Association of virus-like particles with internal brown spot of yam (Dioscorea alata)
AbstractTubers of yam (Dioscorea alata cv. 'White Lisbon '), affected by internal brown spot, produced foliage with mosaic symptoms whereas normal-looking tubers produced leaves that were more uniformly green. Almost all the normal-looking and mosaic-affected plants that were tested contained slightly flexuous virus-like particle of about 750 x 13 nm. Mosaic-affected plants, in addition, contained bacilliform virus-like particles of 130 x 29 nm. Infection with this bacilliform virus thus seems to be a prerequisite for the development of internal brown spot.