First discovered in the Badger State in the early 2000s, the invasive beetle is native to Asia, but they had been in the Midwest for at least a decade or so before they were discovered, right under people's noses.
"So for more than a decade, people were accidentally moving this unknown insect around the lake states and the Midwest inside firewood, nursery stock or logs, not realizing we have this hidden green tree killer lurking in our midst," said Bill McNee, DNR Forest Health Specialist.
Now, they've moved up to the Northwoods. The city of Tomahawk realized its trees were infected in the fall of 2022, but the beetles were likely there far earlier.
"So when you start noticing signs, the tree has probably already been infected for a year or two before it starts to show symptoms," said Michael Hooper, Sales Arborist, Foley's Tree Service.
Now, the city has elected to cut most of their public ash trees down, in an effort to keep the insects from spreading.
"What we will be doing will be proactive and reactive, at the same time, we'll be reactively taking trees that are already noticeably infected and in decline as well as taking trees that do not appear to be in decline but are more than likely infected already," said Nick Rosenmeier, Street Department Leadperson for the city of Tomahawk.
So how can someone tell if their tree is infected?
"Browning of leaves, definitely like I said before, dieback, so you'll see branches without leaves and on the trunk of the tree you might notice little area that look like checkered pattern, that's called flecking and that's actually birds trying to get at the insects inside of the bark," said Hooper.
They said if anyone sees any signs of infection, call a professional to take a look to see what the best path forward is.
