This regulation establishes a tolerance for residues of dimethenamid in or on onions (dry bulb), garlic, shallots (dry bulb), tuberous and corm vegetables, sugar beets, garden beets, and horseradish. Interregional Research Project No. 4 (IR-4) requested these tolerances under the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the Food Quality Protection Act of 1996 (FQPA). In addition, this regulatory action is part of the tolerance reassessment requirements of section 408(q) of the FFDCA 21 U.S.C. 346a(q), as amended by the FQPA of 1996. By law, EPA is required to reassess all tolerances in existence on August 2, 1996 by August 2006. This regulatory action will count for thirteen reassessments towards this August 2006 deadline.