Viruses and virus diseases of grapevine in Tunisia

Mature canes were collected from vines in the main grapevine-growing areas in Tunisia (Cape Bon, Bizerte, Ben Arous), from commercial vineyards and mother-plant plots, to assess the presence of virus and virus-like diseases. Biological (mechanical transmission onto herbaceous hosts and grafting onto indicator woody plants) and serological detection (ELISA) methods were applied. ELISA showed that 96.4% of 669 vines tested were infected, most of them (88.1%) by at least two viruses. Grapevine leafroll-associated 3 closterovirus (GLRaV-3) was the most widespread virus (87.9%), followed by grapevine A vitiviras (GVA, 69.4%), grapevine fleck virus (GFkV, 51.9%), grapevine leafroll-associated 1 closterovirus (GLRaV-1, 36.8%), grapevine leafroll-associated 2 closterovirus (GLRaV-2, 19.1%), grapevine fan leaf nepovirus (GFLV, 18.2%) and grapevine B vitiviras (GVB, 14.8%). ELISA tests yielded negative results for grapevine leafroll-associated 7 closterovirus (GLRaV-7) and potato X potexvirus (PVX). The highest infections were found in Bizerte and Cape Bon regions (100 and 99.2%), and in vineyards aged over 20 years (98.5%) as compared with the younger ones (81.1%). Rootstocks in mother-plant plots were practically free from all the viruses tested (1 plant infected out of 81), whereas severe infections were found in Vitis vinifera mother plants (67.4% of 341 samples), in particular table grapes (92.6%) compared with wine grapes (47.9%). In these mother-plant plots, the prevailing viruses were GLRaV-3 (41.3%), followed by GFkV (36.7%), GVA (27.9%), GLRaV-1 (17%) and GLRaV-2 (15.2%). GFLV and GVB were far more limited (1.5 and 0.6%, respectively). The presence of vein necrosis and vein mosaic was ascertained by transmission onto 110R and Vitis riparia indicators, whereas only GFLV was mechanically transmitted onto herbaceous hosts (from about 20% of the samples).     

Viruses and virus diseases of grapevine in Lebanon

Grapevines were surveyed for the presence of virus and virus-like diseases in the main viticultural areas of Lebanon (Bekaa valley, Mount Lebanon, South and North Lebanon). Symptoms of rugose wood were observed in vines ofall cultivars and areas surveyed, whereas leafroll was observed only in some vineyards of the Bekaa valley and, to a lesser extent, in South Lebanon on cvs Tfaifihi, Cinsaut and Cardinal. Symptoms of fanleaf and of phytoplasma-induced yellows were also observed with low frequency in the Bekaa valley on wine-grape cultivars. ELISA tests showed that 53% of 1536 Vitis vinifera vines individually checked were infected by one or more viruses. Grapevine trichovirus A (GVA) was the prevailing virus (32.4%), followed by grapevine fleck virus (GFkV) (19.5%) and grapevine leafroll-associated closterovirus 3 (GLRaV-3) (12.4%). Grapevine leafroll-associated closterovirus 1 (GLRaV-l), grapevine trichovirus B (GVB) and grapevine fanleaf nepovirus (GFLV) were also detected to a lesser extent, their incidence ranging between 1.1 and 3.6%.     

