What visual symptoms are associated with an emerald ash borer infestation?

FAQ
Question: 

What visual symptoms are associated with an emerald ash borer infestation?

Answer: 

Noticeable symptoms of emerald ash borer usually appear in the second or third year of the infestation or later.  Emerald ash borer infested trees exhibit thinning of the leaf canopy and dieback in the crown.  Also, infested ash trees may produce epicormic (“water”) sprouts on or at the base of the trunk.  When the adult beetles emerge, they create small, 1/8 inch, D-shaped exit holes in the bark.  Extensive woodpecker activity/damage is another symptom of an emerald ash borer infestation. (Several woodpecker species feed on the emerald ash borer larvae.)  Infested trees often exhibit vertical cracks in the bark due to callus tissue forming around larval galleries.  Ash trees exhibiting 2 or more of the aforementioned symptoms should be examined closely to determine if the ash tree’s problems are due to the emerald ash borer. 

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