Philaenus spumarius L., the main vector of Xylella fastidiosa (Wells) in Europe, is a univoltine species that overwinters in the egg stage, and its nymphs emerge in late winter or spring. Predicting the time of egg hatching is essential for determining the precise times for deploying control strategies against insect pests. Here, we monitored P. spumarius eggs from oviposition to egg hatching together with the daily temperatures and relative humidities at four field locations that were located at different altitudes in central Spain. The collected data were used to build a growing degree day (GDD) model to forecast egg hatching in the Iberian Peninsula. The GDDs needed for hatching were in the range of 197-331. Moreover, we found that humidity is a critical factor that regulates egg hatching in P. spumarius. Furthermore, the model was validated with field observations that were conducted in the Iberian Peninsula, which suggested that oviposition is dependent on latitude and occurs later in the southern part of the Iberian Peninsula than in the north. The model was then used as a decision- support tool to calculate the optimum timing for applying control actions against P. spumarius. Our results suggest that controlling nymphs at two different dates would target the highest percentages of nymphal populations present in the field. Our model represents a first step for predicting the emergence of nymphs and to adopt timely control actions against P. spumarius. These actions could limit disease spread in areas where X. fastidiosa is present.
Also available from BioRxiv at https://doi.org/10.1101/2022.11.10.515963