On the presence and distribution of olive viruses in Lebanon

Abstract

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.

Detection of Olive-infecting Viruses in Tunisia

“…(2004), with a mean infection rate of 49.1% (Table 2), a value slightly higher than that previously reported from other Mediterranean countries, i.e., Lebanon (23.6%) and Syria (14.5%) (Al Abdullah et al. 2005; Fadel et al. 2005).…”

Phytosanitary Certification

“…OLV-2 was isolated by mechanical inoculation from symptomless olive trees in Apulia, Southern Italy (Savino et al, 1984). It has subsequently been identified in Lebanon (Fadel et al, 2005), Syria (Alabdullah et al, 2005), Croatia (Bjelis et al, 2007) and Tunisia (Martelli, 2011) from symptomless olive cultivars. The host range of OLV-2 was limited to olive trees until castor beans (Ricinus communis L.), showing yellowish vein netting and systemic mottling on leaves, were reported in Greece to be infected with this virus (Grieco et al, 2002).…”

“…The OLY syndrome, consisting of poor fruit set, bright yellow discoloration of the foliage, mottling, necrosis, extensive defoliation and dieback, has been associated to other viruses such as Olive vein yellowing associated virus (OVYaV) (Faggioli & Barba, 1995) and Olive yellow mottle and decline associated virus (OYMDaV) , but their presence on olive trees was very rare. On the other hand, OLYaV seems to be one of the most widespread olive viruses: in Italy it infects more than 60% of southern Italy olive cultivars (Faggioli et al, 2005) and it has also been reported in high percentages in Israel (Martelli, 2011), Egypt, USA (Saponari & Savino, 2003), Lebanon (Fadel et al, 2005), Spain (Martelli, 2011), Syria (Alabdullah et al, 2005), Albania (Luigi et al, 2009), Croatia (Bjelis et al, 2007, Tunisia (Martelli, 2011) and California (Al Rwahnih et al, 2011). A study on the rooting and grafting capacity of OLYaV-infected 'Carolea' and its respective healthy controls showed that the virus does not influence the rate of rooting of the cuttings and does not interfere with the grafting success rate; positive significant effects in grafting ability were observed on infected material only during a temperature stress, probably due to the reduced water need of infected shoots (Roschetti et al, 2009).…”

“…The virus was isolated for the first time from olive in cv. 'Corregiolo' in Italy (Savino et al, 1979) and later in Portugal (Henriques et al, 1992), Spain (Bertolini et al, 1998), Egypt, USA (Saponari & Savino, 2003), Turkey (Çağlayan et al, 2004), Lebanon (Fadel et al, 2005), Syria (Alabdullah et al, 2005), Croatia (Bjelis et al, 2007), Tunisia (Martelli, 2011) and Albania (Luigi et al, 2009). Small, pearshaped, puckered fruits with deformed kernels (bumpy fruits), narrow and twisted leaves, bushy growth and reduced crop were described in olive trees of cv.…”

“…Jordan (Martelli et al, 1995), Portugal (Felix & Clara, 2002), Egypt, USA (Saponari & Savino, 2003), Lebanon (Fadel et al, 2005), Syria (Alabdullah et al, 2005), Tunisia (Martelli, 2011) and Turkey (Serce et al, 2007). Several OLV-1 isolates have been obtained from symptomless or weakened trees.…”