In Vitro Evaluation of Two Plant Extracts for the Control of Post-Harvest Fungi Rot of Sweet Potato Tuber (Ipomoea Batatas L. Lam) in Makurdi, Nigeria

Abstract

The study investigated the pathogens causing postharvest deterioration of sweet-potato tubers in Makurdi and their control in vitrowith aqueous extracts of Moringa oleifera and Eucalyptus globulus. Rhizopus stolonifer and Aspergillus niger were isolated from rotted sweet potato tubers. The pathogenicity test revealed that both pathogens were pathogenic on healthy potato tubers with Rhizopus stolonifer being the most virulent.Three extract concentrations (25, 50 and 75 %) were obtained from the leaves of M.oleifara and E.globulus by blending 25, 50 and 75g of air-dried leaves in 100 ml of sterile distilled water to produce 25, 50 and 75 % concentrations respectively. The extracts of both pathogens were more effective in inhibition of mycelial at higher concentration. The fungitoxic effects of the extracts of M.Oleifera induced mycelial inhibition in the ranges of  26.31-75.65 %, while extracts of E. globulus induced mycelial inhibition in the ranges of  21.28- 61.25 %. Extracts of E. globulus at 75 % concentration exhibited the strongest fungitoxicity against the text pathogens. This study indicated that M. oleifera and E. globulus were able to suppress rot-causing fungi of sweet potato. Therefore, they will serve as a good natural plant fungicide against sweetpoato tubers.