Evaluations of Auxin Nozzles for Irrigation

Georgia cotton growers who have rapidly adopted the auxin crop production systems [Xtendflex™ (dicamba) or Enlist™ (2,4-D choline)] are required by label to use nozzles designed to mitigate potential off-target movement of the herbicides used in these systems. These nozzles are engineered to deliver very coarse to ultra-coarse droplets. Since most cotton growers in Georgia also produce peanut, growers would like to be able to use these auxin nozzles for pest management in peanut thereby reducing the need for sprayers to be equipped with multiple nozzles. However, these coarser droplet sizes may or may not be acceptable for the application of the various types of pesticides applied in peanut (herbicides, fungicides, insecticides, fertilizers, and growth regulators). From 2018 to 2020, a UGA crop and soil scientist, in cooperation with county Extension agents, growers, and other members of the UGA Peanut Team, coordinated seven field trials in commercial peanut fields using commercial pesticide applicators to compare the performance of standard flat-fan nozzles to auxin nozzles. All agri-chemicals for the entire peanut production year were applied by the grower according to the grower’s typical production practices. Research was conducted in several counties including Bulloch, Miller, Pierce, and Worth. Results of these field trials indicate that peanut growers can use auxin nozzles for pest management without concern for reduced pesticide performance. Consequently, growers can save about $200 to $500 per applicator/sprayer in extra nozzle expenditures, depending upon nozzle type/spacing/spray boom width.