European Corn Borer Field Day Set for July 17 near Ames

A major pest of corn production is the focus for the event


(SBA) - AMES, Iowa – A pest that most corn farmers haven’t had to worry about since the late 1990s appears to be making a comeback.

European corn borer (ECB) has largely been controlled thanks to Bacillus thuringiensis corn (better known as Bt corn), which was first introduced in 1996. But field-evolved resistance is showing up in several Canadian provinces and most recently, in Connecticut.

In an effort to address the issue and train crop scouts on what to look for, entomology experts with Iowa State University Extension and Outreach and the United States Department of Agriculture are teaming up to offer a special field day July 17 west of Ames.

A day-long educational program will be held at the Field Extension Education Laboratory, located at 1928 240th St. near Boone.

Expert insight

Erin Hodgson, professor and extension entomologist at Iowa State, and Ashley Dean, extension education specialist, will lead participants through educational sessions that include an industry update, as well as hands-on trapping and detection, and first- and second-generation scouting.

They will be joined by Tom Sappington, Brad Coates and Craig Abel – all entomologists with the U.S. Department of Agriculture’s Agricultural Research Service.

“This educational event will explain how to detect European corn borer, why it’s showing up again and what agronomists and crop consultants can do to help safeguard the industry,” said Hodgson. “It’s been so long since it was an issue that many people may have forgotten what it looks like, or that it even still exists.”

Before the development of Bt seeds, ECB was estimated to have cost U.S. farmers over a billion dollars annually in yield losses and control efforts, earning it the title “the billion-dollar bug.”

It is estimated that just one corn borer can cause 3-5% yield loss, and multiple borers can wipe out a crop. Hodgson and Dean want to remind farmers and those who advise them of what to look for and how to do their part to prevent an infestation from starting.

Their best advice is to plant pyramid Bt hybrids to ensure multiple toxins are contributing to ECB control. They also advise farmers to conserve beneficial insects and shred or bury corn residue to reduce the survival of overwintering larvae within fields.

Hodgson and Dean provide further information in an Integrated Crop Management news article they co-authored in May 2024 called Blast from the Past: European Corn Borer is Back on the Radar.

Registration details

The field day is free to attend and lunch and continuing education credits will be provided. Registration is required by July 10 and can be done online at

Participants need only to register for one session, as both sessions feature the same topics. For assistance with registration or questions about the program, contact Erin Hodgson at or 515-294-2847. Ashley Dean can be reached at or 515-447-3766.