Emerald Ash Borer

The Emerald Ash Borer (EAB) is an invasive pest introduced from Asia that attacks ash trees.

This metallic wood boring beetle was found in Detroit, Michigan and Ontario, Canada in 2002, and has continued to spread into neighboring states and eventually across the U.S. and Canada. The adult is a small, metallic green beetle only 10-15 mm in length and about 3 mm in width. The larvae live under the bark of the tree and feed in the vascular cambium. The adults typically emerge around June, leaving D-shaped exit holes in the bark. This ash tree insect briefly feeds in the canopy before reproducing and laying eggs in the twigs and branches.

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Photo: Jim Zablotny, USDA APHIS

 

Common Symptoms

EAB larvae live under the bark and feed on the vascular tissues. Larvae create meandering galleries through the phloem, vascular cambium and etch the xylem, effectively girdling the tree. Dieback of the canopy is a symptom of EAB larval infestation.The tree responds by sprouting new branches below the disrupted tissues. The bark will split over dead vascular tissues, and trees may die within only two years of the onset of symptoms.

When To Treat

Treat ash if EAB is reported within 30 miles of your area. Do not wait for visible dieback in the canopy, as there is a significant delay between disruption to the vascular tissues and expression of symptoms in the canopy. Delaying Emerald Ash Borer treatment could result in canopy dieback or tree loss.

 

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