, “buy it where you burn it.” By moving firewood across long distances, she said, “you could be spreading hemlock woolly adelgid, as well as many other insects, pests or diseases that may not be visible to the naked eye.”