Role of spittlebugs in Xylella fastidiosa subsp. fastidiosa sequence type 1 (ST1) epidemiology in Southern Italian vineyards

The recent finding of Xylella fastidiosa fastidiosa ST1 ( Xff ) in almond, grapevine, and cherry plants in South-Eastern Italy, and specifically in one of the most economically relevant table grape districts worldwide, urgently calls for data on insect vectors involved in bacterium spread for informing management strategies. A survey of potential vector species was conducted from April to October 2024 in five table-grape vineyards using the “tendone” system and five mixed plots (wine grapevines, olives, almonds, and other plants) located in the municipality of Triggiano (Bari, Italy). Data were collected on: i) presence and abundance throughout the year of xylem-sap feeding species, i.e. competent vectors of the bacterium; ii) host plants for both juveniles and adults; iii) infectious status of the plants the adults were collected from; iv) vector infectivity throughout the year. The two species competent for the bacterium transmission present in the surveyed area were Philaenus spumarius and Neophilaenus campestris . The data collected suggest N. campestris could be responsible for both secondary "almond-to-almond" and primary "almond-to-grapevine" transmission, while P. spumarius could be the main driver of the secondary "grapevine-to-grapevine" Xff transmission. However, the data presented here refer to a single year of sampling in the epicenter of the outbreak; therefore, spatial and temporal sampling limitations do not permit to draw definitive conclusions about vector-driven Xff epidemiology. Nevertheless, our preliminary findings are crucial for informing containment strategies and attempts to eradicate the outbreak.