Evaluation of Pathogenic Microorganisms that Cause Onion Bulb Rots in Selected Markets in Abuja, Nigeria

Onion bulb rots are caused by microorganisms especially fungi and bacteria leading to economic loss. The research study evaluated the microorganisms associated with the rots of onion bulbs. The microorganisms isolated include fungi species such as Saccaromyces cerevisiae, Aspergillus niger, Rhizopus stolonifera, Fusarium oxysporum and Penicillium digitatum and bacterial species such as Pseudomonas spp., Enterobacter spp., and Escherichia coli. Results from the percentage distribution of the fungi in the spoilt onion bulbs about the markets showed the highest percentage distribution of 42.85% for the samples from Bwari market and the lowest percentage distribution of 28.57% for Dutse and Zuma respectively. It was observed that the percentage distribution of the bacteria about the markets were 42.85% for the samples from Bwari market and 21.42% from Zuma market. Pathogenicity tests for Fungi revealed that all the isolated fungi were pathogenic on onion bulbs, however; Saccaromyces cerevisiae, Aspergillus niger and Penicillium digitatum were the most pathogenic leading to the rapid disintegration of the infected bulbs within 14 days of inoculation while Rhizopus stolonifer was the least pathogenic. Pathogenicity tests for Bacteria revealed that all the isolated bacteria were pathogenic on onion bulbs with Pseudomonas spp. as the highest pathogenic and Escherichia coli the least.