GRAND RAPIDS, Mich. — Spongy moths, formerly known as “gypsy moths,” will start to emerge in West Michigan soon.
On Tuesday, FOX 17 talked with Joanne Foreman, Communications Specialist with the Invasive Species Program at the Michigan Department of Natural Resources, to find out what Michiganders can expect this year.
The DNR says spongy moth caterpillars typically start to hatch mid-May; however, it’s weather dependent.
As many people know, spongy moths tend to feed on leaves— oak trees and sometimes whatever else may be around— until they finally go into their pupal stage and emerge later in the fall as moths.
“It’s a little early right now, but I have just spoken with the DNR’s forest health specialists and they’re telling me that we can expect a much smaller spongy moth season for 2023,” Foreman told FOX 17 Tuesday. “They’ve explained that we’ve kind of hit our peak in a lot of areas in 2021 and it’s been going down since then.”
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“We may have pockets of areas that had, maybe, a fresh infestation in 2022 that might see a little more defoliation but overall, statewide, we’re looking at much-decreased populations,” Foreman added.
She says the state invested in several spray programs back in the late 1980s and early 1990s that spread a fungus that remains in our soil today.
Because of that, the spongy moth population in Michigan is cyclical— it will never go away but as the population increases, the moths spread the fungus and a virus amongst themselves causing the population to crash.
“Usually, a trend is about eight to ten years,” Foreman explained. “So, once we cool down on this current trend, hopefully, we’ll be free for a while of any real nuisance from these caterpillars and moths.”
When it comes to preventing spongy moth invasions on your property, Foreman says you can buy BTK spray and apply it to the leaves of affected trees between late May and early June.
“Make sure that they are labeled for spongy moth or gypsy moth use, and you’d want to apply those to the leaves of your trees in that early period if you’re seeing those caterpillars coming up and down,” Foreman advised. “Another thing you can do is…you can use a band of burlap or fabric around the tree, that’s folded over, and the young caterpillars will get caught in there.”
She says you can remove the band, get the caterpillars off and put it back on.
Additionally, you should scrape off any egg masses as soon and as often as possible.
“Do what you can to reduce the potential of caterpillar hatch. You’ve still got some time to do that. Also, keep an eye on your trees,” Foreman said. “If you’ve got trees that are very special to you or are over your outdoor use areas, keep an eye. If you think you’re going to need help with management, please consult a professional.”
