High-resolution climate data reveals increased risk of Pierce's Disease for grapevines worldwide

Range shifts in plant disease distributions are sensitive to scaling processes, but few crop case studies have included these predictions under climate change. High-quality wines are increasingly produced in topographically heterogeneous river valleys, whereby disease models that capture steep relief gradients become especially relevant. Here we show how non-linear epidemiological models more accurately reflect the threat of an emerging grapevine pathogen in areas with significant spatial gradients. By comparing the results of simulations using climate data with different spatial resolutions, we identify an increased risk of Pierce's disease (PD), caused by the vector-borne bacterium Xylella fastidiosa, in wine regions globally. Over 100,000 vine presence records worldwide were analysed with respect to their closer risk-grid cell, observing an increase from 21.8% to 41.2% of the area at risk in European vineyards, from 5.6% to 47.2% in South Africa and to a lesser extent in other wine-growing regions. This general trend has been preceded by an accelerating rate of increase in risk within wine-growing areas. Our analysis demonstrates the importance of microclimatic conditions, highlighting previously unresolved risk zones in areas close to rivers and valleys, and the insufficiency of lower resolution data sets to capture complex climatic variations.