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How to Manage Pests
UC Pest Management Guidelines
Grape
Eutypa Dieback
Pathogen: Eutypa lata, E. leptoplaca, and other fungi in the Diatrypaceae family.
(Reviewed 6/06,
updated 6/06)
In this Guideline:
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Eutypa dieback delays shoot emergence in spring, and causes shunted
shoots and leaves that are chlorotic, tattered,
and cupped. Symptoms in the wood are characterized by darkened cankers that develop in the vascular tissue. The cankers are often wedge shaped (like a
pie chart) in cross-cuts of affected cordons or trunks. Cankers develop faster
in the direction of the roots than toward the end of cordons. Extensive
infections lead to vine death.
Eutypa dieback is not generally visible in vines younger than 5 to 6
years old although vines may still be infected. The disease is most easily seen
in vines established for
10 or more years. The fungus survives in diseased wood and produces perithecia in old, infected
host tissue under conditions of high moisture. In California several plants in
addition to grape serve as reservoirs for the pathogen including almond,
apricot, blueberry, cherry, crab apple, Ceanothus spp., kiwi,
pear, oleander, and native plants including California buckeye, big leaf maple,
and willow. Ascopores are discharged from perithecia soon after rainfall.
Infection occurs through pruning
wounds,
which remain susceptible much longer early in the dormant season than later in
the dormant season. Overall susceptibility is about 6 weeks.
Prune late in the dormant season to promote rapid healing of wounds.
Remove and burn infected wood inside the vineyard and dead wood in adjacent
vineyards and orchards to reduce the spread of the pathogen. Cut out and remove
dead arms and cordons from the vineyard during dormancy. Completely remove all
cankers, pruning below the canker on the vine or trunks until no darkened
canker tissue remains. Make large cuts directly after a rain because the risk
for infection is lowest at this time as the atmospheric spore load has been
washed out temporarily (or is at its ebb). Double pruning cordon-trained vines
can help final pruning cuts to be made quickly and late in dormancy, thus
reducing the chance for infection.
For additional
protection, consider treating pruning wounds.
| Common name |
Amount/Acre** |
| (trade name) |
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| When choosing a pesticide, consider information relating to environmental impact. |
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| A. |
THIOPHANATE-METHYL |
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(Topsin-M) WSB |
1% |
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MODE
OF ACTION: A MBC (Group 1)1 thiophanate fungicide. |
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COMMENTS: Restricted
entry interval: 7 days. Mix as a 1% paste and apply to cut or pruned surfaces immediately after cutting. Use allowed under a Special Local Needs label. |
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UC IPM Pest Management Guidelines: Grape
UC ANR Publication 3448
Diseases
W. D. Gubler, Plant
Pathology, UC Davis
R. J. Smith, UC Cooperative Extension, Sonoma Co.
L. G. Varela, UC IPM Program, Sonoma Co.
J. J. Stapleton, UC IPM Program, Kearney Agricultural Research Center,
Parlier
G. M. Leavitt, UC Cooperative Extension, Madera Co.
A. H. Purcell, Environmental Science, Policy and Management, UC Berkeley
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