Pathogenicity of Fungi Associated with Post-Harvest Deterioration of Two Cocoyam Varieties (C. Esculenta Var. Antiquorum and C. Esculenta Var. Esculenta) Schott in some Parts of Jos

Abstract

An investigation was carried out to test for the pathogenicity of fungi associated with the deterioration of two varieties of cocoyam corms and cormels. Fifty (50) infected corms and cormels with symptoms of post-harvest rots were purchased from six markets within Plateau Central zone and analyzed. Eleven (11) fungal isolates were implicated in the deterioration of the two varieties of the cocoyam (C. esculenta var. antiquorum and C. esculenta var. esculenta) corms and cormels and were identified as; Alternaria alternata, Fusarium oxysporum, Verticilium lateritium, Botryodiplodia theobramae, Colletotrichum coccoides, Phythium myriotylum, Fusarium verticillioides, Rhizopus stolonifer and Geotricum candidum. The result showed that all these fungi were highly virulent on the two varieties, except C. coccoides, F. verticillioides and A. alternata which did not caused rot on C. esculenta var. esculenta. Meanwhile, the fungus Rhizopus stolonifer induced the highest percentage mean area of rot (39.96%) followed by Alternaria alternata (39.36%), Phythium myriotylum (38.60%), Botryodiplodia theobromae (36.89%) while the least was Fusarium oxysporium (27.66%) in C. esculenta var. antiquorum. The study further revealed the highest rot induced on C. esculenta var. esculenta by the isolated fungi, V. lateritium (42.45%) followed by G. candidum (34.29%), F. oxysporum (27.96%) while the least was Rhizopus stolonifer (20.33%). The result also showed that C. esculenta var. esculenta was comparatively more susceptible or significant (P<0.05) to the fungus V. lateritium since it showed a greater (extensive) mean percentage area of rots of 42.45% on the corms and cormels than on C. esculenta var. antiquorum with 36.01%.