Epidemiological studies on grapevine bois noir in France
Epidemiological studies have been carried out in the Rhône valley in France on grapevine bois noir phytoplasma for 3 years. This grapevine yellows is caused by a stolbur type phytoplasma. Wild plants and insects present in vineyards or in their vicinity were tested by PCR, and transmission trials were also carried out in the laboratory. Many insects species (Hemiptera) were captured and tested. Results showed that bois noir phytoplasma could be detected in Hyalesthes obsoletus (Hemiptera: Cixiidae), and to a much lesser extent in Mocydia crocea and Euscelis lineolatus. The phytoplasma was not detected in the genus Aphrodes, Neoaliturus and Psammotettix, although this had been the case in other studies. However, successful transmission of the phytoplasma to grapevine, periwinkle (Catharanthus roseus) and thorn-apple (Datura stramonium) could only be obtained with Hyalesthes obsoletus. In addition, 34 wild plant species were monitored for the presence of the phytoplasma. It was detected in Cardaria draba, Convolvulus arvensis, Prunus avium, P. domestica, Syringa vulgaris, Ficus carica and Ulmus. Grapevine is a poor host of H. obsoletus which feeds on it only occasionally. It has also been confirmed that Convolvulus arvensis and Cardaria draba are hosts plants of the insect vector of grapevine bois noir phytoplasma.
Sources
Sforza, R.; Clair, D.; Daire, X.; Larrue, J.; Boudon-Padieu, E. (1998) The role of Hyalesthes obsoletus (Hemiptera: Cixiidae) in the occurrence of Bois Noir of grapevines in France.
Journal of Phytopathology, 146(11-12), 549-556.