Dicamba is a widely used herbicide in Minnesota to control weeds in crops such as corn, wheat, and barley in addition to various non-agricultural sites. Starting in 2016, select new dicamba formulations were approved for use on dicamba-tolerant (DT) soybeans, which resulted in a sharp increase in use. However, with the new use of dicamba on DT-soybeans came new challenges related to off-site transport. Dicamba is a volatile chemical that has the potential to move off-site via drift and through surface runoff. Damage to sensitive crops, including non-DT soybeans, has been an issue in recent years due to the volatilization of dicamba. The Minnesota Department of Agriculture (MDA) receives and tracks dicamba drift complaints, including over 300 complaints received in 2021. The MDA also has an extensive water monitoring program that analyzes for over 175 pesticide chemicals, including dicamba, in ground and surface waters throughout the state. Since 2016, there has been an increase in both detection frequency and concentration of dicamba in rivers and streams, though concentrations remain below the Environmental Protection Agency’s lowest available aquatic life benchmark (61 µg/L). This poster will present monitoring data and trends for dicamba in surface waters over the past decade, report on drift complaints in the state, and summarize the MDA’s regulatory actions to prevent the off-site transport of dicamba. As struggles with herbicide-resistant weeds continue, dicamba remains an important tool; however, it is critical to understand its impacts and work to protect water resources and sensitive crops.

Decade of dicamba: Water monitoring, drift complaints, and regulation in Minnesota

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.