Abstract

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The bacteria species associated with post-harvest rot of Colocasia esculenta Lin (Cocoyam) tubers sold in Bukuru market of Plateau State were investigated. Fifty (50) Samples of C. esculenta were obtained randomly from 3 different Markets within Bukuru and brought for analysis. The tubers were surface disinfect with Sodium Hypo chloride (NaOCl) for 5 minutes. A portion of the rotten sample and the surface tissue were sliced into thin sections and inoculated on Nutrient agar and incubated for 24 hours at 37 °C followed by Subculture for another 24 hours to obtain pure cultures. Pure cultures were examined using microscopic examination and biochemical test to identify the bacteria species while a pathogenicity test was carried out using healthy C. esculenta corms and cormels. The study identifies nine different bacteria species associated with post-harvest rot of cocoyam. They include with Pseudomonas aeruginosa (16.7 %) Corynebacterium spp (4.2 %) Enterobacter cloacae (4.2 %), Staphylococcus aureus (8.3%) Escherichia coli (20.8%), Bacillus subtilis (12.5 %), Shigella spp (4.2 %) Salmonella spp (12.5 %) and Bacillus pumillus (12.5 %). The percentage frequency of the identified bacteria species shows that Escherichia coli had the highest frequency of occurrence to be 20.8 % while Corynebacterium spp, Shigella spp Enterobacter cloacae had the least percentage of occurrence to be 4.2 % each. The pathogenicity test confirmed that the organisms isolated were the actual causal agents of rots in cocoyam sold in Bukuru market. Efforts should be made to put preventive and control measures, which includes proper handling of tubers during harvest, Post harvest, transportation and storage to reduce loss of the crop.

Keywords: Bacteria, Post-harvest, Rot, Cocoyam