Dicamba Archives

To keep the Dicamba page current, older Dicamba information is moving off of the front page, and will be stored here.

2019 through June 8, 2020

June 3, 2020 Opinion:  U.S. Court of Appeals for the Ninth Circuit

U.S.EPA Response

AAPCO Response

Registrant Responses:



“DTN/Progressive Farmer is keeping an updated list of state actions and responses to the court order in an article on the legal status of dicamba herbicides. See them below, and you can find the article here, which will continue to be updated:


— The Illinois Department of Agriculture has interpreted the order to mean all sales and uses of these herbicides are halted: http://bulletin.ipm.illinois.edu/….

— The North Dakota Department of Agriculture is now stating that its state registrations of these herbicides are not affected, and will remain legal for use and sales in the state: https://www.nd.gov/….

— The Iowa Secretary of Agriculture Mike Naig has said sales and use may continue until EPA gives further instructions, which he specifically requests in a letter to the agency: https://iowaagriculture.gov/….

— The Indiana Office of the State Chemist is also stating that sales and use can continue, based on the state’s registration of these herbicides, until EPA says otherwise: https://www.oisc.purdue.edu/….

— Texas Agriculture Commissioner Sid Miller states that sales and use may continue and calls on EPA to allow existing stocks of the herbicides to be used: https://texasagriculture.gov/….

— The Minnesota Department of Agriculture posted a statement saying the herbicides are banned from sale or use: https://www.mda.state.mn.us/….

— The Missouri Department of Agriculture issued a news release stating that the herbicides are still available for use and sale in the state until EPA says otherwise: https://agriculture.mo.gov/….

— The Louisiana Department of Agriculture and Forestry issued a news release stating that the herbicides are available to sell or use in the state: http://www.ldaf.state.la.us/….

— The Nebraska Department of Agriculture has put out a statement says that the products can continue to be utilized until further notice.  Statement here.

— Kansas State University published an article stating that the Kansas Department of Agriculture believes that the products are still legal for use and sale in the state, despite the order: https://webapp.agron.ksu.edu/….

— The Tennessee Department of Agriculture has stated that, absent an order from EPA, the products are still labeled for use in the state: https://www.tn.gov/….

— The Wisconsin Department of Agriculture has concluded for now that the order will not take effect in Wisconsin until EPA formally revokes the registrations itself: https://content.govdelivery.com/….

–The South Dakota Department of Agriculture has issued a statement saying that until EPA says otherwise, these products are discontinued for sale and use in the state, per the court order: https://sdda.sd.gov/… .

— The Alabama Department of Agriculture and Industries has issued a statement saying at that current time, state registrations are still active and may be distributed and used until EPA says otherwise.

The plaintiffs who brought the lawsuit to the Ninth Circuit argue that many of these state actions are illegal. “The Court’s decision could not be clearer,” George Kimbrell, legal director for the Center for Food Safety, told DTN. “The three pesticide products are unlawful, their new use registrations null and void, and they are illegal to use over the top of cotton and soy. Any state interpretation contrary is flat wrong and contrary to law. And EPA’s silence on that is a dereliction of duty on their part.”

Dicamba-tolerant seeds were registered for use during the 2016 growing season.  Due to the lack of the accompanying dicamba formulation which was required to be used with the seeds, many growers used older formulations and the resulting drift and volatilization issues caused widespread crop damage and enforcement issues.

EPA registered the new dicamba formulation in the fall of 2016.  During the 2017 growing season we continued to see widespread crop damage and enforcement issues.  EPA and the registrants negotiated new labels for the 2018 season.  During 2018 there were still many issues with crop and non-crop damage and enforcement.  EPA approved a conditional 2-year registration with revised labels and requirements for the 2019 and 2020 seasons.


AAPCO to USEPA 2020 Dicamba Registration Letter

April 2020 Dicamba States Survey results


University of Missouri’s IPM Program:  What Have We Learned from Four Years of Studying Temperature Inversions?

