MINNEAPOLIS (WCCO) – At the University of Minnesota researchers are studying small wasps to see if they’ll survive a Minnesota winter.

Why? Because these wasps kill the larvae of the Emerald Ash Borer, which is killing trees in Hennepin, Ramsey, Houston and Winona counties

The U.S. Forest Service wants to stop these pests before they reach huge stands of black elm in northern Minnesota, which would have an economic impact.

If the Ash Borer can survive our winters, it’s important to know the wasps that control them can also live through the cold.

“What we’re finding is that [the wasps] are extremely cold tolerant,” said Rob Venette of the Forest Service. “We’re not actually getting much mortality until temps fall to around minus 20, minus 25 degrees Fahrenheit.”

In one test, researchers put the wasps into capsules, connect a sensor to a computer, and put the whole thing in an insulation block. The block goes into an extremely cold freezer that simulates winter.

In a different lab, the wasps are attached to thin wires, and fly in a circle while driving a sensor. The sensor records how long the wasp flies.

Researchers want to know if the wasps are going to stay close to their homes or fly further away, said Brian Aukema, of the U of M.

“These are happy fliers,” Aukema said. “Some of these can go up to five miles at a time.”

The wasps are raised in Michigan, and cost $5 each. At that price, the Forest Service and the Minnesota Agriculture Department need them to survive and reproduce in the wild.