Minnesota is about to unleash a new weapon in its fight to slow the spread of the emerald ash borer.
The Minnesota Department of Agriculture plans to release stingless wasps in rural Houston County in the far southeastern corner of the state on Wednesday. The wasps are natural enemies of the ash borer and are approved by the U.S. Department of Agriculture as a biocontrol measure.
The metallic green beetles have killed tens of millions of trees in other Midwestern states, and now threaten to devastate Minnesota's estimated 900 million ash trees. They were first found in St. Paul last year and in Minneapolis and Houston County earlier this year.
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