Joining the ranks of mosquitoes as one D.C.’s dreaded pests is a small, shiny green beetle, the Emerald Ash Borer (known as EAB). These small green beetles are from East Asia and pose a devastating threat from the tree from which it gets part of its name: the ash. There’s a near 100% mortality rate to ash trees it invades. The adult beetles themselves don’t cause harm – but their offspring burrow through the layers of bark which disrupts the flow of nutrients throughout the tree, thus killing the tree from the inside out.
D.C. was included in the federal EAB quarantine, which was instituted to contain the movement of infected trees, and in the 10 years since its first appearance, we’ve observed signs, symptoms, and adult EAB in District trees. While EAB is killing trees, we’re lucky that the ash population in the city is small relative to surrounding areas. However, there have been significant losses in other areas, most notably, Theodore Roosevelt island was closed last year to remove trees and we’ve partnered with Gallaudet University to replace large swaths of their campus’ lost Ash canopy. Likewise, we’re also working with Kenilworth Park and Aquatic Gardens to restore their canopy, which took a hit from EAB.
If you think you have Ash trees on your property, there are some treatment methods that are effective for controlling EAB, many of which are discussed in a fact sheet, although if your trees have experienced significant canopy loss and are beyond treatment options, removal sooner than later is often the best option, as removing heavily infested dead ash trees can become hazardous. Unsure about whether your ash tree is in trouble? Contacting a certified arborist is your best bet.
Emerald ash borers are impressive and terrifying in their ability to rapidly destroy mature Ash trees. Want to learn more about how you can advocate for tree health and protection in your community? Sign up to attend our upcoming Stand Up for Trees class on June 23. The National Arboretum is also offering an EAB workshop on July 10.