High-resolution climate data reveals rising Pierce’s disease threat to global vineyards

Recent research using high-resolution climate data has revealed a growing risk of Pierce’s disease for grapevines in wine regions around the world. The study, conducted by an international team of scientists, used advanced climate modeling to assess how changing temperatures and weather patterns are affecting the spread of Xylella fastidiosa, the bacterium responsible for Pierce’s disease. This pathogen is already known for causing significant damage to vineyards in California and other parts of the world.

The research team applied a climate-driven epidemiological model that incorporates detailed temperature data from the CHELSA dataset, which offers a spatial resolution of about one kilometer. This level of detail allowed scientists to capture subtle variations in local climate that can have a major impact on the life cycles of both the bacterium and its insect vectors, such as sharpshooters and spittlebugs. These insects feed on plant sap and transmit Xylella fastidiosa between plants.

By comparing results from high-resolution CHELSA data with those from the more widely used ERA5-Land dataset, which has a coarser nine-kilometer resolution, researchers found that previous models may have underestimated the risk of Pierce’s disease in many regions. The new analysis shows that areas previously considered at low or moderate risk could face higher rates of infection as local microclimates become more favorable for both the pathogen and its vectors.

The study focused on major wine-producing regions across North America, Europe, South America, and Australia. In California, where Pierce’s disease already causes annual losses exceeding $100 million in the grape industry, the new model predicts an expansion of high-risk zones into areas that were previously less affected. In Europe, Mediterranean coastal regions and islands are projected to see increased risk as warming trends continue. The findings also highlight potential threats to vineyards in South America and Australia, where Xylella fastidiosa has not yet caused widespread outbreaks but could do so if conditions become more suitable.

Researchers emphasize that vineyards are particularly vulnerable because they are often located in areas with complex topography—valleys, hillsides, and riverbanks—where microclimates can vary dramatically over short distances. These variations can influence not only the growth of grapevines but also the survival and reproduction of insect vectors and pathogens. As a result, even small changes in temperature or humidity at the local level can trigger significant shifts in disease dynamics.

The study period was chosen to reflect recent increases in global temperatures due to climate change. Scientists found that high-resolution climate data not only identified more areas at risk but also showed a faster rate of risk increase compared to models using lower-resolution data. This suggests that as global warming continues, the threat posed by Pierce’s disease could accelerate more quickly than previously thought.

Xylella fastidiosa is already considered one of the most dangerous plant pathogens worldwide. In addition to grapevines, it affects citrus trees, almonds, olives, and other crops. In Brazil, it infects about 200 million citrus trees each year. In Italy’s Apulia region, it has killed approximately 21 million olive trees. Economic losses from Xylella-related diseases are estimated in the billions annually across affected countries.

The new findings underscore the importance of using high-resolution climate data for predicting plant disease risks and developing management strategies. Accurate risk maps can help growers and policymakers target surveillance efforts, implement control measures, and plan for future outbreaks. The researchers note that ongoing monitoring and adaptation will be essential as climate change continues to reshape agricultural landscapes worldwide.

This study highlights how advances in climate modeling can provide critical insights into emerging threats to global food security. As vineyards and other crops face increasing pressure from pests and diseases driven by environmental change, precise forecasting tools will be vital for protecting agricultural production and rural economies around the world.