Spread of grapevine phytoplasma diseases in Europe

“Flavescence dorée” is a quarantine disease in Europe as it is epidemically transmitted by the grapevine leafhopper Scaphoideus titanus, an insect of North American origin now widely distributed in the vineyards of Southern Europe. Strains of FD phytoplasma mainly spread from grapevine to grapevine but surrounding wild Vitis regrowth, infected alders and Clematis may constitute potential epidemic reservoir. “Bois noir” disease is endemic in the Euro-Mediterranean area and is mainly transmitted by Hyalesthes obsoletus, a planthopper residing in weeds such as bindweeds and stinging nettles which also act as plant reservoirs for the BN phytoplasma. “Bois noir” is caused by the accidental transmission of different “stolbur” phytoplasma strains that are maintained by epidemiological systems based on different endemic weed species as reservoir plant. The geographic distribution of the two diseases and some of their epidemiological features are described.