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Emerald Ash Borer

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The City of Joliet has adopted an Emerald Ash Borer (EAB) Management Plan on May 16, 2011. This Management Plan will help guide the City of Joliet Forestry Division in the detection and action needed to address the Emerald Ash Borer Insect Infestation within the City of Joliet.

Emerald Ash Borer infested trees will be removed in this order:

  •  The larger older trees will come down first due to public safety hazard.
  •  Then, throughout the entire City the small younger trees will be removed.
This could take 5-7 years before all infested trees are removed. The stumps will be removed at a later date. 

As of now there is No replacement program, but the City is working on funding a tree replacement program.

For more information on EAB in Joliet or with question call the EAB Automated Hotline to leave a message for the City of Joliet Forestry Division call (815)724-4000 or click here to make a request or complaint.

Recent Developments

According to City Forester Jim Teiber, Emerald Ash Borer has been confirmed within Joliet city limits. “It is yet to be determined the exact time of the infestation but we are estimating that the first infestation occurred about three years ago.” Traps placed around the city for the past few years had no positive results, but evidence of borers is now visible in upper branches of bare trees and the Department of Agriculture has recently confirmed their presence.

Confirmed EAB Locations:

  • Citywide



During the summer of 2002, an exotic beetle called the Emerald Ash Borer (EAB) was discovered in southeastern Michigan near Detroit where it has killed over 500,000 ash trees and has spread throughout the Midwest. The adult beetles nibble on ash foliage but cause little damage. The larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree’s ability to transport water and nutrients. Emerald ash borer probably arrived in the United States on solid wood packing material carried in cargo ships of airplanes originating in its native Asia.

In 2004, the City of Joliet took the initiative to start planning for the borer, which could turn out to be more devastating than Dutch Elm Disease. Dutch Elm reached the U.S. in 1928 – Chicago by 1950 and spread throughout the area for decades killing millions of trees.

Signs and Symptoms of EAB

Symptoms of Emerald Ash Borer [PDF] (with pictures)

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 if 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 tree 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.

Early Detection/Management Early Efforts

In 2005, it was estimated that ash trees made up 20% if all street trees with over 505 in some neighborhoods. Initial steps taken to lessen the impact of the borer included:

  • City Forestry Division, after consulting with Planners and City Administrators, removed all ash tree species from the city’s approved tree list. Neither the city, homeowners, nor developers could plant ash trees in the public right-of-way.
  • Educational information was provided to homeowners and a TV interview with the City Forester was aired on local TV on a daily basis warning Joliet residents of the problems associated with Emerald Ash Borer and ash trees.
  • The City began removing some of the older declining ash trees in the city right-of-way. The Forestry Department estimates 300 ash trees has been removed since 2005 and that quantity increases daily.
  • Preventive treatment was not an option in 2005, since positive results were questionable. Current results of treatment to non-infested trees show promise.

Typical signs and symptoms of Emerald Ash Borer include bark splitting, serpentine galleries and D-shaped exit holes in the trunk, and increased woodpecker activity in and around area ash trees. Upper branches of trees show bare wood and insect holes first. Homeowners who notice any of these signs are strongly encouraged to contact the City Forester. For other identification features, visit

Management Plan

The city has implemented 3 options in the process once the borer has been confirmed.

  1. The city will remove the tree as time allows but before the next flight season (May 1). Trees will be replaced when funding is available.
  2. The city will not be treating parkway ash trees at this time. Homeowners may opt to treat the tree, but must give the city proof of work to be done and by whom.
  3. Once a tree dies, the city will remove it. The city will use a color-coded system to identify those trees with infestation and removal of notifications. Trees may be replaced when funding is available.

Residents whose ash tree has been confirmed with having EAB and those who have an ash tree located in the city parkway adjacent to an infested ash tree will receive a letter from the city notifying them of the situation and the steps that follow.

At this time, the city does not have the available funds to replace all trees that may have to be removed. Residents will have the option to purchase a tree for the parkway. The city forester will contact tree nurseries to get the best price possible for residents who opt to purchase and plant their own tree in the city parkway. A permit is required if residents choose to plant a parkway tree. This allows the Forestry Department to keep an inventory of tree species and other data in order to manage diversity and eliminate anticipated future problems.


If the resident wishes to treat their parkway tree/s or privately owned trees to help protect and minimize the threat of EAB infestation, they would be responsible for the cost of this treatment. It is important to understand that this treatment may need to continue for a number of years. Listed below are two chemicals that are currently being used for treating ash trees. There are more treatments available but these appear to be more effective.

  • The first chemical is Merit (imidacloprid), which can be applied as a soil drench. The homeowner can purchase at your local home improvement store and should only be applied to smaller trees less than 12” in diameter. A certified arborist must do this application and must be licensed with the City of Joliet to do tree work.
  • The second chemical is Tree-Age; this chemical must be injected into the trunk of the tree. A certified arborist must do the application and must be licensed with the City of Joliet to do tree work.

Pricing will vary between companies based on the chemicals used and the diameter of the tree being treated. Each of these chemicals has shown promising results in combating the EAB. Should you decide to chemically treat your parkway tree, you must contact the City’s Arborist will determine is the tree is appropriate for chemical application. If a resident chooses to treat chemically, the City Arborist must be consulted regarding the treatment process and documentation required. With all applications, nutrients and water are also very important in maintaining the health of the tree.

According to the treatment guide, a do-it-yourself insecticidal control option is to apply a product like Bayer Advanced Tree and Shrub Insect Control, containing imidactoprid, onto or injected into the soil around the tree annually. To ensure the insecticide is in the leaves by the time adults emerge to feed in early June, products are most effective when applied mid-April until the end of June. The larger the diameter of the tree, the earlier the product should be applied. The imidacloprid strength in the home use product if less than the product available by professional arborists.

A program of sustained treatment will be needed to conserve trees throughout peak EAB infestation. However, as the local EAB population may decline do to the death of untreated ash, it is possible that treatment frequency may be reduced.

Stay Informed

The City of Joliet has taken major steps forward in their forestry program over past 15 years. A tree board was established 20 years ago and a forester was brought on staff to oversee the urban forest, administer daily care functions, and manage critical situations, in which the city’s tree and damaged due to storms, destructive diseases and insects.

When Dutch Elm Disease wiped out the stately elm in America’s cities, a replacement was sought to fill in the gaps left by dead elms. Instead of looking fro diversity in tree spices many municipalities, from the 1960’s through the 90’s repeated the mistake of the past by over-planting a few species. Together, the tree board, the Forester and city staff have stopped the practice of planting a mono-culture of trees. Many ash trees, possibly 30,000 or more will be lost due to the over-planting of ash trees 15 years ago. The city forester and tree board have taken major step forward to ensure situations like the Emerald Ash Borer will never again drastically effect to city’s tree population through educational literature, Arbor Day Celebrations, and other educational event for the public.

Residents can act individually to improve their natural environment through the planting and care of trees and by supporting community-wide forestry programs. Technology is helping people learn more about trees and how they benefit mankind, and how every person can for a better job of planting and caring for trees that make up the urban forest that we admire everyday.

Please contact the city forester with any questions or concerns you may have pertaining to Emerald Ash Borer and all other tree-related questions. If you feel your parkway tree of private tree may have EAB please contact the City Forester, Jim Teiber, or click here to make a request or complaint.