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Emerald Ash Borer in Downers Grove

Photo credit: David Cappaert, Michigan State University, Bugwood.org

The first case of Emerald Ash Borer, the destructive non-native, invasive pest whose larvae feast on the trunks of ash trees, has been found in Downers Grove. The infected ash tree, located on private property in the 1900 block of Warren Ave., was in declining health, prompting the owners to contact several tree services for estimates on removal.

On May 26, 2011, two of those companies contacted Village Forester Kerstin von der Heide to advise of their suspicion that the tree was infected with EAB, which was verified upon her own inspection and confirmed by the Illinois Department of Agriculture on June 6, 2011. Village forestry staff surveyed the area surrounding the infected tree and has not found any other ash trees that are compromised.

The Emerald Ash Borer (EAB) is a small, dark green metallic beetle from Asia, only about ½ in length.  It was first discovered in the United States in 2002 in southeast Michigan and has since spread to Illinois and several other states.

The beetle larvae feast on the trunks of ash trees, thereby cutting off their ability to transport nutrients and ultimately causing the tree's decline. Adult EAB beetles emerge from infested trees beginning in mid-May, peaking in late June, and continue emerging until late July. Ash trees can be infested with EAB for a few years before the tree begins to demonstrate any signs of EAB infestation.

Symptoms of EAB include canopy dieback, D-shaped exit holes, shoots sprouting from the tree trunks and S-shaped larval galleries underneath the bark. Ash tree owners may ask about treatment options in order to avoid removing their trees; however the only guaranteed method to control EAB is to remove the host tree(s).

There are 4,007 ash trees located on public property in Downers Grove, accounting for 17.2% of the Village's parkway tree inventory. The Village continually monitors parkway trees throughout the year looking for problems that may seriously impact tree health or threaten public safety. Residents are encouraged to report any unusual insects near parkway trees or declines in tree health at (630) 434-5460.

Additional information about the Emerald Ash Borer and preventive measures taken by the Village can be found on the Trees: Insects and Diseases page.