Viruses and virus diseases of grapevine in Egypt

Surveys for virus and virus-like diseases were carried out in commercial vineyards of the main grapevine-growing areas of Egypt along the river Nile and in recently reclaimed desert lands. The only symptoms observed and identified with reasonable confidence in the field were those of leafroll disease in red-berried cultivars. No virus was transmitted to herbaceous hosts by mechanical inoculation from glasshouse-forced cuttings of about 300 vines (40% of total samples). By contrast, ELISA tests showed that 78% of the assayed European vines (521 out of 664) were infected by one (29%) or more (49%) viruses. Grapevine virus A (GVA) was the most widespread virus (67.9% infection), followed by Grapevine leafroll-associated virus 3 (GLRaV-3) (55.9% infection). All the other viruses tested for were scarcely represented, i.e. Grapevine leafroll-associated virus 1 (GLRaV-1) 1.8% infection, Grapevine leafroll-associated virus 2 (GLRaV-2) 1.4% infection, Grapevine virus B (GVB) (0.6% infection) and Grapevine fleck virus (GFkV) (0.2% infection), or, like Grapevine fanleaf virus (GFLV), were totally absent. The infection rate of native cultivars (86%) was particularly heavy. 'Banaty Abiad' and 'Romy Ahmer', the two major Egyptian cultivars, had infection levels of 78% and 89%, respectively, and 'Fayoumy', the most important cultivar in the Fayoum area, had 96% infection. Totally infected were the tested samples of several minor native cultivars such as 'Farg El-Tair', 'Siwi Abiad', 'Ta'afi', 'Romy Abiad', 'Eswid El-Wady', 'Edkawy' and 'Bez El-Anza'. Slightly better was the sanitary situation of imported European grapevine cultivars (60% infection) and of American rootstocks (11.5% infection). In rootstocks, infection rate by GVA and GLRaV-3 was 5.5%, whereas GVB and GLRaV-1 were only sporadically detected.     

High prevalence of viruses in table grape from Spain detected by real-time RT-PCR

Table grapes from one of the most important growing area in Spain (Vinalopó, Alicante) protected by the Designation of Origin “Vinalopó bagged table grape”, were surveyed and analysed to determine the prevalence of the five viruses included in the Spanish certification program: Arabis mosaic virus (ArMV), Grapevine fanleaf virus (GFLV), Grapevine fleck virus (GFkV), Grapevine leafroll associated virus-1 (GLRaV-1) and Grapevine leafroll associated virus-3 (GLRaV-3). Ninety five sampling points were selected and the position of grapevine plants georeferenced. Samples were collected in two different vegetative periods and analyses were performed by ELISA and real-time RT-PCR. Purified RNA and immobilized viral targets from plant extracts on nylon membranes were used in parallel assays as templates for PCR assays. In order to analyse these five viral species by real-time RT-PCR, new specific primers and TaqMan probes were designed for detection of ArMV and GFkV. Real time RT-PCR from purified RNA was more sensitive than spot version and ELISA tests. The most prevalent virus was GFLV (95.8%) followed by GLRaV-3 (94.7%), GLRaV-1 (66.3%) and GFkV (65.3%). ArMV was not detected in any sample. The high level of viral infections and the presence of mixed infections suggest that initial infected plant material and uncontrolled traffic of propagation material have played an important role in the spread of viruses.     

Viruses and virus diseases of grapevine in Palestine

Surveys were carried out in vineyards in the main grapevine-growing areas of Palestine (Hebron, Bethlehem, Gaza, Jerusalem, Ramallah, Jenin, Jericho and Nablus) to assess the presence and incidence of virus and virus-like diseases. Leafroll symptoms were observed in Bethlehem, Ramallah and Jerusalem in native and imported cultivars, with higher rates in the red-fruited Shami, Beitoni and Smari. Rugose-wood symptoms were also observed in local and foreign cultivars, especially on grafted vines with a high incidence in Bethlehem. Fanleaf symptoms were rarely observed, while phytoplasma-induced symptoms were observed in Jenin, Jericho and Bethlehem on cvs Biadi, Superior Seedless and Beitoni. ELISA tests showed that 463 out of 566 (82%) tested vines were infected by at least one virus. GVA was the prevailing virus (66.1%), followed by GLRaV-1 (45.6%), GLRaV-3 (21.7%), GFkV (15.7%) and GLRaV-2 (8.3%). GVB and GFLV were also detected to a lesser extent, their incidence ranging between 3.7 and 1.2%, whereas GLRaV-7 was detected in a single vine of cv. Sultanina of foreign origin. Vineyards in the Bethlehem area were particularly badly damaged (97.5%), and some local cultivars were totally (Jandali, Marrawi and Shoyoukhi) or heavily infected (Zaini, Biadi and Shami). ELISA testing of 69 young rootstock mother plants showed a relatively high incidence of virus infection (20.3%). Vein necrosis and vein mosaic diseases were also ascertained on graft-inoculated 110R and Vitis riparia indicator plants, whereas no viruses other than GFLV were mechanically transmitted from about 200 vines onto inoculated herbaceous hosts.     

