By Bob Scott, 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 Division of Agriculture 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 VaperGrip 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 (Xtendimax) of dicamba can be used in Arkansas until April 15th. After April 15th Engenia is the only dicamba formulation labeled for use in Arkansas crops.
Engenia is labeled for use in Xtend crops including in-season after the April 15th cut-off date.
It should be noted that the Board approved DOW’s new product Enlist (a combination of glyphosate and a new lower volatile 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 15th in the same set of regulations.