Dicamba

Thank you to the University of Arkansas for the dicamba injury on soybeans photograph.

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.  So far during the 2017 growing season we are still seeing continued widespread crop damage and enforcement issues in some states.

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

AAPCO is collecting educational materials, Special Local Need registrations, and dicamba webpages from the states to share in one place.

Please send info to Amy Bamber, AAPCO Executive Secretary, aapco.sfireg@gmail.com

*Please scroll down to find the Laboratory Considerations, Research & Resources, and Articles and Letters, sections.


State Updates

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

Arkansas

Arkansas has cancelled the sale and use of agricultural dicamba due to unprecedented enforcement issues.  Arkansas’ Dicamba Updates webpage

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

Missouri

Missouri’s Department of Agriculture had issued a temporary SSURO for all dicamba products while they are developing 24(c) labels. The 24(c) labels are now registered and include significant restrictions on wind speed, application timing, only certified applicators (no applications under the supervision of…), must complete a notice of application prior to application, and recordkeeping for all applications, even private applicators, kept for 3 years. See their Dicamba Facts webpage.

Georgia

Georgia has issued 4 Special Local Need/ 24(c) labels for dicamba.  See their 24(c) labels and mandatory training information here:  Georgia’s Auxin Training webpage

Tennessee

Tennessee has issued several restrictions on dicamba due to enforcement issues, including banning all use of older formulations for the remainder of the 2017 growing season.  See their updates here.

Mississippi

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

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.

Florida

Florida has an Organo-Auxin rule in place, which restricts many uses of auxin herbicides.  Florida’s Extension Service has issued guidance regarding the new dicamba products as well.

North Carolina

North Carolina has issued five 24(c) labels and has an Auxin Resources page.  The 24(c) labels require mandatory training through the Extension Service, and include a 10 mph windspeed restriction.

Indiana

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. The state pesticide policy board, the Indiana Pesticide Review Board, is scheduled to meet on August 30, 2017. The agenda and link for that meeting are at http://www.oisc.purdue.edu/pesticide/iprb.html

Minnesota

Minnesota has created a dicamba page and an online survey they are asking complainants to complete: www.mda.state.mn.us/dicamba.

North Dakota

North Dakota is now experiencing damage and has on online survey for growers as well.


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.
Director
South Dakota Agricultural Laboratories
1006 32nd Ave. Suite 105
Brookings, SD 57006
Ph 605-692-7325
Fax 605-692-7326
www.sdaglabs.com


Research and Resources

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

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

 


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.

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

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