Preharvest Treatments on Skinning of Sweet Potato Roots1,2

Chemical and mechanical treatments were applied to 3 cultivars of field grown sweet potatoes, Ipomoea batatas (Lam.), in an attempt to reduce the amount of skinning injury from harvest and handling. Treatments that destroyed the leaves and vines, i.e. sodium arsenite, paraquat, and mowing at soil level, reduced skinning of fleshy roots later during harvest. The reduction in fleshy root skinning from harvest treatments was significant but not visually apparent in field containers. Thickness of periderm of the sweet potatoes was not influenced by chemical or mechanical treatments but dates of application and time of harvest influenced periderm development. Skinning was most severe when the periderm was thickest. There appeared to be an association between low soil temperature (60° F) and skinning. Changes in carbohydrate composition of ‘Nemagold’ roots were partly associated with changes in soil temperature. Accumulation of carbohydrates in roots varied with cultivar and season, and there was no relationship between the carbohydrate composition and severity of skinning. Yield of roots was reduced in most plots where vines were killed or stunted by treatments, especially those made early in the harvest season and in treatments applied 2 weeks prior to harvest.