Emerald Ash Borer at Hopewell Culture National Historical Park

Emerald Ash Borer at Hopewell Culture National Historical Park

Written by Biological Technician Alex Smith

Channels dug by the emerald ash borer (Agrilus planipennis) in a deceased ash tree.

NPS photo/A.Smith

The emerald ash borer (Agrilus planipennis) is one ruthless invasive insect! Although it may look like it would be at home in the Emerald City of Oz, it is anything but a wizard. The Emerald Ash Borer (EAB) was first discovered in 2002, but was probably introduced sometime in the 1990’s. This sneaky beetle most likely hitched a ride on infected ash wood used in shipping and got a free ride to the United States.

Native to northeast Asia, this beetle only infects dying ash trees in its home range. However, once introduced, these insects began a devastating crusade against our native ash trees. Over the last 20 years, the borer has wiped out tens of millions of ash trees across the United States! The presence of the emerald ash borer is unfortunately, best determined by dead ash trees. Infected ash trees will start to show symptoms such as decreased canopy cover, D shaped holes in bark, and bark that peels to reveal winding channels chewed into the wood.

What makes the EAB so deadly is that their larvae feed on the “bloodstream” of the tree. This prevents the tree from transporting energy and nutrients, causing it to slowly die. With no natural immunities to these foreign invaders, nearly all of our ash trees are in danger of being wiped out.

A white ash tree (Fraxinus amercana) with two visible plugs used to treat for emerald ash borer (Agrilus planipennis).

NPS photo/A.Smith

At Hopewell Culture National Historical Park, our Natural Resource Team has been doing their part to protect our ash trees. We treat our healthy ash trees with an insecticide that while harmless to the tree, will kill off the EAB larvae before they can do any damage.

If you come across one of our living ash trees at the park, you can find the small plastic plugs in a spiral pattern around the trunk, that we use to give them their medicine. Once the borers have wiped out all untreated ash trees and have gone away, it is our hope that these healthy trees will provide seeds, to help the next generation of ash recolonize our forests.

While treating healthy ash trees can be very costly, there are other way you can help to stop the spread of EAB. These beetles can only spread one mile per year on their own. Promising to not move fire wood will help to avoid spreading them further. Having dead and dying ash trees removed, can also help prevent the EAB from reproducing, and will protect your property from damage as well.

Our park biologists need your help to stop the spread of this deadly invasive insect. Together, we can be partners in protecting our ash trees from this ruthless invader!