Utilization of Moringa oleifera extracts in postharvest disease management of yam (Dioscorea rotundata)

Abstract

Yams are widely used as food and livestock feed, and their availability could help address hunger affecting over one billion people in developing nations. Postharvest losses caused by plant diseases are among the most costly. This study monitored yam tuber spoilage, isolated spoilage pathogens, and evaluated the efficacy of Moringa oleifera leaf, seed, and bark extracts. Pathogenic microorganisms were isolated and identified using standard procedures. Moringa oleifera samples collected from the Wesley University ethnobotanical garden were shade-dried for 21 days. Ten grams of each plant part were extracted in 100 ml of hot water and allowed to stand for one hour. Extract efficacy was tested on nutrient agar and potato dextrose agar and validated in vivo on infected yam tubers. Fungal isolates included Aspergillus flavus, A. fumigatus, A. niger, Botryodiplodia theobromae, Rhizopus stolonifer, and Mucor mucedo, while bacterial isolates included Bacillus, Erwinia, Micrococcus, and Staphylococcus species. The moringa leaf extract showed the highest inhibition (22 mm). Moringa leaf and bark extracts are effective biocontrol agents against postharvest yam spoilage.