The phytosanitary emergency caused by the spread of Xylella fastidiosa in the Mediterranean has raised demands for a better understanding of the ecology of its presumed and candidate insect vectors. Here, we present the results of a two-year survey carried out in olive groves across southern, eastern and Central Spain and northeastern Portugal. Several sampling methods were tested and compared to select the most appropriate to estimate population levels of potential vectors of X. fastidiosa. The spittlebugs Philaenus spumarius and Neophilaenus campestris (Hemiptera: Aphrophoridae) were the main species associated with olive groves. Both species were widely present on herbaceous ground vegetation within the olive groves; P. spumarius mainly associated with Asteraceae and N. campestris with Poaceae. Due to the patchy distribution of spittlebugs within the olive groves, sweep nets were the most effective and least time-consuming sampling method for the estimation of population size both in the ground cover and tree canopies. Trends in population density showed that spittlebugs can be abundant on ground vegetation but very rare on olive canopies. Spittlebugs disperse in late spring to non-cultivated hosts that act as natural reservoirs. In late fall, adults return to the olive groves for oviposition. However, olive trees may act as transient hosts for spittlebugs and high population densities of these insect vectors should be avoided in areas where X. fastidiosa is present.

No abstract

The phytosanitary emergence triggered by Xylella fastidiosa introduction in Europe urgently calls for research on its main vector, the meadow spittlebug, Philaenus spumarius. The difficulties faced in altering P. spumarius life cycle setting up a continuous indoor rearing under artificial conditions, obtaining a continuous availability of insects for laboratory trials, represent a great limit for research. Here, we propose a methodology to rear P. spumarius in the laboratory allowing the supply of nymphs and adults before they become available in the field. This crucial step forward will permit to overcome the seasonality barrier, reducing time and efforts currently required for experimentation on the meadow spittlebug. The proposed methodology would allow producing the data urgently required to fill the knowledge gap and finally set up an effective and environmentally friendly control strategy of P. spumarius.