FUNGAL SPECIES ASSOCIATED WITH POST-HARVEST SPOILAGE OF COCOYAM

The identification of fungal pathogens responsible for the spoilage of cocoyam corms was demonstrated on Sabouraud dextrose agar media and subsequent microscopic observation. The fungi which were isolated from rot affected tissue identified to be the causative microorganisms responsible for cocoyam spoilage included Aspergillus niger, Sclerotium rolfsii, Fusarium solani, and Penicillium species. All the fungi were found to be responsible for spoilage of healthy cocoyam. Rot was observed by the softness of the corms and oozing out of fluids. Sclerotium rolfsii and Fusarium solani has the highest frequency of occurrence (56.3%) and 37.5% respectively followed by Aspergillus niger (31.2%) and Penicillium species with 18.7% frequency of occurrence. Pathogenicity test showed that the isolated fungal species induced rot in healthy cocoyam corms after days of inoculation. Sclerotium rolfsii and Fusarium solani were the most pathogenic with rapid deterioration of the fresh cocoyam corms in 21days having a rots diameter of 27mm and 22mm, respectively. The least pathogenic fungus was A. niger having a rots diameter of 16mm. This study showed that virulence varied amongst the fungal pathogens. S. rolfsii and F. solani were more virulent whilst Aspergillus niger, and Penicillium species were mildly pathogenic during the 28days storage period.