The movement of firewood from camp sites to urban areas was among the factors that lead to the spread of the tree-infesting Emerald Ash Borer to Illinois.

The Emerald Ash Borer, a beetle native to Asia, was discovered in the United States near Detroit, Mich., in 2002, said Philip Nixon, extension entomologist at the University. He also said evidence suggests the insect was in Michigan about 10 years prior to its detection. During these years, people moved firewood out of areas that were infested with the beetles to areas that were not infested. Currently these areas have been quarantined.

Areas in Kane and Cook counties in Illinois are reportedly infested as of 2006.

“The larvae of this insect feeds under the bark of ash,” said James Appleby, entomologist in the department of Natural Resources and Environmental Sciences at the University. “When it does that, it interferes with nutrient transport … inside the tree.”

Appleby said the Emerald Ash Borer girdles the tree, or cuts away the bark and cambium in a ring around the tree, eventually killing it. He said people should only use firewood purchased locally.

Nixon said since the appearance of the beetles in Michigan in 2002, it seems that new infestations are due to the movement of firewood, rather than transport by nurseries. He said the U.S. Department of Agriculture suggests not moving firewood more than 50 miles from where it was grown.

“Probably from what we can tell … there is nothing that is going to stop it,” Nixon said. “Eventually it will eliminate all ash trees in North America. Ash trees make up, in many of our cities and towns, about 20 percent of the trees.”

Appleby said that ash trees line both sides of the street in many cities and towns, which is not suggested.

“Never plant all of one species in an area,” Appleby said. “Plant a variety and then if something like this comes along you may lose one or two trees, but you don’t lose both sides of the street. That’s terrible, but you see that all the time.”

Attempted treatments for the problem include cutting down ash trees in infected areas, Nixon said. This approach has not stopped the problem because the Emerald Ash Borer can move to ash trees outside of these areas. Nixon also said insecticides can be used, but they have only slowed the spread of the Emerald Ash Borer, not stopped it all together.

“The trees here are not familiar with this insect,” Nixon said. “(They have) never been able to adapt to it, so they are easily killed.”

Appleby said it is difficult to spot infestation in ash trees, which starts in the high branches. He said when the beetles emerge from the trees, they leave D-shaped holes, one eighth inch wide. Those who spot the metallic, dark green beetle should contact the Illinois Department of Agriculture or the local extension office.