Simulated dew increases volatility of dicamba from soybean leaves

Abstract

Abstract Adoption of dicamba tolerant soybeans [Glycine max (L.) Merr.] accompanied by postemergence applications of dicamba resulted in off‐target movement and damage to nearby crops. The underlying cause, in some cases, has been attributed to weather‐related phenomena such as temperature inversions, which are often accompanied by the formation of dew. The objective of this controlled study was to determine if the formation of simulated dew on soybean leaves treated with dicamba led to increased short‐term dicamba volatility. Over a 48‐h period after the application of dicamba, dicamba volatility concentrations quantified in air samples increased by 20% when soybeans were exposed to simulated dew for 3 h compared with soybeans that were not exposed to dew. Concentrations of volatilized dicamba were elevated in the first (0–24 h) and second (24–48 h) 24‐h period after initiating collection of air samples. Dew may alter the stability of dicamba, ultimately contributing to increased off‐target movement.