Innovative research helps combat emerald ash borer

The Minnesota Department of Agriculture (MDA) is using innovative research from the University of Minnesota (U of M) and the U.S. Forest Service to help determine the next steps against emerald ash borer (EAB), a destructive tree pest found in 18 states including Minnesota. EAB larvae kill ash trees by tunneling into the wood and disrupting the flow of nutrients.

The metallic-green adult beetles are a half inch long, and are active from May to September. Signs of infestation include increased woodpecker activity, D-shaped exit holes in ash bark and serpentine tunnels under the bark.

MDA started EAB biological control in Minnesota in 2010. The strategy seeks to control EAB populations through introductions of EAB’s natural enemies: stingless wasps that prey on the tree pests.

Rob Venette, a biologist with the Forest Service’s Northern Research Station in St. Paul, is leading studies of EAB cold hardiness as well as the hardiness of three species of stingless wasps to determine the insects’ potential range.

Sam Fahrner is a U of M graduate student working with Assistant Professor Brian Aukema to study the distance stingless wasps can fly. Fahrner’s research incorporates an unusual machine called a flight mill. The device allows an insect to fly while attached to a tiny wire. The flight mill is connected to a computer, which tracks the distance the stingless wasps can fly. The mill Fahrner uses can track up to 32 stingless wasps simultaneously.

“We will use the cold tolerance information to determine where to release each stingless wasp species,” MDA Biological Control Coordinator Monika Chandler said. “Knowing how far the stingless wasps can fly will help us decide how to allocate the stingless wasps among EAB infestations.”

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