By Bob Scott, University of Arkansas Extension Weed Scientist
There has been some confusion over the regulations on dicamba that were put in place this year for the state of Arkansas.
I want to note, that while University Division weed scientists are asked to provide data and input on many herbicide-related issues, ultimately this was a decision made by the Arkansas State Plant Board. Having not had the opportunity to evaluate the volatility and drift potential of XtendiMax with Vapor Grip from Monsanto, we were unable to provide feedback to the board on this product.
Currently, research projects are being planned to address this issue as quickly as possible in 2017. These regulations came about due to the off-label use and, ultimately, the drift issues caused by dicamba in 2015 and 2016.
In summary, the regulations include a ban on certain formulations of dicamba. These include all acid, and DMA (dimethylamine) formulations. Only DGA (diglycolamine salts of 3,6-dichloro-o-anisic acid) formulations, as well as the new formulation of dicamba that is in Engenia from BASF, are legal to use in burn-down. DGA salt formulations include Clarity, XtendiMax and many others.
DGA formulations of dicamba, including XtendiMax, can be used in Arkansas until April 15. After April 15, Engenia is the only dicamba formulation labeled for use in-season in Xtend crops in Arkansas.
It should be noted that, in the same set of regulations, the Board approved Dow AgroSciences’ new product Enlist Duo – a combination of glyphosate and a new lower volatility formulation of 2,4-D (2,4-D Choline) for use in Enlist crops, including the counties where other formulations of 2,4-D are banned after April 15.