IOWA CITY, Iowa (AP) – State officials say an invasive insect that kills ash trees has been confirmed in Iowa City. The Iowa Department of Agriculture announced Tuesday that a specimen collected from trees that appeared to be under attack on the University of Iowa campus was confirmed as an emerald ash borer. With Johnson County added to the list, there are now 30 Iowa counties where the pest has been confirmed.

The insects are native to Asia and were first spotted in the U.S. in 2002, when they showed up in the Detroit area. Authorities say the insects have spread to at least 25 other states, killing millions of trees. Once infected, trees typically die within five years. University of Iowa officials estimate there are 560 ash trees on campus.