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Ceresini treehoppers are present in northern California vineyard ecosystems, including the closely related <i>Spissistilus</i> and <i>Tortistilus</i> (Hemiptera: Membracidae). These membracids are not direct pests of wine grapes, but <i>S. festinus</i> is a vector of grapevine red blotch virus (GRBV). No information is available on the ability of <i>Tortistilus</i> spp. to transmit GRBV. In this study, <i>Tortistilus</i> were collected on yellow panel cards across 102 vineyard sites and surrounding areas in Napa Valley, California, USA in 2021–2023. Specimens were morphotyped, sexed and tested for GRBV ingestion and acquisition by multiplex PCR or qPCR. Phylogenetic analysis of the partial sequence of mt-COI and ITS gene fragments of a subset of 40 <i>Tortistilus</i> specimens revealed clustering in a monophyletic clade with <i>T. wickhami</i> with the former barcode sequence. Only 6% (48/758) of the <i>T. wickhami</i> tested positive for GRBV, but none of the heads with salivary glands (0%, 0/50) of the dissected specimens tested positive for GRBV, indicating no virus acquisition. In contrast, half of the dissected heads with salivary glands of <i>S. festinus</i> (52%, 12/23), from the same collection vineyard sites, tested positive for GRBV. Together, our findings confirmed the presence of <i>T. wickhami</i> in northern California vineyards and suggested a dubious role of this treehopper as a vector of GRBV.