USA - Herbicide regulations continue to get closer look

Atrazine has become a common tool for corn producers, but restrictions were being heavily discussed by the U.S. EPA toward the end of the 2022 growing season.

The idea of limiting one of the more prominent weed control tools for farmers has been met with resistance, particularly ahead of a new growing season.

″This could be a substantial change in the way we use Atrazine, particularly in Missouri,″ said Kevin Bradley, University of Missouri Extension weed specialist, said in a press release.

Bradley said limiting Atrazine would be a negative as it is an ″effective and inexpensive″ herbicide during a time of increased input costs.

The EPA is proposing five changes to Atrazine labels, with an overall goal to prevent excess runoff after application. Those restrictions come in the form of reduced rates, a narrower application window based on precipitation and soil saturation, and prevent all aerial applications.

As of now, there are no changes in effect for 2023.

″There’s nothing that we didn’t already have in 2022,″ Bill Johnson, weed specialist at Purdue University, said.

Commodity groups are largely opposed to these changes.

These efforts to restrict use on herbicides is nothing new for producers in the U.S. Purdue University weed specialist Bill Johnson said he has been writing about it since shortly after he started at the university in the mid-2000s.

At the time, he wrote an article discussing a switch to herbicides that are tank-mixed with Atrazine to reduce the amount used, planting crops that do not need Atrazine near waterways and establishing buffers.

Twenty years later, those aspects are largely the same.

″What they are talking about doing is making the farmer or applicator make sure that fields have a selected criteria in order to allow some of the higher rates to be applied,″ Johnson said. ″If you have some of these things, like no-till and cover crops in place, you should be able to use the same rates you have used in the past.″

One of the large reasons for the EPA’s proposed restrictions is from the enforcement of the Endangered Species Act. It requires that the EPA evaluate pesticides for negative effects on any species deemed threatened or endangered, looking at impacts from leaching, runoff or volatilization.

When looking at the list, Bradley said there is one notable species not represented in the list, but could make its way on there soon — the monarch butterfly. If moved to the list, it would have a ″significant″ impact on weed management tools in the Midwest as seen by the EPA. However, while the harmful effects of pesticides are considered, the benefits are often overlooked.

Johnson said no decisions or changes will likely occur for the 2023 growing season, but a mid-February decision to add labels to dicamba illustrates that a last-second change is not out of the question. That means preparation and knowing when to make all passes count the most is key for the upcoming growing season.

″The areas that have the greatest reduction in the amount that may lose out on the benefit of pre emerge because they need to do an effective post emerge spray,″ Johnson said. ″That being said, many of the basic chemical manufacturers have come up with new soil-applied premixes that don’t have Atrazine in them. They’ve done a nice job in anticipating any changes in Atrazine regulation.″