The emerald ash borer

Hoping to defeat the emerald ash borer (EAB) where it lives, the U.S. Forest Service last week let fly a new species of wasp along the North Shore Channel and the Des Plaines River. This species, one of three that are being raised by the Forest Service in cooperation with Michigan State University, searches the bark of ash trees for EABs or their eggs, which they use as food and protection for their own eggs. They do not harm humans or other animals and are important natural enemies adapted to controlling EAB populations, according to the Forest Service.

The Evanston launch site was the west bank of the Channel just south of Isabella Street, said Paul D’Agostino, superintendent of Parks/Forestry for the City. He said, “This emerald ash borer biocontrol effort is Evanston’s chance to be on the leading edge of the research effort to find a way to slow the spread of this destructive pest. I believe that the potential benefits of this effort far outweigh the risks, based on all the research performed thus far.

The potential devastation of the EAB is enormous if we cannot find some way to suppress its populations soon.” Since 2006, the EAB has killed about 2,000 ash trees in Evanston. The Forest Service has been working with these wasps since 2007 and has seen results with these wasps, Mr. D’Agostino said.

Evanston was chosen for several reasons, Mr. D’Agostino said: “We have a natural riparian area, where we can leave the trees standing for three years, even if they are dead. Our trees are infested with the EAB. Plus, we knew what was coming down the pike – we’ve been in contact with Forest Service officials, the Illinois Department of Agriculture and the Morton Arboretum. So when we heard about the wasps, we raised our hands.”

Depending upon the progress in East Lansing, Evanston may see a second species of wasp taking flight in the fall. “It depends upon the rearing process,” Mr. D’Agostino said. In addition to the possibility of savings of trees, Mr. D’Agostino said the City will not see a major outlay of cash for the program. “The only cost to the City is in staff time – a couple of hours here and there.”

Finally, to set the record straight, he said “emerald” refers to the color of the pest, not of the tree.

Mary Gavin

Mary Gavin is the founder of the Evanston RoundTable. After 23 years as its publisher and manager, she helped transition the RoundTable to nonprofit status in 2021. She continues to write, edit, mentor...