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.

Epidemiological research was carried out in two vineyards affected by "Bois noir" (BN). Auchenorrhyncha potential vectors of BN, were monitored periodically between May to November 2004 in a vineyard and between May to June 2005 in the other. Auchenorrhyncha samples were tested to assess phytoplasmas presence using PCR and RFLP. Euscelis ttneolatus was positive to 16SrI-C ("Clover phyllody" reference strain) in 2004 while, in 2005, at the preimaginal age, at the 16SrXII -A ("Stolbur" reference strain) phytoplasmas. Exitianus taeniaticeps acquired 16SrI-B ("Maryland aster yellow" reference strain), 16SrV-A ("Elm yellow" reference strain) and 16SrX-C ("Pear decline" reference strain) phytoplasmas in 2004. Resulted news host of phytoplasmas: Psammotettix alienus was positive to 16SrI-B, 16SrV-A, 16SrX- A phytoplasmas ("Apple proliferation" reference strain) in 2004 and to 16SrXII -A in 2005. K lineolatus and P. alienus for 16SrXII -A E. taeniaticeps for 16SrV-A 16SrX-C and P. alienus for 16SrV-A and 16SrX-A Researches on the effective epidemiological role of K lineolatus and P. alienus in BN are in progress.