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Emerald Ash Borer - Text Only

Visit the Interactive EAB Treatment Map

Spring 2016: The City will continue comprehensive EAB treatment in April. Due to differences in treatment products, not all trees require a treatment this year. Only healthy trees will be treated.

Visit the Interactive EAB Treatment Map to see if and when your tree will be treated.

Please Water Your Trees


Proper watering is critical in the 4-6 weeks after treatment. Watering aids in treatment take-up and lowers tree stress levels.


Key: A long and slow soaking, not a short and fast hosing. Moisten the soil to several inches deep, but don't overwater. Water under the dripline, but focus near the trunk.


April to September, weekly, when less than one inch of rain has fallen.

Ash Trees & EAB

The Emerald Ash Borer (EAB) is an invasive pest that attacks and kills native ash trees. Ash trees are native to Illinois and commonplace in Naperville.

For more information about EAB:

Treating Your Ash Trees

Homeowners with ash trees have two options: treatment or removal. Treatment has been proven to save ash trees, and Naperville's own parkway ash treatment program has been very successful.

If you've treated one of your ash trees, please let the City know about its treatment. You can either submit a fillable PDF (link on the right side of the page) or download and mail the form: EAB Treatment Form

Emerald Ash Borer 2016 Program Update

Year 5 - 2016 is the 5th year of treatment in an 8-year plan designed to preserve Naperville's canopy. So far, the program is fulfilling its mission to save trees.

Treatment Program Success in 2016

Since 2012, EAB treatments have been 87 percent successful. 14,000 treatments have saved 14,000 of the City's ash trees from Emerald Ash Borer. 69 percent of trees are in good condition, 22 percent are in fair condition, 6 percent are in marginal condition and 3 percent are in poor condition.

The Future of EAB

EAB population, or "beetle pressure" is a measure of EAB intensity. The beetle pressure wave in Naperville is currently cresting as EAB feed on untreated private property ash trees. As those trees die, the beetle population will ultimately crash due to a depleted food source.

  • 2016 - Nearing peak beetle pressure, aggressive treatments must continue
  • 2017 - All untreated ash trees are predicted to die. Beetle pressure begins crashing.
  • 2020 - Treatment interval and intensity are reduced in a low beetle pressure environment.

Sources: Sadof, C. (2015). 2015 EAB Toolkit Update and the Best of EAB University. in P. University (Ed.), EAB University Spring Webinar Series. Retrieved from

Naperville Emerald Ash Borer Program

Emerald Ash Borer (EAB) is a serious threat to the urban forest but Naperville has taken pro-active steps to address the problem and now operates a model EAB management program.

  • 2008 - Discovery: EAB is found in Naperville in July. In the fall, a containment-based treatment strategy is adopted.
  • 2012 - Treatment: EAB has spread throughout the City. City Council approves a comprehensive, City-wide treatment plan to save the ash.
  • 2015 - Results: 4 cycles in, treatments are 87 percent effective, saving thousands of trees and millions of dollars.

In 2016, ash trees are vital to Naperville's urban forest. At 14,000 strong, ash trees are the second most populous tree on the parkway. One of out every five (20 percent) parkway trees is a live ash.

Annually, Naperville's ash trees give back over $2,000,000 in benefits to the City. This includes property value increases, storm water capture, energy reductions and air quality improvements.

Three Components of EAB Management

  • Inspection - All ash trees are assessed for condition at least once per year.
  • Treatment - Trees are treated every 1-2 years to combat Emerald Ash Borer.
  • Removal - Poor condition trees are removed and replaced with a diversity of species.

Three Treatments to Protect Ash Trees

  • Tree-Age - Applied bi-annually to larger trees via trunk injection - 95 percent success rate
  • Imidacloprid - Applied annually to smaller trees via soil injection - 79 percent success rate
  • Safari - Applied annually to select trees via soil injection - 95 percent success rate

The Bottom Line

The average annual cost to treat an ash tree is $35. The average cost to remove and replace an ash tree is $625. The number of years a tree can be treated before it equals the cost of removal is 17.

How Can You Help?

  • Water - Watering trees after treatment and during dry periods helps the tree. The City recommends homeowners water their trees every week with less than one inch of rainfall from April to September.
  • Treat - If your private property ash tree is still healthy, saving the tree through treatment is an option. Consult a local arborist.
  • Remove - Untreated ash trees are a food source for EAB and a hazard to the community. Hazardous trees are also a municipal code violation. Remove dead or heavily infested ash trees promptly.
  • Do Not Transport - EAB can be easily transported in ash logs. Do not help to spread EAB by transporting firewood. Infested materials may not be stored in City limits.


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