
The infamous emerald ash borer (Agrilus planipennis) is considered one of the most destructive tree pests in North America. This metallic green jewel-like beetle is anything but a treasure to have. Emerald ash borers (abbreviated EAB) are an invasive species that attack and kill all species of North American ash trees, which have no natural resistance against the pest. When you consider the fact that there are more ash trees in the USA than there are people in the world – that’s a lot of trees at risk! Not only is the value of the tree lost, but the costs of removing these fragile trees can get expensive. The idea of protecting these trees can be daunting, but not to worry, RTEC is here to help one yard at a time!
The emerald ash borer is native to many parts of Asia and was first detected as an invasive species in the United States in 2002. Since it was first discovered in Michigan, the EAB has spread to over 36 states and has destroyed hundreds of millions of ash trees in its wake. Due to their wood boring nature, emerald ash borers tunnel through wood for most of their life span. They spend months inside of tree bark cutting through the connective tissues that transport water and nutrients throughout a tree. Once a tree is infected, it will eventually become strangled from its inability to move nutrients throughout itself. This means that the best way to save your tree is to get a preventative plan before you notice an infestation. Below are three foolproof steps to protecting your trees from emerald ash borers!
Step One: Identifying An Ash Tree
It may seem silly, but this is an important first step that makes or breaks the process! We don’t expect everyone to all have the tree species in their backyards memorized (that’s what you have RTEC for!), so here is a helpful guide to identifying potential ash trees on your property.

- Look at the leaves. All ash trees have compound leaves (i.e., multiple leaflets attached to a middle vein. Ash trees have at least 5 leaflets per leaf).
- Look at the branches. Ash tree branches come in pairs! Branches and buds form directly opposite each other.
- Look at the bark. Ash tree bark has a shallow diamond-shaped pattern along the trunk.
Step Two: Checking for an Infestation
If you’re lucky, you will never see any of these signs on your ash tree. As we said, preventative care is the best care. After identifying that you have an ash tree, the next step will be to go outside and check for these signs of an infestation.

- Canopy thinning/canopy dieback that occurs from the top down can be a sign of an emerald ash borer infection.
- “D” – shaped holes in the outer bark. As adult beetles emerge from the bark, they create a perfect capital D-shaped hole that has become a tell-tale sign of EAB.
- Later stages may include sprouts growing from the bottom half of the tree trunk or even from the roots.
- Increased woodpecker activity – they are trying to eat the bugs inside!

Step Three: Get A Preventative Plan

Didn’t notice any of those symptoms? Great! Now we need to keep protected by enrolling in a preventative plan! Do not wait utility your tree is showing signs of infestation. As a mater of fact, the Nation Park Service claims that emerald ash borer has nearly a 100% mortality rate of killing a tree once infected. This means there are only two real choices – protect your tree with a preventative treatment before it gets invaded or wait until the tree is infested and has to be removed due to irreversible decline. It is known that once approximately 30% of the canopy has died there is little to no recovery for the tree.
Left: A healthy tree treated for EAB.
Right: A dying tree untreated for EAB.

Here at RTEC we are doing our part to combat the emerald ash borer throughout NOVA by partnering with Fairfax County to treat ash trees at regional parks! We encourage you to take on the responsibility to protect your trees and with our help we will reduce the spread of this killer pest.
Enroll in our Emerald Ash Borer Preventative Program Today!
Don’t Wait Until It’s Too Late