Foundation Plant Services (FPS) has been testing grapevines in its foundation vineyards for grapevine red blotch virus (GRBV) since 2013. Red blotch infection rate remains extremely low in the Classic Foundation Vineyard. Infection rates ranged from 0% to 0.21% from 2013 to 2019, with only one of 4,075 vines infected in 2019 (see table). Russell Ranch Vineyard (RRV) remained unaffected until 2017 when five of 4,132 vines, only 0.1%, were infected with GRBV. Since then, despite significant efforts to prevent the occurrence of the disease, the infection rate in the vineyard has increased to 0.5% (24 of 4,406) in 2018 and 7.1% (339 of 4,761) in 2019 (see table).
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