Emerald Ash Borer

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Emerald Ash Borer (EAB) FAQ's
- What is the emerald ash borer (EAB)?
  The emerald ash borer (EAB) is an invasive insect that has killed tens of millions of ash trees in North America since it was first discovered in 2002. It attacks all ash tree species and is considered one of the most destructive tree pests in North America.
- How does EAB damage ash trees?
  EAB larvae feed on live tree tissue, which prevents the tree from transporting water and nutrients. Signs that a tree may be infested include:
  - Thinning or dying branches at the top of the tree
  - Excessive woodpecker activity
  - Numerous sprouts growing from any part of the tree
  - Presence of EAB larvae or adult insects
- Why are dead or dying ash trees dangerous?
  Dead and dying ash trees are brittle and unstable, which makes them a serious safety hazard.
  - Branches can fall unexpectedly, even in calm weather
  - Falling branches can damage property, vehicles or people
  - Trees that pose a risk to neighboring property may be considered a nuisance, and the City can require their removal
  Property owners with untreated ash trees should have them assessed by a licensed professional and either treated or removed.
- What has the City of West Des Moines done about EAB?
  The City implemented its EAB Management Plan before EAB was confirmed in Polk County, treating the area as if the insect was already present.
  - The Parks & Recreation Department assessed all public ash trees - over 1,100 trees in parks, rights-of-way, medians, and around city buildings
  - The Urban Forestry Supervisor used this information to schedule pre-emptive removals of high-risk trees
  - Preventative treatment of over 800 public ash trees began in May 2015
  - Most removed trees were replaced with a diverse species from the Iowa DNR Ash Replacement List
- What should residents do if they have ash trees on private property?
  Residents should monitor their ash trees for signs of EAB. If trees are untreated and at risk, they should be assessed by a licensed professional and either treated or removed to prevent hazards and protect neighboring properties.

Emerald Ash Borer (EAB) Update - 2026

The City continues to treat more than 700 ash trees located throughout the community, including trees in:

Public parks
City facilities
Medians
Public rights-of-way

EAB Treatment

Preventative treatments remain highly effective in protecting ash trees from the Emerald Ash Borer. However:

Most untreated ash trees in the community are already dead or in decline
Ash trees that stop receiving treatment are at high risk of infestation
Untreated trees typically die within a few years

Public Safety and Tree Removal

To protect public safety, the City has removed all untreated ash trees from:

Public parks
Public facilities
Medians
Public rights-of-way

The City appreciates residents who have worked proactively with the City to remove hazardous ash trees from private property. Review City Code 7-10-7E (Dead, Diseased or Insect Ridden Trees or Shrubs) which addresses hazardous trees on private and public property.