Distribution of yam anthracnose disease in Nigeria

Abstract

Yam anthracnose disease, characterized by leaf necrosis and shoot die-back, is a major constraint to the cultivation of yam, especially water yam (Dioscorea alata Linn.). Studies were conducted on the distribution of the disease in the major yam growing zones in Nigeria. Yam anthracnose disease was found to be widely distributed in 148 farmers' fields in three agroecologies. The incidence was 52.2% in the southern Guinea savanna, 51.3% in the forest/savanna transition, and 40.3% in the humid forest, with D. alata having the highest severity score followed by D. rotundata. Colletotrichum gloeosporioides (Penz) was the pathogen most commonly associated with the symptoms of anthracnose based on isolations from leaf samples collected from the farmers' fields. Fusarium spp., Rhizotonia solani (Kuhn), Botryodiplodia theobromae (Pat), and Macrophomina phaseolina (Tassi) were also isolated from the infected yam leaves.