EAB Warning Signs to Watch for Ash Trees in Denver

Emerald Ash Borer Warning Signs Denver


The Emerald Ash Borer beetle, or the EAB as it’s more commonly known, is already multiplying in northern Colorado communities.

The EAB was first recognized in Boulder in September 2013 and it poses an imminent threat on the city of Denver. CBS News in Denver reported that a Longmont-based arborist identified the EAB in a homeowner’s backyard in Longmont in June 2016.

What tipped off the arborist that the EAB was on the move into Longmont? Several telltale signs of EAB infestation. It breaks our hearts to hear the EAB is on its way to Denver to destroy ash trees that are several years old. Much of beautiful south Denver and Douglas County is home to over 1.45 million ash trees. Sadly, it’s not a matter of if, but when the EAB beetle will move south into Denver and devastate our favorite ash trees.

How will we know the EAB is starting to infest ash trees in Highlands Ranch, Littleton, Lakewood, Parker, Castle Rock, Lone Tree, and other parts of our service area? By looking for the warning signs of the Emerald Ash Borer beetle, our new archenemy. These are the signs we’re asking homeowners to be aware of when inspecting their ash trees. If you see any of these EAB warning signs, your first step is to call our Fielding Tree Care team.

EAB Warning Sign – EAB Adult Beetles and Larvae present

Of course, the most obvious warning sign is the actual presence of adult EAB beetles and/or larvae. The adult beetles are metallic green in color and approximately half-an-inch in length. They typically have a flattened back with dark gray or purple segments under their wing covers on their abdomen.

The EAB larvae are a creamy white color and legless. EAB larvae are most often found under the bark of an ash tree. Their bodies are typically divided into flattened, bell-like segments. The larvae leave S-shaped tunnels under the bark, which can be easily identified with any exposed section of bark.

EAB Warning Sign – Dying canopy of leaves

One of the most obvious signs of EAB infestation is a thinning of branches and leaves for a seemingly healthy ash tree. The twigs and branches begin to thin out as the tree infestation continues. Unfortunately, a dying canopy often occurs after years of EAB devastation.

EAB Warning Sign – D-shaped exit holes in ash tree bark

When the larvae hatch into adult beetles, they exit the bark of the ash tree by burrowing into the open. The D-shaped hole is not perfectly round because the EAB adult beetle has a flattened back.

EAB Warning Sign – Broken branches towards the trunk of the tree

Healthy branches typically break in the middle of the branch, not close to the tree trunk. If your ash tree recently experienced a broken branch, check to see where the break occurred. Obviously, there’s no need to break any branches to determine if the tree is infested with the Emerald Ash Borer.

EAB Warning Sign – Bark splintering and S-Shaped Tunnels

Ash trees suffering from EAB infestation often lose their bark as a result of damaged tissue. Bark splitting or bark peeling on ash trees may be reason enough to look for the telltale S-shaped galleries (tunnels) caused by EAB larvae.

EAB Warning Sign – Increased woodpecker interest or damage

A variety of woodpecker species have a healthy appetite for EAB. Unfortunately, their appetite is not strong enough to keep the EAB in check. Even if that were the case, the woodpecker would destroy your tree in the process to get their fill of the beetles. If you notice an unusual increase in interest or damage from woodpeckers, it’s often an ominous sign of EAB infestation.

EAB Warning Sign – Epicormic Shoots

You may have never heard the term ‘epicormic shoots’ but chances are you know what they are. Epicormic shoots are the short ‘tree-like’ shoots that grow out from the base of your trees. Most homeowners simply disregard these shoots as wild growth from a tree, and often that is the correct assumption.

However, ash trees infested with EAB larvae will send out epicormic shoots because the tree knows its life is at risk. The epicormic shoots are the tree’s survival mode kicking in to try outgrowing its new threat. Ash trees with EAB damage will often grow larger-than-normal leaves on its epicormic shoots.

The EAB adult beetles are typically active from early May through July. Now is your chance to protect your ash trees against EAB infestation. Your first step to keeping your ash trees is to connect with one of our certified arborists. Schedule your complimentary on-site ash tree inspection today.

Fielding Tree provides ash tree and EAB treatment services in Denver, Lakewood, Littleton, Highlands Ranch, Lone Tree, Centennial, Parker, Castle Rock, and other parts of Douglas County, Colorado.