March 21, 2019:  SFIREG’s Dicamba Work Group has worked closely with the U.S. EPA to develop the Dicamba Guidance Document – revised 7/25/19 for use by states and trainers during the 2019 season.  This includes definitions, label language interpretations, and related Q&A.

Endangered Species:  On November 19, 2018, EPA posted Dicamba Pesticide Use Limitation Areas.  The county list may be found at: https://www.regulations.gov/document?D=EPA-HQ-OPP-2016-0187-0974

On October 31, 2018 EPA released changes to the Dicamba registration.

December 2018 after the new labels were finalized:

The Q&A below was received by AAPCO and posted to the website on December 17, 2018 and removed at EPA’s request on February 14, 2019. 

Q&A on the new labels-answers from U.S.EPA:

  1. Will 24 C labels be allowed to make labels more restrictive if a state determines it to be necessary to ensure “no unreasonable adverse effect” from the post-emergent use of these products?

Under the authority of 24(c) of FIFRA, states may register an additional use of a federally registered pesticide product, or a new end use product to meet special local needs. Special local need (SLN) means an existing or imminent pest problem within a state for which the state lead agency, based upon satisfactory supporting information, has determined that an appropriate federally registered pesticide product is not sufficiently available. Because of the unique goals states are looking to accomplish in managing the dicamba over-the-top (OTT) registrations, EPA is requesting that states consult with the agency prior to submitting an SLN for the 2019 season.

2. Does “for retail sale to and use only by certified applicators” mean that applicators who are not fully certified, i.e. registered technicians who have passed only the core/general standards exam, cannot purchase or use these products?

The products may only be purchased and used by a person who is a fully certified applicator. Persons who are not certified applicators may not perform any activities with these dicamba products, including mixing or loading, even if under the supervision of a certified applicator.

  1. Does the training requirements reference to “before applying this product in-crop” suggest that the CRP and noncropland uses are not covered by the training requirements?

Training requirements apply to any use of the product, not just in-crop use.

  1. Application records must include start and stop times. If the wind direction shifts toward neighboring sensitive crops or residential areas, and the applicator stops the application, but doesn’t pick up the application until the following day, is that a separate application or the same one?

Accurate records must be maintained. Each time the certified applicator starts or stops an application it needs to be recorded, regardless of which applicator is performing the application or which day. Certified applicators must comply with the requirements of the states who certify them.

  1. The label states, “DO NOT apply to soils classified as sand with less than 3% organic matter and where groundwater depth is shallow.” How deep is shallow?

EPA intended this label statement to be advisory for states to apply their judgement in training certified applicators and providing oversight on this label section.

  1. The resistance management section states, “the following steps should be followed”, but then states “DO NOT rely on a single herbicide site of action…”  We assume the DO NOT is for effect and not enforceable, correct?


  1. The label states, “DO NOT apply XXX later than 45 days after planting or R1, whichever comes first.” Any suggestions on how to document planting date or R1 growth stage 3-8 weeks after application?

These parameters are subject to the applicator reporting. Planting and application dates are items that are subject to the mandatory reporting protocol.

  1. The label states, that non-sensitive crops and areas include, “Roads, paved or gravel surfaces, mowed and/or managed areas adjacent to field, such as roadside rights-of-way.” We assume this means that mowed and/or managed roadsides are no longer to be protected by buffers, correct?

Correct. Including roadside rights-of-way as non-sensitive areas was intended to aid in buffer calculations.

  1. The spray drift management section states, “DO NOT allow herbicide solution to drip, physically drift or splash onto desirable vegetation…” We assume that physical drift excludes off-target movement from volatility, but does “physical drift” include or exclude off-target movement from application into an inversion? Our understanding is that application into an inversion should affect all pesticides equally, regardless of active ingredient, correct?

EPA is looking forward to further discussing this issue and coordinating with the states.

  1. Do the endangered species and corresponding buffer zones apply to all endangered species or just endangered terrestrial dicot plant species, as suggested by BASF?

