Relazione fra Hyalesthes obsoletus, fitoplasma dello stolbur e piante ospiti in agroecosistemi vigneto della regione Marche.

Stolbur phytoplasma (Bois noir) is occasionally transmitted to grapevines by the planthopper Hyalesthes obsoletus Signoret (Hemiptera, Fulgoromorpha, Cixiidae) that has various herbaceous host plants that act as phytoplasma reservoirs so it ensures the complex transmission cycle of phytoplasma. In the Marche region (Eastern-Central Italy) nettle is the only known genuine host plant of H. obsoletus, and adult planthoppers can also be found on bindweed in abundance in some vineyards. The relashionships, among H. obsoletus, its herbaceous host plants and stolbur phytoplasma strains (tuf-type) were studied in five different vineyard areas. Phytoplasma was detected by molecular analysis of planthoppers and of their main host plants. The planthopper specimens were caught from bindweed and nettle and divided according to host plant. H. obsoletus percentage level of infection varied 26.3% to 44.5% in samples collected on bindweed, and from 0% to 14.3% in samples collected on nettle. H. obsoletus and its host-plant samples showed the presence of two stolbur phytoplasma strains: tuf-type I and tuf-type II, with tuf-type I predominating in the H. obsoletus sampled on nettle.