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Home > Ag Chemicals & Fertilizers > Pesticides > Dicamba Herbicide Information > Dicamba FAQs

Frequently Asked Questions on Dicamba Post Emergence Use in DT (Dicamba Tolerant) Soybeans

Question: What is dicamba herbicide?

Response: Dicamba is an active ingredient in selective, systemic, and plant growth regulator herbicides primarily used for post emergence broadleaf weed (for example, waterhemp, ragweed, horseweed) control in a variety of crops, residential areas, and other sites. Dicamba herbicide belongs to Group 4 site-of-action chemical family.

Question: What are the new dicamba products and why are they used?

Response: Dicamba has long been used in agricultural and nonagricultural herbicide products. In 2016, the United States Environmental Protection Agency (EPA) registered three products, XtendiMaxTM with VaporGripTM Technology (EPA Reg. No. 524-617, Monsanto), EngeniaTM (EPA Reg. No. 7969-345, BASF), and FeXapanTM with VaporGripTM Technology (EPA Reg. No. 352-913, DowDuPont) with a dicamba active ingredient . The EPA conditionally approved the post emergence use of these three new dicamba products on DT (dicamba tolerant) soybeans until the end of 2018.

Reference to commercial products or trade names here or elsewhere on this site is made with the understanding that no discrimination is intended and no endorsement is implied.

Question: Why are manufacturers making DT (dicamba tolerant) soybean technology available in Minnesota?

Response: In Minnesota, waterhemp has evolved resistance to several herbicide classes (for example, glyphosate, ALS, PPO herbicides). Growers can use these new tools in DT soybeans to control herbicide-resistant weeds such as waterhemp because they are not currently resistant to dicamba.

Question: What are the concerns about dicamba use in Minnesota?

Response: Dicamba is a highly volatile chemical that can drift and/or volatilize. Dicamba drift can damage non-DT (dicamba tolerant) soybeans, other sensitive crops, and non-crop plants. Midwestern state agencies received wide-spread reports of crop damage on large acreages of soybeans during the 2017 growing season. The Minnesota Department of Agriculture received numerous reports of dicamba related damage to non-target crops in 2017.

Question: What steps have been taken to minimize the damage to off-target plants from dicamba use on DT (dicamba tolerant) soybeans in the next growing season?

Response: New use restrictions have been put into place. First, there are new requirements and restrictions spelled out on the federal label. Second, the MDA has put forth additional label use restrictions when the products are used in Minnesota. Finally, there requirements specified in the Minnesota Pesticide Control Law that all applicators must follow.  A person that applies any of the new dicamba products must adhere to all three of these legal requirements and restrictions. 

Questions: What are federal label mandated requirements?

Response: The U.S. Environmental Protection Agency engaged state lead agencies, such as the Minnesota Department of Agriculture, U.S. Department of Agriculture, Cooperative Extension Service and the pesticide manufacturers to find fixes that address the underlying causes leading to dicamba-related incidents of crop damage. The additional requirements and restrictions included on the federal label for the new dicamba products in 2018 are:

  • Classification as Restricted Use Pesticides and permitted use only by certified applicators;
  • Dicamba training for applicators to reinforce product stewardship;
  • Records of use consistent with content and format specified on the federal label;
  • Limit application to conditions where maximum wind speed is below 10 mph;
  • Applications made only between sunrise and sunset;
  • Tank clean-out in a manner that prevents cross contamination; and
  • Susceptible crop language and sensitive crop registries to increase awareness of risk to especially sensitive crops nearby.

Applicators must always read and follow all label directions. It is a violation of federal label to use any new dicamba product in a manner inconsistent with the label.

Questions: What are the label mandated dicamba training and recordkeeping requirements?

Response: Each label for the new dicamba products specifies that applicators must attend training. Manufacturers will provide training that meets the requirements of the label. Information about dicamba use and training is available on the Minnesota Crop Production Retailers web page.

Each label for the new dicamba products also specifies content and a format for records that applicators must maintain for each application. Manufacturers may provide record-keeping templates that meet the requirements of the label.

Complying with each of these federal label requirements is mandatory.

Question: Do I need mandated dicamba training if I plant DT (dicamba tolerant) soybeans but do not plan to use dicamba products?

Response: No, dicamba training is mandated only for those who use one of the new dicamba products.

Question: What are the additional label restrictions added by the Minnesota Department of Agriculture (MDA) for new dicamba product use to help in reduce off-target damage in the 2018 growing season?

