The discovery of an emerald ash borer (EAB) in an ash tree on the University of Iowa campus means that Iowa City is now categorized as an EAB infestation area, according to the Iowa Department of Agriculture and Land Stewardship. There are now 30 counties in Iowa, including Johnson County, that have been confirmed as EAB infestation areas.

Zac Hall, Iowa City Superintendent of Parks and Forestry, said it can take eight to 12 years for the insect to decimate the local ash tree population, so it is not necessary for property owners to immediately remove ash trees that are not showing signs of EAB. Hall recommends that property owners follow the same protocol as the City of Iowa City:

  • Watch for signs of damage, including thinning or dying branches at the top of the tree, woodpeckers that may be feeding on the EAB larvae, S-shaped feeding trails under dead or splitting bark, tiny D-shaped exit holes and water spouts in the trunk and main branches. Also be on the lookout for the insect itself, an iridescent, metallic green beetle that measures about a half-inch in length. If you believe you have found an EAB specimen, you should contact the Iowa Department of Natural Resources.
  • The tree should be taken down when it is no longer viable. Hall indicated that ash trees are generally weaker varieties, and should be removed when they pose a hazard of injury or damage to people or property.
  • Community members who wish to try to save their ash trees with a preventive treatment should contact a certified arborist, landscape company or tree service. The City of Iowa City does not provide that service for trees on private property. While bids could be sought now, treatment should not begin until April or May.
  • The trees in the right-of-way -- the strip of land that runs adjacent to the street or between the sidewalk and the street -- are the responsibility of the City. Property owners do not have to manage ash trees planted in the right-of-way.
  • Hall recommends that homeowners select a variety of species for replacement trees. Diversifying the tree population will help ensure that future insect or disease issues will not destroy a full canopy of trees in areas where the same variety was repeatedly planted.

A statewide quarantine is in place, so Iowans should not transport firewood across county or state lines to help prevent spread of the insects.

For more information, visit or contact Hall or Iowa City Parks and Recreation Director Juli Seydell Johnson at 319-356-5100.

Date of publication

Tuesday, February 09, 2016