04
Aug
EPA To Allow Dicamba Herbicide Used in Genetically Engineered Crops, Prone to Drift and Weed Resistance
(Beyond Pesticides, August 4, 2025) Comments on EPA proposal to bring back controversial use of herbicide dicamba due by Friday, August 22, 2025, at 11:59 PM ET. With more than 90 percent of soybeans (also corn and the most common species of cotton) planted in varieties genetically engineered to be herbicide-tolerant, the agrichemical industry and industrial agribusiness are lining up to bring back agricultural spraying of the controversial weed killer dicamba—linked to crop damage associated with the chemical’s drifting off the target farms. The courts in 2020 and 2024 vacated EPA’s registration authorizing “over-the-top” (OTT) spraying of dicamba, leading to these uses being stopped in the 2025 growing season. (See Daily News.)
Genetically engineered crops, widely adopted in 1996 with Monsanto’s glyphosate-tolerant (Roundup Ready) soybean seeds and plants, have been plagued by weed resistance to the weed killers, movement of genetic material, chemical drift, and health and environmental hazards associated with pesticide exposure. Despite the problems and escalating herbicide use in chemical-dependent no-till (no tillage) agriculture, regulators at the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Agriculture (USDA) have facilitated the astronomical growth of a genetically engineered food system. The industry makes the environmental argument that less disturbance to soil is better for soil health. However, the purveyors of toxics downplay the adverse effects of the petrochemical pesticides and fertilizers, and are silent on the fact that certified organic food production prohibits genetically engineered seeds and plants (as well as synthetic fertilizers) with competitive yields and increased economic returns, while protecting health, biodiversity, and climate.
The pattern of pesticide dependency, often referred to as the pesticide treadmill, continues with EPA’s latest proposal to allow the return of OTT dicamba uses, after Bayer submitted a new registration request to EPA with claims of a “low-volatility” formulation and proposed product label changes. Bayer, in a statement cited in Progressive Farmer on dicamba’s use in genetically engineered crops, said, ”This technology provides tremendous value to soybean and cotton farmers across the U.S.” Recognizing the continuing problem of target weed resistance to the weed killers, the American Soybean Association is quoted by the news outlet, saying, “Dicamba is a critical crop-protection tool for soybean farmers, particularly in managing herbicide-resistant weeds like Palmer amaranth.” The court decision cites survey data that finds “weed resistance is not being effectively managed,” as required by the dicamba’s original registration.
Despite the history of dicamba drift and a history of failed weed resistance management in genetically engineered crops, EPA is now considering three new dicamba registrations that continue use of the chemical in its most drift-prone uses. As a result, Beyond Pesticides is calling on the public to: Tell EPA to ban use of dicamba and other drift-prone herbicides.
Pesticide drift harms people, crops, and wildlife. Although the term “drift” applies to airborne movement off the target site, pesticides may also move as runoff and in soil carried by water or wind. Drift may consist of particles or droplets of pesticide as it is applied or vapors that evaporate and are carried in the air. Farmers and applicators may take steps to avoid drift—including buffer zones, thickening agents, and attention to wind direction—but drift-prone pesticides like dicamba are not adequately controlled by these actions. Those harmed by the drift are generally not those whose crops are sprayed, so the risk-benefit analysis pits farmer against farmer, neighbor against neighbor, with one case involving a murder resulting from a dispute over crop damage. The manufacturers of dicamba-based herbicides—who also sell seeds of crops engineered to tolerate dicamba—benefit from this conflict, as farmers buy the engineered seeds in an effort to defend themselves against drift damage, a strategy encouraged by pesticide manufacturers.
Despite findings of dicamba’s harm and EPA failure to comply with standards, the continued use of the weed killer through the 2024 growing season was effectively authorized in a decision of the U.S. District Court of Arizona, which vacated the EPA’s 2021 authorization of the use of three OTT uses of dicamba-based herbicide products. In response, EPA issued an existing stocks order, with a February 2024 stop sale order and allowances of state-specific end-uses through spring and early summer of 2024. It is this decision that will effectively be overturned by Bayer’s and EPA’s changes to the products’ registrations and labels, despite concerns about the limited effectiveness of the proposed changes.
Now, proposed registrations would allow those uses to continue. The docket on these registrations is open for comment until August 22. (See Beyond Pesticides’ comments from August 2025.)
