If you have been following tree news in Texas recently, you may have heard more about the emerald ash borer.
There is a reason.
Emerald ash borer, commonly called EAB, has continued to spread across Texas, with new detections being reported in 2026. While the insect has not currently been confirmed in Harris or Fort Bend counties, its movement into additional parts of Texas makes it something Houston-area homeowners — especially those with ash trees — should understand.
The goal isn’t to panic or assume every struggling ash tree has emerald ash borer. It is to know what is happening, recognize the warning signs and pay a little more attention to the ash trees already growing on your property.
What Is the Emerald Ash Borer?
The emerald ash borer (Agrilus planipennis) is a small, metallic-green beetle native to Asia. Despite its size, it has become one of the most destructive invasive insects affecting trees in North America.
The beetle attacks ash trees in the genus Fraxinus.
The adult beetle itself isn’t responsible for most of the damage. The real problem develops underneath the bark.
After eggs hatch, emerald ash borer larvae feed on tissue beneath the bark that the tree relies on to transport water and nutrients. As the larvae create winding galleries through this tissue, they gradually interfere with the tree’s ability to move those resources between its roots and canopy.
Over time, the tree begins to decline.
According to the Texas A&M Forest Service’s Emerald Ash Borer information, all native ash species are considered at risk from EAB.
Why Are We Talking About Emerald Ash Borer in Houston Now?
Emerald ash borer isn’t new to Texas.
It was first detected in the state in Harrison County in 2016. Since then, it has steadily appeared in additional counties.
The movement in 2026 is particularly worth watching for Southeast Texas.
In June, Hardin County was added to the state’s emerald ash borer quarantine following detection of adult beetles. Then in July, Walker County was added following another detection.
The Texas Department of Agriculture’s Emerald Ash Borer information maintains the current list of quarantined Texas counties.
At the time of this article, Fort Bend and Harris counties are not on that list.
Emerald ash borer can spread naturally, but movement of infested ash wood and firewood can carry the insect much farther. This is one reason Texas maintains quarantines in counties where EAB has been detected.
For homeowners around Richmond and Greater Houston, that doesn’t mean every declining ash tree should suddenly be considered an EAB case. It does mean this is a good time to identify ash trees on your property and become familiar with what emerald ash borer damage actually looks like.
How Do You Know If You Have an Ash Tree?
Before worrying about emerald ash borer, the first question is much simpler:
Is the tree actually an ash?
One useful characteristic is the branching pattern. Ash trees typically have two leaves per node. This gives the branches and leaves an appearance of grow opposite one another rather than alternating along the stem.
Ash leaves are compound, consisting of multiple leaflets, and mature ash trees often develop bark with an interwoven or diamond-shaped pattern.
Tree identification isn’t always as straightforward as comparing a leaf to a photo online, however. If you’re unsure what species you have, proper identification is imperative for tree health care and ultimately correct disease diagnosis.
What Does Emerald Ash Borer Damage Look Like?
One of the difficulties with EAB is that an ash tree may show few or no obvious symptoms during the early stages of infestation. The USDA’s emerald ash borer guidance notes that early infestations can be difficult to detect through visual inspection alone.
As an infestation progresses, there are several signs homeowners can watch for:
- Dieback near the top of the canopy
- Thinning or dying branches
- New leafy shoots growing from the trunk
- Splitting or loose bark
- S-shaped galleries underneath the bark
- Increased woodpecker activity
- Small D-shaped exit holes in the bark
Those D-shaped holes are one of EAB’s characteristic signs. Adult beetles leave them behind as they emerge from the tree.
However, a declining canopy by itself does not prove that a tree has emerald ash borer.
Drought, root damage, soil problems, construction injury, other insects and diseases can all produce symptoms that a homeowner may simply interpret as a “dying tree.”
That is why the entire tree — and what is happening around it — matters.
A Healthy-Looking Tree Can Still Have a Problem
Emerald ash borer also demonstrates something important about tree health: what we can see from the ground doesn’t always tell the entire story.
Much of EAB’s destructive activity occurs beneath the bark.
During the early stages, the canopy may still appear relatively normal while larvae are already feeding inside the tree. USDA guidance notes that visual inspection alone may have difficulty detecting early infestations.
By the time significant canopy decline becomes obvious, the infestation may already be well established.
This is one reason knowing the species of trees on your property — and noticing changes from year to year — can be valuable.
Can an Ash Tree Be Saved?
An emerald ash borer diagnosis does not automatically mean a tree needs to be removed.
There are insecticide treatments available for protecting certain ash trees, particularly when treatment begins early enough. The Texas A&M Forest Service identifies systemic treatments containing emamectin benzoate as one option used in areas where EAB is present, with some trunk-injection treatments providing protection for multiple years.
Whether treatment makes sense depends on the individual tree.
Its size, condition, location, value to the property and degree of infestation all matter. A large, structurally sound shade tree may justify an entirely different decision than an already declining tree in a poor location.
The important part is making that decision based on the condition of the tree rather than assuming that every ash should immediately be removed — or that every ash can necessarily be saved.
What Should Houston-Area Homeowners Do Right Now?
For most homeowners in the Greater Houston area, emerald ash borer isn’t a reason to start removing healthy ash trees.
It is a reason to start paying attention.
If you have an ash tree:
- Make sure the tree has been correctly identified as an ash.
- Take note of its current canopy and overall condition.
- Watch for unusual thinning, upper-canopy dieback, bark splitting or increased woodpecker activity.
- Look more closely if you find D-shaped exit holes or galleries underneath loose bark.
- Have unusual decline evaluated rather than assuming emerald ash borer is the cause.
- Keep up with new Texas detections as monitoring continues.
If you believe you’ve found emerald ash borer or a symptomatic ash tree in an area where the insect hasn’t previously been confirmed, suspected cases can be reported through the Texas A&M Forest Service.
The Bigger Picture for Houston’s Trees
Emerald ash borer may be getting attention right now, but it is also a reminder of why tree care involves more than reacting when a tree is already dying.
Trees change slowly. So do many of the problems affecting them.
Knowing what species are growing on your property, recognizing changes in their structure and canopy, and investigating unusual decline early can give you more options than waiting until a tree becomes an obvious hazard.
For homeowners in Richmond, Fort Bend County and the Greater Houston area, emerald ash borer isn’t currently a reason for panic.
It’s a reason to know your trees and pay attention to what they’re telling you.
As of August 2026, Harris and Fort Bend counties are not listed among Texas’ emerald ash borer quarantined counties. However, EAB has continued to spread in Texas, including 2026 detections in Hardin and Walker counties. Homeowners should consult current Texas Department of Agriculture and Texas A&M Forest Service information because the known range can change as new detections are confirmed.
No. Emerald ash borer specifically attacks ash trees (Fraxinus species). Damage to an oak tree would have another cause.
Early infestations can be difficult to see. As damage progresses, signs may include upper-canopy dieback, thinning branches, shoots growing from the trunk, bark splitting, increased woodpecker activity, S-shaped galleries beneath the bark and characteristic D-shaped exit holes.
Not necessarily. Treatment options exist, and whether treatment or removal is appropriate depends on the tree’s condition, location and extent of infestation. Early identification generally provides more management options.
The presence of EAB elsewhere in Texas alone isn’t a reason to automatically remove a healthy ash tree. Tree condition, structural quality, location and value should all be considered before making a removal decision.
Yes. Transporting infested wood is an important way EAB can spread over long distances. Texas officials recommend buying and burning firewood locally rather than transporting it between areas.