Specificity of Flavescence Dorée Phytoplasma of Some Hemiptera Species

Introduction Identification of vectors and potential vectors of Grapevine yellows (GY) diseases is crucial for epidemiology and control of these important diseases (Boudon-Padieu, 2005). Few information are reported in literature concerning the specificity of vector transmission of phytoplasmas. Some phytoplasma strains seem to be specifically transmitted, for example phytoplasmas in the Elm yellow group seem to be transmitted by only a few leafhopper species. Other strains have low vector specificity, such as those clustered in the Aster yellows group, which are transmitted by several leafhopper species. Flavescence dorée (FD) of the grapevine is associated with a phytoplasma (FDP) that seems to be specifically transmitted in the field by the leafhopper vector Scaphoideus titanus Ball (Hemiptera, Cicadomorpha, Cicadellidae) (Schvester et al., 1963; Vidano, 1964; Mori et al., 2002). However Caudwell et al. (1972) showed that in experimental conditions, Euscelidius variegatus Kirschbaum (Hemiptera, Cicadomorpha, Cicadellidae) was an efficient alternative vector of FDP to herbaceous hosts although it cannot feed-acquire FDP from infected grapevines. Hence the species of source and recipient plants are very important both in natural diffusion and experimental assays.