L.N. Dongo, J. d’A. Hughes and G.I. Atiri
Leaves of Dioscorea spp. from the major yam growing areas in Nigeria were tested by enzyme-linked immunosorbent assay (ELISA) for known viruses infecting yams. Some samples with mosaic, mottling, leaf necrosis and distortion did not test positive for these viruses. Vigna unguiculata cvs 2657 and 84s-2114, and Glycine max cv. Malayan, were diagnostically susceptible by mechanical inoculation, to three potentially distinct 17-22 nm isometric viruses (tentatively named Dioscorea mild chlorosis mosaic (DMCV), Dioscorea mottle (DMV) and Dioscorea necrosis (DNV) viruses,). The viruses were transmitted mechanically back to Dioscorea spp. seedlings. Spur formation in agar gel double diffusion tests indicated that some of the viral antigens are related, but not identical. The viruses were found to be related to cowpea mottle carmovirus (CMeV).