Additional Testing Finds No Grapevine Leafroll-associated Virus-3 or Grapevine Red Blotch Virus
Since the discovery of grapevine red blotch disease, caused by grapevine red blotch virus (GRBV), in Foundation Vineyards during 2017-2018 annual disease testing, Foundation Plant Services (FPS) implemented a “Test-to-Order” policy for 2018-2019 custom grapevine orders. Selections from all 139 orders, regardless of prior test results, were individually tested prior to distribution. To minimize the risk of false negatives, 12 leaves/canes were sampled per vine for testing. Thus far, the stringent testing policy confirmed the negative results of annual composite testing: all 2,332 vines tested were negative for both grapevine leafroll-associated virus-3 (GLRaV-3) and GRBV.
Since 2017, FPS has implemented additional precautions to prevent the spread of red blotch disease. Moving forward, all vines in Foundation Vineyards will be tested annually for GRBV and GLRaV-3 prior to distribution, visual inspections will occur more frequently, and subsequent testing will be implemented as needed.