Orientus ishidae, un nouveau vecteur de la flavescence dorée au Tessin = Orientus ishidae, a new vector of flavescence dorée in Ticino = Orientus ishidae, un nuovo vettore della flavescenza dorata in Ticino

Orientus ishidae, a new vector of flavescence dor\ue9e in Ticino This study was carried out in Ticino during the 2013\u20132015 time period. Its objective was to establish the presence of alternative insect vectors and plant hosts for grapevine flavescence dor\ue9e (FD).The results show that while the mosaic leafhopper Orientus ishidae constitutes a second vector of FD, it does not help spread the disease in an epidemic way as Scaphoideus titanus, the main vector, does. O. ishidae is present in all studied vineyards, but with varying population densities.Corylus avellana and Salix sp.are its preferred plant hosts and FD-positive individuals were found among them.Moreover, four other FD-positive leafhoppers were identified, but, contrary to O. ishidae, their ability to transfer the disease to grapevines has still to be demonstrated. The FD ecology appears to be a much more opened system than previously thought, where the landscape surrounding the vineyards plays an important role by determining which alternative plant hosts are present, it also determines their associated insect vectors.The present control strategy, based on the eradication of FD, is challenged and must be reassessed.Cette \ue9tude, conduite au Tessin pendant la p\ue9riode 2013\u20132015, a pour but d\u2019\ue9tablir la pr\ue9sence de vecteurs et de plantes h\uf4tes alternatifs de la flavescence dor\ue9e de la vigne (FD). Les r\ue9sultats ont montr\ue9 que la cicadelle Orientus ishidae constitue au Tessin un deuxi\ue8me vecteur de la FD, sans toutefois diffuser la maladie de fa\ue7on \ue9pid\ue9mique comme Scaphoideus titanus, le vecteur principal de la maladie. O. ishidae est pr\ue9sent dans toutes les parcelles de l\u2019\ue9tude, mais \ue0 des densit\ue9s de populations diff\ue9rentes. Corylus avellana et Salix sp.sont ses plantes h\uf4tes de pr\ue9dilection et des individus positifs \ue0 la FD y ont \ue9t\ue9 identifi\ue9s. En outre, quatre autres esp\ue8ces de cicadelles se sont r\ue9v\ue9l\ue9es porteuses de FD, mais, contrairement \ue0 O. ishidae, il reste \ue0 d\ue9montrer pour ces derni\ue8res la capacit\ue9 de transmettre la maladie \ue0 la vigne. L\u2019\ue9cologie de la FD se r\ue9v\ue8le donc \ueatre un syst\ue8me bien plus ouvert qu\u2019anticip\ue9, o\uf9 le paysage bordant les vignes joue un r\uf4le important en d\ue9terminant la pr\ue9sence (ou l\u2019absence) de plantes h\uf4tes alternatives pouvant h\ue9berger la FD ainsi que la pr\ue9sence des esp\ue8ces vectrices qui leur sont associ\ue9es.La strat\ue9gie de lutte actuelle ax\ue9e sur l\u2019\ue9radication de la FD est remise en question et doit \ueatre repens\ue9e et adapt\ue9e