Beetle bust: Beware of the Emerald Ash Borer

Main Image

Have an ash tree? Act fast to beat back the beetles who seek to destroy it. A little beetle is causing a big problem in North America where ash trees are prevalent. Government officials are working hard to fight off the the Emerald Ash Borer (EAB) and the billions of dollars of damage the species is poised to unleash on the landscape. Identify your ash trees, watch for signs of infestation throughout the year, and treat the trees preventatively this spring.

Identify your trees

We’re not all arborists. For most of us, our knowledge is limited. We can pick out a maple leaf (thanks, Canada!) but beyond that, we’re going to need help identifying the trees. Any ash tree in North America can be affected by the EAB. There are five species of North American ash trees: Black Ash, European Ash, European Mountain Ash, Green Ash, and White Ash. The typical method of identification is a tree’s leaves, but the fruit may be a good way to identify the tree when you can’t remember the leaf shape during the winter months. It’s easy to remember the fruit we have to clean up every year. Here are a few resources to help you in your identifying quest:

            •           Leafsnap is an app that will compare a photo of your trees leaves or fruit to its database of photos. With any luck the app will identify your tree
            •           A knowledgeable neighbor
            •           Your local Extension office: a governmental agency dedicated to working with residents to grow and maintain gardens and greenery.Find your local Extension services office by plugging in your zip code at the Gardening Know How site
            •           The USDA Emerald Ash Borer Hotline at (866) 322-4512
            •           The Emerald Ash Borer Info site has more information and pictures

Look for signs of infestation

The first signs of EAB infestation is a decreased tree canopy. If the leaves at the very top of the tree seem to be thinning, look for other signs of EABs, like D-shaped holes and vertical breaks in the bark, serpentine-like scars on the bark, and an increase of woodpecker activity.


If your trees are showing only a few signs of EAB infestation, it may be worth it to treat them. To help you decide on whether or not you need professional help, the Purdue Extension has a handy decision-tree guide (.pdf). If you want to treat the trees yourself, look for an over-the-counter soil-soaking treatment that contains 1.47% imidacloprid. Follow the directions on the container. Purdue suggests applying the solution to the soil around the tree starting on April 1 and before May 15th.

Saving the tree will be much more cost-effective than removing it, even if you hire a professional tree expert to help you diagnose your trees.

Warn neighbors

Spread the word. Large shade trees are a joy and an essential part of a neighborhood's character and landscape. Help others find and save the Ash trees in your town.