Sanitary status of grapevines in south-eastern and central Anatolia (Turkey)

Surveys were carried out in commercial vineyards in the main grapevine-growing areas of south-eastern (Adiyaman, Diyarbakir, Merdin, Sanliurfa, Elazig) and central (Nevşehir) Anatolia (Turkey) to assess the presence and incidence of virus and virus-like diseases. Typical fanleaf symptoms were observed in most of the surveyed areas, but they were particularly frequent in Elazig in cvs Kirmizi, Agin, Sirfoni and Kohnu. Leafroll symptoms were present in most vineyards in Adiyaman, Sanliurfa and Elazig, primarily in the red-fruited cvs Antep Karasi, Humusi, Kohnu and Siyah Kabarcik, and in Nevşheir. Rugose wood symptoms were common in Adiyaman, where vineyards were established with grafted planting material, but not in any of the self-rooted Cappadocian cultivars. Phytoplasma-like symptoms were sometimes observed in Elazig and Nevşheir. Biological (sap inoculation to herbaceous plants and graft transmission to woody indicators) and serological (ELISA) assays were used for virus detection and identification. A total of 55.3% of ELISA-tested vines (296 out of 535) were infected by one (11.4%) or more (43.9%) viruses. GVA ¹ was the most widespread virus (42.4%), followed by GLRaV-1 (38.5%), GFLV (10.7%) and GFkV (7.1%). Surprisingly low (2.4%) was the infection rate by GLRaV-3, and even lower (<1%) that of the other viruses tested, i.e. GLRaV-2, GLRaV-6, GVB and ArMV. GLRaV-7 was not detected. The occurrence of vein mosaic and vein necrosis was ascertained by testing on woody indicators. A putative nepovirus was isolated from a single vine of cv. Kizlar Tahtasi, the identification and characterization of which is still under way.     

Crude garlic extract significantly inhibits replication of grapevine viruses

Efforts to control viral diseases of grapevine include the production of certified material and development of virus-resistant transgenic grapevines. However, effective antiviral agents, once the viruses have infected the plants, are still lacking. This study shows that a crude garlic extract has significant antiviral activity against grapevine viruses. Replication of grapevine leafroll-associated virus 2 (GLRaV-2) was obviously inhibited in grapevine cv. Cabernet Sauvignon calli treated with diluted (1:100) garlic extract. The relative RNA levels of GLRaV-2 and grapevine fleck virus (GFkV) in cv. Summer Black grapevine in in vitro-grown plantlets 10 days after treatment with diluted (1:100) garlic extract were about 22% and 20%, respectively, of that in controls. The viral RNA accumulation of GLRaV-2, GFkV, grapevine virus A (GVA), grapevine fanleaf virus (GFLV) and grapevine rupestris stem pitting-associated virus (GRSPaV) in field-grown grapevine cv. Centennial Seedless plants sprayed with diluted (1:100) garlic extract were about 31–40%, 26–38%, 18–31%, 17–42% and 15–18%, respectively, of that in controls. Moreover, the garlic extract treatment led to a significant decrease in viral RNA accumulation of GLRaV-3, GLRaV-2, GVA, GFkV, GFLV, GRSPaV and grapevine Pinot Gris virus in pot-grown grapevine cv. Shine Muscat plants, and viral disease symptoms in these plants were obviously attenuated. In addition, this extract significantly induced expression of pathogenesis-related protein genes and stimulated activity of antioxidant enzymes in grapevines. Taken together, these results indicate that the crude garlic extract acts as a significant inhibitor against a broad range of grapevine viruses.     

