Page 54 - Grapevine Jan-Feb 2020
P. 54
Around The Vineyard
(some include trials of grapevine virus infected rent situation of the CDFA R&C vines demonstrates
vines) and the town and is routinely tested by the the need for more applied research to mitigate dis-
UC Davis Foundation Plant Services (FPS) Personnel. ease in nursery and foundation blocks. Due to the
Last year in November, FPS scientists reported progressive spread of GRBV in the Russell Ranch
the progressive spread of GRBV in the Russell Foundation Block, it appears that the only solution
Ranch block. To summarize, four vines were found to produce clean planting stock is to start anew
infected with GRBV in 2017, in 2018 the number
increased to 24 vines, in 2019 the testing results Unfortunately, no back up tissue culture mate-
yielded over 300 vines infected with the virus. rial of the varieties planted at the Russell Ranch
Fortunately, FPS has suspended the sale of vines Foundation Block are available. However, siblings
from the Russell Ranch block until further notice. from some of the varieties subjected to tissue cul-
However, potentially nurseries may have propa- ture were planted in the Classic (older) foundation.
gated vines from mother plants that were infected In the future, these siblings (numbered 02 rather
with the virus and could continue to disperse the than 01) will be tested using the Protocol 2010 to
virus to their mother blocks and newly planted make them available for purchase. To obtain virus
vineyards. free plants, the meristem tissue culture technique
will need to be applied for the elimination of GRVB.
Conclusions Once new plants are produced, these will need to
be protected from new infections. For best results,
Guidelines are not available on the required dis- vines should be grown in insect proof greenhouses
tance between nursery and/or foundation blocks or screenhouses, and in geographical areas where
from commercial or potentially infected vineyards. grapevines are not grown. It is also advisable to
It is expected that transmission of harmful viruses keep a backup of all vine material in case infection
will continue to occur if certified blocks are not is detected in the future. In the meanwhile, it will
carefully monitored and kept in isolation. The cur- be imperative for nurseries and growers to care-
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