Emerald Ash Borer found at the Morton Arboretum

The Arboretum staff found EAB in four trap trees.

  • November 22, 2010

LISLE, Ill. – The Morton Arboretum, the fourth most-visited public garden in the United States, gets all kinds of visitors, including some that fences cannot keep out.

Arboretum staff discovered Emerald Ash Borer (EAB) in four ash trees called "trap trees," which are specifically selected to monitor the area for the borers' presence. State officials later verified the finds. The trees were at three Arboretum locations, all in non- public areas.

"We've been expecting to find EAB here and are fully prepared for it," said Kris Bachtell, Arboretum vice president of collections and facilities, who noted that EAB had earlier been found in several communities surrounding the Lisle tree museum.

EAB has killed tens of millions of ash trees in the United States and Canada. There are an estimated 130 million ash trees in Illinois, and the Arboretum has approximately 9,000 ash among its hundreds of thousands of trees and other plants.

The Arboretum removed its infested trees, and staff will continue to monitor for any additional signs of the insect. Also, the Arboretum has been reproducing almost three dozen ash trees considered to be of high value because of their genetic rarity or other factors, growing the specimens in Arboretum nurseries to safeguard them from EAB.

Additionally, Arboretum experts conduct insecticidal research on 29 trees with landscape or genetic importance in the Arboretum Ash Collection, and on trees offsite. While we expect insecticide to kill EAB larva, this is not a certainty, and testing is still a work in progress.

If homeowners are considering treating their trees with insecticide, the Arboretum recommends they learn the facts and make an informed choice based upon their particular circumstances. The website, www.mortonarb.org, carries a fact sheet on insecticides that will help homeowners consider the options.