Natural areas as reservoir of candidate vectors of Xylella fastidiosa

Spittlebugs have been identified as the main European vectors of the bacterium Xylella fastidiosa Wells et al. in different pathosystems. However, our knowledge about bacterium epidemiology in Apulian (Southern Italy) olive orchards is currently limited to the late spring secondary (olive-to-olive) spread mediated by the spittlebug Philaenus spumarius (L.). Summer dispersal toward wild trees and shrubs is a common trait observed in several spittlebug species that could have important impacts on X. fastidiosa epidemiology. Here, we report preliminary data on presence and abundance of spittlebugs during the year in four different habitats interspersed with cultivated orchards within a natural area in Apulia. In two surveyed habitats, a pine forest and a lake shore, the latter dominated by elm plants, spittlebug adults peaked during the period June-September, with maximum values in July-August on elm. Three spittlebug species, Neophilaenus campestris (Fallen), P. spumarius and Philaenus italosignus Drosopoulos et Remane were evenly collected on pine plants, while the latter was the most abundant on elms. A few individuals were collected on elm throughout the end of the year, while on pines spittlebugs were only collected in summer. The possible implications of our findings for X. fastidiosa epidemiology in both cultivated orchards and natural habitats, together with future research needs are discussed.