Tree Info & Tips

Emerald Ash Borer in Missouri: Signs, Treatment & Removal

If you have ash trees in your Columbia or Boone County yard, the emerald ash borer is one of the most important things you can know about right now. This invasive beetle has spread across Missouri and is killing untreated ash trees in our region. Catching the problem early can mean the difference between protecting a healthy tree and having to remove a dead, dangerous one.

What Is the Emerald Ash Borer?

The emerald ash borer (often shortened to EAB) is a small, metallic-green beetle native to Asia. It was first detected in the United States in 2002 and was later confirmed in Missouri. The state has since dropped its internal quarantine because the insect is now considered established statewide — including across mid-Missouri and Boone County.

The adult beetles do minor damage by nibbling foliage, but the real harm comes from their larvae. After females lay eggs on the bark, the larvae tunnel underneath and feed on the layer of tissue that moves water and nutrients up and down the tree. As those tunnels multiply, they choke off the tree's circulation. EAB attacks all native species of ash, and a healthy, untreated ash tree will almost always die within a few years of being infested.

Is My Tree Even an Ash?

Before you worry about EAB, confirm you actually have an ash. Ash trees share a few telltale features:

• Opposite branching — buds, branches, and leaves grow directly across from one another rather than staggered.
• Compound leaves — each leaf is made of 5 to 9 leaflets arranged along a central stem.
• Diamond-patterned bark — mature ash bark forms tight, interlacing ridges in a diamond or net-like pattern.
• Canoe-paddle seeds — single-winged seeds that hang in clusters on female trees.

If you are not certain, that is normal — ash can be confused with other trees. A quick look from an arborist will settle it.

Signs of Emerald Ash Borer Decline

EAB damage usually shows up before anyone ever sees the beetle. Watch your ash trees for these warning signs:

• Canopy dieback from the top down — thinning leaves and bare branches that start at the crown and work downward, often the first symptom.
• D-shaped exit holes — tiny holes, about an eighth of an inch, with one flat side, left by adult beetles emerging from the bark.
• S-shaped serpentine galleries — winding, S-curved feeding tunnels packed with sawdust just under the bark.
• Bark splitting — vertical cracks in the bark that often reveal the galleries underneath.
• Epicormic and sucker sprouts — new shoots erupting from the trunk and base as the stressed tree tries to survive.
• Woodpecker activity and "blonding" — heavy woodpecker feeding that strips away outer bark and leaves pale, blond patches on the trunk and limbs.

Treat or Remove? Making the Call

Not every ash tree is a lost cause. The right decision usually comes down to how much of the canopy has already declined, and it is exactly the kind of question our arborist consulting and tree health service is built to answer.

As a general guideline:

• Healthy ash with less than 30–50% canopy loss can often be protected with systemic insecticide treatments. These are applied by a professional, move through the tree's tissue to kill larvae, and must be repeated on a regular cycle to keep working. A valued shade ash in good condition is frequently worth protecting this way.
• Heavily declined or dead ash is past the point treatment can reliably save. At that stage, the smart and safe choice is prompt tree removal before the tree becomes a hazard.

EAB is not the only thing that can stress an ash, either. If you are seeing decline and want to understand the full picture, our overview of common tree diseases in mid-Missouri is a useful companion read.

Why Dead Ash Trees Are So Dangerous to Remove

Here is the part many homeowners do not realize: a dead ash does not just sit there waiting. Ash wood becomes brittle remarkably fast once the tree dies. Branches and entire sections can snap and drop without warning, which makes a standing dead ash one of the riskier trees to take down.

In Columbia and across Boone County, that risk is amplified by our weather. Mid-Missouri sees severe thunderstorms, high straight-line winds, and ice loading in winter — any of which can bring a brittle dead ash crashing onto a roof, vehicle, power line, or person. That is why we urge homeowners not to wait. The longer a dead ash stands, the more dangerous and difficult the removal becomes. If a storm has already brought one down, our emergency tree service is available around the clock.

What to Do Next

The best time to act on EAB is before your ash is too far gone. If you have an ash tree showing any of the signs above — or you simply want to know whether yours is worth protecting — reach out for a free consultation. An ISA-certified arborist will inspect your trees, confirm whether EAB is the cause, and give you honest guidance on treating versus removing. Call Columbia Tree Co. at (573) 242-5335 to schedule your free estimate today.