Isolation and Identification of Fungi Associated with the Spoilage of Cocoyam Corms

Abstract

Cocoyam (Colocasia esculenta) is an important tropical root crop grown purposely for its starchy corms. This study was carried out to isolate and identify fungi associated with the spoilage of cocoyam corms. These organisms were isolated from spoilt corms by direct inoculation of the rotten tissues on Sabouraud Dextrose Agar. The fungal isolates were identified using cultural and morphological features such as colony appearance and also through microscopic characteristics. The isolated organisms include Rhizopus stolonifera, Rhizopus arrhizus, Fusarium oxysporum, and Aspergillus niger. Out of the 70 samples that were analyzed, 45 (64%) had Rhizopus stolonifera, 36 (51%) had Fusarium oxysporum, 52 (74%) had Rhizopus arrhizus while 61 (87%) had Aspergillus niger. A pathogenicity test was carried out on healthy corms using isolated microorganisms. The result showed that the organisms were responsible for the deterioration of the corms. These organisms may have infected these corms through contaminated working tools during harvest or improper storage by farmers. Corms are always infected by molds if not properly handled or stored. Hence, proper care should be taken while harvesting, handling, or storing these corms to avoid being infected by these pathogenic organisms since they can be detrimental to human health. It can also cause huge economic losses to farmers.