The buffer requirement was made after we assessed potential risk to both animals and plants that are federally listed as endangered or threatened species. For the full list of species that were assessed in the effects determination document, see the recent and previous assessments:https://www.regulations.gov/document?D=EPA-HQ-OPP-2016-0187-0967. Growers should refer to Bulletins Livefor a listing of Pesticide Use Limitation Areas (PULAs) for endangered species as it relates to dicamba. If a county is listed in the Bulletins Live system, growers in that county must follow the restrictions on the bulletin.

11. The sensitive crops and residential areas section states, “DO NOT apply when wind is blowing in the direction of neighboring sensitive crops or residential areas. The appropriate distance must be determined by the applicator relative to where the application is being made, the environmental conditions, and the potential risk to downwind sensitive crops and residential areas.” What specifically does that mean? It seems very non-specific and vague. It appears that it provides no real direction or instruction to the applicator, rendering it unenforceable? Can the agency provide additional direction on the intent of this statement?

This language is intended to be advisory to growers. At a minimum, certified applicators must not use the product if sensitive crops are directly adjacent to the treated field.



On July 27, 2017 EPA issued a Compliance Advisory for Dicamba.

April 2018 EPA’s Dicamba FAQs Webpage

*Please scroll down to find information on AAPCO State Survey Results, Registrant Training, State Updates, Laboratory Considerations, Research & Resources, and Articles and Letters.

AAPCO’s State Survey Results

Beginning May 15, 2018, AAPCO will send out a survey to the states listed on the dicamba ott labels every other week.  The survey is intended to gather information related to dicamba use and caseloads.  This information is shared with EPA.  We are posting the first page of the survey results to the website.  The format is an excel workbook, and it will download to your computer.

May 21, 2018 Results

June 2, 2018 Results

June 18, 2018 Results

July 9, 2018 Results

July 16, 2018 Results

July 23, 2018 Results

July 30, 2018 Results

August 6, 2018 Results

August 13, 2018 Results

August 20, 2018 Results

August 30, 2018 Results

September 6, 2018 Results

Comments to EPA from States

AAPCO, August 29, 2018

Office of the Indiana State Chemist, August 29, 2018

Registrant Training

For the 2018 season, the dicamba for soybean and cotton labels have been revised.  Part of the revision is the requirement that applicators take dicamba or auxin specific training.  If the state does not provide the training, the registrants are required to do so.

BASF’s 2018 dicamba training materials

DuPont’s dicamba training:  FeXapan Application Requirements and Stewardship-2018 

Monsanto’s website link which includes their online training calendar and online training module.

BASF’s Inversion Video

State Updates

2018 Summary of State Rules and Section 24(c) Labeling for Dicamba Use on Soybeans

Presented to The Pesticide Stewardship Alliance Conference, February 8, 2018, Carol Black, Washington State University

 States with no additional requirement to what is on the label

  • Illinois
  • Iowa
  • Kansas
  • Kentucky
  • Michigan
  • Nebraska
  • Ohio
  • Pennsylvania
  • South Carolina
  • Virginia

Had existing rules impacting auxin herbicides (2,4-D, dicamba)

  • Several states have existing auxin rules that remain in place that impact dicamba and 2,4-D.

 Registrant Training is Currently Not Approved

  • Arkansas Cooperative Extension – online
  • Alabama Cooperative Extension
  • GeorgiaUniv. Georgia & GDA – Use Pesticides Wisely
  • Indiana – OISC & Purdue University
  • Mississippi Cooperative Extension
  • Missouri Cooperative Extension
  • North Carolina Cooperative Extension

Cut Off Dates

  • Arkansas – April 16
  • Louisiana – April 1 – September 15 for Commercial Applicators – can apply for a waiver
  • Minnesota – June 20
  • Missouri
    • June 1 in the 12 southeast counties
    • July 15 all other counties
  • North Dakota – June 30 or after the first bloom (whichever comes first)
  • TennesseeJuly 15 requires a hooded sprayer

