Phenotypic and Pathogenic Characterization of Leaf Fungi of Yam (Dioscorea spp) Varieties Grown In Côte D’Ivoire

Yam (Dioscorea spp) occupies an important place in the diet of the populations of Côte d’Ivoire. It is a real source of starch and therefore generates enormous commercial potential. However, the decrease in production due to pest attacks represents a real threat to this crop. This study was conducted with the aim of improving yam production in Côte d’Ivoire. To do so, isolations carried out on yam leaves showing symptoms of foliar diseases have allowed us to identify 9 fungal genera. These were Colletotrichum sp., Fusarium sp., Pestalotiopsis sp., Pestalotia sp., Botryodiplodia sp., Aspergillus sp., Mucor sp., Curvularia sp. and Phytophtora sp. Among these fungi, the genus Colletotrichum sp. was the most isolated with a rate of 56% followed by the Fusarium and Pestalotia genera (8%). Pathogenicity tests performed on healthy leaves of two yam varieties revealed that the Dioscorea alata is more susceptible to fungi compared to Dioscorea rotundata. The largest average diameter of necrosis was caused by Pestalotiopsis sp. (5.97 cm) on the Dioscorea alata variety while the smallest was caused by Colletotrichum sp.9 on Dioscorea rotundata (0.5 cm). Combatting these fungi need to be developed for effective management of leaf diseases of yam in Côte d’Ivoire.