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New ESA runoff mitigation labels unlikely to disrupt herbicide use, expert says

A weed science professor at the University of Illinois says herbicide use in compliance with updated Endangered Species Act (ESA) regulations may not be as challenging as once thought.

“A year and a half, two years ago, we really weren’t quite sure where these things were actually going to shake out.”

Aaron Hager says all herbicides going through the U.S. EPA’s approval or re-registration process are now assigned ESA runoff mitigation points on their label.

“Liberty Ultra, for example, was one of the first herbicides that will have mitigation points on there.”  He says, “There’s three runoff mitigation points, and there is language on there about a downwind buffer.”

He tells Brownfield recent surveys show that most Midwestern fields can accumulate nearly the maximum number of mitigation points without making any changes.

“On close to 100% of the corn and soybean acres in Illinois, we could get to at least six runoff mitigation points without having to do any modification to the field itself.”  He says, “Nine points, which would be the maximum number of points required, a very high percent of our acres could actually get to nine points.”

Hager says the runoff mitigation points are awarded on a variety of management practices.

“They came out with what they called relief points.”  He says, “It’s a county number of mitigation points that you would get simply by farming in that county. That’s a big plus.  If you’re tracking your mitigations, that’s a point right there. If you’re using mitigations in multiple categories, there’s another point. For example, if you don’t have overhead irrigation, you get points for that. If you had subsurface tile drainage, you can get points for that.”

While Hager says it’s a positive development for agriculture, he still encourages farmers and applicators to utilize online resources, like the EPA’s Mitigation Calculator, to become more familiar with the agency’s updated ESA compliance process.

Brownfield spoke with Hager at the Illinois Soybean Association’s 2026 Field Advisor Forum in Urbana.

AUDIO: Dr. Aaron Hager – University of Illinois