Emerald ash borer continues to spread in Iowa

Emerald ash borer continues to spread in Iowa

Tree-killing insect has now been confirmed in Dubuque County, bringing total to 28 Iowa counties.

The emerald ash borer, a highly destructive insect of ash trees, has been confirmed in Dubuque, Iowa. Twenty-eight of Iowa's counties have now been confirmed positive. Since its initial discovery in Michigan in 2002, this exotic pest has spread to 25 states killing tens of millions of trees.

BAD BUG: Emerald ash borer is a small, shiny green beetle (½ inch long). It kills ash trees, usually in about 2 to 4 years. In the Midwest millions of ash trees have been killed by EAB since 2002.

In addition to the southern Dubuque detection, a tree in a rural area just outside the south Dubuque city limits was also detected. Both sites were declared positive after the collection of EAB larvae. The Iowa Department of Agriculture made the announcement on September 1. Iowans should be concerned about this pest. There are about 3.1 million urban ash trees in the state of Iowa, and an estimated 52 million ash trees in forests in the state.

Watch your ash trees for symptoms of EAB infestation
EAB is a small, metallic-green beetle that is about ½ inch long. The larvae chew into the layer of wood under the bark, cutting off the flow of water and nutrients. EAB infested ash trees include thinning or dying branches in the top of a tree, evidence of woodpecker activity, S-shaped feeding galleries under dead or splitting bark, D-shaped exit holes, and water sprouts (along the trunk and main branches).

"Iowa now has seven counties bordering the Mississippi River that have turned up positive for EAB," says Mike Kintner, Iowa Department of Ag & Land Stewardship EAB and gypsy moth coordinator. "Unfortunate as it is, I wouldn't be surprised to see the remaining three counties declared positive within a year."

The Iowa EAB Team provides EAB diagnostic assistance to landowners and includes officials from Iowa Department of Agriculture & Land Stewardship, Iowa State University Extension, the Iowa Department of Natural Resources, USDA Animal Plant Health Inspection Service and USDA Forest Service.

Don't transport firewood across county or state lines
Since larvae of EAB can unknowingly be transported under the bark of a tree, the Iowa EAB Team strongly cautions Iowans not to transport firewood across county or state lines. The movement of firewood throughout Iowa or to other states poses the greatest threat to quickly spread EAB and other plant pests. A statewide quarantine remains in place, restricting the movement of hardwood firewood, ash logs, wood chips and ash tree nursery stock out of Iowa into non-quarantined areas of other states.


At this calendar date (as of September 1), the window for all preventive treatments has closed, says Kintner. If a landowner is interested in protecting a valuable and healthy ash tree within 15 miles of a known infestation, he or she should have landscape and tree service companies bid on work, review the bids this fall/winter, and treat beginning spring 2016 (early April to mid-May).

Contact Iowa EAB team if you have suspicious looking trees
"Please contact Iowa EAB Team members to have suspicious looking trees checked in counties not currently known to be infested," says Kintner. "The State of Iowa will continue to track the movement of EAB on a county-by-county basis. Before a county can be officially recognized as infested, proof of a reproducing population is needed and an EAB must be collected and verified by USDA entomologists."

To learn more about EAB and other pests that are threatening Iowa's tree population, visit IowaTreePests.com. Contact any of the following members of the Iowa EAB Team for further information:
•Mike Kintner, IDALS EAB coordinator, 515-745-2877, [email protected]
•Robin Pruisner, IDALS state entomologist, 515-725-1470, [email protected]
•Paul Tauke, DNR state forester, 515-725-8450, [email protected]
•Tivon Feeley, DNR forest health coordinator, 515-725-8453, [email protected]
•Emma Hanigan, DNR urban forestry coordinator, 515-725-8454, [email protected]
•Jesse Randall, ISU Extension and Outreach forester, 515-294-1168, [email protected]
•Mark Shour, ISU Extension and Outreach entomologist, 515-294-5963, [email protected]
•Laura Jesse, ISU Extension and Outreach entomologist, ISU Plant and Insect Diagnostic Clinic, 515-294-0581, [email protected]
•Donald Lewis, ISU Extension and Outreach entomologist, 515-294-1101, [email protected].
•Jeff Iles, ISU Extension and Outreach horticulturist, 515-294-3718, [email protected]

TAGS: USDA Extension
Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.