Pathogenic Status of Nursery Stock The 2017/18 testing, grafting and production season saw the first detection of Grapevine leafroll-associated virus 3 (GLRaV-3) and Grapevine Pinot Gris Virus (GPGV) in Protocol 2010 certified stock. GPGV is vectored by the fairly ubiquitous Erineum mite, which results in the development of characteristic galls on the upper leaf blade. GLRaV-3 is mealybug-vectored and continues to have perhaps the greatest impact on new vineyards planted with contaminated stock...