Riverwoods Preservation Council

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Emerald Ash Borer
 Emerald Ash Borer

 September - October, 2007

(photograph of emerald ash borer courtesy of the USDA; photograph of D-shaped exit hole courtesy of the University of Wisconsin)


What can fit on a penny, is bright green and has already killed over 20 million trees?
The answer is the emerald ash borer.
In July, the State of Illinois imposed quarantine on much of northern Illinois, including Lake County. The quarantine prohibits removal from the quarantine area of certain items, including ash limbs, branches, wood chips larger than 1 inch, and all non-coniferous firewood.

The emerald ash borer feeds on the inner wood of ash trees, creating a network of tunnels that quickly kills the tree. The insect was accidentally imported from Asia, and was first found in Michigan in 2002. Since then it has spread throughout the Midwest, destroying over 20 million trees.D-Shaped Exit

Ash borers are difficult to see. The adults are only about 1/2 inch long. Their presence typically is first indicated by thinning and yellowing of foliage, and by small D-shaped holes in the tree, created as they exit the trees in late June or July.

Ash trees account for about 14% of Chicago’s leaf cover. Ash trees account for a somewhat higher proportion of Riverwoods’ trees. All are threatened. There is no cure for an ash borer invasion. Once an insect becomes active in a tree, the effect is invariably fatal. There is no known method to prevent an invasion, other than quarantine and removal of affected trees in an effort to stem the insect’s spread.

Adult ash borers are able to fly about 6 miles, making control difficult. In June 2006 the emerald ash borer was first found in the Chicago area. Since then it has been found in Wilmette, Evanston, Winnetka, Skokie and other nearby towns.
In July, the state of Illinois imposed a quarantine on much of northern Illinois, including Lake County. The quarantine prohibits removal from the quarantine area of certain items, including ash limbs, branches and wood chips larger than 1 inch, and all non-coniferous firewood.

Riverwoods has enacted an ordinance consistent with the quarantine that requires notification of the Village of infected or dead ash trees, and removal under the direction of the Village forester. The ordinance allows the Village to remove dead or infected trees at the owner’s expense if the owner does not do so within 10 days of notice.

For more information, contact:
Russ Kraly, Riverwoods’ Director of Community Services: 847-945-3990

If you suspect infestation, call:
Illinois Department of Agriculture: 847-294-4343
U.S. Department of Agriculture: 312-742-3385
or the US Department of Agriculture in Chicago at 312-742-3385

For more information, visit the Emerald Ash Borer web site or the Illinois Quarantine Site.

© Riverwoods Preservation Council- - Page last updated: December 2009