The ash borer timeline in Scott County
Local measurements and geology — not national boilerplate.
Emerald ash borer was confirmed in Davenport in June 2015, after a state entomologist spotted an infested tree near Lincoln Avenue and Rockingham Road. It has since been found in all 99 Iowa counties. The beetle itself is small — about the size of Lincoln's profile on a penny — but its larvae feed in the cambium just under the bark, cutting the tree's ability to move water and nutrients until it starves. An infested ash typically dies within two to four years, and by the time the canopy visibly thins, the damage underneath is well advanced. The city of Davenport removes ash on public right-of-way rather than treating it, unless the adjacent resident chooses to pay for treatment — which is the same choice every private ash owner in Scott County now faces.
Sources: Iowa Dept. of Agriculture & Land Stewardship (EAB confirmed in all 99 counties); Quad-City Times (2015 Davenport confirmation); Iowa State University Extension / iowatreepests.com (identification, treatment thresholds); City of Davenport Public Works
Identify, then decide: treat or remove
Start by confirming it is an ash. Ash have opposite branching (twigs and buds directly across from each other, which only a handful of species do), compound leaves of 5–9 leaflets on a single stem, and diamond-patterned bark on mature trunks. Then look for the borer's signature: canopy thinning that starts at the top, D-shaped exit holes about an eighth of an inch across, S-shaped galleries under loose bark, epicormic sprouts shooting from the trunk, and heavy woodpecker damage — “blonding,” where birds strip outer bark to reach larvae. Blonding is often the first thing a homeowner notices from the ground.
Then the real decision. Treatment — trunk-injected insecticide, repeated every one to two years — genuinely works, but only on a tree that still has most of its canopy; the rule of thumb is that once more than about half the crown is gone, treatment cannot bring it back. Treatment is also permanent: stop, and the tree dies. So the honest math is whether this particular tree is worth an indefinite recurring cost — a mature shade ash cooling the south side of the house often is; a mediocre ash at the back fence usually is not. Removal ends the cost, and removing while the wood is still sound is materially cheaper and safer than removing a dead one.
That last point is the one most Davenport homeowners learn late. A dead ash goes brittle fast — limbs shed without warning, and climbers will not work a tree they cannot trust, so dead removals need bucket trucks or cranes and get priced as hazard work. Some crews decline them outright. Every year a dead ash stands, it gets more expensive to take down, and there is no version of this where it eventually gets easier.
- Identification: opposite branching, compound leaves, diamond bark
- Infestation signs: top-down thinning, D-shaped holes, blonding, trunk sprouts
- Treat only while the canopy is largely intact — and forever after
- Remove while the wood is sound: cheaper, safer, and always an option today
Related pages
Every page cites its sources — start where your question is.
Davenport Ash Tree Removal & Emerald Ash Borer — FAQ
Is it too late to save my ash tree?
What does the city do with ash trees on the parking strip?
Can I burn or move the wood from my ash tree?
How much does removing an ash tree cost here?
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