Many (if not all) of vineyards east of the Rockies have challenging summer time conditions that promotes develpment of major fungal diseases such as downy mildew, powdery mildew, black rot, Phomopsis cane and leaf spot, and Botrytis, we often focus our discussion on these diseases. However, we should not forget about trunk diseases that can affect the life of grapevines. Some of the examples are: Botryosphaeria canker, Petri disease (aka Esca), Crown Gall, and Eutypa dieback. In addition, some of the other pathogens such as Phomopsis are also capable of infecting woody tissues.
These diseases typically cause damages to the infected vines in a long timespan. Thus, the infection today may not cause any obvious damage until a few years from now. These pathogens act more like a “silent killer” and can shorten the life of the vine by 5-10 years. Thus, the prevention of these diseases will benefit you in a long run. On the other hand, if you have younger vines (up to 5 years or so), these diseases can progress rapidly and cause a decline of the infected vine within a year or two.
Since these pathogens limit the movement of water and nutrients by infecting xylem and phloem, typical symptoms of these diseases are discoloration of leaves and shoots. However, often time it is very difficult to diagnose what is going on because many of symptoms are very similar to each other.
To address these issues, our lab have a collaborative project with Dr. Kendra Baumgartner's group at USDA/ARS in Davis, CA. We obtained USDA/NIFA Specialty Crop Research Initiative grant in 2012 to investigate more on these important diseases. The primary focus of our group is to develop extension tools that can help diagnostics as well as development of management strategies.
If you are interested in our activities, please visit our project site (Note: we are still working on the hosting site, I am hoping to have it published by mid-April 2014). In the future, our plan is to provide 1) Mobile/Web application for trunk disease diagnostics, 2) Updated factsheets for major trunk diseases, 3) Develop a new trunk disease database, 4) Offer webiners and video clips on trunk disease management, and 5) Offer in-service trainings for extension agents, crop consultants, certified pesticide applicators, etc.
Also as a part of the project activities, I have uploaded trunk disease management guide for VA. Please take a look at it.