<Emphasis Type="Italic">In situ</Emphasis> localization of <Emphasis Type="Italic">Grapevine fanleaf virus</Emphasis> and phloem-restricted viruses in embryogenic callus of <Emphasis Type="Italic">Vitis vinifera</Emphasis>

In grapevine, somatic embryogenesis is particularly effective in eliminating several important virus diseases. However, the mechanism whereby regenerated somatic embryos are freed of the viruses is not clear. The distribution of Grapevine fanleaf virus (GFLV), Grapevine leafroll-associated virus-3 (GLRaV-3) and Grapevine virus A (GVA) in embryogenic callus of grapevine was investigated by in situ hybridization using digoxygenin-labelled oligonucleotide probes. Four months after culture initiation, in callus originated by GFLV-infected explants we observed a mosaic of infected and uninfected cells, with high concentrations of viruses in some cell groups in peripheral zones of the callus. In addition some abnormal somatic embryos showed a high hybridization signal. In callus originated by GVA- and GLRaV-3-infected explants the viruses were concentrated in few cells surrounded by areas of virus-free cells. The two viruses were generally localized in different clusters of cells inside the callus and the levels of infection were lower than those observed in GFLV-infected callus. No virus was detected in callus nor in somatic embryos after 6 months of culture. The results highlight the difficulties of some viruses at stably invading callus tissues and the differential ability of GFLV to spread in the callus cells compared to the phloem-limited viruses.     

Grapevine leafroll-associated viruses and grapevine virus A in selected Vitis vinifera cultivars in northern Italy

The occurrence of grapevine leafroll-associated virus 1 (GLRaV-1), grapevine leafroll-associated virus 3 (GLRaV-3) and grapevine virus A (GVA) was demonstrated in a viticultural region of northern Italy (Emilia-Romagna) using immunoelectron microscopy. Virus incidence was subsequently assessed using ELISA. A total of 60.6% of the 150 clone selections tested, from 18 local Vitis vinifera cultivars, were found to be infected. ELISA did not reveal the presence of grapevine leafroll-associated virus 2 (GLRaV-2) or grapevine leafroll-associated virus 5 (GLRaV-5). GLRaV-1, GLRaV-3 and GVA were found individually and in various combinations. The most common findings were GLRaV-1 alone (25.3%) and associated with GVA (33%). Serological data confirmed that the majority (91%) of the clones known to be affected by grapevine leafroll (GLR), on its own or in association with rugose wood (RW), contained viruses. On the other hand, where the RW phenomenon was present on its own, only 40% of these clones were ELISA-positive. The implications for the biology of GLR and RW are discussed and the complex aetiology of these grapevine diseases is confirmed.     

Transmission of six ampeloviruses and two vitiviruses to grapevine by Phenacoccus aceris

Grapevine leafroll disease is caused by grapevine leafroll-associated viruses (GLRaVs). These viruses are common in vineyards worldwide and often associated with vitiviruses that are involved in the rugose wood complex of grapevine. Ten mealybug species are known as vectors of one or several of these grapevine viruses, including the apple mealybug Phenacoccus aceris which is widespread in Holarctic regions and able to transmit Grapevine leafroll-associated virus-1 and -3 (GLRaV-1 and -3). Our aim was to characterize the transmission features of leafroll viruses by Phenacoccus aceris in order to better understand the contribution of this mealybug to leafroll epidemics. Results showed that Phenacoccus aceris is able to transmit GLRaV-1, -3, -4, -5, -6, and -9 to grapevine but not GLRaV-7. This is the first report of GLRaV-6 transmission by a mealybug. Also, for the first time it was shown that Phenacoccus aceris could vector vitiviruses Grapevine virus A (GVA) and Grapevine virus B (GVB). First instar nymphs were the most efficient stage in transmitting GLRaV-1, -3, and GVA. This research sheds light on the transmission biology of grapevine viruses by Phenacoccus aceris and represents a step forward to leafroll disease management.     

