Sanitary assessment of olive varieties in a collection plot in Perugia (Umbria, Italy).

A survey was carried out to assess the sanitary status of olive trees in a collection plot in Perugia (Umbria, Italy). A total of 95 samples were tested by RT-PCR to check for the presence of the following olive-infecting viruses: Arabis mosaic (ArMV), Cherry leaf roll (CLRV), Cucumber mosaic (CMV), Olive leaf yellowing-associated (OLYaV), Olive latent ringspot (OLRSV), Olive latent -1 (OLV-1), Olive latent -2 (OLV-2), and Strawberry latent ringspot (SLRSV). About 82% of the plants were infected with at least one virus. All the tested viruses were present, with the prevalence of CMV and OLRSV (more than 30%), followed by OLYaV (21.1%) and SLRSV (19%). DsRNA and mechanical transmission assays were also applied to all PCR-negative samples. Eight out of the 17 samples tested showed different dsRNA patterns, thus suggesting that they were infected with viruses different from those previously checked by PCR. This study allowed the identification of 9 "virus-free" and 39 "virus-tested" (i.e. olive plants free from SLRSV, ArMV, CLRV, OLYaV and OLV-1, according to the Italian certification protocols) candidate clones which could potentially be used as mother plants in future Certification programmes.