Jan 5, 2018
UC Davis vineyard: Red blotch found and destroyed at Russell Ranch

According to Deborah Golino, director, UC Davis Foundation Plant Services (FPS), on Dec. 20, 2017, FPS determined that Grapevine Red Blotch Disease, caused by grapevine red blotch virus (GRBV), has been found in the Russell Ranch Vineyard (RRV).

According to a news release, “all affected vines (only five of 4,132 vines in RRV tested positive for GRBV) have been removed and destroyed. FPS is carefully monitoring the vineyard blocks in which GRBV has been found and additional testing has been implemented to ensure that any occurrence of disease is immediately detected and contained. Russell Ranch vineyard has been tested for GRBV since 2013 and this is the first time it has been detected. While FPS is always committed to maintain foundation material at the highest standard, additional precautions are being implemented to prevent the spread of this disease. To that end:

  1. Every grapevine in RRV has been tested for GRBV.
  2. The five GRBV positive vines have been removed and destroyed and are being monitored for regrowth.
  3. All mother vines and vines related to GRBV positives tested negative in every case, indicating that this is a field transmission of GRBV.
  4. Additional spray treatments specifically targeting the vector have been applied and a more comprehensive program for control of the vector is being developed.
  5. Vitis spp. in proximity to RRV have been tested; positive vines have been removed and destroyed.
  6. Material from these plants was distributed prior to the last negative test date, indicating that material was likely GRBV-free at the time of distribution. Nevertheless, the one customer who received material from these vines has been contacted by FPS.
  7. The one vine that tested positive in the Classic Foundation was removed.
  8. Preliminary sequence analysis showed high similarity (99% identity) to GRBV isolates from two different groups which indicates separate infection events.

Moving forward FPS will be even more vigilant. Visual inspections will be conducted more frequently. All vines in RRV will be tested for GRBV annually by composite testing. Classic Foundation selections will be subject to regularly scheduled maintenance testing as well as testing as needed prior to distribution.

A collaborative approach from FPS, nurseries, and vineyards is our best defense to protect grapevine material from exposure to viruses. FPS is committed to maintaining the highest testing standard for our foundation vineyards and making every effort to keep you informed as new information becomes available.”

FPS was established in 1958 to distribute virus-tested, professionally identified grape, fruit and nut tree propagation stock. Selections originated from University of California (UC) and United States Department of Agriculture (USDA) variety improvement programs. UC faculty and California Department of Food and Agriculture (CDFA) scientists developed indexing techniques for detection of the most common virus diseases affecting production of these crops in California. Today, FPS has programs for grapes, strawberries, fruit and nut trees, roses, and sweet potatoes.

The department is housed in the National Grapevine Importation and Clean Stock Facility, which was built with federal, state and industry funds in a cooperative effort to strengthen FPS programs. FPS works closely with CDFA to register and certify grapevines, fruit and nut trees, and strawberry plants. FPS research programs develop new techniques for disease detection and elimination to improve the quality of propagation materials.

UC provides the infrastructure and faculty support to FPS; operating expenses are provided from the agricultural communities served by FPS, through purchase of plant material, user fees, and contributions from industry funding agencies. The programs are primarily focused on the sale of disease-tested propagating stock to nurseries.


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