Differential Spread of Grapevine Red Blotch Virus in California and New York Vineyards

Abstract

Limited information is available on the spread dynamics of grapevine red blotch virus (GRBV, genus Grablovirus, family Geminiviridae) in vineyards. In this study, we investigated red blotch disease progress in three vineyards with a disparate initial inoculum prevalence. Secondary spread was documented in Cabernet Sauvignon and Cabernet franc vineyards in California, but not in a Merlot vineyard in New York. Increase in annual disease incidence (4.8, 0.13, and 0%) was unrelated to the estimated initial source of inoculum at planting (1, 40, and 40%) in the Cabernet franc, Cabernet Sauvignon, and Merlot vineyards, respectively. Limited genetic diversity of GRBV populations in newly infected vines supported localized spread in California vineyards, and suggested the planting material as the primary source of inoculum. Among the community of hemipteran insects visiting two of the three study vineyards, populations of Spissistilus festinus, the vector of GRBV, were absent in the Merlot vineyard and low in the Cabernet Sauvignon vineyard. Furthermore, all cover crop samples collected from GRBV-infected California vineyards each spring of 2016 to 2018, particularly legume species which are preferred hosts of S. festinus, tested negative for GRBV, suggesting a minimal role, if any, in GRBV spread as inoculum reservoirs. Together our findings illustrate differential disease progress in distinct vineyard ecosystems, and support the elimination of virus inoculum sources as an actionable disease management strategy across vineyards.

A first Canadian and three new Québec records of Cicadellidae (Hemiptera) in grapevine (Vitaceae): potential virus vectors

“…Moreover, Empoasca sp. was recently tested positive for the grapevine red blotch virus (Cieniewicz et al 2019).…”

Two Distinct Genotypes of Spissistilus festinus (Say, 1830) (Hemiptera, Membracidae) in the United States Revealed by Phylogenetic and Morphological Analyses

“…However, the southern and northern limits of its range are not well described, and should be further investigated. Noteworthy, although S. festinus was not found in a vineyard on Long Island during 2017-2018 insect surveys [4], the Cornell University Insect Collection has a single S. festinus specimen collected on Long Island, New York in 1933. Was this specimen migrating from southern habitats before it was caught on Long Island or was it an indigenous specimen?…”

“…The sensitivity and specificity of the diagnostic PCR was validated by testing for cross-amplification of the S. festinus genotypes and for amplification of the mt-C2OI gene fragment from other hemipteran insects, respectively. The DNA extracts of various hemiptera were available in a laboratory collection at Cornell University from previous insect survey studies in California and in New York vineyards [3,4].…”

“…Recently, the capacity of S. festinus to transmit the grapevine red blotch virus (GRBV) from infected to healthy grapevines in the greenhouse was reported [2]. Spissistilus festinus is also associated with the red blotch disease spread in vineyards in California [3,4]. Spissistilus festinus is not considered to be a direct pest of Vitis spp.…”

The Epidemiology of Plant Virus Disease: Towards a New Synthesis

“…Having an explicit spatial basis for disease and vector surveys leads naturally to the generation of maps which illustrate the spatiotemporal progress of disease. Such maps were generated in a study of grapevine red blotch virus disease and the vector Spissistilus festinus at vineyards in California and New York [ 67 ]. Although there was evidence for some local spread in California, this was not observed in New York where the vector was absent.…”