Synergy between grapevine vitiviruses and grapevine leafroll viruses

An interactive relationship between vitiviruses and grapevine leafroll viruses was characterized in grapevine. Grapevine viruses A and B (GVA and GVB) were found more frequently in the presence of co-infecting Grapevine leafroll associated viruses (GLRaV-1, ?2 or ?3) than in their absence. The titers of the vitiviruses in co-infection with leafroll viruses were found to be higher than were their titers in the absence of leafroll virus infection. The occurrence of vitivirus-associated stem-pitting symptoms was correlated with leafroll virus co-infection. Specific pairing associations on the species level were found between different viti- and leafroll virus species: GVB was associated preferentially with GLRaV-2; GVA was associated preferentially with GLRaV-1 and GLRaV-3. In contrast to the increase in vitivirus titer seen with leafroll virus co-infection, the incidence and titer of grapevine leafroll virus appeared to be unaltered by vitivirus co-infection. The potential for a synergistic enhancement of grapevine disease in co-infected vines is discussed.     

新疆三种葡萄病毒RT-PCR检测及序列分析

为研究新疆葡萄中沙地葡萄茎痘伴随病毒(Grapevine rupestris stem pitting associated virus,GRSPa V)、葡萄斑点病毒(Grapevine fleck virus,GFk V)及葡萄病毒A(Grapevine virus A,GVA)的发生情况和新疆分离株系统进化关系,分别克隆3种病毒新疆分离株部分基因区域,应用RT-PCR对新疆64份葡萄样品中上述3种病毒进行检测,并进行系统进化分析。结果显示,GRSPa V、GFk V和GVA的检出率分别为31.3%、62.5%和25.0%。新疆GRSPa V分离株(KJ801847)与美国GRSPa V分离株(AY368590)同源性达96.59%;新疆GFk V分离株(KJ801846)与日本GFk V分离株(AB222861)及中国辽宁GFk V分离株(JF927942)的同源性分别为91.70%和91.03%;新疆GVA分离株(KJ801845)与波兰GVA分离株(JN860997)同源性为93.88%,与中国四川GVA分离株(HQ671655)及辽宁GVA分离株(FJ445220)的同源性分别为92.92%和89.53%。表明3种葡萄病毒在新疆发生比较普遍,且新疆分离株与国内其它地方的分离株存在较大差异。     

Spatio-temporal association of GLRaV-3-infected grapevines,and effect of insecticidal treatments on mealybug populations in Virginia vineyards

Grapevine leafroll disease (GLD) is caused by a number of viruses in the grapevine leafroll-associated virus complex (GLRaVs). GLRaV-3 is the most commonly found GLRaV and is transmitted by mealybugs (Hemiptera: Pseudococcidae) and soft scale insects (Hemiptera: Coccidae). A series of investigations were conducted to understand spatio-temporal patterns of GLRaV-3 and mealybugs, and to examine management strategies of mealybugs under the environmental conditions of Virginia, USA. During the study, a rapid increase (185 % per year) of GLRaV-3 positive vines was observed at an experimental vineyard. Spatial Analysis by Distance IndicEs (SADIE) indicated a mix of aggregated, random, and uniform distributions of GLRaV-3 within six surveyed vineyards, and a temporal association of GLRaV-3-positive vines over three years at the experimental vineyard. Results from a field experiment in 2009–2011 showed the effect of a delayed dormant application of acetamiprid (Assail, 0.182 L/ha) to be not significantly differing in mealybug abundance from the unsprayed check in 2010 and 2011. Moreover, an application of the contact insecticide beta-cyfluthrin (Baythroid XL, 0.219 L/ha) resulted in significantly higher numbers of mealybugs counted in 2011. This study also demonstrated that GLRaV-3 was spread from mature vines to newly planted sentinel vines during the first growing season, with no apparent effect of prevailing wind direction. Results from another insecticide trial conducted in 2010–2011 demonstrated that both dinotefuran (Scorpion, 0.292 L/ha) and spirotetramat (Movento, 0.439 L/ha) treatments significantly reduced mealybug counts when mealybug populations were high, but only spirotetramat significantly reduced mealybug counts when mealybug populations were low.     

