Transmission of Grapevine Red Blotch Virus by [Say, 1830] (Hemiptera: Membracidae) between Free-Living Vines and 'Cabernet Franc'.

Grapevine red blotch disease emerged within the past decade, disrupting North American vine stock production and vineyard profitability. Our understanding of how grapevine red blotch virus (GRBV), the causal agent of the disease, interacts with its hosts and insect vector, , is limited. Here, we studied the capabilities of to transmit GRBV from and to free-living vines, identified as first-generation hybrids of and 'Sauvignon blanc' (Vcal hybrids), and to and from 'Cabernet franc' (Vvin Cf) vines.

Identification of grapevine Pinot gris virus in free-living Vitis spp. located in riparian areas adjacent to commercial vineyards.

Grapevine Pinot gris virus (GPGV) is a recently identified pathogen of grapevines in California. To advance our knowledge about the epidemiology of GPGV, we investigated if free-living Vitis spp. can represent a source of virus infection.

Prevalence and Genetic Diversity of Grabloviruses in Free-Living Vitis spp.

The distribution and diversity of grapevine red blotch virus (GRBV) and wild Vitis virus 1 (WVV1) (genus Grablovirus; family Geminiviridae) were determined in free-living Vitis spp. in northern California and New York from 2013 to 2017. Grabloviruses were detected by polymerase chain reaction in 28% (57 of 203) of samples from California but in none of the 163 samples from New York.

Hybridization of cultivated Vitis vinifera with wild V. californica and V. girdiana in California.

Hybridization of introduced domesticates and closely related natives is well documented in annual crops. The widespread introduction of the domesticated grapevine, Vitis vinifera, into California where it overlaps with two native congenerics, with which it is interfertile, provides opportunity to investigate hybridization between woody perennials. Although geographically widespread, the introduction over the past two centuries has been limited to a few elite clonal cultivars, providing a unique opportunity to study the effects of hybridization on the native species.

Grapevine red blotch-associated virus is Present in Free-Living Vitis spp. Proximal to Cultivated Grapevines.

Red blotch is an emerging disease of grapevine associated with grapevine red blotch-associated virus (GRBaV). The virus spreads with infected planting stocks but no vector of epidemiological significance has been conclusively identified. A vineyard block of red-blotch-affected Vitis vinifera 'Cabernet franc' clone 214 was observed in California, with a clustering of infected, symptomatic vines focused along one edge of the field proximal to a riparian habitat with free-living Vitis spp.