Gypsy moth battle opens in Duluth

Gypsy moth
The gypsy moth was introduced to North America in an effort to create a silk industry.
Courtesy Purdue University/File

The Minnesota Department of Agriculture on Friday sprayed over 1,000 acres of trees in Duluth with an insecticide to try to slow the spread of the invasive gypsy moth.

The insect has defoliated millions of acres of trees over the past several decades as it's slowly migrated from the East Coast to the Midwest. Last year, it gained a foothold in northeast Minnesota along the North Shore.

Agriculture officials aim to slow its spread across the rest of the state, said Kimberly Thielen Cremers, a pest mitigation supervisor for the department. Unless the effort is successful, she said the gypsy moth won't simply be a forest pest.

"They're going to be a pest that's going to be established in urban areas, and areas in Minnesota all the way from the North Shore to the southwest corner," Thielen Cremers said. "So it's a pest that definitely has huge impacts for the state of Minnesota in general.

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The department is planning to treat an additional 50,000 acres of trees in the Duluth area in July.

The moth has slowly munched its way westward since the European insect arrived in Boston in the1800s, stripping leaves off oak, poplar, and 300 other species of trees and shrubs. It was first detected in Minnesota in Duluth in 1980.

Since then, the state has largely kept the pest at bay. But Thielen Cremers said last year the moth established reproducing populations along the North Shore.

The department plans to treat an additional 50,000 thousand acres in Duluth next month. A quarantine is also scheduled to go into effect in Cook and Lake Counties on July 1 to restrict the movement of logs and trees outside the two counties.