Gill's mealybug, Ferrisia gilli, can Transmit Grapevine Leafroll-associated Virus-3 after a 24-hour Acquisition Time

Abstract

Grapevine leafroll disease (GLD) is a virus disease present in all grapevine-growing regions of the world. Mealybugs and scale insects have been reported as vectors of some grapevine leafroll-associated viruses belongs to the ampeloviruses (family Closteroviridae) in particular with grapevine leafroll-associated virus-1 (GLRaV-1) and GLRaV-3. Both grape (Pseudococcus maritimus) and Gill’s mealybugs are commonly present in Virginia vineyards, but we have limited information on acquisition and transmission of GLRaV-3 by Gill's mealybug (Ferrisia Gilli). We conducted acquisition and transmission assays in the greenhouse to examine the threshold for shorter acquisition time of GLRaV-3 with F. gilli. Approximately 67% and 58% rates of GLRaV-3 acquisition by F. gilli following 24 and 48 hours, respectively, of feeding period were documented. F. gilli first instars fed on a GLRaV-3-positive grapevine for 24 and 48 hours successfully transmitted GLRaV-3 to healthy grapevines after 24 hours of feeding/transmission time. The quick acquisition demonstrated in this study could be one of the factors that promoted the rapid expansion of GLRaV-3-infected vines in vineyards documented in previous studies.