Dicamba is an important herbicide for controlling post-emergent resistant weeds in soybean farming. Recently, the scientific community and general public have further examined off-target transport mechanisms (e.g., spray drift, volatilization, and tank contamination) and the visual responses of soybeans to ultralow dicamba concentrations. This paper synthesizes key chemical concepts and environmental processes associated with dicamba formulations, transport mechanisms, drift measurements, and plant responses. This paper proposes additional areas of research and actions to increase our understanding and communicate the science findings, which should provide farmers with more robust tools and practices for sustainable dicamba use.

Auxins such as dicamba and 2,4-Dichlorophenoxyacetic acid (2,4-D) may volatilize when used as herbicides. In this work, a fast, straightforward method to determine the relative volatility of auxin formulations is presented. The method uses a sprayed soil substrate in a disposable closed dome system. For a 24-h period, air is drawn out of the closed dome and passed through a polyurethane foam (PUF) plug where any volatile auxin is trapped. The auxin is extracted from the PUF with methanol, and the resultant extract solution is analyzed for the auxin by liquid chromatography-mass spectrometry (either LC-MS or LC-MS\MS). The data are then used to determine the relative volatility of the formulations.