Risk of establishment of Pierce's disease in main wine-producer regions worldwide

Pierce’s disease (PD) of grapevines caused by Xylella fastidiosa is currently restricted to North America with a few recent reports in Taiwan and the island of Mallorca in Spain. The underlying biotic and environmental conditions explaining why PD has not spread worldwide remain unexplained. There have been several attempts to predict the climatic conditions suitable for PD using species distribution models. However, few studies have taken into account the distribution of the vectors, an essential factor for accurate risk assessment. Here we first modelled the climatic effects that determine both the development and survival of Xf within the plant. This includes the effect of climatic oscillations in the initial population dynamics of the infected plants under different basic reproductive number scenarios. Secondly, we accounted for the distribution of the main known vector Philaenus spumarius in Europe. We also made predictions in other regions worldwide assuming that the vectors responsible for the disease spreading are abundant enough. The simulation output predicts accurately PD known invaded ranges in the US, Mallorca and Taiwan, and explain the past epidemic patterns in North America. When combined with the distribution of the main vector P. spumarius, the risk for chronic PD in Europe is downscaled to unconnected areas of the Mediterranean coast and islands, with much lower risks in the south Atlantic coast.