Vitis californica and Vitis californica x Vitis vinifera Hybrids are Hosts for Grapevine leafroll-associated virus-2 and -3 and Grapevine virus A and B

Vitis and non-Vitis spp. surrounding nine Napa Valley vineyards were surveyed for Grapevine leafroll-associated virus (GLRaV)-1 to -5 and -9, Grapevine virus A (GVA), Grapevine virus B (GVB), and Grapevine virus D (GVD). Vitis spp. from three riparian areas not adjacent to vineyards were also included. DNA fingerprinting and probability analyses indicated that the Vi: is samples consisted primarily of Vitis californica followed by V californica x V vinifera hybrids. Single and mixed infections of GLRaV-2, -3, OVA, or GVB were detected by conventional or quantitative reverse-transcription polymerase chain reaction in 6 of the 66 V californica and 11 of the 19 V. californica x V. vinifera hybrids. GLRaV-1, -4, -5, -9, and GVD were not detected. Phylogenetic analysis of GLRaV-2 and -3 partial coat protein gene nucleotide sequences indicated that the isolates from V californica and V californica x V vinifera hybrids were closely related to isolates from V. vinifera.