EAB Is Active in Wentzville Right Now
The emerald ash borer was first confirmed in St. Charles County in May 2015 — the same month it arrived in the City of St. Louis. A decade later, it has spread to every Missouri county. Ash trees die within 2–4 years of infestation. By 2025–2030, regional ash tree mortality is expected to approach 100%. If you have ash trees on your Wentzville property, the question is no longer if — it's when, and whether there's still time to act.
What Is the Emerald Ash Borer?
The emerald ash borer (Agrilus planipennis) is a small, metallic green beetle native to Asia that was accidentally introduced to North America before 2002, first detected in Michigan. Since then it has killed hundreds of millions of ash trees across at least 36 states. Unlike most native borers that attack only weakened trees, EAB kills healthy trees — making it uniquely devastating.
The damage is done by the larvae, not the adult beetles. After adult females lay eggs on the bark in summer, larvae hatch and bore through the bark into the tree's vascular layer — creating distinctive S-shaped feeding galleries that block the flow of water and nutrients from roots to canopy. The tree effectively starves from the top down. Most homeowners don't realize their ash tree is infested until significant canopy dieback is already visible — by which point the tree is often past saving.
How to Identify an Ash Tree
Before you can assess EAB risk, you need to know whether you have ash trees. All species of ash (Fraxinus) are susceptible — green ash, white ash, blue ash, and ornamental varieties alike. Here's how to identify them:
Ash tree identification features
Check for these characteristics — ash trees have a distinctive combination of all of them.
Opposite branching: Branches grow directly across from each other in pairs — not alternating. This is the single most reliable identifier.
Compound leaves: Each leaf is actually 5–11 leaflets arranged in pairs along a central stem, giving a feathery appearance.
Diamond-pattern bark: Mature ash trees have distinctive interlaced ridges forming a diamond or X pattern on the trunk.
Paddle-shaped seeds: Ash trees produce clusters of single-winged seeds (samaras) that hang in bunches and persist into winter.
Gray-brown bark: Younger ash trees have smooth, light gray bark; older trees develop the distinctive diamond-ridged texture.
Common in Wentzville: Green ash was heavily planted as a street and shade tree throughout St. Charles County subdivisions from the 1970s through the early 2000s.
Signs of EAB Infestation
EAB infestation is often invisible in the early stages — the larvae work under the bark before symptoms appear above ground. By the time you see visible signs, the tree has typically been infested for 1–3 years. Here's what to look for:
🔍 D-shaped exit holes
Adult beetles emerge leaving distinctive D-shaped holes approximately 1/8 inch wide in the bark. This is the most definitive confirmation of active or past EAB infestation. Look carefully — they're small and easy to miss on rough bark.
🐛 S-shaped galleries under bark
Peel back loose or peeling bark sections and look for winding, S-shaped tunnels in the wood beneath. These are the feeding paths left by EAB larvae as they destroy the tree's vascular tissue.
🌿 Crown dieback from the top
As EAB disrupts nutrient flow, branches begin dying from the top of the canopy downward. If your ash tree's upper branches are bare while lower ones still have leaves, EAB is a likely cause.
🦅 Heavy woodpecker activity
Woodpeckers aggressively target EAB larvae under the bark, stripping large sections of bark from the trunk and major branches — called "bark blonding." Heavy woodpecker damage on an ash tree is a strong EAB indicator.
🌱 Epicormic sprouts on trunk
When a tree is under severe stress, it sends up clusters of weak, spindly shoots from the trunk or main branches — a last-ditch attempt to produce foliage. On an ash tree, these sprouts often indicate advanced infestation.
🍂 Sparse, yellowing canopy
Reduced, off-color, or late-emerging foliage compared to previous years. Many homeowners notice their ash tree "just doesn't look right" — trust that instinct and get an assessment.
How Fast Does EAB Kill a Tree?
Understanding the timeline helps you know whether you're still in a window to act:
Year 1 — Infestation begins, no visible signs
Adult beetles lay eggs on the bark. Larvae hatch and begin boring under the bark. The tree looks completely healthy. This is the best window for treatment — but almost impossible to detect without a professional assessment.
Year 2 — Early symptoms appear
Minor crown thinning and some dieback in upper canopy. D-shaped exit holes may appear as first-year larvae mature and emerge. Woodpecker activity increases. Trees with less than 30% canopy loss may still be treatable.
Year 3 — Significant decline
Major crown dieback (50%+), epicormic sprouting from trunk, bark begins sloughing off. Trees at this stage are generally beyond treatment and should be removed before structural failure begins.
Year 4+ — Structural failure risk
Dead ash trees lose structural integrity rapidly. Brittle wood fails unpredictably — a 50-foot dead ash can drop a major limb without warning. Removal cost and complexity increase significantly once a tree is fully dead.
Treat or Remove? Making the Decision
Whether to treat an infested ash tree or remove it depends primarily on how far the infestation has progressed. Here's how we assess:
Consider treatment if...
- Less than 30–50% of the canopy has died back
- The tree has good overall structure and form
- It's a specimen tree with significant shade or landscape value
- No bark sloughing or significant woodpecker damage yet
- You're committed to ongoing treatment every 1–3 years
Remove the tree if...
- More than 50% canopy dieback is visible
- Bark is sloughing off or heavily woodpecker-damaged
- Epicormic sprouts are prominent on the trunk
- The tree is already structurally compromised
- It's near your home, car, or area where people gather
Important note on treatment: Systemic insecticide treatment (typically emamectin benzoate trunk injections) must be administered by a licensed pesticide applicator — not a tree removal company. We assess the tree and provide an honest recommendation. If treatment is viable, we refer you to a licensed applicator in the St. Charles County area. If removal is the right call, we handle that safely and completely.
Why Dead Ash Trees Are Especially Dangerous
Dead ash trees aren't just an eyesore — they're among the most structurally hazardous trees to leave standing. Unlike oaks or maples that hold their structural integrity for years after death, ash wood deteriorates rapidly once the tree dies. The same vascular destruction that kills the tree also accelerates decay throughout the trunk and major branches.
An EAB-killed ash that's been dead for one season can have wood that's already brittle enough to fail in wind that wouldn't trouble a live tree. A fully dead ash near your home, car, or anywhere people spend time is a genuine emergency — not something to defer until next year's budget. The removal cost of a dead ash standing upright is a fraction of the cost of a fallen ash on your roof.