• Dicamba applications in Roundup Ready 2 Xtend® soybeans will be happening soon.
• Following the label is paramount to the success of this technology.
• Managing weed height, application techniques, and using approved tank mixtures and adjuvants must be a top priority.

The long anticipated dicamba-tolerant soybeans have reached the commercialization along with three new dicamba formulations that are approved for in-crop use.  These products are: XtendiMax™, Engenia™, and FeXapan™.  It is conceivable that these products will be applied in the next several weeks to help manage our hard to control weeds, including waterhemp and Palmer amaranth.  These new products have a conditional registration period of only two years, so it is imperative that we steward this technology correctly to ensure its viability in the marketplace for many years to come.  To secure reregistration, the herbicide labels need to be followed to reduce the risk of off target applications and delay the evolution of herbicide resistance.  These labels have a few additional considerations that may not have been fully developed in previous herbicide labels.  These considerations include weed height, application techniques, and approved tank mixes and adjuvants.

Weed Height
The labels of these new herbicides permits spraying weeds up to four inches in height.  A smaller weed is generally easier to manage.  If weeds are taller than four inches, the desired level of control may not be reached.  This ultimately may lead to less weed control and expedite the evolution of resistance to these new dicamba formulations. 

Application Techniques
One major goal of all pesticide applications is to apply the product to the field and make sure the product stays on the intended acre.  When making an application of XtendiMax™, Engenia™, or FeXapan™, we need to full understand the label and the requirements that will limit the potential for off target movement of spray particles.  Buffers, nozzle selection, boom height, wind speed, and environmental conditions that must be followed are listed on the label.  By choosing a nozzle that limits driftable fines, keeping the boom low, spraying in the target wind speed of 3-10 mph, and making applications when a temperature inversion is absent will help to keep the herbicide in the right field. 

Approved Tank Mixes and Adjuvants
With these new herbicides we must visit their respective website to see which products may be mixed together.  For a product to be approved with XtendiMax™, Engenia™, or FeXapan™, it cannot increase particle drift or negatively influence the vapor pressure of the dicamba formulation.  In some cases, a drift reduction adjuvant (DRA) is required when mixing another herbicide with one of the three approved dicamba formulations.  In short, check the website for the product that is being sprayed and only use approved tank mixes. 

One major change in adjuvant usage will be the lack of AMS products on the approved list.  AMS can negatively impact vapor pressure of these dicamba products.  AMS has been used for many decades to help condition water and replacement adjuvants will be needed to fill this void.  The FS System has a wide variety of approved adjuvants that complement these new products.  FS Certin™ is a water conditioner that is approved with all three dicamba formulations that will help manage positively charged ions that may reduce herbicide efficacy.  FS Intention™ is an approved DRA that manages particle drift risk and helps ensure droplets stay in the target area.  FS Attero™ is a premix that includes a water conditioner and drift management aid.  In addition to these new products, FS has a complete lineup of activator adjuvants that may increase the efficacy of common herbicides that may be tank mixed with these new dicamba herbicides.

Before making any application of these products, make sure to read and understand the herbicide label.  When we follow the label, we are helping to steward this needed technology for many years to come.  Happy spraying!

Contact your FS Crop Specialist for your agronomic information.

Tank Mix Websites:
www.xtendimaxapplicationrequirements.com
www.engeniatankmix.com
www.fexapanapplicationrequirements.dupont.com