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Signs & Symptoms
Sign: S-Shaped Galleries under the bark
Emerald ash borer larvae feed extensively just under the bark in the phloem, disrupting the flow of water and nutrients in the trees.
Sign: D-Shaped Exit Holes
Beginning in May, adult emerald ash borer emerge, by chewing a d-shaped exit hole in the bark. The top of the borers head is flat and the bottom is round, which creates the D. The D can be in any direction.
Sign: Leaf Feeding by Adult Emerald Ash Borer
When emerald ash borer emerge as adults, they spend several weeks feeding on ash leaves before beginning to mate.
Symptom: Canopy Dieback
In the spring, ash trees will not leaf out in portions of the canopy due to the feeding of emerald ash borer larvae. This feeding leads to canopy dieback and eventually death.
Symptom: Epicormic Shoots or Water Sprouts
In response to stress and the loss of leaves in the canopy, the ash tree begins sending out vigorous shoots along the trunk. This flush of growth helps the tree to continue making food through photosynthesis.
Symptom: Bark Splits
The tree attempts to callous over the tunneling that the Emerald Ash Borer larvae make underneath the
bark. This callous tissue puts stress on the bark
causing the bark to split.
Symptom: Woodpecker Damage
In searching for emerald ash borer larvae,
woodpeckers will create bark flecking and
holes in the trunk. Woodpecker damage
is first noticed in the tree canopy.