Town of Saukville - Tiny parasitic wasps, Wisconsin's newest weapon in the war against the emerald ash borer, took flight Wednesday in a forest that is under siege from the invasive tree killer.
Two species of stingless Asian wasps that feast on the larvae of the emerald ash borer were released by scientists from the University of Wisconsin-Madison at the Riveredge Nature Center.
A third species that feeds on the egg stage of the bug will be introduced later this summer.
It was the first time that the wasps - which are invasive species in their own right - have been used in Wisconsin to battle the destructive beetle.
UW-Madison entomologist Ken Raffa and research assistant, Todd Johnson, released about 800 wasps from four plastic cups late Wednesday morning in a soggy, mosquito-ridden forest infested with the emerald ash borer.
The bug was first detected in the state in 2008 in nearby Newburg, where the skeletal remains of dead ash trees have become an all-too-common site.
Since then, they have been found in Cudahy, Franklin, Oak Creek, Green Bay, Kenosha and Victory in Vernon County.
Some chemical treatments have shown to be effective, including emamectin benzoate, according to a joint study by several Midwestern universities, including UW-Madison.
But chemical treatments are not feasible to protect entire forests.
The wasps arrived by mail on Tuesday from a federal breeding facility in Michigan, which is doling them out as a biological predator of the emerald ash borer.
The wasps parasitize the larvae and eggs of the insects.
Watch a video about the Riveredge Nature Center wasp release on Fox News website. http://www.fox6now.com/