A fairly common occurrence in late June and July is the appearance of distorted leaves on soybean plants. The most common cause of this response is exposure to a growth regulator herbicide (2,4-D; dicamba; etc.). Dicamba is the most commonly used growth regulator herbicide in Iowa crop production, and is present in numerous products (Banvel®, Clarity®, Marksman®, Distinct®, Status®, and many others). Soybeans may be exposed to dicamba in three ways: spray particle drift, vapor drift (volatilization), and sprayer contamination. Injury from spray drift or sprayer contamination usually is fairly straightforward in diagnosing, but questions often arise regarding volatilization.
Iowa State University
Hartzler, Robert G., "Dicamba, stress, and distorted soybean leaves" (2007). Integrated Crop Management News. 1020.
The Iowa State University Digital Repository provides access to Integrated Crop Management News for historical purposes only. Users are hereby notified that the content may be inaccurate, out of date, incomplete and/or may not meet the needs and requirements of the user. Users should make their own assessment of the information and whether it is suitable for their intended purpose. For current information on integrated crop management from Iowa State University Extension and Outreach, please visit https://crops.extension.iastate.edu/.