Emerald Ash Borer has now been found in trees in 50 of the state's 99-counties.
Benton, Buena Vista, Floyd, Howard and Warren Counties are the latest to be added to the list.
Mike Kinter of the Iowa Department of Agriculture says lately they've been getting a lot of phone calls about this ash-tree killing insect.
Kintner says trees have had a chance to fully leaf out, and trees that are struggling are easy to spot.
He says in parts of eastern Iowa, where EAB was detected several years ago, infected trees look very sparse, most of the upper canopy of the tree is dead.
Emerald Ash Borer was first found in Iowa in 2010 in Allamakee County, and has continued to spread.
This year alone, about a dozen counties have been added to the list.
Kintner says there are an estimated 55 million ash trees in Iowa, 3.1 million are in cities.
It's estimated that ash trees make up around 17 percent of a tree canopy in most cities in Iowa.
The Warren County infestation was spotted by a Department of Natural Resources forester in a wooded area near Milo.
Property owners wanting more information about EAB, click HERE