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Emerald Ash Borer in Iowa: All 99 Counties and What Ash Owners Can Do

Updated · By Kasey, Waukee, Iowa

If you have an ash tree in your Des Moines yard, or anywhere else in Iowa, emerald ash borer is no longer a "someday" problem. In October 2024 the Iowa Department of Agriculture and Land Stewardship (IDALS) announced that the insect had been confirmed in all 99 Iowa counties, from Ames and Cedar Rapids to Waukee and the Des Moines metro.

That does not mean every ash tree is already lost. Iowa State University (ISU) Extension says preventive treatments can protect a healthy ash, as long as they start before the tree is badly damaged. This guide covers how to spot it, your options, and when to call a licensed pro or certified arborist.

What it is and how to identify it

Emerald ash borer (often shortened to EAB) is a non-native, wood-boring beetle from Asia that attacks all species of ash native to North America, according to ISU Extension. IDALS says it was unknown in North America until it was found in southeast Michigan in 2002. It was first discovered in Iowa in 2010, in Allamakee County, and the last county to confirm it was Emmet County in 2024.

What the insect looks like, according to ISU:

You are much more likely to notice the damage than the beetle itself. IDALS and ISU list these warning signs:

Other insects bore into trees, too, and ISU Extension publishes a guide to native borers and EAB look-alikes. If you are unsure what you have, the ISU Plant and Insect Diagnostic Clinic identifies insects for Iowans. Check its website for current forms, fees and mailing instructions.

How it kills an ash tree

ISU explains that the damage comes from the larvae, not the adults. Adults nibble ash leaves, but ISU calls that damage insignificant. The larvae tunnel through the inner bark just beneath the surface and cut off the tree's ability to move water and nutrients.

IDALS says the cumulative damage typically kills a tree within two to four years after it becomes infested. ISU adds that decline can happen in as little as one year or take as long as five.

Why it shows up (season and local angle)

ISU describes the yearly cycle like this:

On its own, the beetle does not travel far. ISU says females usually lay eggs on ash within a few miles of where they emerged. The long jumps happen when people move infested firewood, logs and nursery stock. That is why IDALS still reminds Iowans to buy or gather firewood locally, where it will be burned, even now that every county has a detection.

What you can do yourself

First, decide what kind of tree you have

IDALS outlines three choices for ash owners:

  1. Wait and see what happens.
  2. Remove a declining ash and replace it with a different species.
  3. Use preventive insecticide treatments to protect a valuable, healthy ash.

ISU is blunt that without preventive treatment, infested ash trees will die. Treatment only makes sense for the right tree. ISU's guidelines:

Timing matters

Both IDALS and ISU say the best time to treat is spring, from mid-April to mid-May, when the tree is actively growing. ISU says a few products also work when applied from early August to mid-September, but spring applications control EAB more effectively. IDALS adds that tree service companies can apply trunk injections through the summer if there is enough soil moisture.

Homeowner products

ISU says treatments can be applied as a trunk injection, soil drench, soil injection or basal trunk spray, depending on the product. Some products, mainly soil drenches, are sold for homeowner use, but most EAB treatments can only be applied by licensed pesticide applicators. Treatments must be repeated every 1 to 2 years for the rest of the tree's life, depending on the product.

If you use a homeowner product, read and follow the label every time. The U.S. EPA notes that every pesticide label says it is a violation of federal law to use the product in a manner inconsistent with its labeling. We do not recommend specific brands. ISU Extension's free publication Emerald Ash Borer Management Options compares treatment types in more detail.

Firewood from your own ash

If you cut down an ash and keep the wood, ISU says to use it on your property and not move it to new locations. ISU also says firewood brought indoors, especially in the first year after cutting, can have beetles emerge inside. Those beetles will not infest anything in your home and will not live long, and they can be vacuumed up near windows. ISU says not to treat firewood with insecticides.

When to call a licensed pro

A professional makes sense when:

How to choose a licensed Iowa applicator

Under Iowa's administrative rules, anyone in the business of applying pesticides to another person's property must be licensed and certified by the state. Tree treatments generally fall under Category 3, Ornamental and Turf Pest Control, which the rule says covers pest control on ornamental trees, shrubs, flowers and turf. Before you hire:

  1. Ask for the company's Iowa license and the technician's certification, and which category it covers.
  2. Verify both in the Iowa Department of Agriculture and Land Stewardship lookup.
  3. Ask whether they think your tree is a good treatment candidate, which application method they plan to use, and how often it will need to be repeated.
  4. For removal, ISU suggests looking for a certified arborist.

See our guide to choosing a pest pro for more questions to ask.

Local pest pros in the Des Moines metro

See all 77 listed companies by town →

Listings are informational, not endorsements or rankings, and no company paid to be listed. Details come from each company’s own website. Always verify an Iowa pesticide license with IDALS before hiring. Companies can request a correction or removal.

Is your business missing or wrong? Contact us with your website and the towns you serve.

Frequently asked questions

Is emerald ash borer in my Iowa county?

Yes. IDALS confirmed EAB in all 99 Iowa counties in October 2024, when Emmet County became the last county with a detection.

Can my ash tree still be saved?

Possibly. ISU says preventive treatments work best on healthy trees with no EAB damage, and a tree should have less than 50% canopy thinning, or less than 30% of its branches dead, to be a treatment candidate.

When is the best time to treat an ash tree for EAB?

IDALS and ISU say spring, from mid-April to mid-May. ISU says a few products also work from early August to mid-September, but spring control is more effective.

Can I burn wood from an ash tree I cut down?

ISU says you can use it on your own property, but do not move it to new locations. Beetles may emerge from wood brought indoors, but they will not infest your home and will not live long.

Nearby towns we cover

Related guides

Sources

  1. Emerald Ash Borer Now Confirmed in all 99 Counties - Iowa Department of Agriculture and Land Stewardship (checked 2026-10-24)
  2. Emerald Ash Borer - Iowa State University Extension and Outreach (checked 2026-10-24)
  3. Introduction to Pesticide Labels - U.S. EPA (checked 2026-10-24)
  4. Iowa Admin. Code r. 21-45.22, License and certification standards for pesticide applicators (checked 2026-10-24)
  5. Pesticide applicator and company license lookup - Iowa Department of Agriculture and Land Stewardship (checked 2026-10-24)

We link to the original sources so you can read them yourself. Product names are not endorsements.