Surveys of virus diseases on pepper (Capsicum spp.) in South-west Nigeria

Surveys to determine the incidence, diversity and distribution of viruses infecting pepper (Capsicum spp.) were conducted in six states (Oyo, Ondo, Osun, Ogun, Ekiti and Lagos) of South-west Nigeria in 2010 and 2011. Leaf samples from symptomatic and asymptomatic plants were collected at random from farmers’ fields and were analyzed for viruses using antigen coated plate enzyme-linked immunosorbent assay (ACP-ELISA). Symptoms observed on infected plants included mosaic, mottling, puckering, reduction in leaf size, vein yellowing, leaf and fruit deformation and stunting. The average disease incidence was 79% in 2010 and 76% in 2011; the average disease severity score was 2.9 in both years. This study identified eight viruses in the leaf samples as follows: Potato virus Y (PVY), Potato virus X (PVX), Pepper veinal mottle virus (PVMV), Pepper mild mottle virus (PMMV), Tobacco mosaic virus (TMV), Cucumber mosaic virus (CMV), Tobacco etch virus (TEV) and Tomato mosaic virus (ToMV). Incidence of PVY was the highest (79%), followed by TEV (67%), CMV (61%), and PVMV (58%); lowest in ToMV (23%). Mixed infections were common in the farmers' fields and high incidence suggests the cultivars are highly susceptible to viral infections.Keywords: Pepper viruses, Capsicum spp., virus survey, enzyme linked immunosorbent assay (ELISA), Nigeri