Illinois hunting and fishing

A tree next to the soccer field at Knox College shows signs of emerald ash borer infestation. The Illinois Department of Agriculture added Knox County to its 39-county EAB quarantine after being alerted by the grounds staff at Knox College. Photo by Steve Davis.

Galesburg set to do battle with emerald ash borer

December 12, 2012 at 06:46 AM

GALESBURG — With at least 600 ash trees at risk in the city, Galesburg Public Works officials are buckling down and preparing to battle a highly destructive enemy — the emerald ash borer.

After the insect was discovered on Knox College grounds, the Illinois Department of Agriculture announced Monday that, along with 40 other counties in the state, Knox County is now under emerald ash borer quarantine. The state’s quarantine prohibits the movement of ash wood, including limbs, firewood and wood chips larger than 1 inch, from the county, in an effort to prevent the spread of the beetle.

On Monday, the city’s tree committee met to discuss an action plan it intends to present to the City Council in January which would include $12,000 in treatment and removal in 2013 and a 25-year work plan that would require $912,000 in contractual costs.

Grounds staff at Knox College discovered the pest festering inside at least one of the 40-plus ash trees on campus, but officials suspect the emerald ash borers could have been in Knox County for four to six years.

“Unless you’re at the top of the tree, you’d never notice them (until now),” said city arborist Gary Johnson. “Chances are, it’s been here, and we’re just starting to see it.”


Illinois hunting and fishing
An adult emerald ash borer.


It can take years for the infestation to become noticeable, as the borers first attack the tops of trees and work their way down, Johnson said.

Emerald ash borers lay eggs in crevices of ash bark, and when the larvae hatch, they bore into the trees, chewing curvy trails through wood and cutting off the water circulation within the tree, said Stuart Allison, a Knox College biology professor.

Once a tree is infected, it is nearly impossible to save it, he said.

“The expectation is a lot of them will die,” Allison said. “You can really expect that in areas that are affected, (the insects) will continue to spread and increase, and you’ll probably lose most of the ashes.”

Out of Galesburg’s total 1,200 public street trees and 7,500 public park trees, approximately 600 are ash trees, according to the Public Works Department.

Without any treatment, it is anticipated that all 600 trees will die within 10 years, according to the department.

“The sad thing is, Galesburg is not going to look the same,” Johnson said. “There are a lot of areas where (ash trees) are all that’s planted there. The city is going to look barren.”


Illinois hunting and fishing
Map of quarantined counties courtesy of the Illinois Department of Agriculture.