I asked Nikolas Clarkson, one of our 2017 Plains Pest Management Interns, to cover a hot topic for 2017, The implementation of the new cotton herbicide technologies in West Texas. Nik and I worked together on this article to keep the facts as facts and share our impressions from what we have seen from the field so far.
Cotton producers and those that work closely with them are becoming more familiar with the new herbicide technologies and herbicides finally labelled for use this year. It has not been overnight but we are becoming better aware of how they should best be utilized. Early in the discussion about these new technologies, there was quite a bit of confusion about these traits and products, what they actually were, and where they could be used. So, I am going to start off by listing the new cotton herbicide technologies and the herbicides that go with them.
First off, I will discuss Enlist. This trait is currently only in Phytogen cotton varieties. The herbicides that can be utilized with these traits are Enlist Duo, Enlist, Roundup (all formulations), Liberty, and all conventionally labeled cotton herbicides. It is a misnomer that this is 2,4-D cotton. While the base chemistry is there and the cotton would tolerate the old formulations, they are not labeled and the salt utilized in this formulation is much different which should keep this notorious class of herbicides for moving much, much closer to target and from escaping unintentionally.
Next, we have Xtend cotton. For this trait, we can use XtendiMax with Vapor Grip, and XtendiMax from Monsanto and Engenia from BASF, Roundup (all formulations), Liberty, and all conventionally labeled cotton herbicides. This trait has also been miss-named by layman as Dicamba cotton. Much like Enlist cotton, the Xtend cotton can tolerate the older formulations of this class of chemistry but these herbicides should be improved on multiple values.
With the improvement factor of all of these newer herbicides coinciding with the release of these cotton traits and a conscious fair price setting near the cost of the old herbicides, I cannot see any reason to use the older herbicide chemistries with these new traits. Hopefully, no one is as the labels of these new herbicides really need to be adhered to if we are to keep the traits registration. It seems the application of these technologies in cotton is under the EPA’s microscope.
All of that does seem quite the mouthful. It has taken almost all summer for me to wrap my head around these technologies, herbicides, and implications as we scout fields in front of and behind weed control applications.
In following these labels, we have had some hard-earned lessons, and some successes. Drift has been a paramount concern for everyone in the area this year. Built into the labels of these new herbicides are some serious restrictions about nozzle size and pressure to ensure that drift is minimized and won’t make a significant impact on any neighboring fields. While there notable are drift incidents around the area, Blayne seems to feel it may actually be less this year compared to most growing seasons. This is likely due to the fact everyone is paying closer attention and correcting any mistakes much quicker. What we have noted more of are, as Blayne calls them, ‘self-inflicted wounds,’ or damage to cotton from contaminated sprayers, sometimes from custom applications and sometimes from the producers own sprayer. This seems to be another way that an all Roundup system in the region has ‘spoiled us’ and that is in tank cleanout.
Producers need to know how to properly clean out their spray tank of Enlist Duo, XtendiMax, Engenia, or any other new herbicides once they are finished using it to prevent from becoming an issue for the next treated field. It is not as easy as we have been doing recently. Each herbicide has some minor but specific and labeled differences in how tank should be cleaned out. For the sake of time I am about to going to go with the recommended way on the Enlist Duo product label. The time to clean out the tank is right after you are finished using it. Do not wait until the next day. Triple rinse is a minimum, not a suggestion with these herbicides.
For the first rinse, completely drain the system and leave for about 5 minutes and then fill the tank with water to about 10% of the total tank volume and circulate it throughout the entire system for 15 minutes and then spray it out the boom. Drain out the system again for 5 minutes and remove and clean the filters. For the second rinse fill the tank with water and add the recommended rates of cleaning agents. Circulate the solution for 20 minutes and then let it stand for a few hours. For the next rinse, drain the whole spray system again, fill the tank with clean water to 10% of the tank volume and circulate so that all surfaces are contacted for 15 minutes. Drain the entire system again and remove nozzle tips and clean them separately.
This is not any ‘fun.’ Blayne makes sure we follow these rough guidelines for our backpack sprayer and bottles we use for the Plains Pest Management research plots, so I feel the pain of this extra work. In a zero-tolerance situation, such as a small plot research trial or an Enlist field about to be sprayed with a sprayer that has just sprayed Enginia or XtendiMax (or vice-versa), the results are terrible and impact unpredictable. In these cases, either a ruined trial or a severely damaged field, which I have seen a fair amount of this season.
Keeling, J.W. Keeling, E.M. Koonce, A.T. 2015. Weed Management with Engenia In Bollguard II XtendFlex Cotton. Minneapolis, MN. Entomological Society of America.
Reed, B., 2017. Herbicide Discussions and Intern Trainings. Plains Pest Management.