How to Manage Pests
UC Pest Management Guidelines
Pathogen: Phomopsis viticola (sexual stage: Diaporthe ampelina)
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.
See EUTYPA DIEBACK for management practices.
UC IPM Pest Management Guidelines:
R. J. Smith, UC Cooperative Extension, Sonoma County
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