Field studies were conducted to determine sweetpotato tolerance to and weed control from management systems that included linuron. Treatments included flumioxazin preplant (107 g ai ha–1) followed by (fb) S-metolachlor (800 g ai ha–1), oryzalin (840 g ai ha–1), or linuron (280, 420, 560, 700, and 840 g ai ha–1) alone or mixed with S-metolachlor or oryzalin applied 7 d after transplanting. Weeds did not emerge before the treatment applications. Two of the four field studies were maintained weed-free throughout the season to evaluate sweetpotato tolerance without weed interference. The herbicide program with the greatest sweetpotato yield was flumioxazin fb S-metolachlor. Mixing linuron with S-metolachlor did not improve Palmer amaranth management and decreased marketable yield by up to 28% compared with flumioxazin fb S-metolachlor. Thus, linuron should not be applied POST in sweetpotato if Palmer amaranth has not emerged at the time of application.
Nomenclature: Flumioxazin; linuron; oryzalin; S-metolachlor; Palmer amaranth, Amaranthus palmeri S. Watson AMAPA