Surveyors found the emerald ash borer in Miami and Wyandot counties in mid-September, the Ohio Department of Agriculture reported.

The latest infestation likely resulted from the movement of firewood, ash tree nursery stock, ash logs or other ash tree materials, the department said.

So far, the tree pest has been found in 17 Ohio counties.

The ash borer has killed about 20 million ash trees in Michigan, Ohio and Indiana. It was first discovered in Ohio in 2003.

The department has extended its quarantine area, making it illegal to move ash trees and all hardwood firewood out of Miami and Wyandot counties.

In July, officials in Evanston, Ill. sounded the alarm after ash borers were found in a local park.

“I would urge any city foresters, if you’re doing routine pruning of ash trees, go ahead and peel the bark back,” and look for signs of the borer, said Mark Cinnamon, an Illinois Department of Agriculture official.