Researchers at North Carolina State University have found a post-harvest curing treatment greatly reduces the incidence of necrosis in the sweet potato variety Covington, the university says in a news release on Sept. 23.
Internal necrosis is a physiological disorder, not caused by a pest or pathogen, where the sweet potatoes develop black spots and patches on the inside of the root, the release notes. A survey of North Carolina sweet potato storage rooms in 2010 and 2011 found at least 90 per cent of them had some roots with internal necrosis. In these rooms it was found less than 10 per cent of potatoes had it, but some had as high as 30 per cent infected roots making them unmarketable.
It was found though by curing roots at a lower curing temperature for a shorter time it greatly reduced the incidence and severity of internal necrosis in Covington sweet potatoes. In the study, roots were cured at either 75 F or 85 F for three days, one week, two weeks, three weeks or five weeks.
“The bottom line is, this has saved the industry millions of dollars of crop loss,” Jonathan Schultheis, a professor and extension specialist in the Department of Horticultural Science at NC State, says in the release. “One grower called me up and told me he lost a million dollars due to internal necrosis in one season. This solution also helped maintain the reputation of North Carolina for the high-quality sweet potatoes we produce.”