 Cut Off Temperatures

  • 85°F at time or if National Weather Service (NWS) forecast 85°F for the day
  • Minnesota
  • North Dakota

 Application Time Restrictions

  • Missouri – Cannot apply – before 7:30 am or after 5:30 pm
  • North Dakota – Can apply – One hour after sunrise to one hour before sunset
  • Tennessee – Can apply between 9:00 am and 4:00 pm


  • Louisiana
    • LDAF-approved training required for “seller, purchasers, and applicator”
  • Minnesota
    • No “under the supervision” applications for any RUP – existing rule
  • Missouri
    • Online dicamba “Notice of Application” daily prior to each application
  • North Dakota
    • Sprayer speed limit of 12 MPH
    • No 80-degree or narrower spray nozzles
  • North Carolina
    • Do not apply when wind is blowing toward adjacent sensitive crops: Including: tobacco, grapes, watermelon, sweet potato, peanut, pepper, beans, NDT cotton, NDT soybeans – was in 2017
  • South Dakota
    • Engenia – buffers based on application rate/product
    • Minimum 10 GPA delivery
    • All dicamba formulations are state RUP


Alabama is requiring training for all dicamba and 2,4-D uses on dicamba and 2,4-D tolerant crops, through 24(c) registrations, as well as a wind speed restriction up to 10 mph.  See their guide here.

Alabamba’s Dicamba Training page


Arkansas’ Dicamba Updates webpage


Florida has an Organo-Auxin rule in place, which restricts many uses of auxin herbicides.


Georgia’s Auxin Training webpage


Illinois’ Dicamba Training page


Indiana has an extensive Dicamba resources page that includes details about the state RUP status of the products, as well as tank mix cleaning, reporting damage and other topics.

Indiana’s Office of the State Chemist has developed training for compliance with the 2018 label.


Minnesota has created a dicamba page and a 2017 online survey is being compiled: www.mda.state.mn.us/dicamba.


Mississippi’s 2018 How to Comply

Mississippi’s Dicamba Training page


See their Dicamba Facts webpage.

North Carolina

North Carolina’s Auxin Resources webpage

North Dakota

North Dakota state specific protocols are online.

South Dakota

South Dakota’s Dicamba webpage

article on SD and dicamba


Tennessee’s Dicamba Resources

Tennessee’s Dicamba Training page

AAPCO’s State Dicamba Survey, November 2017:  All Survey responses and All Survey data.

Updated maps of enforcement numbers as of October 4, 2017.  Thank you to VDACS for the maps!

Laboratory Considerations

USEPA is offering Laboratory Assistance to States for Dicamba Analysis

This guidance document is to be used by states that may be in need of assistance with dicamba laboratory analysis. Be aware that the guidance requires the request for assistance come through the EPA regional office.

This addendum to the guidance document clarifies which sample seals, and other forms, should be used on the submitted samples.

Provided by EPA Headquarters:

“We have been told that the EPA lab is telling regional labs that to recover dicamba in resistant crops like cotton and soybeans you need to test down to the 1 ppb level. Can you confirm this information?”

Note, that because dicamba breaks down quickly and completely to DCSA, it is recommended that for dicamba-resistant crops, testing for DCSA be performed in addition to dicamba.

Based on field and laboratory studies for dicamba resistant crops, dicamba breaks down quickly (within hours) into metabolite DCSA.  Therefore, residue of dicamba on those crops will be minimal (estimated to be in low ppb level based on a 1 lb ai/A application rate) during the first day or so after application, and non-existing afterwards.  So if you are looking for dicamba in dicamba resistant crops, sampling of those crops must be done no later than a day or 2 after application, and yes, you need to go down to at least to 5 ppb level or below for LOQ (2 ppb or below for LOD).  Otherwise, look for DCSA.  This metabolite is more persistent and can still be detected in samples that were collected a month or so after application.

As for “Is there any difference when testing if it is a low-volatility formulation or the old suspected of the crop damage”, the answer is “no.”

