A decade of grapevine red blotch disease epidemiology reveals zonal roguing as novel disease management.

Abstract

Red blotch disease, a threat to the grape industry, is caused by grapevine red blotch virus. This work is the first to study epidemiological patterns in a vineyard over the course of a decade, revealing an increase in disease incidence from 3.9% in 2014 to 36.4% in 2023 with rapid virus spread proximal to a transmission hotspot. Logistic and exponential models provided the best fit of spread in areas of high and low disease incidence and aggregation, respectively. An inverse spatial incidence of virus strains 1 and 2 suggested secondary spread mostly from diseased to neighboring vines and virus influx from background sources. Precipitation (3-4 years later) and air temperature (the same or 1 year later) significantly influenced epidemic parameters. Finally, asymptomatic infections contributed to spatial aggregations at increasing lags. These findings were salient for considering zonal roguing, the removal of diseased and surrounding vines, as a disease management option.