SHORT COMMUNICATION OCCURRENCE OF FUNGAL PATHOGENS OF OGOJA AND PEPA WHITE YAM (Dioscorea rotundata Poir.) TUBER CULTIVARS IN ZAKIBIAM, NIGERIA

Abstract

Isolation and identification of fungi pathogens on Ogoja and Pepa white yam cultivars was carried out on rotted tubers collected from farmers’ barns at Zaki-Biam, Benue State, Nigeria. Fungi organisms isolated and identified from the rotted tubers included Botryodiplodia theobromae, Aspergillus niger, A. flavus, Fusarium oxysporum, F. moniliforme, Penicillium purpurogenum, P. expansum and Pestalotia sp. The most frequently occurring fungi from Ogoja and Pepa cultivars of the white yam tubers were B. theobromae (23.03% and 26.35%), A. flavus (15.64% and 20.02%) and A. niger (21.95% and 25.76%), respectively while the correspondingly least frequently occurring fungi were P. purpurogenum (7.54% and 1.37%), P. expansum (6.33% and 7.23%) and Pestalotia sp. (2.31% and 4.63%), respectively. Student’s t-tests on mean percentage frequency of occurrence of fungi pathogens from Ogoja and Pepa tubers after four months of isolation showed significant (P≤ 0.05) differences between the cultivars only in F. moniliforme, F. oxysporum, P. purpurogenum and Pestalotia sp. Pathogenicity tests carried out on healthy Ogoja and Pepa white yam tubers after fourteen days of inoculation with the isolates revealed that the identified fungi were both pathogenic to the two yam tuber cultivars. The results revealed that Ogoja and Pepa white yam tubers are susceptible to pathogenic attack in storage. It is therefore, suggested that adequate measures should be taken to prevent pathogenic infectivity of tubers in order to minimize postharvest losses and increase shelf life of yam in storage.