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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 10/08)
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.
In table grapes, note
locations in the vineyard with poor budbreak in spring. Examine these areas in
fall for disease damage. Mark locations of vines with poor growth for future
confirmation and management.
| Common name |
Amount/Acre** |
R.E.I.+ |
P.H.I.+ |
| (trade name) |
|
(hours) |
(days) |
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| When choosing a pesticide, consider efficacy and the general properties of the fungicide as well as information
relating to environmental impact. |
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| A. |
THIOPHANATE-METHYL |
| |
(Topsin-M) WSB |
1% |
7 days |
NA |
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MODE
OF ACTION GROUP NAME (NUMBER1): Methyl benzimidazole (1) |
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COMMENTS: 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 County
L. G. Varela, UC IPM Program, Sonoma County
S. Vasquez, UC Cooperative Extension, Fresno County
J. J. Stapleton, UC IPM Program, Kearney Agricultural Research Center, Parlier
A. H. Purcell, Environmental Science, Policy and Management, UC Berkeley
Acknowledgment for contributions to Diseases:
G. M. Leavitt, UC Cooperative Extension, Madera County
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