New threat arrives for Northland gardeners

• The bronzed cutworm adult

The bronzed cutworm adult

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Jana Albers has been studying bugs in northern Minnesota for 32 years, and she’s never seen this before.

A new bug for our region, the variegated cutworm, has invaded, sending light-brown moths across the Northland, laying eggs on the siding of homes and windows — and even on laundry hanging on the line.

“We got that laundry report from Two Harbors. But the calls are coming in from all over,” said Jana Albers, bug expert and forest health specialist for the Minnesota Department of Natural Resources. Her husband, Mike Albers, is also a DNR forest bug expert. “I’ve never seen this moth before. Mike has been here 35 years and he’s never seen it.”

The Albers even found a moth in their house.

Variegated cutworms “is our best guess what this is,” Albers said. The insects are native to Minnesota, but are usually seen in the agricultural southern reaches of the state.

It’s the first time they’ve thrived this far north. It’s possible they blew up here from southern states last year, she said, but no one knows how or why they are here.

“We’re getting the same reports from northern Wisconsin, too. People are wondering what the heck this new moth is,” Albers said. “We had a very warm winter — unprecedented — and we’re seeing things that made it through the winter that normally wouldn’t make it. I think we’re going to see a lot more things suddenly show up that we haven’t had before.”

The variegated cutworm moth is about 1½ inches long and fairly streamlined, usually brown or tan or mottled gray: “Pretty nondescript,” Jana Albers noted.

The insects overwinter as pupae. They hatch as moths about when leaves are fully out.

After they fly around and mate, the female moth will lay eggs on smooth surfaces: tiny clusters of eggs usually in a line. Sometimes the eggs are described as white, butterscotch or reddish.

“I’ve only seen one of the moths. But we have eggs all over our window screens and our soffits,” said Dave Thibault of Duluth’s Kenwood neighborhood. “When I first saw them without my glasses, I thought we had paint peeling. But my wife said, no, those are eggs.”

The moths soon die. But the caterpillars, or larvae, that hatch from the eggs can last for weeks, munching on all sorts of greenery. They get their names because they often cut the plant stem off near the soil.

“People are complaining about the egg masses already. And we’re seeing some of the caterpillars hatching,” Albers said. “It’s probably happening faster here (in Grand Rapids) than Duluth, where it’s a bit cooler.”

Those newly hatched caterpillars will be hungry. They will come out at night and munch on tree leaves, fruits, tomatoes and other stuff in your garden, Albers said.

Because they climb as caterpillars, they cause damage to plants — both by cutting the stem off young seedlings and by defoliating leaves in older seedlings and perennials and trees.

Albers suggests picking as many of the caterpillars off sensitive plants as possible. Some gardeners use aluminum foil or a tin can around the base of a seedling to block the caterpillar. Gardeners also can control caterpillars with contact insecticides applied late in the day. She said to use Neem products, carbaryl and other insecticides.

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