Abstract Since the emergence of Xylella fastidiosa in Europe, research has mainly focused on plant resistance to the pathogen, whereas plant traits influencing insect vector–plant interactions and transmission dynamics have received less attention. Plant genotypes with anatomical and/or chemical traits that reduce suitability for insect vectors may limit pathogen spread by decreasing vector abundance and host permanence. Using the Electrical Penetration Graph (EPG) technique, we evaluated host suitability for the meadow spittlebug Philaenus spumarius , the main European vector of X. fastidiosa , in 14 olive varieties widely cultivated in the Apulia region (southern Italy). Olive palatability and potential resistance traits to the vector were assessed using a plant suitability index (PSI) developed by integrating multiple EPG variables reflecting the ease of access to xylem vessels and the ability to initiate and maintain sustained feeding activity (escape event frequency, time to initiate probing and reach xylem vessels, total probing time, and duration of xylem sap ingestion), as well as by considering the xylem ingestion index alone. According to the PSI, olive varieties as Arbequina, Pendolino, and Leccio del Corno present a combination of anatomical and/or chemical traits affecting host acceptance by the meadow spittlebug. In contrast, when considering only the xylem ingestion index, the varieties Leccino, Pendolino, and Picholine emerged as the poorest food sources for the vector. These results suggest that vector abundance and permanence on certain olive varieties may be reduced, with potential implications for X. fastidiosa spread; however, field-scale studies are needed to confirm this hypothesis.
Hamouche et al. (Sun,) studied this question.