Invasive gypsy moth population continues to rise in Minnesota


The Minnesota Department of Agriculture (MDA) trapped nearly about 70,000 gypsy moths so far this year, setting a record high.

The number is more than double the previous record high of nearly 28,000 gypsy moths trapped in 2009, according to a news release. The count for 2013 is expected to rise after officials gather 14,500 insect traps that were set out this spring.

Gypsy moth caterpillars defoliate trees and shrubs, causing major damage to forests in Minnesota over the last 40 years. Severe, repeated infestations can kill trees, the department says.

Over the next several weeks, MDA officials in northeast Minnesota, where gypsy moth populations are highest, will search for evidence of egg masses, a sign the pest has taken up permanent residence in the state.

Currently. gypsy moth populations are controlled with a biocontrol agent that kill the insects when ingested. Over 767,000 acres have been treated in the state, mostly in northern Minnesota.

The National Science Foundation awarded an Illinois State University researcher a three-year, $150,000 grant to study the spread of gypsy moths at Apostle Island National Lakeshore in northwest Wisconsin. The research may be able to provide insight on more effective control methods.

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