Botanical products for managing Philaenus spumarius, vector of Xylella fastidiosa subspecies pauca

Abstract

Xylella fastidiosa, a notorious bacterial plant pathogen with a broad host range, has recently emerged as a significant threat to olive trees worldwide, causing the Olive Quick Decline Syndrome (OQDS). This disease severely affects olive production and leads to the death of the plants, causing significant economic losses and dramatic changes in the landscape. To date, no determined control strategies have been identified to fight the OQDS. Since the pathogen is an obligate host of some species of spittlebugs, managing the insect vectors themselves may be an effective approach for limiting OQDS. For that, plant-based products, due to their low toxicity to non-target organisms and minimal adverse effects on the environment, have gained significant interest as tools to tackle the diffusion of OQDS through X. fastidiosa insect vector management. Ongoing studies are exploring the role of plant secondary metabolites as infochemicals in insect–host plant interactions. Some of these focus on essential oils, plant extracts, and their major constituents, examining their potential role as toxic or attractive/repellent active ingredients against insects. These compounds are being evaluated as bioinsecticides or in semiochemical-based control strategies (e.g. mass trapping, push–pull, attract-and-kill) potentially relevant for monitoring and controlling the meadow spittlebug Philaenus spumarius (L.), the primary vector of X. fastidiosa subspecies pauca. In this scenario, our review offers an analysis of the current state of research on botanical products applied as toxicants or behaviour-modifying tools towards P. spumarius, highlighting emerging developments, innovative technologies, and recent breakthroughs.