States with strictest dicamba restrictions saw less dicamba applied after cotton planting in 2019

Dicamba is a common herbicide used to control annual and perennial broadleaf weeds. Federal and State restrictions for the use of dicamba can influence a farmer’s decision to adopt genetically engineered dicamba-tolerant (DT) seeds. In 2019, for example, Federal restrictions limited the application of dicamba on cotton fields from one hour after sunrise to two hours before sunset, limited applications to 60 days after planting cotton, and required that fields in areas with endangered plant species maintain buffers on all sides of the field. Different States imposed additional restrictions or extensions for dicamba application. For example, Georgia, Oklahoma, and Texas were among states that expanded the dicamba spraying window further into the growing season from the allowed 60 days after planting by granting Special Local Need registrations to their farmers, which were allowed at the time. Data from USDA’s 2019 Agricultural Resource Management Survey show that, in States with earlier dicamba cut-off dates, less dicamba was applied after planting during the growing season. In Arkansas and Louisiana, where cut-off dates occur early in the growing season, 16 percent and 23 percent, respectively, of DT cotton acres were sprayed with dicamba after planting in 2019. By contrast, Georgia allows dicamba spraying until one week before harvest, which can occur as late as December. About 57 percent of DT cotton acres received after-planting applications of dicamba in Georgia in 2019. In 2020, the U.S. Environmental Protection Agency instituted a single nationwide cut-off date of July 30. This chart appears in the July 2021 Amber Waves data feature, “Adoption of Genetically Engineered Dicamba-Tolerant Cotton Seeds is Prevalent Throughout the United States.”

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