In 2017–2018, grapevines of cultivar ‘Vermentino’ infected with grapevine Pinot gris virus (GPGV) in Sardinia, Italy, exhibited leaf symptoms of mosaic, chlorotic mottling, and curling, and stunted shoots. Disease incidence assessed in 2018 was greater (67%, 103 symptomatic plants out of 153 monitored) than in 2017 (26%, 40 of 153 plants). All symptomatic samples tested by RT-PCR were positive for GPGV in both years, while 70% (53 of 76) of the asymptomatic samples in 2017, and 42% (19 of 45) in 2018, were also positive for GPGV. Characterizing six GPGV isolates from ‘Vermentino’ by RT-PCR and sequencing of a genomic fragment covering the movement and coat protein genes showed high conservation at the nucleotide level (98.7% to 100.0%) among Sardinian isolates and isolates for which sequence information is available in GenBank. Phylogenetic analysis indicated that most Sardinian GPGV isolates grouped with other European isolates. This is the first characterization of GPGV in a Sardinian vineyard.

Grapevine virus G (GVG) and grapevine virus H (GVH) (genus Vitivirus) are recently discovered viruses. Analysis of 38 samples from Sardinian grapevine cultivars for the presence of GVG and GVH was carried out using RT-PCR. All samples were also tested for grapevine Pinot gris virus (GPGV) using RT-PCR, and for grapevine leafroll virus -1, -2 and -3, grapevine virus A (GVA) and B (GVB), arabis mosaic virus (ArMV), grapevine fanleaf virus (GFLV) and grapevine fleck virus (GFkV) using multiplex RT-PCR. GVG was confirmed in four vines, and GVH was detected in only one sample. In phylogenetic analyses of the coat protein (CP) region, the Sardinian GVG isolates clustered separately from isolates from Croatia and New Zealand. The Sardinian GVH isolate clustered with most sequences from other countries, but with greater affinity to isolates from California (USA) for the CP region, whereas it clustered with isolates from Croatia in the RNA-dependent RNA polymerase (RdRp) region. In addition to GVG and GVH, many samples were coinfected with GVA, viruses from the leafroll complex, and GPGV. This is the first record of GVG and GVH occurring in Italy.

Fusarium culmorum is the most commonly reported root rot pathogen in Tunisian durum wheat. Isolates of the pathogen from four durum wheat growing areas in the north of Tunisia were analyzed for their chemotypes. Two chemotypes were detected at unequal abundance (96% of 3-ADON and 4% of NIV). Distribution of a SNP mutation located at the position 34 bp after the first exon of the EF-1α partial sequence was analysed, to verify whether the haplotype was specifically associated to Fusarium root rot. A and T haplotypes were homogeneously distributed in three different Tunisian regions (Mateur, Beja and Bousalem) but not for the region of Bizerte, from which greatest number of A haplotype strains were detected. The isolates were tested for their virulence under glasshouse conditions, and a mean of 91% of crown and root infection was observed. Chemotype influenced virulence, but there was no significant influence of the geographical origin or haplotype on virulence. The distribution of three inter simple sequence repeats (ISSR) was examined, to better understand the structure of F. culmorum populations in Tunisia. A total of 27 fragments were obtained with eight polymorphic bands. Cluster analysis showed a high level of similarity between isolates. Analysis of molecular variance confirmed that there was little genetic differentiation among F. culmorum strains from different locations.

Grapevine leaf stripe disease (GLSD) symptom expression was analysed in four vineyards and four cultivars, in Sardinia (Italy), taking into account ten-year annual and five-year monthly surveys. The cumulative incidence of symptomatic plants reached high values on Sauvignon blanc, Cabernet sauvignon and Cannonau (81.9, 79.4 and 66.5% respectively), but low on Merlot (25.1%). Symptoms appeared during or before the 50% flowering stage and maximum increments were assessed in June and partially in July. Annual incidence of foliar symptoms fluctuated in the ten years of the survey. Positive regressions were found between incidence of vines that exhibited foliar symptoms in year n but were symptomless in year n-1 and rain parameters in the 30 days after stabilization of mean temperature around 10°C, when colonization of pruning wounds begins. This relationship could suggest the involvement of new infections or re-infections on symptom expression in the following growth season. Significant regressions between incidence of vines that exhibited foliar symptoms in year n but were symptomless in the year n+1 and climatic parameters were also recorded. High temperatures and low rainfall in the period from pre-flowering to veraison were conducive to a higher number of asymptomatic plants. Regarding monthly foliar symptoms evolution, an increase in temperature from 50% sprouting until June led to a greater number of new symptomatic plants. On the other hand, a smaller percentage of new symptomatic plants was associated with an increase in temperature from June to July, which may have influenced vine water balance and transport of toxins by the sap flow.

Studies were carried out in north Sardinia (Italy) in Chardonnay and Vermentino grapevines infected with "bois noir" to verify productive performance of the yields of plants healthy, infected and in recovery for one or two years. Statistical significant differences were observed in the yield among the symptomatic and the healthy plants, and among the healthy plants and those in recovery for one year, but not always between healthy plants and those in recovery for two years. Not statistically significant was the comparison between the two recovered groups. Productive increase was progressive in plants recovered for one year and in those in symptomatic remission for two years.

Myrtus communis is a bushy species of the Mediterranean area that produce very popular liquor: Red mirto and White mirto. Preliminary studies in North Sardinia, resulted in the observation of a severe symptomatology associated with phytoplasma presence. These studies continued, and recently a total of 33 symptomatic plants belonging to different cultivars in two plantations were mapped and repeatedly tested using molecular methods. Phytoplasmas belonging to the 16SrI, 16SrII-F, 16SrIII, 16SrV-A, 16SrX-A, and 16SrXII-A subgroups were identified. Molecular assays on potential insect vectors showed that 16SrX-A+16SrI-B, 16SrXII-A and 16SrIII subgroups were present.