The Emerald Ash Borer, Agrilus planipennis Fairmaire, is an exotic beetle that was discovered in southeastern Michigan in the summer of 2002. The adult beetles nibble on ash foliage but cause little damage. The larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree’s ability to transport water and nutrients.
The infestation is determined to be the result of beetles from eastern Asia that traveled to the United States in solid-wood packing materials. From there, they have spread to several states and even into Canada, reportedly killing tens of millions of trees over the last decade.
Because the species seems to have no natural predators in North America, it has flourished. But people are now taking steps to stop the growth of this tiny pest and save the many species of ash that exist in rural and urban areas alike.
How to Identify Emerald Ash Borer
- Crown (top of tree) dieback on mature trees
- “D” shaped holes in the bark
- “S” shaped feeding galleries under the bark
- Woodpecker feeding damage on bark
- Low sprouting (suckers) branches on the trunk of the tree
Tips for Managing Emerald Ash Borer
It is assumed that no control measure will be 100% effective at preventing Emerald Ash Borer over time, so our first suggestion is to plant a different type of tree nearby for the future. For information on alternative shade trees, see our Midwest Plant Library or contact your local Earl May Nursery and Garden Center.
To get the most out of your existing ash trees, use these preventative measures:
- Treat your existing ash trees in the spring or fall with Earl May Annual Tree & Shrub Insect Control. This control is a soil drench and should be applied in the soil next to the tree trunk when the soil is moist but not saturated. It is also advised to remove all organic matter (leaves/mulch) so the insecticide solution is poured directly on the soil.
- Fertilize and water your trees as needed because a healthy vigorous tree is less likely to be attacked. We suggest fertilizing your tree with a root feeder or fertilizer spikes.