Investigating the antifungal activity of moringa leaf extract against Fusarium dry rot in vitro

C.N. Mncube, I. Bertling, K.S. Yobo
Phytofungi continue to cause devastating diseases in horticultural crops, resulting in large economic losses. Due to many fungal species continuously developing resistance towards chemical pesticides, controlling phytofungal diseases remains a challenge. Enhancing plant defence mechanisms, so that crops become resistant to phytofungal diseases, is the ultimate method of preventing disease outbreaks. Certain medicinal plants contain antimicrobial properties usable as natural pesticides. Plant extracts are likely to be safer to the environment and to humans, and fungi are less likely to develop resistance towards these natural pesticides. Moringa oleifera is a medicinal plant that has an array of compounds with antifungal, antiviral, antibacterial and antioxidant properties. Thus, moringa extracts have the potential to control fungal diseases, while improving shelf life of crops due to their high antioxidant concentration. This study was carried out to investigate the inhibition activity of moringa extracts towards Fusarium dry rot in potatoes. Extracts of moringa leaf powder in either water, or ethyl acetate, or acetone or methanol were used for phytochemical analysis. The same extracts were used to evaluate antifungal activity. The pathogen was isolated from potatoes infected with Fusarium dry rot using Nash-Snyder Agar (semi-selective medium for Fusarium) and cultured in the presence of MLEs using a disc diffusion method. All extracts showed antifungal activity against Fusarium dry rot; however, the methanolic moringa leaf extract (MLE) showed higher efficacy with 100% inhibition at all concentrations. Furthermore, potatoes coated with methanolic MLE had the highest concentration of both, free and bound phenolics. This study provides justification for further investigations into MLE, as a potential fungicide for stored potato.
Mncube, C.N., Bertling, I. and Yobo, K.S. (2021). Investigating the antifungal activity of moringa leaf extract against Fusarium dry rot in vitro. Acta Hortic. 1306, 233-240
DOI: 10.17660/ActaHortic.2021.1306.29
potato, phytochemical compounds, phenolics, Fusarium oxysporum

Acta Horticulturae