A Wright State University researcher has found evidence that the emerald ash borer, a destructive invasive insect, has found a new host—which means ash trees might not be the only trees at risk.
The emerald ash borer was first detected in southeast Michigan about 12 years ago, and it has decimated ash tree populations fanning out from there. Yellow Springs resident and Wright State biologist Don Cipollini had a suspicion that another tree, the ornamental white fringetree that is native to the region, could be a host.
He went tree-to-tree along the bike path near his house looking for signs of ash borers.
“It was about the fourth tree that I found a characteristic exit hole,” he said. He found larvae beneath the bark that resembled ash borers, and just last week found evidence of an adult. Cipollini has verified the identity of one adult ash borer, and is still working to verify the identity of the larvae. It’s not clear yet whether it will kill the infested fringetrees, but he says his initial findings have big implications. When the borer is done with the ash tree, it could just find a new host.
“It’s just one of these lessons I think about it being hard to predict what an invasive species might do,” Cipollini said.
An estimated one in ten trees in Ohio is an ash tree, and the economic impact of losing those could end up in the billions, as ashes are both valuable hardwood for timber and numerous and expensive to remove or clean up. White fringetrees, which are identifiable by their delicate, fringey-looking white flowers, are already rare. If they are hosts to ash borers it could further contribute to their disappearance as well as to the spread of the ash borer across the country.
This would be the first time in North America that an emerald ash borer has been found to grow to adulthood in a host that is not an ash tree. Cipollini says if white fringetrees are susceptible to ash borers, other related trees such as olive trees could be susceptible; regardless, the discovery calls for further study.
"The initial finding indicates that there is a concern here that's worth following up with more research," he said. "It has basically identified a new research direction for us."
Cipollini and other scientists who study ash borers say people should be vigilant for evidence of the insects in their own yards, and report and treat infestations when possible. Bringing firewood or tree material from town to town or across state lines can also contribute to spreading invasives.
Lewis Wallace is WYSO's managing editor, substitute host and economics reporter. Follow him @lewispants.
