The association of Salicaceae and Aphrophoridae: a potential Xylella fastidiosa-based threatening pathosystem for European temperate areas.

Casarin, Noemi [UCL] Hasbroucq, Séverine [UCL] Glibert, Audrey [UCL] Carestia, Gabriel [UCL] Bragard, Claude [UCL] Grégoire, Jean-Claude [Spatial Epidemiology lab (SpELL), Université libre de Bruxelles, Brussels, Belgium]

(eng) Riparian areas have been highlighted as favorable sites for Xylella fastidiosa spread and persistence [1,4] as they are considered to be a niche for several insect vectors [2,3]. To assess the risk of X. fastidiosa for Belgium, and more extensively for regions with a similar temperate oceanic climate, plant species from riparian environments as well as potential insect vectors associated with these plants have been studied, revealing yet undiscovered host plants. The distribution and the abundance of five potential insect vector species were evaluated on the Belgian territory. The dispersal capacity of two of them, Philaenus spumarius and Aphrophora salicina, was surveyed by mark-release-recapture and flight mill experiments. A. salicina reveals a higher flying capacity than P. spumarius, with an average travelling distance four times longer. While P. spumarius remains particularly dangerous because of its polyphagy, A. salicina is considered also a threat because of its specificity to the Salicaceae, a plant family typical of riparian zones for which some species showed in parallel studies their potential as good hosts for the bacterium. These features, combined with its dispersal capacity, make A. salicina a significant potential insect vector to be considered in temperate oceanic climate regions. [1] Baumgartner K. and Warren J.G., 2005. Persistence of Xylella fastidiosa in riparian hosts near northern California vineyards. Plant Disease, 89, 1097–1102. [2] Purcell A.H., 1974. Spatial patterns of Pierce’s disease in the Napa Valley. American Journal of Enology and Viticulture, 25, 162–167. [3] Purcell A.H., 1975. Role of the blue-green sharpshooter, Hordnia circellata, in the epidemiology of Pierce’s disease of grapevines. Environ. Entomol. 4:745-752. [4] Purcell A.H. and Saunders S.R., 1999. Fate of Pierce’s disease strains of Xylella fastidiosa in common riparian plants in California. Plant Disease, 83, 825–830.