High occurrence of Flavescence dorée phytoplasma early in the season on grapevines infected with grapevine yellows

Research NoteA survey for the presence of phytoplasmas associated with grapevine yellows in about 500 Italian vineyards was conducted from 1999 to 2004. Grapevines with the earliest symptoms were mostly infected with Flavescence dorée type C phytoplasma (FD-C). As the season advanced, a steady relative decrease in the occurrence of FD-C coincided with a clear relative increase in Bois noir phytoplasma. The relative occurrence of Flavescence dorée type D phytoplasma remained stable.