LU-CAEHS Research Seminar

“Identification and Impact of Soilborne Fungal Pathogens in Sweet Potato and Heirloom Tomato Production”

Heirloom tomatoes and sweet potatoes are prone to infection by various fungal pathogens during growth and/or after harvest, compromising their yield and/or quality and resulting in economic losses. Our research aims to identify prevalent fungal diseases caused by soilborne pathogens affecting heirloom tomatoes and sweet potatoes in mid-Missouri; and to use this information to evaluate costeffective and sustainable disease management practices.

Heirloom tomatoes and sweet potatoes were evaluated for their resistance to naturally occurring soilborne fungal pathogens at Lincoln University’s farms. During the growing season, incidence of disease on heirloom tomatoes was recorded and pathogen isolation was performed from symptomatic samples. Sweet potato storage roots were evaluated for postharvest disease a few months after harvest.

The heirloom tomato cultivars varied in their reactions to disease, with the susceptibility of some cultivars being influenced by the location. Several fungal isolates were successfully isolated from diseased tomato leaves and/or fruit, and from stored or purchased diseased sweet potato storage roots. Initial pathogenicity assays on tomato fruit and sweet potato storage roots showed that many of the isolates are pathogens, and identification of some of these pathogenic isolates suggests that diverse fungal genera are present in our cropping systems. While our research is still ongoing, our initial findings provide valuable information on potentially important fungal pathogens as well as insights into probable resistance sources among cultivars.

Presented by Dr. Waana Kaluwasha, Assistant Professor of Plant Pathology.

Waana Kaluwasha earned her Ph.D. in Plant Pathology from Louisiana State University. Her previous research included the use of cultivar resistance, biological products and cover crops for the sustainable management of sweet potato postharvest fungal diseases. In her current role, she and her team are working on identifying prevalent soilborne fungal pathogens causing preharvest diseases in heirloom tomatoes and postharvest diseases in sweet potatoes. They are also working on understanding the physiological and molecular responses of different cultivars to different pathogens and evaluating the use of green manure for sustainable disease management.