Technical Abstract: In recent years, emerging phytoplasma diseases of potato (Solanum tuberosum L.) have increasingly become important in central and eastern Europe. Accurate identification of phytoplasmas and their insect vectors is essential to developing effective management strategies for diseases caused by these plant pathogens. Potato phytoplasma diseases in Europe were for a long time diagnosed only on the basis of visual symptoms. However, this approach is not very reliable and the use of modern molecular techniques such as PCR is required in order to accurately determine the etiology of these phytoplasma diseases. A survey and identification of phytoplasmas associated with potato crops in Romania and southern Russia were conducted based on modern molecular techniques. Symptomatic potato plants were collected from several fields and tested for phytoplasmas by PCR. Also, selected crops and weeds in the vicinity of these potato fields were sampled and tested for phytoplasmas. Stolbur (16SrXII-A) was the only phytoplasma detected in potato and adjacent crops, including tomato (Solanum lycopersicum), pepper (Capsicum annuum), eggplant (Solanum melongina), beet (Beta vulgaris), and corn (Zea mays). This phytoplasma was also detected in weeds, particularly Convolvulus arvensis, Cuscuta spp., and Euphorbia spp. Genotyping of obtained stolbur isolates on tuf genes revealed that they all had the same RFLP profile corresponding to the tuf-b type (VK Type II). Stolbur-affected potato plants produced a large number of spongy tubers that resulted into commercially unacceptable potato chips upon processing.