Transmission of ‘Candidatus Phytoplasma asteris’ (16SrI) by Osbornellus horvathi (Matsumura 1908) co-infected with “Ca. Phytoplasma phoenicium” (16SrIX)

High population levels of Osbornellus horvathi (Matsumura 1908) in Mediterranean natural environments and our previous findings of adults infected by ‘Candidatus Phytoplasma phoenicium’, in Sicily in 2012, highlight the potential role of this species as a phytoplasma vector. In the present work, O. horvathi and other Auchenorrhyncha species were collected using sticky traps between May-October of 2013 in a natural area in Sicily. The insects were analyzed for phytoplasma detection and characterization. Among the 20 Auchenorrhyncha species collected, only O. horvathi was positive for phytoplasmas. Phytoplasma transmission to periwinkle and broad bean plants by field-collected phytoplasma-infected O. horvathi individuals was also carried out. The number and composition of Auchenorrhyncha populations in the area were described together with information on the biology of O. horvathi. ‘Candidatus Phytoplasma asteris’ was successfully transmitted to broad bean and periwinkle by field-collected ‘Ca. P. asteris’ and ‘Ca. P. phoenicium’ double-infected O. horvathi, thus highlighting its vector competence for the former phytoplasma. Further studies are required to assess the ability of O. horvathi to transmit ‘Ca. P. phoenicium’.