Planococcus ficus and the spread of grapevine leafroll disease in vineyards: a 30-year-long case study in north-West Spain

Abstract The mealybug Planococcus ficus is one of the main vectors Grapevine leafroll associated virus-3 (GLRaV-3), which was commonly detected in cv “Albariño” planting material before certified stock available. Mealybug infestations were rare vineyards southern Galicia (NW Spain) during 1990s (2.2% surveyed) and are still inland zones. However, have spread since 2000, with 15% surveyed infested 2004 80% 2016. spatial temporal distributions plants infected GLRaV-3 quantified over a 30-year period an experimental plot established 1989. disease progress curve (DPC) linear for 25 years, slow constant rate less than newly plant per year (0.6%). Since 1992, >82% located on west side as 84% plants. Newly contact plants, suggesting vector-mediated transmission, but no potential found. In 2013, small infestation identified Pl. . Between 2014 2016, infection increased to >21% year, 2019 all tested positive GLRaV-3. This valuable case study illustrating how changes vector fauna can increase economically important virus grapevine.