By Blake Jackson
Sweet potatoes may spend months developing beneath the soil, but their quality after harvest depends heavily on how they are handled, cured and stored.
Lincoln University of Missouri (LU) recently held a half-day workshop to help growers better understand postharvest diseases and ways to reduce crop losses, according to Jenny Marie Lawrence with Lincoln University of Missouri.
The workshop combined research findings with practical discussions on how diseases develop after harvest and which management practices can help protect sweet potatoes during storage.
“Most of the pathogens that cause sweet potato postharvest diseases require a wound,” said Waana Kaluwasha, Ph.D., LU Assistant Professor of Plant Pathology, who led the workshop.
Harvesting can create opportunities for infection because sweet potatoes may be cut, scraped, bruised or broken while being dug, separated from vines or moved into containers.
Growers can reduce the risk by curing freshly harvested roots in warm, humid conditions, allowing wounds to heal and the skin to strengthen before washing and storage.
“Curing is typically done for four to 10 days,” Kaluwasha said, adding that conditions should remain around 85 degrees Fahrenheit with at least 85% relative humidity.
Ye Su, Ph.D., LU Associate Professor in agribusiness, presented findings from a recent survey on sweet potato harvesting, curing and storage practices. All eight growers who participated said they cured their crop, but more than half reported that they did not regulate temperature or humidity during curing and storage.
After curing, recommended storage conditions are 55 to 60 degrees Fahrenheit with relative humidity of at least 85%. Higher temperatures can promote sprouting and moisture loss, while colder conditions can cause chilling injury and increase disease susceptibility.
Growers were also advised to maintain clean, well-ventilated storage areas and promptly remove decaying roots. Some pathogens can produce spores that spread to other damaged sweet potatoes.
Kaluwasha discussed diseases such as Fusarium rot, Rhizopus soft rot and bacterial soft rot. Some infections may begin in the field and remain hidden until storage, while others develop after harvest when environmental conditions favor disease.
Research supported by a Missouri Department of Agriculture Specialty Block Grant examined how curing duration affects disease development.
Results showed the most disease in uncured sweet potatoes, while longer curing generally reduced infection. Four days was adequate for some varieties, while others benefited from seven to 10 days.
The workshop also gave growers an opportunity to exchange experiences involving storage, pests and different varieties, including Beauregard, White Bonita, and Murasaki.
Mary-Jane McCoy, who grows hundreds of sweet potato plants near Jefferson City, said curing was one of her biggest takeaways.
“I learned how important it really is to cure sweet potatoes,” McCoy said. “There’s a big benefit to waiting seven to 10 days.”
Photo Credit: pexels-kindelmedia
Categories: Missouri, Crops, Fruits and Vegetables, Education