In wake of EAB confirmation, City urges homeowners to identify Ash trees and weigh options

December 11, 2012 01:31 PM
With news that the Emerald Ash Borer (EAB) has been detected in Knox County, Galesburg city staff has implemented its EAB Readiness Plan which identifies resources and procedures for combating the EAB in Galesburg. This plan can be found on the city's website. It is recommended homeowners 1) check their property for Ash trees, 2) look for signs of EAB, 3) consider all options, and 4) work with a professional (insured contractors with a State EAB compliance agreement and/or certified pesticide applicators) in deciding whether to treat or remove an Ash tree. Homeowner workshops are planned for early 2013.
In preparing the plan, staff identified public trees that could be infested and estimate 25 percent of the trees located on public streets and approximately 4 percent of the city's park trees are Ash trees. In total, 600 public trees are in danger of EAB infestation. 
The city will be responsible for removal of all public Ash trees that have been destroyed by the EAB. Some trees may be treated to prevent infestation if the tree is deemed valuable. Treatment has been found effective when applied as directed or by a licensed tree contractor.
Identify Ash trees by the following characteristics:
  • Compound leaves made up of seven small, glossy green leaflets (5-9 leaflets).
  • Leaves, twigs and branches grow symmetrically in opposite pairs. 
  • Bark of mature trees is gray and furrowed, often appearing in a diamond pattern.
  • Some Ash trees will produce small canoe paddle-shaped seeds.
  • Seedless Ash trees are common. 
  • Some Ash trees produce conspicuous hard, brown "flower galls" on their twigs.
The most visible sign of infestation is crown dieback. Branches at the top of the crown will die and more branches will die in subsequent years. As the tree declines, 'suckers', or new young branches, will sprout from the base of the tree and on the trunk. The bark may also split vertically and woodpeckers may feed on the beetle leaving visible damage on the bark. Adult beetles emerging from trees will leave a unique "D" shaped exit hole. This is a small 1/8 inch diameter distinctly "D" shaped hole that may appear anywhere on the trunk or upper branches.
After EAB infestation is found in a county, it could take up to 5 years for a tree to become infested and completely die. Ash trees on public and private property will need to be either treated or removed after falling victim to the EAB.
Emerald Ash Borer is an exotic beetle that was discovered in southeastern Michigan near Detroit in the summer of 2002. 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 or airplanes originating in its native Asia.
The adult emerald Ash borer emerges May - July and the female lays numerous eggs in bark crevices and between layers of bark. The eggs hatch in 7-10 days into larvae which bore into the tree where they chew the inner bark and phloem creating winding galleries as they feed. This cuts off the flow of water and nutrients in the tree, thereby causing the tree's dieback and death.
Insecticide treatments are available and homeowners should review and consider all their options. In addition, tree contractors should have a signed State of Illinois EAB Compliance Agreement which indicates the contractor will follow Illinois Department of Agriculture guidelines as it relates to disposal of infected wood. Area tree contractors will be offered education opportunities to become EAB compliant.
Trees that are cut down as a result of being infected by the EAB may be used in outdoor fire pits, ground fires and indoor fireplaces. The wood poses no hazard to homes or structures when stored or burned. In addition, infected trees from private property may be disposed of by the homeowner at the city's Oversized Limb and Brush Drop Off Facility located at 636 Pickard Road, just west of Farm King. Another option is to sell the wood to a mill to be used in the manufacture of wood products. 
The quarantine implemented by the Illinois Department of Agriculture on December 10, 2012, now covers 40 percent of the entire state, and is intended to prevent the artificial or "human-assisted" spread of the beetle through the movement of infested wood and nursery stock. Specifically, it prohibits the movement of the following items from Knox County:
  • The emerald Ash borer in any living stage of development.
  • Ash trees of any size.
  • Ash limbs and branches.
  • Any cut, non-coniferous firewood.
  • Bark from Ash trees and wood chips larger than one inch from Ash trees.
  • Ash logs and lumber with either the bark or the outer one-inch of sapwood, or both, attached.
  • Any item made from or containing the wood of the Ash tree that is capable of spreading the emerald Ash borer.
  • Any other article, product or means of conveyance determined by the Illinois Department of Agriculture to present a risk of spreading the beetle infestation.
Consult with the Illinois Department of Agriculture website to help identify infected trees, find a certified tree contractor, learn about treatment options, and more. For more information about EAB in Galesburg, contact the Public Works Department at 309/345-3623 or visit the city of Galesburg website at .
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Online resources:
  1. City of Galesburg -
  2. Illinois Department of Agriculture -
  3. International Society of Arboriculture -


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