Armyworms causing ‘heavy defoliation’ of trees around Lake Mille Lacs
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"There’s some live ones here and they’re pretty active," Carol Thaemert-Fox said, pointing to some forest tent caterpillars in a container.
She captured them climbing up her trees near Aitkin, on the northwest shores of Lake Mille Lacs.
"Armyworms, I guess, and they were an army, believe me," she said.
Thaemert-Fox first noticed them on her lilac bushes, and then her birch trees.
"The birch trees got eaten the worst I think because I noticed they weren’t casting the shade we used to get," she said.
Armyworms pose danger to Minnesota trees
The Minnesota Department of Natural Resources monitors forest health, and in fact, just did an aerial survey over Lake Mille Lacs on Tuesday.
"There was heavy forest tent caterpillar defoliation of the forest on the east side of Mille Lacs Lake," Brian Schwingle, a forest health specialist with the DNR, said.
He said this pest is cyclical and comes around every 10 to 16 years.
"We haven’t had a big outbreak for a long time, and so we’ve been expecting an increase in forest tent caterpillar population for several years now," he shared.
The concern with the caterpillars is they go from tree to tree and cause damage to the tree canopy, and experts say the dry conditions are worse, making the trees less tolerable.
"What I recommend is pick a couple trees that you would hate to lose, put a drip irrigation hose line under their canopy and turn that on once every two weeks and let it run for several hours," Schwingle said.
He said that will help alleviate the drought stress and make the tree stronger to handle caterpillar stress.
Thaemert-Fox has used Dawn dish soap and water to keep the worms away.
Her neighbor is wrapping larger trees in plastic and putting Vaseline on the outside, hoping to prevent the crawlers from making it up to the leaves.
"They’ve eaten so much away from the trees that I’m afraid they will die, and I don’t want to lose the trees," Thaemert-Fox said.
It’s a battle she’s not letting up on.
"I was in the Navy and I have to have battle with the army… worms, but it looks like I’m winning," she said with a smile.