A field with and without a soybean burndown herbicide program. Photo: Dwight Lingenfelter, Penn State Weed Science
During the winter meeting season, we have been asked about the registration status of the many dicamba products and their utility with respect to the Roundup Ready 2 Xtend soybean system. First of all, not all of the dicamba-containing products are registered as “Restricted Use Pesticides” (i.e., RUP) – only Engenia, FeXapan plus Vapor Grip Technology, and XtendiMax with Vapor Grip Technology have this designation. In Pennsylvania, because of this status, the applicator must have a PA Certified Applicators license and also must have special training and a subsequent certificate provided by one of manufacturers (i.e, Monsanto, BASF, or DowDuPont) in order to buy and use one of these mentioned dicamba products (no matter the setting). Special records must also be documented when using these products. At this point, no other dicamba products are considered restricted use in our state and can be used similarly as in the past. This is not necessarily the situation in other states.
Regarding the use of other dicamba products (Clarity, Banvel, “generic” dicamba brands, etc.) as preplant applications prior to planting Xtend soybeans, there is also some confusion. In short, farmers are asking if Clarity, for example, can be sprayed in the burndown mixture and then immediately plant Xtend soybeans. The answer is no. Whether it is Clarity, Banvel, or most other post patent dicamba-containing products the label states that at least 28 days plus 1 inch of rainfall/irrigation is necessary before any kind of soybean is planted if 1 pint of product is applied. (The labels of the specific products may vary slightly but essentially state similar information.) Since Xtend soybeans are not specified on their labels, this longer wait period must be applied. Currently, the only dicamba products that can be legally applied near planting or over-the-top in Xtend soybeans are Engenia, FeXapan, and XtendiMax. Before any application can be made, all of the guidelines must be followed to reduce off-target spray drift to other crops. To reduce drift and the other negative impacts to non-target areas, these labels and associated websites list what herbicides can be tank-mixed with these products. Other guidelines include prescribed nozzle types, boom heights, sprayer speed and wind speed limits. Depending on the landscape setting, field buffers must be included if susceptible crops are present and downwind at the time of application. Guidelines for using Xtendimax, Engenia and FeXapan can change periodically as new information is acquired. Refer to their labels and websites for additional information and updates online by Monsanto, BASF, and DowDuPont.