What You Need to Know About Roundup Ready 2 Xtend and Enlist

If you haven't heard about Enlist and Roundup Ready 2 Xtend herbicide traits over the past two years you have been hiding under a proverbial agricultural rock.  These traits will be here before you know it and will take some understanding and increased management on the part of retailers and farmers. 

PGR injury to soybeans

"Did you say increased management, I thought it was supposed to be easier?"  While these technologies will make it easier to bring down weeds post emerge in soybeans, and to a lesser extent in corn, it will take knowledge of the risks associated with these traits and their accompanying herbicides along with what herbicides you can use on them.  First you have to understand what each trait contains, and the limitations around them.

The Enlist trait from DOW Agrosciences in soybeans will be tolerant to 2,4D, and not Dicamba.  While these herbicides have the same mode of action, plant growth regulators or PGR's, they do not have the same site of action.  The Enlist trait in corn will include 2,4D tolerance along with tolerance to "Fop" grass herbicides like Assure II and Fusilade DX.  This is nice in that we can use new effective grass control herbicides in Enlist corn, but also frustrating when it comes to volunteer corn control in soybeans.  This will take away two very effective, low rate, and cheap volunteer corn herbicides in soybean fields following Enlist corn.  The problem here for retailers will be knowing who had Enlist corn the previous year along with what happens when you show up with a Fop in your tank.  Likely, we will have to switch to products like Select Max as our only options to control volunteer corn. 

The Roundup Ready 2 Xtend soybeans trait will be tolerant to Dicamba, and not 2,4D.  This trait is nice in that it will add the ability to do burndowns with Dicamba with no plant back restrictions to
Xtend soybeans.  With the better crop safety of our Dicamba based corn herbicides there is no reason to add this trait to corn.  There are no grass herbicide traits built into this as well so no worries about volunteer corn herbicides.

You also have to understand what these herbicides do, and the forms we will have to use on these traits.  DOW will be coming out with only one form of 2,4D that will be labeled to use on Enlist tolerant crops.  Enlist Duo will be the herbicide that DOW releases, and it contains a premix of glyphosate (Roundup) and 2,4D choline, a new form of 2,4D that will be less volatile.  Generic 2,4D's that we commonly use on crops will likely not be labeled for use in Enlist crops so using them will be an off label application.  In Enlist corn we will be able to use Fop grass herbicides, but they will also have to be labeled for application and will be up to the chemical company to determine if they are going to apply for a new label or supplemental label.  Until that happens these applications will also be off label.  While 2,4D is a good broad leaf chemical, it will have to be managed for drift, volatility, and potential resistance.  There is also very little residual activity with 2,4D. 

Monsanto will be coming out with their own premix as well to be used on Roundup Ready 2 Xtend soybeans.  This premix will include glyphosate (Roundup) and a lower volatility form of dicamba.  One nice thing about Xtend beans is there will be a label on Clarity from BASF to allow it to be applied to these soybeans along with straight Dicamba call Xtendimax from Monsanto.  Attention will have to be paid to not using Dicamba formulations meant for corn like Status, Banvel, and Distinct.  These products contain a safener meant only for corn so you can't spray corn with these herbicides and not rinse your tank, or hang your boom into soybeans with the Xtend trait.  There is slightly better residual to Dicamba, don't expect much more than about 2 weeks of activity.  So you still need to consider a pre residual, or a post residual.  There will also still be drift, and volatility concerns with Dicamba.

Dicamba injury to soybeans from improper tank rinse out

Most retailers are slightly wary of this technology due to confusion between the traits and what can be used on them, along with potential for tank contamination with both 2,4D and Dicamba.  There are also concerns with some seed companies using both traits in their lineup leading to even more confusion.  Think Roundup Ready launch with the potential for more tank contamination issues.  Like any other herbicide trait, we will have to make sure to apply following label recommendations.  There are already a couple of weeds with resistance or suspected resistance to 2,4D.  Managing drift, and volatility around sensitive crops along with tank proper tank rinse procedures will be things retailers and farmer applicators will have to pay more attention to. 


 Farmers are cautiously optimistic here where we have little to no resistance issues, I can't imagine how happy those that are in heavy weed resistance are about this trait.  These traits are just the first in a line of new herbicide traits coming to soybeans.  While these are a step in the right direction, it's important to remember the weed spectrum you are targeting, and respecting labeled rates.  There will inherently be some growing pains as we adjust to new traits, but if we can overcome them this should help us all in managing weed resistance.