S M A R T V I T I C U LT U R E
American Vineyard Foundation-funded
projects for 2013-14, 2012, 2011 and 2010,
totaling 95. Of these, 42 were related to
grapevine pests and diseases including
breeding, and of these only two were
about grapevine trunk diseases.
• the National Grape and Wine
Of
Initiative research programs under way
in 2013, one of the 10 is about trunk
diseases. A multi-crop (grape, pistachio and almond) project was funded
in 2012 to tackle trunk diseases, Dr.
Themis Michailides (UC Davis-Kearney
in Parlier) and Dr. Kendra Baumgartner
(ARS) pulled together a trans-disciplinary team to develop diagnostic tools
and, eventually, measures to reduce the
impact of diseases including Eutypa and
Botryosphaeria. The research will cover
wine grapes from five different regions
and table grapes from two regions.
•Why is there not much written about
trunk diseases in California now, in
magazines such as PWV, nor discussed
at conferences, as occurs elsewhere in
the world? I note that "red blotch" is to
be discussed at the January 2014 Unified
Symposium, but not trunk diseases.
However, the Lodi Winegrape
Commission held a 2011 conference
about trunk diseases, and another is
scheduled. An outstanding presentation
by Gubler and others is available on their
website, with wonderful photos of symptoms. Lodi links are: lodigrowers.com/
guide-to-managing-vineyard-trunkdisease-in-lodi/ and lodigrowers.com/
eutypa-dieback-in-northern-californiavineyards-part-ii-of-ii.
•
Maybe trunk diseases are not an
issue in young vineyards anymore. Has
"young vineyard decline" declined,
and disappeared? Has concern for "red
blotch virus" and "mealybug spread
of leafroll virus" dominated disease
thinking? Both are obviously serious
issues, and worthy of attention. I believe
grapevine trunk diseases are certainly
more widespread. Concern raised by
consultant Lucie Morton about "Black
Goo" (Petri) disease in California in the
1990s led to the eventual formation of
the International Council of Grapevine
Trunk Diseases (see icgtd.ucr.edu), which
held its eighth international meeting in
Valencia in 2012.
•
California growers do not think the
trunk disease issue unimportant. A 2012
poll of AVF members found that trunk
diseases were the third highest viticulture research topic, ahead of leafroll
virus (fifth) and mealybugs (11th), from a
total of 22 presented.
•I speak here of California, but the U.S.
wine sector is more than California.
What about other U.S. wine-producing
states? I ask the same questions about
health of young and old vineyards, and
research and extension efforts.
•Somewhat like José Úrbez-Torres, I find
trunk disease, especially Botryosphaeria,
wherever I travel. This was most recently
in Japan, on both young and old vines,
and both Botryosphaeria and Diaporthe
eres were found, the latter two on the
island of Hokkaido. Again, the diseases
were not previously described, and the
death/decline was put down to old age
or winter damage.
Might I have trunk disease
in my vineyards?
American grape growers may well ask
this question.
Let me list typical symptoms in mature
and young vineyards, another column
with photos is obviously required.
For mature vineyards, common symptoms are:
•Dead arms or whole vines. Often they
were winter-pruned but fail to grow in
the spring. They are often in patches,
contiguous in vine and tractor row. These
Disease Testing
PCR MultiScan for quick
identification of all viruses
and other pathogens.
Includes
Red Blotch virus
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pr actica l win ery & vin eya r d JANUARY 20 14 11
