In Vitro Evaluation of the Fungicidal Activity of Garlic (Allium sativum L.) Extract Against Fungal Pathogens Associated with Potato (Solanum tuberosum L.) Tuber Rot in Bokkos, Plateau State, Nigeria
Nigerian potato (Solanum tuberosum L.) production is hindered by post-harvest fungal infections that lower tuber quality and market value. Therefore, this study examined the prevalence of fungal pathogens linked to potato tuber rot in Bokkos Local Government Area of Plateau State and assessed the aqueous garlic (Allium sativum L.) extract’s in vitro fungicidal efficacy against the isolated fungi. Ninety-six rotten potato tubers were gathered from eight different places, and using conventional mycological methods on Potato Dextrose Agar, fungi were isolated and identified. Standard qualitative and quantitative techniques were used to assess the phytochemical components of garlic extract, and GC-MS analysis was used to identify the main bioactive chemicals. Agar disc diffusion was used to measure antifungal activity at various extract concentrations. Rhizopus stolonifer (23.5%) was the most common of the seven fungal species that were isolated, followed by Alternaria solani (19.6%) and Mucor hiemalis (17.6%). The incidence of fungal species did not change significantly between isolates, according to chi-square analysis (χ² = 9.2549, df = 6, P = 0.1597). Garlic extract outperformed nystatin in some cases, displaying concentration-dependent antifungal activity with inhibitory zones ranging from 17 to 37 mm at 25-100% dosages. Phytochemical screening revealed flavonoids, alkaloids, saponins, terpenoids, and resins, whereas GC-MS identified bioactive compounds such as p-cymene, phenolic derivatives, and fatty acid esters. The study validates the use of garlic extract as a sustainable botanical fungicide for post-harvest disease management by demonstrating its excellent antifungal activity against potato rot pathogens.
Keywords: Potato rot, Allium sativum, antifungal activity, GC–MS, phytochemicals, Bokkos, Nigeria
