Importance of Fungal Root Rot Pathogens of Cassava in Benin

Cassava root rots are important diseases in different agroecological zones of West Africa. The causing pathogens were collected from 101 farmers’ fields in forest mosaic savanna, southern guinea savanna, northern guinea savanna and sudan savanna of Benin were isolated, identified and analyzed for their virulence. A total of 51 isolates were found showing different disease reaction with 13.7% highly virulent, 17.6%, virulent and 13.7% moderately virulent. The potential root rot pathogens found in the agroecological zones of Benin were Botryodiplodia theobromae accounting for 66.7% (most frequently in the southern guinea savanna and the forest mosaic savanna), Fusarium solani for 11.7%, Fusarium oxysporum for 9.1%, Nattrasia mangiferae for 3.9%, Fusarium semitectum for 1.9% and Sclerotium rolfsii for 1.9%. Nattrasia mangiferae was found only in the sudan savanna at the frequency of 3.9%. Trichoderma and Rhizopus species were also found during our investigations but theirs effects were non virulent on cassava root.