How to Manage Pests

UC Pest Management Guidelines

Grape

Phomopsis Dieback

Pathogen: Phomopsis viticola (sexual stage: Diaporthe ampelina)

(Reviewed 7/15)

In this Guideline:


SYMPTOMS AND SIGNS

Phomopsis dieback, Botryosphaeria dieback, Esca, and Eutypa dieback make up a complex of ‘trunk diseases' caused by different wood-infecting fungi. Wedge-shaped wood cankers form in infected wood and are indistinguishable from those associated with Botryosphaeria dieback and Eutypa dieback. Dead spurs and dieback caused by Diaporthe ampelina are symptoms shared in common among multiple trunk diseases, which often occur in mixed infection within the vineyard and even within an individual vine.

COMMENTS ON THE DISEASE

Symptoms first become apparent in vineyards 5 to 7 or more years old, but the infections actually occur in younger vines. Pycnidia, the overwintering structures that produce spores, are embedded in diseased woody parts of vines. During fall to spring rainfall, spores are released and wounds made by dormant pruning provide infection sites. After a pruning wound is infected, the pathogen establishes a permanent, localized wood infection, which cannot be eradicated by fungicide applications.

MANAGEMENT

See EUTYPA DIEBACK for management practices.

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Grape
UC ANR Publication 3448

Diseases

R. J. Smith, UC Cooperative Extension, Sonoma County
L. J. Bettiga, UC Cooperative Extension, Monterey County
W. D. Gubler, Plant Pathology, UC Davis

Acknowledgment for contributions to Diseases:
G. M. Leavitt, UC Cooperative Extension, Madera County
A. H. Purcell, Environmental Science, Policy and Management, UC Berkeley
J. J. Stapleton, UC IPM Program, Kearney Agricultural Research Center, Parlier
L. G. Varela, UC IPM Program, Sonoma County
S. Vasquez, UC Cooperative Extension, Fresno County

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