Emerald ash borer facts
The emerald ash borer is an Asian beetle that has infested ash trees in the northern United States. The beetles feed on — and eventually kill — the trees they inhabit. If you have an ash tree in your yard, take precautions to keep it safe. (A dying tree can shed limbs and harm your property or your family.)
Emerald ash borers were first discovered in Michigan and Canada in 2002. The hardy beetle has since spread east to Massachusetts and west to Colorado, mostly due to people transporting infested trees or wood to non-infested areas.
Emerald ash borer damage
Emerald ash borer larva hatch on ash tree bark and then burrow into the tree to feed on it. This invasion disrupts the tree's nutrition system, which eventually kills it.
Early detection can be difficult but is key to preventing spread. Start by learning the general warning signs of a sick or dying tree. Also look for woodpecker holes and subsequent bark loss — early signs of an emerald ash borer infection. As the beetles take over, the tree's leaves will start to thin at the top and then throughout the canopy.
You can sometimes spot vertical splits in the bark where larvae are feeding underneath. Adult emerald ash borers also leave D-shaped holes when they exit a tree. Iowa State University Extension and Outreach has developed a video to help you identify the emerald ash borer and determine whether your tree may be infested.
Emerald ash borer treatment
Prevention is the most effective way to keep your tree healthy. The first step is to have your tree inspected by a professional who can also determine if there are any other conditions that should also be addressed.
- Soil injection,
- Trunk injection,
- Bark spray, or
- Canopy spray.
Soil and trunk injection are the most common treatments as they bring the treatment to the entire tree.
There are also DIY treatments for emerald ash borers. It’s critical, however, to choose a product with a high enough concentration and to apply it at the correct dose and timing.
Emerald ash borer map
Learn if emerald ash borer has been detected in your area. If you suspect a nearby infestation, insecticides can help protect trees on your property. However, trees already infested should be cut down and burned or buried.
States are working to quarantine areas of infested ash trees. You can help prevent spread by keeping infected wood out of noninfested areas, like only burning firewood cut within 50 miles of your location.