Grape vine canker disease
Vineyard Trunk Diseases in California
by Kendra Baumgartner, USDA Agricultural Research Service Plant Pathologist and
Renaud Travadon, Plant Pathology Dept, UC Davis
Supported by a USDA-NIFA Specialty Crop Research Initiative grant
All vineyards in California are likely to be infected with trunk diseases (a.k.a. wood-canker diseases). The main trunk diseases are Botryosphaeria dieback, Esca, Eutypa dieback, and Phomopsis dieback. The infections are chronic and accumulate over time. Farming vines with trunk diseases becomes less and less profitable with each additional year, to the point at which the entire vineyard must be replanted. In this way, trunk diseases significantly limit vineyard longevity.
Follow this guide to identify trunk diseases in your vineyard. It is not critical to identify the exact trunk disease because the management practices are the same and because they typically occur in mixtures of one or more trunk disease. What is important is that you:
1) Recognize trunk diseases as a problem,
2) Understand the preventative practices,
3) Adopt these practices in newly-established vineyards,
4) Do so on an annual basis throughout the life of the vineyard.
Botryosphaeria dieback and Phomopsis dieback do not have specific symptoms. Instead, they are best characterized by the presence of one or more of the common symptoms listed above.
That said, Phomopsis dieback is caused by the same fungus as Phomopsis cane & leaf spot (Phomopsis viticola or, according to its new name, Diaporthe ampelina), which does cause specific symptoms on the leaves. However, the relationship between the foliar symptoms of Phomopsis cane & leaf spot and the wood symptoms of Phomopsis dieback is not well understood. A vine can have one and not the other, which may be due in part to the fact that our California climate is rarely conducive to foliar infections by the fungus or to differences in strains that attack certain plant tissues.
Prevent Trunk Diseases
Trunk pathogens attack primarily through pruning wounds with rain during the dormant season. Susceptibility to infection depends in part on when the pruning cuts are made. Pruning wounds made early in the dormant season (December) are more susceptible to infection... READ MORE HERE... Prevent Canker Disease Baumgartner
Do you have a trunk disease?
Look for these common symptoms, which are typical of all trunk diseases:
1) Dead spurs
2) Stunted shoots
3) Wood symptoms
Esca and Eutypa dieback have specific symptoms, which are diagnostic of these two trunk diseases:
2) Eutypa dieback
Photo credits: K. Baumgartner and R. Travadon