Vineyard age-specific cohorts display similar climate x esca relationships but suggest hidden drivers in younger vineyards

Esca is a grapevine disease with a unique visual impact. Plants exhibit leaf necrosis with a tiger-striped pattern, sometimes dramatically apoplectic. Together with the variability in leaf symptom expression from one season to the next, esca is conspicuously visible to vine growers, amplifying their perception of its propagation. A global increase in esca incidence has been observed in the first 10–15 years of this century, making esca one of the major causes of vine mortality and vineyard decline. Research has improved the understanding of this complex disease with symptoms caused by a combination of distinct pathogens in association or succession, as well as by structural and physiological changes. The multifactorial complexity of esca has made understanding the disease challenging. Among the factors environment plays a critical role. Climate change could be contributing to the observed growth in esca incidence, and if true, could continue to exacerbate the disease in the future. This study builds upon an extensive surveying effort carried out by annually monitoring ~57,000 vines across 12 estates in the Bordeaux region for 9 years. We integrated this extensive regional esca incidence database with localised daily weather data to quantify the impact of climatic and pedoclimatic factors on esca incidence. The study confirmed that factors previously explored such as the amount of precipitation early in the season and temperature dynamics later in the season have a clear relationship to disease incidence, but also highlights an important change in disease behaviour in plots planted in the last 10–15 years. Isolating the effect of age of the plots uncovered disease patterns that suggest hidden drivers unrelated to climate which could possibly include changes in propagated vines and/or management techniques.