Grapevine virus A in Rheinland-Pfalz: Vorkommen und Bedeutung für den deutschen Weinbau

Grapevine virus A (GVA) is associated with Kober stem grooving disease which belongs to the Rugose wood complex. The virus is frequently found in grapevine affected by leafroll but is not strictly associated with this disease. Probably the virus has a worldwide distribution – but very little information is available about the occurrence of GVA in Rhineland-Palatinate. The detection of GVA was conducted with indexing procedures using Kober 5BB as indicator and serological methods (ELISA). Indexing trials with infected material did not show any symptoms of Kober stem grooving two years after wooden grafting and five years after green grafting. The most suitable tissue to detect GVA serologically was petioles from mature leaves or cortical scrapings from dormant canes. In all experiments the tests with petioles resulted in much higher extinction values compared to the blades. About 46.9% of the 209 samples tested had an infection of GVA, 87.8% in mixed infections together with GLRaV-1 and 5.1% together with GLRaV-3. Only 7.1% of the tested plants were exclusively infected by GVA, none of the other ampelo- and closteroviruses could be detected. None of the GVA positively tested plants showed any symptoms of Rugose wood. The results indicated that the importance of a GVA infection on vines in Germany seems to be extremely low.     

<Emphasis Type="Italic">Grapevine virus A</Emphasis> transmission by larvae of <Emphasis Type="Italic">Parthenolecanium corni</Emphasis>

Grapevine virus A (GVA, Vitivirus) was transmitted experimentally by first and second instars of the scale insect Parthenolecanium corni from grapevine to grapevine and to the herbaceous host Nicotiana benthamiana. This is the first report of GVA transmission by P. corni. Grapevine leafroll-associated virus-1 (Ampelovirus) was always present in the donor grapevines and, in every case, GVA was transmitted simultaneously with this ampelovirus from grapevine to grapevine, suggesting possible interactions between the two viruses for transmission.     

Partial Genome Organization, Identification of the Coat Protein Gene, and Detection of Grapevine leafroll-associated virus-5

ABSTRACT The genome of Grapevine leafroll-associated virus-5 (GLRaV-5) was cloned, and the sequence of 4766 nt was determined. Degenerate oligonucleotide primers designed from the conserved closterovirus heat shock 70 protein (HSP 70) homologue were used to obtain viral-specific sequences to anchor the cloning of the viral RNA with a genomic walking approach. The partial nucleotide (nt) sequence of GLRaV-5 showed the presence of four open reading frames (ORF A through D), potentially coding for the HSP 70 homologue (ORF A); a 51-kDa protein of unknown function with similarity to GLRaV-3 p55 (ORF B); the viral capsid protein (ORF C); and a diverged viral duplicate capsid protein (ORF D). The ORF C was identified as GLRaV-5 viral capsid protein based on sequence analyses and the reactivity of the recombinant protein to GLRaV-5 specific antibodies by western blot analyses. The antiserum produced with the in vitro-expressed GLRaV-5 ORF C protein product specifically reacted with a 36-kDa polypeptide from GLRaV-5 infected vines but did not react with protein extracts from vines infected with other GLRaVs or uninfected vines. Furthermore, specific primers were designed for the sensitive detection of GLRaV-1 and GLRaV-5 by polymerase chain reaction.     

