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Emerald Ash Borer

Emerald Ash Borer

Infected Ash Tree
Emerald Ash Leaves
The Emerald Ash Borer, a devastating insect pest from Asia, has become a great concern in Illinois with the detection of a residential infestation occurring in Hanover Park in 2009.  The beetle was first identified in the United States in July 2002 feeding on Ash trees in southeastern Michigan.  Since the infestation in southeastern Michigan, the Emerald Ash Borer has also been found in the following states:  Michigan, Maryland, Ohio, Indiana, and Illinois.  The borer was brought to the United States on wood packing crates from Asia.  It is estimated that approximately 20% of the tree population in the Chicagoland area and 30% of the Hanover Park parkway tree population is Ash species.  Illinois has approximately 110 million Ash trees according to the Illinois Department of Agriculture.

The Emerald Ash Borer larvae tunnel throughout the phloem and outer sapwood of Ash trees creating large galleries, eventually killing branches and entire trees.  The borer is difficult to detect in newly infested trees because symptoms usually begin at the top of the tree.  The adult is a small, metallic-green beetle, about half the size of a penny.  Typical signs of infestation include the presence of the small metallic-green beetle on or near an Ash, small D-shaped holes in the bark of the trunk and/or branches, dieback in the crown of the tree, and suckers growing on the trunk.  Large vertical splits may also occur in the bark, and woodpeckers may feed on the beetle leaving visible damage to the bark.  This borer infests and eventually kills all Ash trees, regardless of size or health conditions.

The Emerald Ash Borer moves only short distances by flying, but can survive long distances on Ash nursery stock, logs, branches, and firewood.  Therefore, the Illinois Department of Agriculture has quarantined DuPage and the surrounding Counties to avoid its introduction into other areas.  Do not transport firewood as this is thought to be one of the main methods this insect is spread.  Be sure to use all firewood in the winter so that no hidden larvae or adult beetles can survive on logs left through the spring.

Currently, options for treating infested trees are limited and will depend on Illinois Department of Agriculture mandates.  In most cases, complete removal of the tree is required.  While preventative treatments are available for non-infected Ash trees, they will not work on already infested Ash trees.  Results from the Illinois Department of Agriculture survey will determine the appropriate action to contain this pest.

It is important for residents of Hanover Park to be diligent in inspecting their Ash trees for this pest.  A resident reported the initial find in Kane County.  If you suspect you have found an adult or larval form of this insect, freeze the insect and bring it to the Village's Forestry Division for identification.  If you suspect an infestation you may contact the Illinois Department of Agriculture toll-free hotline at (800) 641-3934.