State plans to introduce wasps to combat ash borer

The state of Minnesota plans to introduce stingless wasps to help eradicate the emerald ash borer.

The ash borer has been discovered in areas of the Twin Cities, and in Houston County in southeastern Minnesota. Gier Friisoe, the Division Director for Plant Protection with the Minnesota Department of Agriculture said the state will introduce a natural predator of the emerald ash borer.

"There's three wasps, stingless wasps, that prey on the emerald ash borer, and they prey on both the larvae and the eggs," Friisoe said. "We're hopeful by introducing those biological control agents that we'll get a bit of a balance; at least bring down the infestation level."

Friisoe said stingless wasps have worked well in other parts of the world.

"In China, where emerald ash borer [are] native, some of these stingless wasps have been shown to parasitize up to 90 percent," Friisoe said.

Stingless wasps prey on the larvae and eggs of the emerald ash borer. The wasps have been introduced into Michigan, but Friisoe said it's too early to determine their effectiveness. Scientists are also concerned the stingless wasps won't survive winters.

Currently, the state surveys areas for infested ash trees, then removes or treats those affected by the insect. Friisoe said the Forest Service, the U.S. Department of Agriculture, and the Department of Natural Resources are working together to bring the emerald ash borer under control.