New Dicamba Label Requirements

Published: April 12, 2021

With the recent EU approval of Xtendflex soybean, commercial launch will begin in 2021. In addition, the US EPA has registered 3 dicamba products (Xtendimax, Engenia, Tavium) for use through 2025. The new labels have a few new requirements. Here is a brief overview of what's new:

• Only labeled for use in Xtend and XtendFlex crops.
• Application cut-off dates for soybean: Engenia = June 30th; Xtendimax: = June 30th or R1 growth stage, whichever comes first; Tavium = June 30 or through the V4 growth stage, whichever comes first
• Maximum amount applied per year is 2 lb of the active per acre
• Max single application rates are 0.5 lb per acre or 22 fl ozs/acre Xtendimax, 12.8 fl ozs/acre Engenia, and 3.5 pts/acre Tavium.
• Downwind buffer distance has increased to 240 ft, unless an approved hooded sprayer is used. Then a 110 ft downwind buffer is required. If the field is located in a county with endangered species, a downwind buffer of 310 ft is required with a 57 ft omnidirectional buffer. If an approved hooded sprayer is used, a 240 ft downwind buffer is required as well as a 57 ft omnidirectional buffer. Affected Missouri counties include: Cape Girardeau, Dade, Dunklin, Franklin, Henry, Jasper, Lawrence, Lincoln, Pike and St. Clair.
• Addition of a pH buffering agent or volatility reducing agent (VRA) is required. Check each label website to get the updated lists of approved products. We conducted one simple experiment last season to evaluate waterhemp control when a VRA was included with Xtendimax or Engenia plus glyphosate. All three VRAs we tested resulted in increased pH of the spray solution and similar waterhemp control to treatments that lacked VRAs (results are summarized in this YouTube video starting at the 2:55 mark).

This is just a brief overview of some of the more significant new changes to these herbicide labels. If you plan to use these products, it is important that you thoroughly read through these labels and follow all label requirements. In addition to the new requirements listed above, other previously established requirements such as the use of nozzles that create ultra-coarse droplets, spraying when wind speeds are between 3 and 10 mph, NOT spraying during a temperature inversion, maximum boom height of 24 inches above canopy, maximum ground speed of 15 MPH, etc. must still be followed. These products remain restricted use products (RUPs) and still require special training prior to use. You will need to contact the manufacturers of these products in order to complete the 2021 dicamba certification training.

It is also important to note that glufosinate (Liberty, Interline, Cheetah, Scout) can be applied for post-emergence weed control in the Xtendflex system. However, glufosinate cannot be mixed with dicamba products according to the Engenia, Tavium, and Xtendimax labels. Glufosinate can increase dicamba volatility, resulting in greater injury to nearby sensitive plant species.

The University of Missouri Weed Science program has research results available from weed control systems in Xtendflex soybean, which can be found by selecting the 'research results' tab on our website and searching for Xtendimax, Engenia, or Tavium.