This regulation establishes tolerances for combined residues of isoxadifen-ethyl (ethyl 5,5-diphenyl-2-isoxazoline-3-carboxylate, (CAS No. 163520-33-0), and its metabolite: 4,5-dihydro-5,5-diphenyl-3- isoxazolecarboxylic acid, in or on corn commodities. Aventis CropScience requested this tolerance under the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the Food Quality Protection Act (FQPA) of 1996.