Alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide] at 3.4 and 6.7 kg/ha controlled weeds present in sweet potatoes (Ipomoea batatas L. ‘Jewel’, ‘Centennial’, ‘Caromex’) at two locations in North Carolina. Yield was not reduced from slight early season injury observed with the herbicide treatments. Most sweet potato root samples contained less than the detectable limit of 0.05 ppmw of alachlor. At one location, samples of the cultivars Jewel and Centennial that received 6.7 kg/ha contained 0.06 and 0.05 ppmw, respectively. Averaged over locations, residue levels in soil samples from plots treated at 6.7 kg/ha decreased from 1.55 ppmw initially to less than 0.05 ppmw by 16 weeks after application.
