The occurrence of grapevine rugose wood disease in Algeria

Rugose wood disease constitutes one of the major grapevine disease complexes causing significant economic damage worldwide. It is widely distributed in all grapevine growing areas of the world and comprised of four individual syndromes, which may be caused by different viruses. These syndromes are Corky bark, LN 33 stem grooving, Kober stem grooving and Rupestris stem pitting (RSP). The present study focuses on the prevalence of three viruses associated with rugose wood complex (RWC) in Algeria. Field inspections and collection of symptomatic samples were conducted on autumn 2012 in the table wine and autochthone accession in the western and central regions of Algeria. A total of 202 samples were tested by RT-PCR using specific primers for Grapevine virus A (GVA), Grapevine virus D (GVD) and Grapevine rupestris stem pitting associated viru s (GRSPaV). The results of RT-PCR indicated the presence of the viruses GVA, GVD and GRSPaV with 68,81% (139 out of 202 infected samples) total average infection rate. The results also indicated the predominance of GRSPaV compared to the prevalence of GVA and GVD with an infection rate of 57,92% vs. 36,63% (74 out of 202) and 2,97% (6 out of 202), respectively. Mixed infections of these three viruses were not observed in any of the samples analysed, however the mixed infection of GVA and GRSPaV was noted with a high rate of 26.73%. The grapevine cultivars; Kings Rubi, Carignan and Mersguerra were the most infected, while the Alicante Bouschet cultivar presented the lowest infection rate. To the best of our knowledge, the present study reports for the first time on the presence of GVD in Algeria.