Reminders on Dicamba Use for Soybeans Control

Mark VanGessel, Extension Weed Specialist;

There were changes made to the dicamba formulations labeled for use in dicamba-resistant soybeans when reissued last fall, so be sure to revisit the labels and information from the company’s website before applications are made. Furthermore, there are some differences between the brands of dicamba so be sure check out the appropriate website. A few key points to remember:

  • Volatility and off-target movement is always a concern, and the risks increase with temperature. That is why there is a cutoff date of June 30th. So as temperatures begin to increase, so should our concern of off-target movement.
  • Do not spray when wind is blowing towards sensitive plants

>Note there is no distinction for wind speed, nor how far away these sensitive plants are located

>When in doubt don’t spray

  • All dicamba formulations require additional approved volatility reduction agent (or pH buffers)
  • Tankmixtures of glufosinate (Liberty) and dicamba products are not allowed with XtendiFlex soybeans
  • Some tankmixtures require use of an approved drift reduction agent

In addition, there have been reports of excessive foaming and pressure building in the spray tank when glyphosate (multiple formulations tested), Engenia, and Sentris were tankmixed together. University of Arkansas tested this is small batches and were able to replicate what was reported. They also found a de-foamer was effective, but it did not eliminate the pressure buildup. University of Tennessee is recommending to fill the tank with half the required water and then add Sentris. With inductor systems, add Sentris, flush it with water and get it circulating. Do not mix glyphosate and Sentris together in the inductor tank; and be sure to flush the inductor between each added product. However, other universities were not successful in replicating the excessive foaming or pressure buildup and the manufacturer has not reported any issues. For more details on the University of Arkansas study see: