European Corn Borer Resurgence Sparks Educational Field Day In Iowa

After nearly three decades of relative peace, the European corn borer (ECB), a pest largely controlled since the late 1990s, is reemerging as a significant threat to corn farmers.

The introduction of Bacillus thuringiensis (Bt) corn in 1996 nearly eradicated the ECB problem. However, recent reports of field-evolved resistance have surfaced in several Canadian provinces and, most recently, in Connecticut.

In response, Iowa State University Extension and Outreach and the United States Department of Agriculture (USDA) are organizing a special field day on July 17, just west of Ames, to address this issue. The event aims to educate and train crop scouts on identifying and managing ECB.

The day-long program will take place at the Field Extension Education Laboratory, located at 1928 240th St. near Boone.

Expert Insight and Training

Erin Hodgson, professor and extension entomologist at Iowa State, and Ashley Dean, extension education specialist, will lead the sessions. They will be supported by USDA entomologists Tom Sappington, Brad Coates, and Craig Abel. The program includes industry updates, hands-on trapping and detection exercises, and scouting for first- and second-generation ECB.

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

Before Bt corn, ECB was a costly pest, causing U.S. farmers over a billion dollars annually in yield losses and control efforts, earning it the nickname “the billion-dollar bug.”

One ECB can cause a 3-5% yield loss, and multiple borers can devastate a crop. Hodgson and Dean emphasize the importance of recognizing and preventing infestations.

Their advice includes planting pyramid Bt hybrids to ensure multiple toxins contribute to ECB control. They also recommend conserving beneficial insects and shredding or burying corn residue to reduce the survival of overwintering larvae.