Page 44 - Grapevine JanFeb 2021_REV

Around The Vineyard

California) has shown that preventative methods
(late pruning, double pruning, and pruning wound
protectants) are sustainable only if applied before
symptoms appear in the vineyard. Adopting these
methods in vines that are 10 years old or older will
not recover the cost of investment.

A more drastic disease management practice
includes vine re-training also known as remedial
surgery. The procedure consists of training a new
shoot from the base of the trunk to replace the old
decayed vine trunk or cordons. The technique can
help gain some years of production but will not
cure the vines from the disease as likely the patho-
gens are systemically established in the vine. In
areas with winter freezing temperatures, it is rec-
ommended to grow more than one trunk per vine.

If one of the trunks is compromised by disease,
others are available to continue with the vine’s pro-
ductive life. Keep in mind that the pathogenic fungi
are systemic in the vine, and as mentioned earlier
this method can buy some time before the vine
declines and dies.

When replacing vines, the grower must under-
stand that the A. vitis and fungal pathogens are
able to survive in dead portions of the roots, there-
fore new vines that are planted (even if free of
bacterial or fungal pathogens) can become infected
over time if vine roots are not completely removed
from the vineyard.

Other methods that have been reported for the
management of fungal diseases include planting
mustard (Sinapsis alba) plants as cover crops that
act as a biofumigant and biological control agents
such as Trichoderma species, and mycorrhizal
fungi. In areas prone to crown gall infection, I have
observed growers produce soil mounds to protect
the trunk from freezing.

New and more sensitive pathogen detection
methods that apply next generation sequencing
(also known as high throughput sequencing) are
now available commercially for the detection at the
species level of microorganisms in plants and soil.
It is my hope that in the near future, these meth-
ods will help reduce the infection levels of planting

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