The proposed labels allow for application preplant, at-planting, preemergent, and post-emergent (in-crop) for broadleaf weeds. There are label restrictions purporting to reduce drift damage, but they are subject to exceptions. For example, there is a downwind buffer of 240 feet—though “downwind” may change during application as well as post-application when vapor drift is likely. The buffer distance may be reduced by reducing the number of passes when applied to fields, presence of a windbreak, or use of directed spray equipment. The maximum allowed temperature during and following application depends on the concentration of additives to reduce drift and volatilization, but may be as high as 95°F. The new proposed uses, since they increase use of dicamba and subsequent harm from pesticide drift, should be denied for failure to meet the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) requirement of no unreasonable adverse effects on the environment.
Increasing global temperatures have become an important factor in pesticide exposure, resulting from the volatilization of dicamba and pesticides generally. All dicamba formulations have the potential to volatilize, since dicamba has a high vapor pressure. Increases in air temperature can cause dicamba to turn into a gas even after successful application on target surfaces. Since volatilization increases with an increase in temperature, this exposure route is more and more concerning as temperatures are rising higher each year and the length, intensity, and onset of seasons have changed with the climate crisis. The longer and hotter summers will exacerbate dicamba volatilization; therefore, any proposal that allows dicamba application in late Spring and Summer will lead to more drift—especially for post-emergent and over-the-top applications.
Although pesticides are by definition harmful, critics say that what makes these adverse effects “unreasonable” is the existence of an alternative—an organic production system—that does not harm human health, other species, or ecosystems and, in addition, helps to mitigate climate change. In this context, these critics argue that EPA’s registration decisions for dicamba and other pesticides must use organic production as a yardstick, denying any use for which organic production is successful.
Tell EPA to ban use of dicamba and other drift-prone herbicides.
Comment to U.S. Environmental Protection Agency (EPA)
Dicamba is a drift-prone herbicide that has proved to be extremely difficult to control by regulation. EPA is now considering three new dicamba registrations that continue use of the chemical in its most drift-prone application uses.
Pesticide drift harms people, crops, and wildlife. The term “drift” applies to airborne movement off the target site—though pesticides may also move as runoff and in soil carried by water or wind. Drift may consist of particles or droplets of pesticide as it is applied or vapors that evaporate and are carried in the air. Farmers and applicators may take steps to avoid drift—including buffer zones, thickening agents, and attention to wind direction—but drift-prone pesticides like dicamba are not adequately controlled by these actions. Those harmed by the drift are generally not those whose crops are sprayed, so the risk-benefit analysis pits farmer against farmer, neighbor against neighbor, even resulting in a murder.
The manufacturers of dicamba-based herbicides—who also sell seeds of crops engineered to tolerate dicamba—benefit from this conflict, as farmers buy the engineered seeds in an effort to defend themselves against drift damage, a strategy encouraged by pesticide manufacturers.
Despite a finding of dicamba’s harm and EPA’s failure to comply with standards, EPA proposes registrations that would allow those uses to continue.
The proposed labels allow for application preplant, at-planting, preemergent, and post-emergent (in-crop) for broadleaf weeds. There are label restrictions purporting to reduce drift damage, but they are subject to exceptions. For example, there is a downwind buffer of 240 feet—though “downwind” may change during application as well as post-application when vapor drift is likely. The buffer distance may be reduced by reducing the number of passes when applied to fields, presence of a windbreak, or use of directed spray equipment. The maximum allowed temperature during and following application depends on the concentration of additives to reduce drift and volatilization, but may be as high as 95°F. The new proposed uses, since they increase use of dicamba and subsequent harm from pesticide drift, should be denied for failure to meet the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) requirement of no unreasonable adverse effects on the environment.
Although pesticides are by definition harmful, what makes these adverse effects “unreasonable” is the existence of an alternative—an organic production system—that does not harm human health, other species, or ecosystems and, in addition, helps to mitigate climate change. In its registration decisions, EPA must use organic production as a yardstick, denying any use for which organic production is successful. This includes the proposed uses.
Increasing global temperatures also need to be considered. All dicamba formulations have the potential to volatilize since dicamba has a high vapor pressure. Increases in air temperature can cause dicamba to turn into a gas even after successful application on target surfaces. Since volatilization increases as temperatures increase, this is more and more concerning as temperatures are rising higher each year. The length, intensity, and onset of seasons have changed, which can be attributed to climate change. The longer and hotter summers will exacerbate dicamba volatilization; therefore, any proposal that allows dicamba application in late Spring and Summer will lead to more drift—especially for post-emergent and over-the-top applications.
EPA must not approve the proposed expanded use of dicamba and must cancel uses of all drift-prone pesticides.
Thank you.
View this document on Regulations gov [EPA-HQ-OPP-2024-0154-1233]. By submitting a comment, you agree to the terms of participation and privacy notice of Regulations.gov.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