Response:  The Commissioner reviewed the U.S. Environmental Protection Agency’s new restrictions and 2017 dicamba survey results, and in consultation with the University of Minnesota, other experts and manufacturers established the following restrictions on the use of new dicamba products in DT soybeans in Minnesota:

  • Cutoff date: Do not apply after June 20; and
  • Cutoff temperature: Do not apply if the air temperature of the field, at the time of application, is over 85 degrees Fahrenheit or if the National Weather Service’s forecasted high temperature for the nearest available location for the day exceeds 85 degrees Fahrenheit.

Question: Why did Minnesota Department of Agriculture chose June 20 as the cutoff date for dicamba post emergence application?

Response: The Commissioner set this cutoff date based on the review. The majority of Minnesota soybeans will still be in the vegetative growth stage by June 20. Research shows that non-DT (dicamba tolerant) soybeans in the vegetative stage are less affected by dicamba than those in the reproductive stage.

Question: Can the new dicamba products be applied to DT (dicamba tolerant) soybean on June 20?

Response: Yes, new products can be applied after sunrise and before sunset on June 20 if the field temperature does not exceed 85 degrees Fahrenheit or if the National Weather Service’s forecasted high temperature for the nearest available location for the day does not exceed 85 degrees Fahrenheit.

Question: Why did Minnesota Department of Agriculture chose temperatures greater than 85°F as cutoff temperature for dicamba post emergence application?

Response: The Commissioner set this cutoff temperature based on the review. Research shows that dicamba volatilization injury increases when temperatures are over 85 degrees.

Question: Can I apply new dicamba products if the air temperature is 85°F or less at the time of application but the temperature exceeds 85°F during the latter part of the day?

Response: No, applicators may not apply dicamba when there is a prediction that the maximum air temperature of the day will exceed 85°F at any time during the day. For instance, a dicamba application is not permitted on a day when the air temperature is 75°F early in the day, but is predicted to exceed 85°F later in the same day.

Question: Can I apply dicamba if the max air temperature prediction is greater than 85°F on the next day or 48 hours after application?

Response: Yes, the actual or the predicted air temperature cannot exceed 85°F only on the day of application.

Question: Where should I look for predicted weather for my location?

Response: Forecasts are available at the Local National Weather Service.

An additional local weather resource is MNDOT Scan WEB.

Question: What are the indicators for the presence of temperature inversion?

Response: Avoid applications when inversion conditions exist. The following are the indicators of presence of temperature inversion conditions:

  • Calm day with wind speed less than 3 mph;
  • Clear night;
  • Dust cloud hanging on the side of the road;
  • Dew or frost present on the ground;
  • Horizontal smoke pattern; and
  • Ground fog in low-lying area.

Question: Who can use new dicamba products?

Response: New dicamba products are classified as Restricted Use Products and can only be used by applicators that are either certified as Private Pesticide Applicators or licensed as either Commercial or Noncommercial Pesticide Applicators and certified in Categories A (Core) and C (Field Crops) as required by the Minnesota Pesticide Control Law. The Pesticide Control Law does not allow uncertified applicators to use the new dicamba products or any RUPs under the supervision of certified applicators.

Questions: What are other applicator requirements established by the Minnesota Pesticide Control Law?

Response: In addition to licensing requirements, Commercial Noncommercial applicators must meet record keeping requirements specified in the Law. The MDA maintains samples of records on our web page that illustrate these requirements. Finally, Private Pesticide Applicators must meet the federally mandated record keeping requirements for Restricted Use Pesticides.

See a summary of applicator requirements.

Question: What are other broadleaf weed control options?

Response: The MDA highly encourages growers to use preemergence herbicides with residual control and to follow resistance management strategies such as:

  • do not rely on a single herbicide site-of-action;
  • apply full labeled rates;
  • use preemergence herbicides with residual control; and
  • zero threshold for herbicide resistant weeds (ex. waterhemp) avoid application of herbicides with same site of action more than twice in the season, incorporate non-chemical tactics (ex. crop rotation, cover crops, weed free seeds) as a part of integrated weed management, etc. that are mentioned  on the label.

Question: What are post emergence broadleaf weed control options after June 20?

Response: Post emergence dicamba applications should be made when the broadleaf weeds are less than 4” in height for best control.

To manage broadleaf weeds, especially herbicide-resistant waterhemp (emerges throughout the growing season) after June 20th, follow University of Minnesota Extension recommendations on layering of residual herbicides (PDF) such as Dual, Outlook, Warrant, and Valor. Incorporation of layering of residual herbicides in herbicide programs provide residual control of late emerging weeds. 

If you do not have herbicide-resistant waterhemp in a field, herbicides from these three sites-of action can be applied:

  • Glyphosate (Group 9)
  • ALS inhibitors such as Pursuit, Classic, FirstRate (Group 2)
  • PPO inhibitors such as Flexstar, Cobra, Cadet, Ultra Blazer (Group 14)

Growers that have glyphosate-resistant waterhemp may consider using tank-mix of glyphosate with an herbicide from Group 2 or Group 14.

