1.3 Arkansas Pesticide Classification System (Classes A-J) & Dicamba Rules

1.3 Arkansas Pesticide Classification System (Classes A–I) & State Restrictions

Core Concept: Beyond the federal EPA label, Arkansas runs an independent state classification system that assigns every registered pesticide to one of ten classes, Class A through Class J (2 CAR Sec. 70-104 and Sec. 70-105). The restrictions stack: each successive class designation includes the restrictions of every class before it. The state restrictions are in addition to the label, and where the label is more restrictive than the class, the label must be followed.

Arkansas built this system because the Mississippi River Delta places conventional soybeans, cotton, rice, tomatoes, melons, and vineyards within drift distance of one another. Rather than rely only on federal labeling, the State Plant Board classifies problem chemistry into escalating tiers of buffers, permits, equipment standards, and seasonal windows.

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The Ten Arkansas Classes

Products are classified when they are registered in Arkansas, and the designation stays put until the Board changes it by rule. All registered pesticides not otherwise assigned are Class A.

[!IMPORTANT] Exam Trap: Class G Is Glyphosate, Not Fumigants Third-party study material frequently describes Class E as "low-volatile hormone herbicides," Class F as "high-volatile esters," and Class G as "soil and structural fumigants." Only part of that is right. 2 CAR Sec. 70-105 names the products directly: Class F is all 2,4-D and MCPA products (the ester restriction is a rule inside Class F, not the definition of the class), Class G is agricultural glyphosate, Class H is dicamba, Class I is quinclorac, and Class J is warfarin used against feral hogs. There is no fumigant class.

How the Stacking Rule Works

Because "each successive class designation includes the restrictions defined in the designations that precede it," a Class F product carries the Class A baseline, the Class B drift-training consequence, the Class C annual equipment inspection, the Class D wind-direction and 300-foot buffer rule, the Class E custom application machinery, and the Class F-specific rules. A Class H product, by contrast, is written to pick up only Class A plus its own restrictions - dicamba is not routed through the custom application program at all.

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Class H: The Arkansas Dicamba Rule

Dicamba-tolerant (DT) cotton and soybeans produced widespread off-target injury across the Arkansas Delta in the late 2010s - leaf cupping, stem twisting (epinasty), and yield loss on non-tolerant soybeans. Arkansas answered with the most detailed state dicamba rule in the country. It has been amended repeatedly, and the version in force is 2 CAR Sec. 70-113, adopted by Ark. R. 2026-38 effective June 29, 2026.

┌─────────────────────────────────────────────────────────────────────────┐
│              Arkansas Class H (Dicamba) Calendar                        │
└─────────────────────────────────────────────────────────────────────────┘

  Jan 1 ─────────── Apr 15 │ Apr 16 ────── Jun 30 │ Jul 1 ──────── Oct 31 │ Nov 1 ── Dec 31
                           │                      │                       │
  In-crop + burndown       │  IN-CROP WINDOW      │  AGRICULTURAL USE     │  In-crop + burndown
  per label and Class A    │  buffers + no        │  PROHIBITED           │  per label and Class A
                           │  glyphosate tank mix │  (5 exceptions)       │
                           │  Burndown: in-crop   │                       │
                           │  ground products only│                       │

1. The July 1 - October 31 Agricultural Prohibition

From July 1 through October 31 of each year, applications of products labeled for agricultural use that contain dicamba are prohibited, with five carve-outs that are allowed year round:

• Turf
• Ornamental
• Direct injection for forestry activities
• Home use
• Pasture and rangeland - allowed year round, but these applications must still maintain the buffers described below.

2. The April 16 - June 30 In-Crop Window

From April 16 through June 30, all applications for in-crop agricultural use must:

• (A) Maintain a one-mile buffer in all directions from University of Arkansas and United States Department of Agriculture research stations;
• (B) Avoid tank mixes of glyphosate with in-crop dicamba - this combination is flatly prohibited during the window; and
• (C) Maintain, during application, a one-quarter-mile buffer in all directions from non-dicamba-tolerant crops and one-half mile from certified organic crops and commercially grown specialty crops. A specialty crop qualifies at a minimum of 1,000 plants or average annual crop sales over the previous three years exceeding $25,000.

3. The Burndown Rule

From April 16 through October 31, dicamba products labeled for agricultural use are prohibited for preplant (burndown) applications, with one exception: from April 16 through June 30, a product labeled for in-crop agricultural use that also allows preplant burndown may be applied by ground, subject to the same buffers.

