Viruses infecting sweet potato in Rwanda: Occurrence and distribution

A survey of sweet potato virus diseases was conducted in the major sweet potato production areas in low, medium and high altitude zones of Rwanda. A total of 205 symptomatic and 103 asymptomatic samples were collected from 51 sweet potato fields and assayed for Sweet potato feathery mottle virus (SPFMV), Sweet potato chlorotic stunt virus (SPCSV), Sweet potato mild mottle virus (SPMMV), Sweet potato chlorotic fleck virus (SPCFV), Sweet potato latent virus (SwPLV), Sweet potato caulimo-like virus (SPCaLV) and Cucumber mosaic virus (CMV) using nitrocellulose membrane enzyme-linked immunosorbent assay. The viruses detected in the samples were SPFMV, SPMMV, SPCSV, SPCFV and SwPLV. Viruses were detected in 83% and 31% of the symptomatic and asymptomatic samples, respectively. SPFMV was detected in 49% of the samples. SPCSV, the second most common virus, was detected in 28% of samples collected from 73% of the fields. About 19% of the samples were tested positive for SPMMV. Thirteen combinations of multiple virus infections were detected in the samples. Viruses were detected in samples from all the fields surveyed, and the frequency of detection was greatest in samples from low altitude zones. © 2008 The Authors.