role of Hyalesthes obsoletus (Hemiptera: Cixiidae) in the occurrence of bois noir of grapevines in France

• Published in: Journal of phytopathology 1998-12, Vol.146 (11/12), p.549-556
• Main Authors: Sforza, R, Clair, D, Daire, X, Larrue, J, Boudon-Padieu, E
• Format: Article
• Language: English
• Subjects: alternative hosts; Bacterial plant pathogens; Biological and medical sciences; Cixiidae; Convolvulus; Convolvulus arvensis; detection; disease transmission; disease vectors; epidemiology; fallow; Ficus carica; Fundamental and applied biological sciences. Psychology; Generalities. Techniques. Transmission, epidemiology, ecology. Antibacterial substances, control; Hemiptera; host plants; Hyalesthes obsoletus; Lepidium draba subsp. draba; new host records; Phytopathology. Animal pests. Plant and forest protection; phytoplasmas; plant diseases and disorders; polymerase chain reaction; Prunus; Prunus domestica; seasonal variation; Syringa vulgaris; Ulmus; Vitis; Vitis vinifera
• ISSN: 0031-9481; 0931-1785; 1439-0434
• DOI: 10.1111/j.1439-0434.1998.tb04753.x

An epidemiological study on a grapevine yellows disease called bois noir was carried out for 3 years in the Rhone valley (France). This yellows is caused by a stolbur type phytoplasma. Vectors and alternative host plants were searched, and the inoculation period was determined. Detection of stolbur phytoplasma in insects and plants was obtained using primers STOLl1 f2/r1. In addition, a nested polymerase chain reaction (PCR) was used with primers P1/P7 and fU5/rU3 for detection in stolbur‐infected plants with low titre. Several thousand insects were captured and species of Hemiptera were listed. Fourteen wild or reared Hemiptera species were used in transmission trials. Thirty‐four wild species were monitored for phytoplasma DNA by PCR. A planthopper. Hvalesthes obsoletus Sign., tested positive for stolbur at a level of 28% (98,/343) in 1995 and 38% (205,529) in 1996. In 1995, two leafhoppers, Mocydia crocea (178) and Euscelis tineolatus (2/309), were infected at a much lower ratio. Successful experimental transmission to grapevine, periwinkle and thorn apple was only obtained with H. obsoletus. Among wild plant species, hoary cress (Cardaria draba L.), bindweed (Convolvulus arvensis L.), sweet cherry (Prunus sp.), plum (Prunus domestica L), lilac (Syringa vulgaris L.), fig tree (Ficus carica L.) and elm (Ulmus sp.) were shown to be stolbur infected and hoary cress was identified as a new host plant for H. obsoletus in France. The role of some fallow lands close to vineyards as sites where the inoculum of stolbur phytoplasma was maintained in insect vector and reservoir plants, is discussed. The natural inoculation period to grapevine was shown to extend from June to August, corresponding to the adult activity of H. obsoletus. Together with the close relationships of the phytoplasmas involved in vergilbungskrankheit, a German grapevine disease, and bois noir. The results of this study suggest that the two yellows are very close. Zusammenfassung Im französischen Rhônetal wurde eine 3‐jährige epidemiologische Studie über die Bois‐noir‐Vergilbungskrankheit der Weinrebe durchgeführt. Diese Krankheit wird von einem Phytoplasma des Stolbur‐Typs ausgelöst. Es wurde nach Vektoren und alternativen Wirtspflanzen gesucht, und die Inokulationsperiode wurde bestimmt. Die Detektion von Stolbur‐Phytoplasmen in Insekten und Pflanzen erfolgte mit Hilfe der Primer STOL 11 f2/r1. Zudem wurde eine genestete PCR mit den Primern P1/P7 und fU5/rU3 zur Detektion in stolburinfizie