Emerald ash borer (EAB) is established in the metro. An untreated ash will almost always decline.
Common species in our area are green and white ash. Blue ash has shown partial resistance in some studies but can still be affected where pressure is high.
What EAB progression looks like
- Years 1 to 2: Usually nothing is apparent — the tree may look normal.
- Years 2 to 3: Thinning in the crown, shoots sprouting on the trunk.
- Years 3 to 4: Major dieback, D-shaped exit holes in bark.
- Years 4 to 5: Canopy failure and death.
Timelines vary with tree size and local pressure. Once decline is obvious, success rates drop.
EAB spreads roughly 1 to 2 miles per year on its own and farther when infested firewood moves around. If nearby ash show symptoms, yours are likely exposed.
Your options
1) Preventive treatment
- Best for healthy, valuable ash.
- Professional trunk injections of emamectin benzoate every 2 to 3 years.
- Very high success when started early.
- Costs are usually a few hundred dollars per treatment depending on tree size.
2) Removal and replacement
- Right choice for declining trees or risky locations.
- Includes removal and stump grinding.
- Price depends on size, access, and hazards.
3) Do nothing
Expect progressive decline and increasing hazard. Dead ash becomes brittle and unpredictable. Keep in mind that removal costs often increase as the tree becomes more brittle and hazardous to manage.
Our usual recommendations
Treat if the tree is healthy, well placed, and often at least 10 to 15 inches in diameter.
Remove if there is significant dieback, poor structure, or if there are targets below. Act before the tree becomes brittle. That keeps costs and safety risks lower.
