The SYBR Green real-time RT-PCR assay with universal primers P19qtF4 and P24qtR was evaluated for the detection of GLRaV-2 RNA from 43 GLRaV-2 isolates arising from a broad range of grapevine hybrids or clones and geographical locations (Table 1a). The isolates representative of the six known groups of GLRaV-2 isolates