The emerald ash borer is deadly to ash trees—and aggravating for homeowners. Here's how to know if your tree has emerald ash borer damage.
How to Identify Emerald Ash Borer Damage
Since the early 2000s, the emerald ash borer has been a thorn in homeowners’ sides—or anyone with trees in their yard. These invasive insect pests cause oft-catastrophic damage to ash trees, and plenty of people have been forced to replace trees the borers killed. Here’s how to tell if the ash trees in your yard have emerald ash borer damage, and what types of trees you might consider replacing them with.
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What Does Emerald Ash Borer Damage Look Like?
“Is this tree damage the work of a woodpecker?” asks Birds & Blooms reader Christine Atkins.
Birding experts Kenn and Kimberly respond, “Unfortunately, the marks displayed on your tree were not caused by a woodpecker or other bird. The tree appears to be an ash, and the damage is a good match for the “blonding” that results from emerald ash borers. (If you do have trouble with woodpecker damage, here’s how to stop them from pecking.)
“These beetles are native to Asia and have caused the destruction of millions of ash trees in North America. The bad news is that once the damage reaches this level, the tree will likely die. We suggest contacting your local extension office to confirm the presence of emerald ash borers and for information on removal,” Kenn and Kimberly say.
The Arbor Day Foundation recommends monitoring your ash trees for these symptoms: thinning or dying crowns, suckers, splitting bark, tunneling under the bark and D-shaped exit holes.
Alternatives to Replace Damaged Ash Trees
“I lost a hedgerow of ash trees to Emerald ash borer damage. I was going to replace them with osage orange trees, but do you have any other hardwood recommendations? asks Birds & Blooms reader Lynn Taylor.
Garden expert Melinda Myers says, “Consider using a mix of trees. Creating diverse plantings reduces the risk of an insect or disease destroying all of the plants. Osage orange trees are durable beauties, but they do produce grapefruit-size fruit when mature. Hackberry grows 40 to 60 feet tall, has a vaselike habit and yellow fall color.
A variety of maple trees, including Miyabe and trident, have interesting bark and fall color. Turkish filbert tolerates drought, has an attractive pyramidal shape and produces edible fruit once it’s mature. Male clones (branch cuttings) of Amur cork tree, such as His Majesty, Macho and Shademaster, are adaptable, have corky bark and yellow-bronze fall color, and do not produce messy fruit.”
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Do Woodpeckers Spread Borers?
“Can woodpeckers spread borers from one tree to another tree?” asks Birds & Blooms reader Cathy Tabako of Coon Rapids, Minnesota.
Birding experts Kenn and Kimberly Kaufman say, “While we hesitate to say that anything in the bird world is totally impossible, it would be very unlikely for woodpeckers to spread borers or other harmful insects from one tree to another. Borers— mostly the larvae of various beetles—are prime targets for woodpeckers, which will eat all the ones they can find. When a woodpecker makes openings in the bark of a live tree, it’s usually because the bird has detected such insects there, and it will proceed to clean them out. So the chances of woodpeckers accidentally carrying borers to another tree are very slim.”
Melinda Myers adds, “One of the many benefits of woodpeckers is that they help manage problem pests. Researchers are monitoring ash trees for frequent visits by woodpeckers as an indication that the emerald ash borer is present. Using this information allows the U.S. Forest Service to move in and manage the borer-infested trees before they are killed. And don’t worry about the woodpecker feeding; it typically does not harm otherwise healthy trees, and the nest holes they create provide homes for a variety of other wildlife.”
About the Experts
Melinda Myers is the official gardening expert for Birds & Blooms. She is a TV/radio host, author and columnist who has written more than 20 gardening books. Melinda earned a master’s degree in horticulture from the University of Wisconsin-Madison.
Kenn and Kimberly Kaufman are the official bird experts for Birds & Blooms. They are the creators of the Kaufman Field Guide series and they lead birding trips all over the world.