New Mealybug Species Vectoring Grapevine Leafroll-Associated Viruses-1 and -3 (GLRaV-1 and -3)

Many grape viruses, such as filamentous Grapevine leafroll-associated viruses in the Closteroviridae family, are spread primarily through infected propagating material. However, there is increasing evidence that leafroll disease are spread in the field by insect vectors, namely mealybugs and other scale insects. This study was carried out in the northern wine-growing regions of France where Grapevine leafroll-associated virus-1 and -3 (GLRaV-1 and -3) are the most widespread grape Ampelovirus species. The vineyards were inspected for presence of mealybug and scale insects and grapes infected by GLRaV-1 and -3. Mealybugs, Heliococcus bohemicus, Phenacoccus aceris (Pseudococcidae) and the soft scale insect Parthenolecanium corni (Coccidae), were capable of a transmission efficiency of 14%, 23% and 29% respectively. GLRaV-1 and -3 infections that resulted from virus transmission were confirmed with DAS-ELISA using polyclonal antibodies. This is the first report of GLRaV-1 and -3 transmission by mealybug and coccid species in France, and the first report of the ability of H. bohemicus and Phenacoccus aceris to transmit these viruses to grapevines. The relevance of these findings with regards to maintenance of virus-free grapevine stocks and to control leafroll spread in commercial vineyards is discussed.     

Phytosanitary status of grapevine in Montenegro

During 2006 and 2007, a survey on the incidence and distribution of fourteen grapevine viruses was carried out in the Skadar Lake basin, one of the two main grapevine‐growing areas of Montenegro. In total 165 samples were collected from four red (‘Vranac’, ‘Krato?ija’, ‘Merlot’ and ‘Cardinal’), two white (‘Chardonnay’ and ‘Rkaciteli’) and a few unknown grapevine varieties in the vicinity of Podgorica and Bar. The phytosanitary status of the collected samples was analysed by DAS‐ELISA and the presence of Grapevine fanleaf virus (GFLV), Grapevine leafroll‐associated virus 1 (GLRaV‐1), Grapevine leafroll‐associated virus 2 (GLRaV‐2) and Grapevine leafroll‐associated virus 3 (GLRaV‐3) was confirmed in some of them. The most frequently found virus in assayed samples was GLRaV‐3 (54.5%), followed by GFLV (23%), GLRaV‐1 (20%) and GLRaV‐2 (0.6%). These serological analyses showed the absence of Grapevine leafroll‐associated virus 6 (GLRaV‐6), Grapevine leafroll‐associated virus 7 (GLRaV‐7), Raspberry bushy dwarf virus (RBDV), Strawberry latent ringspot virus (SLRSV), Tomato ringspot virus (ToRSV), Raspberry ringspot virus (RpRSV), Arabis mosaic virus (ArMV), Tobacco ringspot virus (TRSV), Tomato black ring virus (TBRV) and Cherry leaf roll virus (CLRV) from all tested samples.     

Viruses of grapevine in Albania

Grapevines were surveyed for the presence of virus and virus-like diseases in the Albanian viticultural districts of Shkoder, Lesh, Kruje, Durres, Tirana, Elbasan, Lushnje and Vlora. Symptoms of grapevine degeneration, leafroll and rugose wood were observed in all areas surveyed, whereas fleck was found in volunteer plants of Vitis rupestris at Elbasan, and enation disease in a few vines near Durres. Viruses identified were grapevine fanleaf nepovirus, grapevine fleck virus, grapevine virus A, and grapevine leafroll-associated closteroviruses I and III. ELISA tests showed that 83.5% of 530 Vitis vinifera vines and 46% of 24 American rootstocks individually checked were infected by one or more viruses. The presence of Xiphinema index , the major vector of grapevine fanleaf nepovirus, was recorded from vineyards affected by yellow mosaic.