Read Your Pesticide Labels: Dicamba Edition

June 1, 2020 1:45 PM
Blog Post

In order to keep up with any changes and updates on pesticide uses and restrictions from year to year, it’s important to thoroughly read the label before any applications are made, even if the same product was used the previous year. If nothing else, it helps to refresh our memory on the particulars of specific products that are applied to ensure optimum pest control and environmental protection. Since 2017, growers have been able to utilize dicamba products labeled for over-the-top application in soybean. The first product to be labeled was Xtendimax with VaporGrip Technology, now that list has grown to include Engenia, FeXapan plus VaporGrip Technology, and Tavium plus VaporGrip Technology as well. The dicamba labels include extra precautions and application requirements to decrease the potential of off-target movement of dicamba. As a reminder for the 2020 growing season, below are some of the recommendations and requirements that need to be followed with these products. As always, be sure to read and follow the respective manufacturer’s dicamba label before application.

Training and Certification:

  • All applicators applying dicamba products registered for use on soybean are required to annually complete dicamba or auxin-specific training.
  • Information for Face-To-Face and Online dicamba training in Iowa can be found at the Agribusiness Association of Iowa’s webpage: Dicamba Training in Iowa.

Application Timing & Window

  • Applications must occur between one hour after sunrise and two hours before sunset.
  • Treat weeds early when they’re relatively small (less than 4 inches).
  • Apply prior to beginning bloom (R1) or no more than 45 days after planting, whichever comes first (Xtendimax and FeXapan).
  • For Engenia, you can apply through beginning bloom (R1) or no more than 45 days after planting, whichever comes first.
  • For Tavium, apply through the V4 growth stage, but no later than 45 days after planting.

Record Keeping (Main highlights in regards to dicamba, all are not listed)

  • Certified applicators must fill out records within 72 hours after application and keep them for a period of two years. Also, a record must be kept for each application.
  • Training: Date and provider of training, as well as proof of completion.
  • Product Label: copy of the product label and any special local needs label that supplements it.
  • Record of the crop planting date.
  • Record of the buffer distance calculation.
  • Record that a sensitive crops registry was consulted and that the adjacent fields were surveyed prior to application. An example of a registry for Iowa would be FieldWatch, which can be found here. At a minimum, records must include the name of the sensitive crop registry and the date it was consulted and documentation of adjacent crops/areas and the date the survey was conducted.”
  • The time the application started and the time the application was finished
  • Application Timing: Record whether the application was a pre-emerge, post-emerge, etc. and number of days after planting if post-emerge.
  • Air Temperature: Record the temperature in 0F at both the beginning of the application and after.
  • Wind Speed and Direction: Record the wind speed and direction at boom height at the beginning of the application and after.
  • Nozzle and Pressure: Record the spray nozzle type, manufacturer, orifice size, and pressure for each application.
  • Tank Mix Products: Record brand name & EPA reg. no. for all products that were tank mixed.
  • Spray System Cleanout: Record of compliance to the label of each respective manufacturer’s “Proper Spray System Equipment Cleanout” section.

Sprayer Setup

  • Spray Volume: Apply in a minimum of 15 gallons of spray solution per acre.
  • Ground Speed: Do not exceed a ground speed of 15 mph (Remember, slower speeds will result in better spray coverage and deposition on the target area). If possible, reduce speed to 5 mph at the field edges.
  • Spray Boom Height: Do not exceed a boom height of 24 inches above target pest or crop canopy.
  • Wind Speed: Only apply when wind speeds measured at the boom are between 3 and 10 mph.

Nozzles and Tank-Mix Partners

  • Specific nozzles and operating pressures are prescribed for these dicamba products. Information on approved nozzles can be found at each respective manufacturer’s website. Only products that have been approved for tank-mixing with these dicamba products can used in combination; these products can be found on the manufacturers’ website. Because changes and updates can happen readily, it’s good to periodically check this list to keep up with the options that are available to you.

               Manufacturer Websites for Nozzles and Tank-mix Partners





Buffer Requirements & Sensitive Crop Protection

  • The applicator must always maintain a 110 foot downwind buffer for any application.
  • For Xtendimax and FeXapan, if applying greater than 22 fluid ounces per acre (not to exceed 44 fluid ounces) in a single application, a 220 foot downwind buffer needs to be maintained.
    • Refer to each respective manufacturer’s label to determine what areas can be included in the buffer distance calculation.
  • Do not apply dicamba products when the wind is blowing toward adjacent non-dicamba tolerant sensitive crops which includes non-dicamba tolerant soybean.

Endangered Species Concerns

New for 2020, applicators are required to obtain an Endangered Species Protection Bulletin before a dicamba application is made. This is a protection measure instituted by the EPA for endangered or threatened species that may reside in the county where the application is to take place. A bulletin can be accessed up to six months before pesticide application. For more information on this and how to obtain a bulletin, please read the ICM Blog post by Meaghan Anderson, ISU extension field agronomist, titled: Read your Pesticide Labels: Endangered Species Edition.

The new dicamba products used in combination with dicamba-resistant soybean varieties have given growers another added tool in the toolbox to help with their weed management and weed resistant strategies. However, in order to allow these products to be used in the market as long as possible to meet the needs of producers, it’s imperative that the label is read and followed by all applicators that use these products.


Terry Basol Field Agronomist in NC Iowa

Terry Basol is an agronomist in north central Iowa and field specialist for Iowa State University Extension and Outreach.