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Recent Developments
Emerald Ash Borer
Biology of the Emerald Ash Borer
Ash Trees
Signs and Symptoms of EAB
Treatments
What the City of Naperville is Doing to Prevent EAB Infestation
What You Can Do
Stay Informed
Recent Developments
In July 2009, two infestations of emerald ash borer were confirmed in Naperville at the Route 59 train station and in the Wildflower subdivision. Infested and declining trees at the train station were immediately removed and the remaining healthy trees are being treated. Two trees were removed in Wildflower and additional declining ash trees may be removed in the near future. Ash parkway trees in Wildflower will be treated with insecticide.
In June 2008, the city received confirmation from the United States Department of Agriculture of the presence of the emerald ash borer in a portion of southwest Naperville, making this the first confirmed case of the emerald ash borer in Naperville and Will County. The beetle was discovered during a routine inspection in the Ashwood Park Townhome development, located near 248th and 103rd streets. Trees found to be infested were removed and chipped in accordance with Department of Agriculture disposal protocol.
All 200 city parkway and private property ash trees within a half mile radius of the infestation have been inspected and inventoried by the Department of Public Works. A total of thirty-three trees have been removed. The State of Illinois installed four traps in the area to determine the extent of the infestation. Only one emerald ash borer has been found in the traps. The State of Illinois and the City of Naperville will continue to monitor the traps.
Emerald Ash Borer
 The emerald ash borer (EAB) is a small (1/2 inch long, 1/8 inch wide) metallic green beetle that has killed millions of ash trees across the midwest. Native to Asia, the beetle was first discovered in the summer of 2002 in southeastern Michigan. Since the infestation in Michigan, the emerald ash borer has been found in a number of states, including Ohio, Indiana, West Virginia, Pennsylvania and Maryland.
In June 2006, the emerald ash borer was discovered in Kane County. State officials found exit holes in at least 20 trees left by adult Emerald Ash Borers suggesting that the beetles have been in that area for at least three years. In July 2006, another infestation was found in the City of Wilmette in Cook County. The emerald ash borer has been confirmed in area communities such as Geneva, St. Charles, Evanston, Wilmette, Winnetka, Elburn, Homewood, and Hazel Crest. The emerald ash borer was also found in the City of Chicago in June of 2008.
Biology of the Emerald Ash Borer
The adult emerald ash borer emerges between May-July and feeds on the leaves of ash trees. Soon after they emerge, the adult females lay numerous eggs on the trunk and branches of the tree. The eggs hatch within 7-10 days and the larvae, which are creamy white in color, bore into the bark of the tree. The larvae begin to feed and create S-shaped galleries, which cut off the food and water supply to the tree, causing it to die.
Ash Trees
Ash trees are very common in landscapes and most species, namely white ash and green ash, are native to Illinois forests. Ash trees are the most numerous species in the city’s parkway tree inventory. More than 15,200 of the city’s parkway trees are ash trees. This is 27% of the city’s parkway tree inventory.
The planting of ash trees is not allowed on any city parkways and will not be approved on private property landscape plans reviewed by the city.
Characteristics of Ash Trees:
Ash trees feature compound leaves made up of small, glossy green leaflets
Leaves, twigs and branches grow in opposite pairs
Bark of mature ash trees is gray and furrowed, often appearing in a diamond pattern
Some ash trees will produce small canoe paddle-shaped seeds
 Signs and Symptoms of EAB
Infestation of emerald ash borer can be very difficult to detect until the branches of an infected tree begin to die. The most visible sign that the EAB is present is crown dieback, which appears after the first year of infestation. Usually the leaves on the upper third of the tree will begin to thin and the branches will begin to die. A number of suckers and branches will also sprout from the base of the tree and on the trunk. The bark may also split vertically and woodpeckers may begin to feed on the beetle larvae leaving visible damage on the bark. Adult beetles emerging from trees will leave a very small 1/8 inch diameter distinctly D-shaped exit hole that may appear anywhere on the trunk or upper branches. Distinct S-shaped larval feeding tunnels may also be apparent under the bark. Typically, the tree will die in about three years.
