Mesotrione is the active ingredient in the broadleaf herbicide Callisto, which is labeled for use in field and seed corn. Mesotrione is also an ingredient in the preemergence herbicides Camix and Lumax, which are also labeled for use in field and seed corn. Camix is a premix of s-metolachlor and mesotrione and Lumax is a premix of s-metolachlor and mesotrione and atrazine. It would be desirable to have mesotrione labeled for use in sweet corn because there are many limitations with the currently labeled broadleaf herbicides (see “Life after Bladex in Sweet Corn”). However in field experiments, Callisto has occasionally injured some sweet corn hybrids when applied postemergence. Because mesotrione is a pigment inhibitor, the injury that is observed is a bleaching or whitening of leaves in the whorl of the plant. The injury is most noticeable about a week after the application. To obtain full weed control in field corn, the Callisto label specifies that crop oil concentrate plus a nitrogen additive be used. However, a couple of previous experiments indicated that the amount of postemergence injury from Callisto could be substantially reduced if the nitrogen additive was omitted and only crop oil concentrate was used as the adjuvant. In 2002, we conducted experiments to determine if mesotrione could be safely applied to sweet corn with different application methods and adjuvants and the range in tolerance among sweet corn hybrids.