Leaching of Isoxaflutole and the Herbicide Safeners R-29148 and Furilazole

Abstract

The objectives of this study were to evaluate the leaching of isoxaflutole and the safeners R-29148 and furilazole to test the hypothesis that safeners and isoxaflutole were moving at different rates through the soil profile. The isoxaflutole movement down soil columns was measured by evaluating the visible injury on crop and weed bioassay species seeded into columns split longitudinally. The movement of the safeners was measured by evaluating the isoxaflutole injury to the crop assay species compared to the injury observed without a safener present. The results indicated that a heavy rainfall event could move isoxaflutole through the soil profile in a pulse pattern. If the herbicide pulse moved into the rooting zone of corn, injury resulted. The herbicide safeners leached more slowly than isoxaflutole. For the safeners to be effective, their movement needed to be similar to that of isoxaflutole. Applying a polymeric carrier with the WDG formulation of isoxaflutole reduced leaching compared to two commercial isoxaflutole formulations.