Other Stressors
Ash trees may suffer from a large number of pest and disease problems that cause similar symptoms as the emerald ash borer. Native borers also attack ash trees, although they leave larger exit holes, up to a 1/4 inch in diameter, that are usually circular or oval in shape. If you are concerned about the health of your ash tree and suspect that your tree has been infested by a pest, contact the city's Forestry Section at (630) 420-6095.
Treatments
The only certain method to control the emerald ash borer is to remove the tree. When considering whether to attempt insecticidal control, one should weigh the value of the tree against the cost of treatment.
According to the treatment guide available on www.illinoiseab.com, a do-it-yourself insecticidal control option is to apply Bayer Advanced Tree and Shrub Insect Control, containing imidacloprid, onto or injected into the soil around the tree annually. The imidacloprid strength is less than the product available by professional arborists.
According to the State of Illinois, there are several professional insecticidal control options:
- Imidacloprid (Merit, IMA-jet, Imicide, Pointer) or Emamectin Benzoate (Tree-age) injected into the tree annually. Applications can be made at any time of the year, but are most effective in the spring.
- Dinotefuran (Safari) applied along with PentraBark to the outside bark surface of the tree.
- Foliar and bark sprays of bifenthrin (Onyx), cyfluthrin (Tempo), permethrin (Astro), or carbaryl (Sevin) applied monthly from mid-May to mid-July control visiting beetles and hatching larvae.
The applications of imidacloprid or dinotefuran, which move systemically through the tree, are more likely to provide useful control, according to the State of Illinois. These options require a licensed professional to apply the insecticidal control to the tree.
If residents desire a tree care company to come and remove their tree, or otherwise provide services to them, residents should ask if the company has current certificates of insurance, employs certified arborists and has current references. It is recommended residents get more than one estimate to help make an informed decision. Tree owners are encouraged to thoroughly research the various treatment options currently available and carefully weigh the costs associated with the required repeated treatments. Treatment of an ash tree will not guarantee that a specific tree might not eventually be required to be removed. Visit www.emeraldashborer.info/hiringtreeco.cfm for more information.
Treatment of public and private ash trees will need to be documented as to what chemical was used, when it was treated, and by whom. These records will be collected and stored in a city database. If you decide to treat your ash trees, please complete the Emerald Ash Borer Treatment Form and return it to the Department of Public Works each time the tree is treated.
What the City of Naperville is Doing to Prevent EAB Infestation
The City's Forestry Division is dedicated to protecting Naperville's ash tree population. For the past several years, the city has worked in cooperation with the Morton Arboretum and the Illinois Department of Agriculture on their survey projects to test for Emerald Ash Borer. These projects use 'test' trees to determine whether there are undetected pest populations in our region.
In order to prevent the spread of the Emerald Ash Borer, the Department of Public Works has developed a containment strategy which consists of removing all infested ash trees, inspecting ash trees within a half mile of the infestation, and coordinating efforts with the State of Illinois, the townships, and the Naperville Park District. As part of the City’s containment strategy, the city will be treating all parkway ash trees within a half mile of the initial infestation with insecticide.
The City’s Forestry Division has ten certified aborists that are trained to look for signs of the presence of the Emerald Ash Borer and actively check ash trees everyday during their regularly scheduled work. The City's Forestry Division will continue to evaluate all parkway ash trees and remove any diseased or weakened trees in an effort to reduce the overall percentage of ash trees in the City’s urban forest. Residents are encouraged to report sick or dead trees by calling (630) 420-6095.
What You Can Do
Do Not Transport Firewood: Emerald Ash Borer can easily be transported in ash logs. Make sure to purchase firewood locally from a known source and be sure to use all of the firewood in the cold months so that no hidden Emerald Ash Borer larvae or adults can survive on logs left through the spring.
Monitor the Health of Your Ash Trees: Look for dead and dying branches at the top of the tree's crown. If you suspect an ash tree located in the parkway seems sick or needs maintenance, call the city's Department of Public Works Forestry Section at (630) 420-6095.
Stay Informed
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