The Availability and Utilization of Instructional Materials for the Teaching of Biology in Secondary Schools in Awka South Local Government Area, Anambra State.

ABSTRACTThis study focuses on the isolation and Pathogenicity of fungi that causes spoilage of cocoyam. Two species of cocoyam was used showing spoilage symptoms were examined for rot associated with fungal pathogens. The spoilage organisms were isolated from the corms by explanting the spoilt tissues obtained aseptically onto Sabouraud Dextrose Agar supplemented with chloramphenicol an antibacterial agent. The developing isolates were purified by repeated subculture and identified macroscopically and microscopically using the slide culture technique. The organisms recovered from spoilt cocoyam were Fusarium solani, Fusarium oxysporum, Rhizopus stolonifer, Rhizopus arrhizus, Rhizopus oryzae, Aspergillus niger, Aspergillus flavus, Cladosporium species, Penicillium expansum, Mucor species .The spoilage due to Rhizopus, Mucor and Aspergillus were extensive resulting in complete maceration of cocoyam tissues. The pathogenicity test also showed that the above organisms were responsible for cocoyam spoilage. These spoilage organisms may have had access into these cocoyam corms through air, wounds, working equipment (for harvesting) and pests. Proper care should be taken in the handling of these corms as some of these spoilage fungi are known to have negative impact on both humans and livestock because they produce mycotoxins. Since cocoyam is a food plant consumed by a large population, great care and precaution should be taken in its handling, planting, storage, cooking and preservation.