Field surveys of 80 commercial groves were made in autumn 2003 in six major Syrian olive‐growing regions. A total of 300 olive samples, representative of the main cultivars grown in the country, were collected. As ascertained by dsRNA analysis, 54 out of 125 samples (about 43%) showed visible bands in polyacrylamide gel electrophoresis. All samples were tested by RT‐PCR for the presence of the following viruses: Arabis mosaic virus (ArMV), Cherry leaf roll virus (CLRV), Cucumber mosaic virus (CMV), Olive latent ringspot virus (OLRSV), Olive latent virus 1 (OLV‐1), Olive latent virus 2 (OLV‐2), Olive leaf yellowing‐associated virus (OLYaV) and Strawberry latent ringspot virus (SLRSV). All these viruses, singly or in mixed infection, were detected in about 51% of the samples. CMV was the most prevalent (22.7%), followed by CLRV (15%), OLYaV (14.3%) and OLRSV (11.5%). Less represented were the remaining four viruses. Infection rates ranged from 44% in Dara’a region to 67% in Latakia and Hama.

A survey for viruses was carried out in 2003 in the main olive‐growing areas of Lebanon (South Lebanon, North Lebanon, Mount Lebanon and Bekaa). A total of 300 samples was collected in 31 different locations in 76 different commercial orchards and checked by RT‐PCR for the presence of Arabis mosaic virus (ArMV), Cherry leaf roll virus (CLRV), Strawberry latent ringspot virus (SLRV), Olive latent virus 1 (OLV‐1) and Olive leaf yellowing‐associated virus (OLYaV), using virus‐specific primers reported in the literature. About one third (31%) of the trees were infected. In particular, the closterovirus OLYaV was the most widespread, as it was detected in 23.7% of the samples, followed by the necrovirus OLV‐1 (8.3%), the two nepoviruses CLRV (2%) and ArMV (0.3%), and the sadwavirus SLRV (0.3%). A high variability was detected in the HSP70 gene of Lebanese and Italian OLYaV isolates, for at least nine different patterns were obtained when this genomic region was subjected to single‐strand conformation polymorphism (SSCP) analysis.

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