Ash borer found in all Iowa counties but one

Emmet County in far northern Iowa is the lone remaining county in the state with no confirmed presence of a beetle that kills ash trees, according to the Iowa Department of Agriculture and Land Stewardship.

On Monday, the department said the emerald ash borer was discovered in Palo Alto County for the first time, in a tree in a public area near Emmetsburg.

The beetle was first found in far northeast Iowa in 2010 and has since spread to all parts of the state. The beetle’s larvae eat the living, inner bark of ash trees and typically kill them within two to four years.

The beetle’s spread has led some cities to proactively remove ash trees in anticipation of their demise or to attempt insecticide treatments to prevent it. State conservation officials have estimated there were about 55 million ash trees in Iowa before the beetle’s arrival.

The adult beetles are metallic green and about a half inch long. Ash trees that are infested often have fewer leaves, sprouts with leaves coming from lower parts of the trunk or main branches, and holes where the beetles emerge that are shaped like the letter ‘D’ and are about one-eighth of an inch wide.

Those who see evidence of the emerald ash borer in Emmet County can call the state entomologist’s office at (515) 725-1470.