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Dicamba success depends on integration

University of Illinois weed scientist Aaron Hager says EPA label amendments for dicamba won’t be enough to ensure success in the 2018 growing season.

“In my humble opinion, it’s going to be very, very difficult to find conditions that completely satisfy all the restrictions and requirements of these labels in term of making timely applications,” said Hager.

Numerous off-target dicamba damage complaints in 2017 prompted the EPA to change label requirements for new formulations of dicamba.  The label changes address physical movement of dicamba droplets during application, but Haber says volatility is not addressed.

“And in 2017, university data, really, I think, was pretty straightforward demonstrating that even the new formulations remain volatile,” said Hager.

The label changes could have an impact on weed pressure, he said.  Label restrictions on wind, temperature and time of day limit the conditions under which the herbicide can be legally applied.

“Keep in mind, the longer that weeds are allowed to remain growing with the crop,” said Hager, “the more likely that they will adversely impact yield at the end of the growing season.”

Dicamba should be one component of weed management, said Hager, along with other herbicide or non-herbicide tactics to eliminate weed seed production.

“If we use dicamba in a very integrated system, I think the odds for success in 2018 are going to be much greater than if we simply rely on dicamba as a post-only herbicide,” he said.

Dicamba is the active ingredient in XtendiMax, Engenia, and FeXapan, which are labeled for application on dicamba-tolerant soybeans and cotton.  Hager recommends dicamba as one component of an integrated weed management program with only early postemergence applications of dicamba about 14 days after planting.

AUDIO: Aaron Hager (7 min. MP3)