We are helpless to stop the invasion of the Emerald Ash Borer

An exotic beetle is chomping on trees in the Upstate, and there may be nothing you can do to prevent the damage, says a Clemson professor.

The critter, "one of the worst invasive pests we've seen in North America in our lifetime," has experts wringing their hands, so says David Coyle, associate professor of Forest Health and Invasive Species at Clemson University.

First discovered in summer 2022 in southeastern Michigan near Detroit, the emerald ash borer is a small but mighty force to be reckoned with. What's more is that adult beetles that gnaw on ash foliage don't seem to be causing as much damage as their larvae, which feed on the inner bark of trees. This affects the tree's ability to deliver water and nutrients, per the Emerald Ash Borer Network.

Here's what to know about the beetle and who to call if you spot one this summer.

What does the emerald ash borer look like?

Adult emerald ash borers are metallic green with a coppery red or purple abdomen and are about 1/2 inch in length. Larvae are cream-colored with brown heads, flat, and segmented.

How did the emerald ash borer arrive to the US?

The beetle may have arrived from Asia to the U.S. on solid wood packing material carried by airplanes and cargo ships.

How many states is the emerald ash borer in?

The emerald ash borer has been reported across 37 states and six Canadian provinces as of February 2025.

Emerald ash borer key facts to know, per Emerald Ash Borer Network

• Have destroyed hundreds of millions of trees throughout the country.

• Have caused regulatory agencies and the United States Department of Agriculture to enforce quarantines and fines to prevent potentially infested ash trees, logs, or hardwood firewood from moving out of areas where the beetle occurs.

• Cost municipalities, property owners, nursery operators, and first products industries hundreds of millions of dollars.

• Attack only ash trees, with adults leaving a D-shaped exit hole in the bark when they emerge in spring.

• Heavy woodpecker damage on ash trees is usually an indicator of infestation because woodpeckers like the beetle's larvae.

• The beetles can spread when firewood is moved.

How can I report an emerald ash borer sighting?

If you think you've crossed paths with an emerald ash borer, report it to your county extension. You may also call Clemson's Division of Plant Industry, 864-646-2140