Epidemiological surveys were performed in Northern Sardinia (Italy) in a 10-year-old vineyard
affected by \u201cBois noir\u201d disease. Samples collected between May and October 2003 from
chlorotic and stunted weeds belonging to 14 different taxonomic groups were indexed molecularly
for detection of phytoplasmas. Nested polymerase chain reaction (PCR) assays using primers
specific for the phytoplasma 16SrDNA gene showed three of six Calendula arvensis, one of
two Solanum nigrum, and one of seven Chenopodium spp. assayed positive. Restriction fragment
length polymorphism analyses and sequencing of amplified 16SrDNA fragments identified a
putative phytoplasma in the ribosomal subgroup 16SrII-E. Further characterization of the rps3
gene, coding a ribosomal protein, confirmed the identification. However, the weeds and leafhopper
species collected in the vineyard tested negative by PCR assays for the Stolbur phytoplasma,
the causal agent of \u201cBois noir\u201d. This is the first report of a phytoplasma of the 16SrII-E subgroup
infecting C. arvensis, S. nigrum, and Chenopodium spp
