European corn borer resistance to Bt corn hybrids bears watching, according to Iowa State University pest management expert.

Iowa farmers are advised to scout their fields and consider management practices — such as stacking or pyramiding multiple Bt corn traits — for durable, broad-spectrum protection against European corn borer (ECB), as concerns grow over pest resistance following decades of effective control.

ECB, one of North America’s most destructive crop pests, has been managed successfully for more than 25 years thanks to the widespread adoption of Bt corn. 

However, the recent discovery of field-evolved resistance to Bt toxins — first in Canada and then in Connecticut — has raised concerns about the pest’s potential resurgence as a significant agricultural threat.

Effectively pushed to the brink of eradication in 1996 through the use of transgenic corn engineered to produce insecticidal proteins, ECB has begun to show signs ...