Prevalence of aster yellows (AY) and elm yellows (EY) group phytoplasmas in symptomatic grapevines in three areas of northern Italy.
Flavescence dorée (FD) and other important grape yellows (GY) diseases are known to occur in northern Italy. The results of an extended survey of naturally yellows-diseased grapes growing in 3 provinces of northern Italy, Vicenza, Brescia and Pavia are described. The plants were sampled at the end of Jun. and the beginning of Aug. Direct PCR assay using group-specific primers for universal phytoplasma 16S rDNA amplification or for amplification of 16S rDNA from 16SrI (aster yellows and related phytoplasmas), 16SrIII (X-disease and related phytoplasmas) and 16SrV (elm yellows and related phytoplasmas) phytoplasma groups and RFLP analysis of amplified DNA were conducted. Phytoplasmas belonging to group 16SrV were only detected in grapes in the Vicenza province; whereas, phytoplasmas belonging to group 16SrI subgroup G were found in grapes in all 3 provinces.