If you need additional technical information, please contact Thuy or Yaorong.

Thuy Nguyen nguyen.thuy@epa.gov 410-305-2905 or Yaorong Qian qian.yaorong@epa.gov 410-305-2626

Dicamba and Degradates Residue Analysis – Presentation given to the SFIREG Joint Working Committees in April 2017 by Thuy Nguyen

South Dakota Ag Labs can provide Dicamba and DCSA testing to 1ppb LOQ.  Their turn around time is 7-10 days.  The cost is $162. and can do a screen of the PGRs for $212 (13 analytes).  They are working on the 5-OH Dicamba method and awaiting receipt of the standard to perform that method as well.

For more information contact:

Regina L. Wixon, Ph.D.
South Dakota Agricultural Laboratories
1006 32nd Ave. Suite 105
Brookings, SD 57006
Ph 605-692-7325
Fax 605-692-7326

Research and Resources

This is not exhaustive, and many states are doing research related to what is occuring with dicamba systems.  Some materials we have been provided are below.

AAPCO’s Annual Spring Meeting Dicamba Session PowerPoints:

Dicamba – Baris

Dicamba – Witten- Monsanto requested that we not post their presentation online as the numbers presented are dynamic.  Please contact registration.state@monsanto.com for information on the presentation.

Dicamba – Westberg

Dicamba – BASF Inversion Video

Dicamba – Ikley

Dicamba – Scott

North Carolina’s Auxin Record Keeping Manual

PowerPoint presentation for EPA summarizing several research efforts from State Extension programs, July 28, 2017.

Purdue: 2013 Weed Science paper on soybean yield and dicamba exposure, and August 2017 newsletter on the same topic.

University of Missouri:

Updated Dicamba complaint map, September 15, 2017


Arkansas also has mandatory Dicamba training to use the products in state.

Monsanto petition to Arkansas State Plant Board, September 2017

Comments received by the ASPB on the Monsanto Petition

Comments on the Monsanto Petition by the Center for Food Safety

Mississippi has classified all dicamba products for use in dicamba-tolerant systems as Restricted Use, has a 10mph wind speed restriction, and requires training prior to purchase of the products.

Alabama is requiring training for all dicamba and 2,4-D uses on dicamba and 2,4-D tolerant crops, through 24(c) registrations, as well as a wind speed restriction up to 10 mph.  See their guide here.

Articles and Letters

Although this section includes public outreach by 2 registrants requesting that complainants contact them directly, AAPCO strongly asserts that producers should contact their own state pesticide program when there are issues related to dicamba damage.  It is important for the scope and scale of the issue to be fully understood by the state lead agencies, who have the authority and responsibility of managing pesticide use.   Please see the Control Officials for contact information for state reporting.  AAPCO also encourages the registrants to report issues to EPA and the states when they are investigating complaints.

New York Times article on dicamba damage, November 1, 2017

NPR article: Monsanto and the Weed Scientists-Not a love story, October 28, 2017

American Soybean Association, ASA Steps up Urgency in Search for Answers on Dicamba Damage, September 25, 2017

How often could growers legally spray Dicamba in 2017? DTN, September 15, 2017

Monsanto petition to Arkansas State Plant Board, September 2017

Comments received by the ASPB on the Monsanto Petition

Monsanto letter to AR Gov. Hutchinson, September 7, 2017

Successful Farming at agriculture.com, September 11, 2018  Monsanto Critisizes AR Weed Scientists

Washington Post, August 29, 2017

UPI, August 25, 2017 Letter regarding laboratory testing of glufosinate products

Arkansas Online, August 18, 2017 Dicamba Task Force 

Agweb, August 10, 2017 MO Dicamba Complaints Continue After Label Change

Reuters August 9, 2017

Monsanto Open Letter to Farmers in Crop Life News August 3, 2017

UPI Letter July 25, 2017

BASF Press Release  July 19, 2017

Wall Street Journal July 11, 2017