The Emerald Ash Borer (EAB) has been positively identified in Grinnell (Poweshiek County) bringing the total of confirmed counties to 25 since it was first detected in Iowa back in 2010. This metallic green insect, which only measures about half-inch long and an eighth-inch wide, kills all ash tree species and is considered to be one of the most destructive tree pests ever seen in North America.
Read more about this most recent discovery and confirmations of infestation in the Iowa State University Extension and Outreach Yard & Garden news release from June 22, 2015.
The map below shows the current confirmed reports of EAB in Iowa. The circles around each confirmed infestation indicate a 15-mile radius, an area where ash trees are at risk of attack and it is suggested that homeowners decide which management option they will use to deal with the threat of EAB on their ash tree(s). For more on control options see ISU Extension & Outreach pamphlet PM 2084, Emerald Ash Borer Management Options.