Question: Who will conduct dicamba training mandated by the new dicamba labels?

Response: Dicamba registrants (BASF, DowDuPont, and Monsanto) have prepared training materials and they, or their designees, will conduct training for dicamba applicators that meets the label requirements for 2018 season.

Question: How long does the registrant training last?

Response: The training will last approximately 2 hours depending upon the number of questions and audience participation.

Question: What does the training cover?

Response: The training will cover the product label requirements, recordkeeping requirements, weed management practices, buffer requirements and protection of susceptible crops, chemistry, mixing and handling, window of application, equipment preparation and special considerations.

Question: Do I have to pass an exam?

Response: No, the class is instruction, review and open question and answer session.  

Question: Will I receive a certificate after completing the training?

Response: No, the instructor will maintain a record of those attending the class and will collect the applicator’s name, address, email and other information.

Question: Is the training one-time or do I need training every year?

Response: The U.S. Environmental Protection Agency and the Minnesota Department of Agriculture must approve the continued use of these products after December 2018; requirements may be revisited at that time. For now, applicators must complete the training to use the products in Minnesota in 2018.

Question: Will my applicator credential be amended to show that I’ve received training?

Response: No and pesticide dealers are not required to see the proof of training prior to selling the product to certified applicators.

Question: Do I need to attend training put-on by the manufacturer of the product I purchase? What if I buy two or three different dicamba products?

Response: No, a person only needs to attend one training session provided by any of the manufacturers of the new dicamba products, i.e. BASF, DowDuPont, or Monsanto. One annual training satisfies the training requirement for all three products.

Question: Do I need certification and special training if I am using new dicamba products on crops other than DT (dicamba tolerant)-soybeans listed on the label?

Response: Yes, the new dicamba products are classified as RUP.  A state credential is required to use these products. Additionally, the use of these new dicamba products requires training as mandated by the label for use on all crops listed on the label. These requirements only apply to the new dicamba products described in this document.

Question: Can I attend label mandated training on dicamba in a state other than Minnesota?

Response: Yes, the Minnesota Department of Agriculture (MDA) will recognize training that is based on material prepared by any of the three registrants (BASF, DowDuPont, and Monsanto). If this same training is provided in a neighboring state, and the MDA when notified of the training in advance will recognize this training. The registrant will be responsible for notifying the MDA of training and maintaining a database of attendees. Registrants will make this database available to the MDA.

Question: Do ditches next to an agriculture field count toward the required buffer distance?

Response: No, ditches next to an agriculture field do not count toward the buffer distance calculation (see Scenarios 1 and 2).

Scenario 1: Road and ditch are not a part of required buffer.
Dicamba scenario1 explained in text below
Figure 1 illustrates if a ditch is located within 110 or 220 feet from the edge of dicamba-tolerant soybeans field, applicators maintain required buffer in the downwind direction from the last treated soybean row to the field edge (red line) as depicted by yellow arrow.

Scenario 2: Road is a part of required buffer but not the ditch.
Dicamba scenario2 explained in text below
Figure 2 illustrates that road can be included in required buffer if it falls within 110 or 220 feet distance from the field edge. Buffer distance is measured in the downwind direction from the last treated soybean row to the far edge of the field road (red line) as depicted by yellow arrow.

Question: Where can I report observed dicamba damage in 2018?

Response: The Minnesota Department of Agriculture (MDA) encourages the reporting of all dicamba damage. You can report damage to the MDA by submitting a formal complaint.

Additional instructions for submitting a complaint can be found at the same web address. Use the following contact information to report to dicamba damage to manufacturers:

  • Monsanto (XtendiMax) – 1-844-RRXTEND (779-8363)
  • BASF (Engenia) – 1-800-832-HELP (4357)
  • DuPont (FeXapan) – 1-888-6-DUPONT (38-7668)

Question: Is a Pesticide Dealer License needed to sell or offer to sell the new dicamba products?

Response: Yes, the new dicamba products are classified as RUP and as Agricultural Pesticides because of Worker Protection Standard language included on the product labeling.  The Minnesota Department of Agriculture issues Agricultural Pesticide Dealer Licenses to businesses that offer for sale or sell agricultural pesticides to an end-user for use in the state of Minnesota.

Question: What are a dealer’s responsibilities for selling or offering the new dicamba products for sale?

Response: Dealers may only offer for sale or sell these products to persons that hold a valid Commercial or Noncommercial Pesticide Applicator License or a Private Pesticide Applicator Certification awarded by the Minnesota Department of Agriculture (MDA).  Dealers must keep records of their purchase, sale, and distribution of these products for a period of five years. Additional requirements are detailed on the MDA Pesticide Dealer web page.