The Environmental Protection Agency announced new regulations Friday governing the use of over-the-top dicamba, a herbicide that agricultural officials say is critical for battling resistant weeds in crops but has faced legal challenges over environmental concerns.
The EPA said it established stringent protections for applying the herbicide on dicamba-tolerant cotton and soybean crops. The decision, effective for the next two growing seasons, responded to concerns from farmers, particularly those in the Cotton Belt, who have emphasized the challenges they face without access to the tool.
Friday's announcement came two years after a federal judge vacated 2020 registrations for three dicamba products, forcing the agency to reconsider its regulatory approach.
Dicamba has been used as a pesticide for more than 50 years, though over-the-top applications have only occurred since 2016. The herbicide is used to control weeds in several food and feed crops. Some dicamba products can be sprayed over-the-top of genetically engineered soybeans and cotton once they have sprouted.
According to the EPA, farmers have said over-the-top dicamba is needed to combat weeds like Palmer amaranth, which has become almost impossible to fight with other herbicides. Those weeds can grow 3 inches per day and devastate entire fields.
The new restrictions include cutting dicamba's application rate by half. The 2020 rules allowed up to four applications of a half-pound per acre, with only two of those being over-the-top applications. That meant a farmer could apply a total of 2 pounds each year.
The new rules state that only two applications of a half-pound per acre may occur annually, for a total of 1 pound each year. The EPA said the reduction will decrease the amount of dicamba used and limit exposure to sensitive species.
Additionally, dicamba users must double the amount of volatility reduction agents added to every application. The EPA said this measure will greatly reduce the possibility that dicamba will turn into vapor after application and then drift off its target, one of the main ways it can damage the environment.
The agency said it imposed these measures to reduce drift, minimize volatility and protect ecosystems.
However, environmental groups criticized the EPA's decision. The Center for Biological Diversity said drift remains a significant danger of dicamba use. The center said that since 2016, dicamba drift has damaged millions of acres of farmland and ravaged orchards, home gardens and trees.
The environmental group expressed concern that the approval announced Friday offers fewer protections than those provided in the past.
"The industry cronies at the EPA just approved a pesticide that drifts away from application sites for miles and poisons everything it touches," the Center for Biological Diversity said in a statement.
The controversy over dicamba illustrates the ongoing tension between agricultural needs and environmental protection. Farmers argue that resistant weeds like Palmer amaranth pose an existential threat to crop production, requiring powerful herbicides to maintain viable yields.
Palmer amaranth, in particular, has emerged as a formidable agricultural challenge. The weed's rapid growth rate of 3 inches per day allows it to quickly overtake crop fields. Its resistance to multiple herbicide classes has left farmers with limited options for control.
The EPA's approach attempts to balance these competing concerns by maintaining access to dicamba while implementing stricter controls on its use. The reduced application rates and enhanced volatility reduction requirements represent the agency's effort to minimize environmental risks while preserving the herbicide as an agricultural tool.
The two-year timeframe for the new regulations suggests the EPA may continue to evaluate dicamba's use and potentially adjust restrictions based on environmental monitoring and agricultural outcomes.
The dicamba debate also reflects broader challenges in modern agriculture, where the development of herbicide-resistant crops has created new dependencies on specific chemical treatments. Genetically engineered dicamba-tolerant cotton and soybeans were designed to work with over-the-top dicamba applications, creating a technological system that farmers have integrated into their operations.
The regulatory uncertainty surrounding dicamba has created challenges for agricultural planning. Farmers have had to adjust their weed management strategies multiple times as court rulings and regulatory changes have affected product availability.
The EPA's new restrictions will require farmers to modify their application practices, potentially affecting their overall pest management strategies. The reduced application rates may require farmers to explore alternative weed control methods or adjust their crop management approaches.
Environmental advocates will likely continue monitoring dicamba use under the new regulations to assess whether the additional restrictions adequately address drift and environmental damage concerns. The effectiveness of the enhanced volatility reduction requirements will be particularly important in determining whether the new rules successfully reduce off-target movement of the herbicide.