Emerald Ash Borer

 Ash is an important species in our forests and is facing a new threat. To learn more about ash trees, listen to this pod cast.

The Emerald Ash Borer is an exotic beetle from Asia that was discovered feeding on Ash trees in 2002. The insect was identified as Argrilus planipennis Fairmaire. The larva from this insect feeds on the material between the bark and the wood. This causes girdling which can kill branches and even entire trees. Adult beetles are generally a bright shiny green color and 7.5 to 13.5 mm long. The Emerald Ash Borer generally has a one year life cycle.

It is difficult to detect an infestation in newly infected trees. The most noticeable sign is holes made in trees by wood peckers that are feeding on the larva. After being infected for one year trees start to develop D shaped holes in the bark where the larva is emerging through the bark. Many trees lose 30%-50% of the canopy after 2 years of infestation. Emerald Ash Borer has killed trees of all sizes and conditions.

Inspect firewood for EAB larve (seen at the left) Larvae are creamy white and have flattened, segmented bodies. Older larvae grow up to an inch long. They feed under ash tree bark from mid-summer through spring, damaging the ash tree’s vascular tissue.




As they emerge from ash trees in June and July, adult emerald ash borers leave behind disctinct D-shaped exit holes.  These holes are approximately 1/8″ wide and can be oriented in any direction (i.e., the flat side may be facing upwards, downwards, etc.)