An abundant ' Phytoplasma solani' tuf b strain is associated with grapevine, stinging nettle and .

Bois noir (BN) associated with ' Phytoplasma solani' (Stolbur) is regularly found in Austrian vine growing regions. Investigations between 2003 and 2008 indicated sporadic presence of the confirmed disease vector and frequent infections of bindweed and grapevine. Infections of nettles were rare. In contrast present investigations revealed a mass occurrence of almost exclusively on stinging nettle. The high population densities of on were accompanied by frequent occurrence of ' P. solani' in nettles and planthoppers. Sequence analysis of the molecular markers and of stolbur revealed a single genotype named CPsM4_At1 in stinging nettles and more than 64 and 90 % abundance in grapevine and , respectively. Interestingly, this genotype showed tuf b type restriction pattern previously attributed to bindweed associated ' P. solani' strains, but a different sequence assigned as tuf b2 compared to reference tuf b strains. All other marker genes of CPsM4_At1 clustered with tuf a and nettle derived genotypes verifying distinct nettle phytoplasma genotypes. Transmission experiments with and resulted in successful transmission of five different strains including the major genotype to and in transmission of the major genotype to . Altogether, five nettle and nine bindweed associated genotypes were described. Bindweed types were verified in 34 % of grapevine samples, in few positive , rarely in bindweeds and occasionally in infected by or . ' Phytoplasma convolvuli' (bindweed yellows) was ascertained in nettle and bindweed samples.