another bit of info
http://www.agf.gov.bc.ca/cropprot/grapeipm/decline.htm
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<h1 id="titleBanner">Ministry of Agriculture and Lands</span></h1>
<h2 ="underline">Grape Diseases</h2>
<h2>Young Vine Decline</h2>
<ul>[*]
Introduction[*]<a href="http://www.agf.gov.bc.ca/cropprot/grapeipm/decline.htm#survey" target="_blank">Okanagan Survey
Results</a>[*]
<a href="http://www.agf.gov.bc.ca/cropprot/grapeipm/decline.htm#symptoms" target="_blank">
General Symptoms</a>[*]
Diagnosis[*]<a href="http://www.agf.gov.bc.ca/cropprot/grapeipm/decline.htm#links" target="_blank">Further Information on
Diseases Causing Vine Decline</a>[*]
References[/list]
<h2><a name="introduction"></a>Introduction</h2>
Decline of young vines may have several causes,
including diseases, nematodes, environmental damage
such as winter injury, and cultural factors. Often
more than one factor or more than one disease may be
involved.
<h2><a name="survey"></a>Okanagan Survey Results
(2007-2008)</h2>
A recent survey conducted by Agriculture and Agri-Food
Canada investigated decline problems in Okanagan vineyards (O'Gorman, Haag & Sholberg).
The survey confirmed the presence of several
fungal pathogens causing vine decline symptoms. Diseases detected included:
<ul ="arrow_list">[*]Black foot disease (
Cylindrocarpon
spp.) - isolated from vines ranging from 3-15
years of age in several vineyards. Infection was
associated with both a gradual and a rapid
decline of vines.[*]Esca (
Phaeomoniella chlamydospora and
Phaeoacremonium aleophilum) - detected in
necrotic vascular tissue on young vines up to 6
years old. Both
Phaeoacremonium and
Cylindrocarpon were recovered from vines in
one vineyard where over 50% of the vines showed
decline symptoms.[*]Botryosphaeria canker (
Botryosphaeria
parva and
B. dothidea) - detected in
vines ranging from 3-11 years of age in several
vineyards. The vineyards where
B. parva
was isolated showed severe decline problems.[*]Roesleria root rot (
Roesleria subterainia)
- found in several vineyards in vines that were
also infected with
Cylindrocarpon.[/list]
Note that black foot, esca and botryosphaeria
canker are all new diseases that have not been
previously diagnosed in British Columbia vineyards.
<h2><a name="symptoms"></a>General Symptoms</h2>
General symptoms of grapevine declines caused by
fungal pathogens include delayed and stunted growth,
short internodes, yellowing and premature loss of
leaves, tendril dieback, trunk dieback, dead arm and
cankers. Discolouration may be observed in the wood
when vines are cut open. Decline may be rapid,
causing plant death within 2-3 weeks, or slow,
resulting in reduced vigour and yield over a period
of years.
<h2><a name="diagnosis"></a>Diagnosis</h2>
Vine decline symptoms can be difficult to
diagnose accurately. B.C. grape growers interested
in diagnosis of decline problems should contact the
provincial plant
diagnostic laboratory or PARC Summerland for more
information.
<h2><a name="s"></a>Further Information on Diseases Causing Vine Decline</h2>
<ul ="arrow_list">[*]<a href="http://www.agf.gov.bc.ca/cropprot/grapeipm/cylindrocarpon.htm" target="_blank">Black foot disease (
Cylindrocarpon
spp.) </a> [*]<a href="http://www.agf.gov.bc.ca/cropprot/grapeipm/esca.htm" target="_blank">Esca / Young Esca (
Phaeomoniella
and
Phaeoacremonium spp.)</a>[*]
Botryosphaeria canker (Botryosphaeria spp.)[*]
Roesleria root rot (Roesleria subterainia)[*]<a href="http://www.agf.gov.bc.ca/cropprot/grapeipm/rootrot.htm" target="_blank">Pythium and
Phytophthora root rots</a>[*]
Nematodes[*]
Virus and
phytoplasma
diseases may also cause general decline symptoms
in grapevines.[/list]
<h2><a name="references"></a>References</h2>
O'Gorman, D.T., P. Haag & P.L. Sholberg. 2008. New Diseases Causing
Decline of Wine Grapes in the Okanagan Valley. Canadian Plant Disease
Survey, in press.