While most of our attention is caught up on protests and a deadly pandemic, the EPA has revoked a pesticide registration that has seized the attention of many of our nation’s farmers. Dicamba, an herbicide widely used to protect crops from competition with weeds, has been increasingly relied upon by many farmers. It provided control of many weeds that had developed resistance to glyphosate (a.k.a. RoundUp) – the most widely used herbicide on earth. Furthermore, Monsanto had developed genetically modified strains of many important crops that were resistant to dicamba, allowing the herbicide to be applied to fields growing those crops without damaging the crops themselves. However, dicamba was controversial because of its volatility; vapors rising from treated fields could drift onto neighboring fields and damage any broadleaved, non-resistant vegetation there. This drift can have major environmental consequences, as well as causing tremendous damage to neighboring farms growing susceptible crops.

The revocation came after a court order from the US Court of Appeals for the Ninth Circuit, and covers three products – Extendimax, Engenia, and FeXapan. Under the EPA order, the registration was revoked as of June 3 2020, with immediate prohibitions on sale of dicamba. Farmers who already have a supply of dicamba have until July 31 2020 to use it; any use after that date will be a violation of the Federal Insecticide, Fungicide, and Rodenticide Act. Several states already had limitations on how late dicamba could be applied, so farmers may not be affected for the 2020 growing season but will need to plan a new weed control strategy for 2021. The chemical manufacturer, Bayer, has stated that it will seek EPA registration for a low-volatility formulation of dicamba for 2021, but it is too early to tell whether that will be approved.

To offer a fully subjective opinion on this change, I suspect that the decision to revoke registration probably was sound, but that the short-notice execution is problematic. Farmers need to acquire their pesticide supplies before or at the beginning of the growing season, and the investment in dicamba-resistant seed must be made before the growing season. De-registering the product with such short notice may leave some farmers without an adequate weed management strategy for this year, despite good planning on the part of the farmers at the beginning of the season. Therefore, setting the dates to be sure farmers could finish out the 2020 season as planned would incur less hardship on the farmers, and in the grand scheme of things would probably not result in much additional environmental harm. On the other hand, there are few – if any – pesticide registration revocations that are widely regretted well after the fact. For example, DDT, a highly effective early insecticide that caused tremendous environmental harm, was banned in 1972. At the time it was banned, good replacement products were in short supply and pest managers were left lacking essential tools – as is the case now with dicamba. But that void led to innovations, and the pyrethroids, neonicotinoids, abamectins, oxadiazines, and other products that have replaced DDT are so much safer, yet still effective, that few would call for reinstating DDT to manage insects. It is likely that similar innovations and development of safer formulations or active ingredients will lead to better products than the ones that have just been banned. Even the low-volatility formulation for which Bayer is seeking 2021 registration may be a suitable replacement.

Another concerning point is that the US Court of Appeals had to order the EPA to revoke the registration of these dicamba products. The EPA is the agency responsible for assessing scientific data to determine whether or not a pesticide should be registered for use and how that product should be used. They employ a number of scientists who’s job is to weigh the risks against the benefits and determine whether a product should be registered. The fact that the court stepped in and mandated the EPA to revoke the registrations seems concerning because it suggests that someone is not doing their job properly in our regulatory system. It is possible that the EPA scientists are becoming too lax, or that other political influences and/or corruption are leading to the EPA failing to properly enforce the environmental protections that the EPA exists to provide. Alternatively, the EPA did properly assess the risks against the benefits, and the court forced an action that is not properly justified by the available scientific data. Either case would suggest that regulations are being created and repealed without impartial support of scientific data, which I consider to be a terrifying proposition. A less cynical interpretation is that the weighing of risks against benefits includes a subjective component, and the difference between the ruling of the EPA and the courts may simply come from data interpretation or perception of acceptable risk. With the EPA being responsible for the protecting air quality and water quality, in addition to pesticide use, it seems prudent to pay some attention to its behavior and consider these regulations as we approach another election season.

*Note – opinions expressed in this post are solely those of the author.