SWEET-POTATO (IPOMOEA-BATATAS) CLONES DIFFER IN RESPONSE TO ETHYL-METRIBUZIN

Six commercial sweet potato clones were evaluated in field and greenhouse studies for the ethylthio analog of metribuzin (ethyl-metribuzin) tolerance. 'Southern Delite' was most tolerant in field studies and 'Cordner' the most tolerant in the greenhouse. 'White Delite' was the most susceptible clone in the field and greenhouse. Considering the rates used in this study, all the sweet potato clones generally were tolerant to ethyl-metribuzin. When averaged over all clones, sweet potato injury increased as the ethyl-metribuzin rate increased from 1.6 to 3.2 kg/ha but injury decreased as the season progressed and was minimal in late season, Ethyl-metribuzin did not reduce marketable yields at Clayton, NC. At Clinton, NCI ethiozin PRE, POST, or PRE followed by POST at 3,2 kg/ha or PRE at 1.6 kg/ha reduced yield.