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Dicamba rules tighten: weed scientists caution applicators pay close attention

Weed scientists say U.S. agriculture should expect more rules if they want to keep over-the-top dicamba in the toolbox.

Joe Ikley is with North Dakota State University.

“It seems very a lot of boxes to check and a lot of restrictions we don’t want, but the alternative at this point in time could be worse.”

The U.S. EPA recently issued new over-the-top dicamba labels for applicators planning to use the herbicide for the next two growing seasons.

Some prior restrictions from the EPA will continue to reduce drift, like wind speed requirements, droplet size and low spray height requirements.

There are also new restrictions, like cutting application rates in half and temperature cutoffs. Tom Barber at the University of Arkansas tells Brownfield, “They’re certainly not easy to follow. There’s a lot to it.”

Aaron Hager at the University of Illinois says other significant label changes include adjusted volatility reduction requirements and runoff mitigation points related to the Endangered Species Act.

There’s can also be state-level restrictions on top of that.

“The federal label said there’s no cutoff on application dates, but for Illinois, that’s going to be June 20 again this year. And our temperature restriction actually states that if the actual or forecast air temperature exceeds 85 degrees for the day of application, these products cannot be acquired.”

There is also pending litigation against the over-the-top dicamba labels.

Hager says those legal challenges have an impact on EPA’s product approvals and it’s unclear how long that will weigh on approvals.

Ikley says farmers using the herbicide should take extra caution.

“Even if we remove the court process that may or may not occur in the next two years, it is also a two-year label. We will be doing the whole registration process again two years from now. And anything that could potentially go wrong between now and then may pop up on additional label changes. I think we just need to be very careful with these applications.”

The weed scientists say this could apply to other crop protection tools moving forward.

Catch more in the latest Inside D.C., which can be viewed on Brownfield TV at Brownfield Ag News dot com or Brownfield’s YouTube channel.