Follow label requirements when making applications to dicamba-tolerant crops

Tana Haugen-Brown, Extension educator and Co-coordinator, University of Minnesota Pesticide Safety and Environmental Education, and Larry VanLieshout, Minnesota Department of Agriculture

Photo: Lizabeth Stahl

The Minnesota Department of Agriculture shares these important reminders when making applications to dicamba tolerant crops to help your spray season go well.

Pesticide applicators are urged to take special care while making over-the-top dicamba applications to their herbicide tolerant crops this season. Xtend technology allows the application of specific dicamba products postemergence to soybeans with low risk of crop injury. 

Do not confuse Xtend system with Enlist herbicide system, which provides crop resistance to 2,4-D. Although both are growth regulator herbicides, resistance to one herbicide does not provide protection to the other. 

To prevent off-target movement, the U.S. Environmental Protection Agency has made substantial changes to the 2021 dicamba labels specifically related to application cutoff date, buffer distances, and record keeping requirements.

Dicamba label requirements

For the 2021 growing season, applicators may use the three dicamba products, XtendiMax, Engenia, and Tavium, on dicamba tolerant soybeans until June 30. The federal label prohibits applications of these three dicamba products after June 30 to dicamba-tolerant soybeans. Regardless of cutoff date, applications are prohibited after V4 growth stage for Tavium and after R1 stage for XtendiMax. 

Additionally, the labels require a 240-foot downwind buffer and prohibits applications if the wind is blowing towards an adjacent sensitive crop. Sensitive crops include, but are not limited to, non-dicamba-tolerant soybeans, sugar beets, tomatoes, fruiting vegetables, fruit trees, cucurbits, grapes, beans, flowers, ornamentals, peas, potatoes, sunflower, and other broadleaf plant crops.

Only certified applicators can legally purchase and use these formulations of dicamba because they are classified as “Restricted Use Pesticides” (RUP). The label has extensive and detailed requirements for recordkeeping, and the applicator must create these records within 72 hours of the application. The MDA expects all users of these dicamba products to have fully completed records in accordance with the federal label requirements. Enforcement will be taken for any violations of the product label.

Prevent off-target movement

The following guidelines and resources can help applicators prevent off-target movement while applying dicamba:

• Do not apply XtendiMax, Engenia, or Tavium on soybeans if you have not attended the auxin/dicamba mandatory training offered by dicamba registrants Bayer, BASF, or Syngenta.
• To help applicators, the MDA has developed a video presentation as part of the mandatory dicamba training. This video is not a substitute for the required training.
• Applicators must consult applicable sensitive crop registries, such as DriftWatch, to identify any commercial specialty or certified organic crops that may be located near the application site. Applicators are also required to survey the site for neighboring non-target sensitive crops BEFORE spraying. Be sure to consult with your neighbors before spraying dicamba products.
• If the wind is blowing in the direction of a sensitive crop DO NOT spray until the wind has changed direction. Spraying is forbidden in these circumstances, even with a buffer.
• DO NOT spray during a temperature inversion; only spray between one hour after sunrise and two hours before sunset. Wind speeds less than 3 mph can indicate a temperature inversion which can result in spray droplets being suspended in the air and traveling a great distance. Temperature inversion apps are useful tools which provide notifications if temperature inversions are detected in an area. The MDA has partnered with the North Dakota Agricultural Weather Network (NDAWN) to assist producers with determining if an inversion exists. The network provides 5-minute real-time weather data records, in North Dakota, Northwest Minnesota and Central Minnesota.

Equipment and application requirements

Large spray droplets are less prone to drift than small ones. A number of equipment and application requirements to reduce spray drift are listed on the label, with more specific details provided on product websites - www.xtendimaxapplicationrequirements.com, www.engeniatankmix.com/, and www.TaviumTankMix.com. Requirements include the following:

• Use an approved Volatility Reduction Adjuvant in the tank mix (see websites above). Do NOT add ammonium sulfate which acidifies the solution and increases volatility.
• Use a minimum spray volume of 15 gallons per acre.
• Only use approved tank-mix partners.
• Mix tank ingredients in the proper order described on the label to prevent the buildup pf excessive foam and pressure in the sprayer.
• Only use approved spray nozzles which produce an ultra-course droplet size.
• Maximum boom height is 24 inches above the crop/weed canopy.
• Maximum ground speed is 15 mph.
• Visit the MDA website for frequently asked questions about dicamba.

Finally, remember that avoiding spray drift at the application site is the responsibility of the applicator. With the increase in herbicide resistant weeds, these precautions are necessary to maintain access to a powerful weed control tool.

Injury complaints

Since dicamba was first registered for use on dicamba-tolerant soybeans in the 2017 growing season, the MDA has fielded complaints each year of alleged off-site movement onto neighboring property. The annual totals of complaints in Minnesota are:

2020: 124 reports
2019: 22 reports
2018: 53 reports
2017: 253 reports

An application cutoff date has been in effect in the state each growing season since 2018.

For additional information or assistance, contact Larry VanLieshout, Minnesota Department of Agriculture, Larry.VanLieshout@state.mn.us or 651-201-6115.

IMPORTANT: The information contained in this article is not a substitute for a pesticide label. Always read pesticide labels prior to use. Follow the label directions attached to the pesticide container you are using. Remember, the label is the law.

Disclaimer: Mention of a pesticide or use of a pesticide label is for educational purposes only. Trade names used herein are for convenience only; no endorsement of products is intended, nor is criticism of unnamed products implied.