The emerald ash borer has been found in a fourth Iowa location according to the Iowa Department of Agriculture and Land Stewardship.
The insect showed up in a tree at a Mechanicsville residence in eastern Iowa's Cedar County.
The first three confirmed sightings were in Allamakee, Des Moines and Jefferson counties.
Officials are considering a regional quarantine to slow the accidental transport of the insects. Officials say most infestations have been started because people move infested firewood, nursery plants or sawmill logs.
The beetles are native to Asia and were first detected in Michigan in 2002. Since then the insects have stripped entire neighborhoods of ash trees, killing more than 50 million of the trees.
There are an estimated 3.1 million ash trees across Iowa.