4. Training

• Applications to dicamba-tolerant crops require the commercial, non-commercial, or private applicator to first complete dicamba-specific training provided by a registrant of a dicamba product for use on DT crops.
• Applications to non-dicamba crops or pasture and rangeland require new technology certification training obtained through the University of Arkansas Cooperative Extension Service.
• Proof of training must be provided to the Department on request and to the pesticide dealer before purchase.

5. Dealers

Dicamba products in containers of more than one quart labeled for agricultural use may be sold only by a licensed restricted use pesticide dealer, only to a licensed dealer or applicator, and the dealer must keep a copy of the applicator's license on file. Dealer sale records are entered at the time of sale and kept two years.

6. Class H Records

Applicators must keep a record of each Class H application, retained two (2) years and available for inspection. The rule enumerates the fields:

[!WARNING] Exam Trap: The State Rule Sets No Wind or Temperature Limit for Dicamba Arkansas's dicamba rule is a calendar, buffer, tank-mix, training, and record rule. It contains no wind-speed range, no maximum temperature, no nozzle mandate, and no boom-height limit. Those conditions come from the federal product label, and because the state restrictions are in addition to the label - and the more restrictive of the two governs - you must read and follow both. Arkansas's own numeric weather limits live in other classes: Class F is 8 mph and 90 degrees F, and Class G is 10 mph (15 mph hooded).

[!CAUTION] Federal Cutoffs Are Not State Cutoffs In February 2026 EPA issued new over-the-top dicamba registrations and removed the federal cutoff dates for soybeans and cotton. Arkansas's June 30 state cutoff was unaffected and remains in force. When federal and state rules diverge, follow the more restrictive one - which here is the state rule.

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Class F: 2,4-D and MCPA

Class F covers all 2,4-D and 2,4-D-containing pesticides and MCPA, and it is the reason the custom application program exists.

• Esters: the use of esters of Class F products, except low-volatile esters, is prohibited. No 2,4-D esters at all may be used under the rice-levee spraying provision.
• Baseline buffer: no Class F product may be applied within one-fourth mile of susceptible crops at any time except as the rule otherwise provides.
• The ten-county window: from April 16 through September 15, Class F products may not be applied by ground or air in Clay, Greene, Craighead, Poinsett, Cross, Crittenden, St. Francis, Lee, Phillips, and Mississippi counties. A $100 annual hardship permit is the only exemption, and it carries ten-minute-interval weather logging, a producer signature, and filing with the Department along with a GPS map within 10 days.
• Everywhere else: a four-mile buffer for aerial and one-mile buffer for ground application from susceptible crops (cotton, when applying 2,4-D), unless waivers are obtained from every susceptible-crop producer in the buffer.
• Weather: wind not over 8 mph, temperature not over 90 degrees F, plus the morning/afternoon inversion test - before noon the field temperature must be at least 3 degrees F above the morning low; after noon it must not have dropped more than 5 degrees F from the afternoon high.
• Enlist exemption: Enlist One and Enlist Duo used on Enlist Weed Control System soybeans, cotton, and corn are exempt from the 1/4-mile buffer, the county window, the hardship permit, the statewide buffer provisions, and the 8 mph/90 degree limit - but wind must blow away from sensitive areas, wind may not exceed 10 mph, spray VMD must exceed 300 microns, tank mixes require Board-acceptable drift data, and ground applications require new technology certification training through the Cooperative Extension Service.

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Exam Traps & Regulatory Pitfalls

[!WARNING] Exam Trap: Calm Wind Is Still Dangerous A completely calm day is not the safest time to spray. Zero wind is a classic indicator of a surface temperature inversion, in which fine droplets stay suspended in stable air and move unpredictably when a breeze finally develops. Arkansas addresses inversions directly in the herbicide equipment set-up rules: applications may not be made where the spray could be entrained in an inversion, and the applicator must record the ambient temperature for each application as the indicator that an inversion is unlikely.

[!CAUTION] Exam Trap: The June 30 Dicamba Cutoff The Arkansas dicamba cutoff has moved more than once - it was April 15 for the 2018-2019 seasons and May 25 for several years after. The number that is correct now is June 30. An item describing an in-crop dicamba application to DT soybeans on May 5 is describing a legal application if the buffers, tank-mix ban, training, and label conditions are all satisfied. The same application on July 5 is illegal.