About two years. That’s all the time you have to prove to the Environmental Protection Agency (EPA) you and your neighbors will follow new dicamba formulation label requirements, or the agency could let its approval expire at the end of 2018. “With the possibility of spraying in June and July on lots of additional acres, remember broadleaf plants are very, very sensitive to dicamba,” says Mandy Bish, senior research specialist at the University of Missouri’s weed science program. “It only takes a small amount to injure nontarget plants. That’s the difference between dicamba and other herbicides you’re used to using.”
Dicamba kills susceptible plants by creating a hormone imbalance that interferes with cell division, cell enlargement and protein synthesis, eventually killing the plant. In 2016, more than 200,000 acres were damaged from illegal dicamba use of unapproved, volatile formulations of the herbicide. While new formulations promise reduced volatility, stewardship and following the herbicides’ label are still critical to prove to EPA you can use dicamba ethically long term.
Monsanto, DuPont and BASF offer new over-the-top formulations of dicamba this year. Monsanto’s XtendiMax uses VaporGrip technology to reduce volatility and help minimize drift. DuPont’s FeXapan also uses VaporGrip technology to reduce drift and volatility risks. BASF’s Engenia uses a new salt, BAPMA, to reduce volatility. The labels for these formulations are optimized to protect sensitive crops and include specifi c requirements to reduce drift risk that could cause damage.
Beware of Off-Target Movement
Drift refers to particle movement while volatility refers to evaporation. Review conventional and supplemental herbicide labels as well as EPA-mandated company websites for application instructions. See state restrictions.
Engenia: Do not spray if wind exceeds 15 mph or is less than 3 mph unless you’re sure there is no temperature inversion. Don’t spray if wind is blowing toward neighboring specialty crops or if wind exceeds 10 mph toward sensitive crops. Additional state restrictions might apply.
(Pg. 3 of the Engenia supplemental label)FeXapan & XtendiMax:Optimum wind speed is 3 mph to 10 mph. Do not spray if wind speed is greater than 15 mph or under 3 mph. Also, do not spray if wind direction is blowing toward non-target commercially grown sensitive crops.
(Pg. 8 of the FeXapan supplemental label)(Pg. 2 of the XtendiMax supplemental label)
Be Mindful of What, When and How Much Product Can Go in the Tank
Know what you put in the tank can affect drift and lead to crop damage if you’re not careful. Before mixing herbicide or adjuvant products, make sure the tank mix is approved.
Engenia: Dicamba tolerant soybeans— Max of 12.8 fl . oz. per application and 51.2 fl . oz. per season. Dicamba tolerant cotton—Max of 12.8 fl . oz. per application and 2 lb. dicamba acid equivalent per season.
(Pg. 4 of the Engenia supplemental label)FeXapan & XtendiMax: Dicamba tolerant soybeans—Max of 44 fl. oz. per preplant application, 22 fl . oz. per postemergent application and max of 88 fl. oz. per season. Dicamba tolerant cotton—Max of 44 fl. oz. per preplant application, 22 fl. oz. per postemergent application and max of 88 fl . oz. per season.
(Pg. 3 of the FeXapan supplemental label)(Pg. 1 of the XtendiMax supplemental label)
Engenia: Dicamba tolerant soybeans—Use preplant, pre-emergent and postemergent applications through R1 up to four applications (two preplant/preemergent applications totaling 25.6 fl. oz. and two postemergent totaling 25.6 fl. oz.). Dicamba tolerant cotton—Apply preplant, pre-emergent and postemergent until seven days before harvest.
(Pg. 4 of the Engenia supplemental label)FeXapan: Dicamba tolerant soybeans—Apply preplant, preemergent and postemergent up to and including R1. Dicamba tolerant cotton—Use preplant, pre-emergent and postemergent applications up to seven days before harvest.
(Pg. 3 of the FeXapan supplemental label)XtendiMax: Dicamba tolerant soybeans—Use within 28 days or less of preplant and up to two postemergent applications up to and including R1. Dicamba tolerant cotton—Use within 21 days or less of preplant and up to four day postemergence until seven days before harvest.
(Pg. 1 of the XtendiMax supplemental label)
Engenia, FeXapan & XtendiMax: Can only be tank mixed with specific products listed on EPA-mandated websites, which have been tested and found to not have an adverse effect on the spray drift properties of the dicamba herbicide formulation the applicator will use.
(Pg. 2 of the Engenia supplemental label)(Pg. 4 of the FeXapan supplemental label)(Pg. 2 of the XtendiMax supplemental label)Before mixing:
Applicators are required to check the list of EPA-approved products within seven days of application. The tank-mix must be on the list of tested and approved products and not prohibited on the label.
Note some crop oil concentrates, high surfactant oil concentrates and methylated seed oil adjuvants can cause crop response.
Don’t tank mix products containing ammonium salts such as ammonium sulfate and urea ammonium nitrate.
Double check with drift reduction agent (DRA) manufacturers to see if approved DRA will work with spray nozzle, spray pressure and spray solution.