IRVING TOWNSHIP, Mich. — Nature's "literal" party poopers, according to the Michigan DNR, the spongy moth has reared its hungry, caterpillar head this spring, chomping through the leaves of hardwood trees on southwest side of the state.
The invasive species prefers the trunks of oak trees, where caterpillars hatch from fuzzy, tan-colored egg clusters in April and munch and munch some more through late June, raining down BB-sized droppings (referred to as frass) as they dine.
On their rural property in Barry County, Terry and Chris Bennett can "hardly see the trees for the worms crawling on them."
"They never slowed down," Terry told FOX 17. "They kept getting worse and worse and worse."
While the very hungry caterpillars appear every spring, this season sets a new standard, they say.
"Smushed all over the road," Chris said. "Changes the color of the road. They're that bad."
The Bennetts scrape egg clusters and crush caterpillars when they see them on walks in the woods, but these efforts don't "do a bit of good" against the current population, seemingly crowding every hardwood tree in sight, leaving them vulnerable to disease.
"Pretty sad when you can look up into the trees and see that there's very few leaves," Terry said.
The Michigan DNR says spongy moth populations are dropping statewide, citing sharp declines in defoliation. In 2023, it recorded 386,000 acres of spongy moth-related damage through aerial surveys, compared to the 1.3 million acres of spongy moth-related damage from 2021.
While the department predicted continued population decline in 2024, it said "some defoliation" was still likely in southwest Michigan, including in Barry County.
"Remember that spongy moth outbreaks are cyclical and will collapse in one to three years, even without intervention," the DNR said on its website.
On the farm, though, the Bennetts are still waiting for the bug to break.
"We wonder what's going to happen," Terry said. "What the state or county is going to do to try to control these things."
The pesticide Btk (Bacillus thuringiensis var. kurstaki), which does not adversely affect humans or animals, can be used to target spongy moth caterpillars.
"Are we going to let them kill the trees, or are we going to do something to stop them?" Terry said.
Begone, bugs!
Here's a few tips for how to prevent the spread of the spongy moth:
- Inspect decks, outdoor furniture, fences and trees
- Scrape egg masses into a bucket of soapy water or burn or bury them
- Use a broom to sweep caterpillars into a bucket of soapy water, letting them soak overnight
- Make a tree trunk trap: Cut a band of burlap and wrap it around the trunk. Tie a string around the center of the band and make a two-layered skirt around the trunk. When caterpillars climb the trees, they will get caught in the band. Duct tape will also work as an alternative to burlap.
For more tips, click here.
