Forestry Division
Frequently Asked Questions - Emerald Ash Borer
What does an ash tree look like?
Ash trees have an opposite branch pattern. This means that the twigs on the branches are located directly across from each other. Ash trees have a compound leaf, usually with 5-9 leaflets. The leaflets can either have smooth or toothed margins. The bark is ashy gray and smooth when young, and as the tree matures it develops narrow diamond shaped ridges.
The emerald ash borer only attacks ash trees in the Fraxinus genus. Most of the ash trees in Skokie are green ash (Fraxinus pennsylvanica) or white ash (Fraxinus Americana). Mountain ash trees are in a different family of trees and are not damaged by the borer.
What is an emerald ash borer?
The emerald ash borer (EAB) is an exotic beetle from Asia that was discovered near Detroit, Michigan in 2002. It probably arrived in the U.S. on solid wood packing materials. Since then EAB has been found in Canada, Ohio, Indiana, Maryland, Virginia, and Illinois.
The larvae (immature stage) feed on the inner bark of ash trees, disrupting the tree’s ability to transport water and nutrients. The adult beetle causes little damage to the tree. The EAB prefers to attack and kill trees that are weakened by stresses such as drought, disease, and mechanical injury. Unfortunately, it also attacks and kills healthy ash trees.
How can I identify it?
The adults are dark green metallic in color and are about ½ - inch long and 1/8 – inch wide (about half the size of a penny). They have a violet abdomen, which can be seen when they spread their wings. The adults emerge in mid- to late- May and are present through August.
The larvae are flat and cream colored with wide heads and bell shaped segments. They eventually reach a length of 1 to 1 ¼ inches long. The larvae are found just beneath the bark of ash trees. They create “S” shaped galleries as they feed on the trees. Arborists and other landscape professionals use special tools designed to scrape away the bark in thin layers to look for the insect and galleries.
What are some symptoms found on ash trees?
Some of the symptoms for EAB are canopy thinning and branch dieback, epicormic sprouts or “water sprouts”, woodpecker holes, cracking bark, and small “D” shaped exit holes, roughly 1/8 – inch in diameter.
| Wood pecker Damage |
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| D-shaped exit hole |
How many ash trees are in Skokie?
Skokie has approximately 3,000 ash trees, representing 12% of the Village’s 24,000 trees. There are an additional 735 growing on Skokie Park District property. It is unknown how many ash trees are growing on private property in Skokie.
How is the Village managing for the EAB?
The Illinois Department of Agriculture (IDOA) confirmed the first case of the emerald ash borer in a tree at Crawford and Grant Avenues in April 2007. Village foresters will begin a systematic survey of all parkway ash trees in early summer 2007. They will start the survey in northeast Skokie (due to the proximity of the confirmed cases) and will work south. Those ash trees determined to be in poor condition or with symptoms of emerald ash borer infestation will be slated for removal. The survey will be conducted annually. Residents will be notified if their parkway tree will be removed. The Village will plant as many trees as resources allow. The FY08 budget, effective May 1, 2007, includes $61,000 for replacing some 250 parkway ash trees.
The Village and its contractor for yard waste pick-up will follow the guidelines provided by the IDOA to properly dispose of ash logs and debris.
Why does the Village have to remove the trees? Can’t they be sprayed?
Symptomatic and declining ash trees are removed to help slow the spread of the beetle. Currently there is no known chemical treatment for EAB that has proven consistently effective. The Village plans to work with the Morton Arboretum to test new chemical treatments. Residents will be notified if their parkway ash is chosen for the study and will be informed of any successful treatments.
I have an ash tree on my property. What should I do?
At this time, the Village is unable to inspect or assist with ash trees on private property. Residents should contact a local International Society of Arboriculture (ISA)-certified arborist who as signed the Emerald Ash Borer Compliance Agreement with the Illinois Department of Agriculture. For more information please click on the following link: http://www.illinoisarborist.org/CertifiedArboristsNew.htm
What is being done to stop the spread?
There is a national effort to limit the spread and impact of EAB. Federal, state and local authorities are working together to control the pest. Quarantines have been imposed in infested areas. Eradication of outlying infestations, where all ash trees within one-half mile of infested trees are cut and destroyed has been implemented in many areas, but has not proven very effective.
What can I do?
- Do not transport firewood! Only use local sources of firewood. Many of the new infestations have been tracked to firewood movement. Check bundles of firewood sold commercially; there should be a certification sheet from the state of its origin.
- If you have declining ash trees on your property, have them inspected by an ISA certified arborist.
- Consider planting a tree in your backyard to help off-set the loss of our ash trees. Remember not to plant any new ash trees! There are a variety of shade trees that can be used instead of ash. These include the disease-resistant elms, Kentucky coffee tree, gingko, Marmo Freeman's maple, swamp white oak, chinkapin oak, bur oak, and American linden.
- Call the Village Forester if you are interested in the parkway tree planting program.
Where can I get more information?
The following websites are excellent resources for additional information.
www.emeraldashborer.info
www.illinoiseab.com
www.illinoisarborist.org
www.mortonarb.org
Please contact one of the Village Foresters at 847-933-8427 if you have further questions regarding parkway trees.
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