Dicamba reapproved as Delta growers already locked into seed decisions

By Lora Delhom

For many Delta growers, dicamba is not a debate unfolding in Washington. It is a seed decision made months ago.

The U.S. Environmental Protection Agency on Feb. 6 reapproved over-the-top use of dicamba on genetically engineered cotton and soybeans for the 2026 and 2027 growing seasons, describing the decision as the strongest protections ever required for the herbicide.

Two weeks later, on Feb. 20, a coalition of farmer and environmental groups filed suit challenging that reapproval, arguing the agency again failed to adequately address volatility, off-target movement and ecological harm.

The timing is significant in the Mississippi Delta, where crop planning, seed purchasing and herbicide programs are typically established well before planting — and often before legal challenges are resolved.

A systems decision

Dicamba-tolerant cotton and soybean platforms are part of a broader weed management strategy designed to combat glyphosate-resistant Palmer amaranth and other problematic weed species prevalent in Delta row crops.

Seed ordering generally occurs in December and January to secure preferred varieties and trait systems. Once growers commit to a dicamba-tolerant platform, switching mid-season can be costly or impractical — particularly in tight-margin years when producers may not have the capital to pivot to alternative seed.

EPA acknowledged this dynamic in 2024 after a federal court vacated prior dicamba registrations. At that time, the agency noted that most growers had already placed orders for dicamba-tolerant seed and could not pivot to alternative systems based on timing.

Adoption of dicamba-tolerant soybean traits has been substantial across the Mid-South. U.S. Department of Agriculture data show rapid uptake in Mississippi in recent years.

For Delta producers managing resistant weeds, trait stacking and over-the-top chemistry options are often viewed as risk-management tools. For specialty crop growers and landowners, dicamba has been associated with off-target injury to broadleaf plants, orchards and habitat.

Repeated court scrutiny

Dicamba’s regulatory history has been unusually turbulent.

In June 2020, the U.S. Court of Appeals for the Ninth Circuit vacated EPA’s registration of certain dicamba products used over tolerant crops.

The court found the agency had understated risks and wrote that EPA failed to fully consider how dicamba use could “tear the social fabric of farming communities.”

In February 2024, the U.S. District Court for the District of Arizona again vacated dicamba registrations for products used over the top of tolerant crops, citing deficiencies in EPA’s analysis. EPA later issued an existing-stocks order allowing limited continued use that season.

The 2026 reapproval is now under judicial review.

Plaintiffs include the National Family Farm Coalition, Center for Biological Diversity, Center for Food Safety and Pesticide Action & Agroecology Network.

What changed in 2026

EPA says new measures are designed to address volatility and drift documented in prior seasons.

Under the new registration:

Applications are prohibited if the forecasted high temperature exceeds 95 degrees Fahrenheit on the day of application or the following day.

When forecast temperatures are between 85 and 95 degrees, treatment is limited to 50% of untreated dicamba-tolerant cotton or soybean acres in a county before a two-day pause.

The annual maximum application rate has been reduced from 2 pounds per acre to 1 pound per acre.

Required volatility reduction agent rates have been increased.

EPA describes the measures as its most protective dicamba label to date.

Plaintiffs argue the registration removes previous calendar cutoff dates and eliminates certain buffer protections intended to safeguard endangered species habitat, weakening safeguards during high-volatility summer conditions.

A Delta research question

Stoneville remains home to USDA Agricultural Research Service programs and long-standing public and private agricultural research efforts. Scientists in the region have studied herbicide resistance, meteorological influences and drift dynamics for decades.

Temperature-based restrictions and county-level acreage limits introduce new operational variables under Delta climatic conditions, where summer highs routinely approach or exceed 95 degrees.

Whether forecast-based limits are enforceable and how volatility reduction agents perform in humid subtropical conditions may become areas of continued scientific interest.

For growers, however, the immediate question is practical: how to balance weed control efficacy, neighbor relations and regulatory uncertainty within a compressed production calendar.

The case will now proceed in federal court, once again placing dicamba at the intersection of agronomy, law and community impact.