Monitoraggio dei giallumi della vite e caratterizzazione dei fitoplasmi nell’ambito del progetto finalizzato “GIA.VI” nel 2004.

During the first year of project activity several vineyards located in grape growing areas of almost all Italian regions were monitored for yellows symptoms presence. The vineyards were selected according with previous surveys performed by some of the teams participating into this project; new localities were also surveyed in order to obtain more detailed informations about distribution and aetiology of grapevine yellows (GY) in Italy. The surveys were carried out in September-October, in some cases also in June, and leaf samples were collected from symptomatic plants in order to perform phytoplasma detection and identification. About 500 samples from the regions listed in Table were tested, nucleic acid extraction was carried out by the different teams according with published protocols (Prince et al., 1993; Barba et al., 1998; Angelini et al., 2001). Molecular analyses were carried out by PCR/RFLP and Flavescence Dorée (FD) or Bois Noir (BN) phytoplasmas were identified by direct PCR with universal primers P1/P7 followed by nested PCR with primers specific for ribosomal groups 16SrV and 16SrI/XII and RFLP analyses with BfaI and MseI respectively. Samples positive to 16SrV group phytoplasmas were then riamplified following the protocol described by Martini et al. (2002) to identify ribosomal subgroups. The results of surveys indicate the presence of GY symptoms in almost all the vineyards inspected in several of the provinces belonging to the regions in Table. Phytoplasma molecular identification allowed to confirm that 16SrXII-A phytoplasmas, BN, are widespread in all the vineyards of Italy surveyed. Flavescence Dorée presence (subgroups 16SrV-C, FD-C and 16SrV–D, FD-D) was confirmed in northern Italy regions and was detected also in some vineyards of Central Italy. FD-D appears to be more spread than FD-C, however the latter appears to be with increasing presence since it was identified also in symptomatic samples from some provinces of Umbria and Tuscany regions. Phytoplasmas belonging to aster yellows (16SrI-B) and elm yellows (16SrV-A) groups were occasionally detected in symptomatic grapevines in Calabria and Sardina, and in Emilia-Romagna regions respectively.