Emerald Ash Borer Confirmed in Marshall and Tama Counties, Iowa

55 counties in Iowa have confirmed infestations

March 28, 2018, 9:11 am | Dustin Vande Hoef, Julie Tack, Laura Sternweis

DES MOINES, Iowa – Emerald ash borer, an invasive insect that kills ash trees, has been detected for the first time in Marshall and Tama counties. The discoveries were the result of a landowner who noticed tell-tale woodpecker damage on his ash trees. Further investigation by authorities resulted in the collection of EAB larvae from the trees. Both county detections occurred in a rural area north of Le Grand.

Native to eastern Asia, EAB has decimated tens of millions of ash trees since it was accidently introduced in the U.S. in the Detroit area in 2002. First detected in Iowa in 2010, EAB has been confirmed in 55 Iowa counties. Since the beetle only travels short distances on its own, humans serve as the primary vector for expanding its range. The most common mode of transport for this pest is through movement of firewood. The Iowa EAB Team strongly urges Iowans to use locally sourced firewood, burning it in the same county where it was purchased.  

EAB larvae kill ash trees by tunneling under the bark and feeding on the part of the tree that moves nutrients up and down the trunk. EAB-infested ash trees can include branch dieback in the upper crown, water sprouts along the trunk and main branches, vertical bark splits, D-shaped emergence holes, S-shaped tunneling under loose bark, as well as woodpecker damage.

If you suspect EAB has been introduced to your area, please contact one of the following:

  • Iowa Dept. of Agriculture and Land Stewardship, State Entomologist Office: 515-725-1470
  • Iowa Department of Natural Resources: 515-725-8453
  • Iowa State University Extension and Outreach, Entomology: 515-294-1101

If a landowner is interested in protecting a valuable and healthy ash tree within 15 miles of a known infestation, the treatment window for protecting an ash tree begins very soon. Soil treatments should be made from mid-April to mid-May. Basal trunk sprays should be applied mid-May to mid-June. Trunk injections begin once the tree has a full canopy. Full details are available in Iowa State University Extension and Outreach publication PM 2084: https://store.extension.iastate.edu/product/13114

To learn more about EAB and view maps of its distribution, please visit www.IowaTreePests.com.

For more information contact any of the following members of the Iowa EAB Team:


About the Authors: 

Julie Tack

Iowa Department of Natural Resources