Borers in Declining Ash Trees

Ash trees decline for a variety of reasons, and not just because of the emerald ash borer.

Reminder:  Emerald ash borer has only been found in Allamakee County in Iowa.  See the Emerald Ash Borer Team news release for January 17, 2013.

Declining, dying or recently-killed and cut ash trees will be infested by a variety of native borers.  The most common is the flatheaded appletree borer (Chrysobothris femorata) that attacks a wide variety of hardwood trees.  The larvae create galleries of scooped-out tunnels and chambers just under the bark.  See photo below.  

Ash bark beetle larvae are about one-eighth inch long and feed between the bark and the wood creating a feather-like pattern of parallel tunnels.  

Spray treatments for these borers are not practical.  Maintaining tree health and vigor is our best management option.

These and other common problems of ash are described in ISU Extension & Outreach pamphlet SUL 0021, "Common Problems of Ash Trees," available online at the ISU Extension Online Store.

Flatheaded appletree borer damage - below - and ash bark beetle tunnels - above.Flatheaded appletree borer damage - below - and ash bark beetle tunnels - above.

Issue: 
Category: 
Tags: 
Authors: 

Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on June 7, 2013. The information contained within may not be the most current and accurate depending on when it is accessed.