Victory, Wis. — Several thousand new insects burrowed into trees in southeastern Minnesota on Wednesday as scientists released stingless wasps along the Mississippi River.
Their target: the emerald ash borer, an invasive pest that feeds on ash trees and kills them. Borers have been found from the Twin Cities metropolitan area to Houston County in the far southeastern tip of Minnesota.
State and federal officials delivered the wasps to a forested island just east of Houston County, a control site for the first release. The wasps are a natural predator of the emerald ash borer.