Skip to main content

Trunk Disease Projects

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. 


  1. The second picture depicting vine leafs with brown areas and brownish wilting leaves caught my eye. I've got this in a few areas of my vineyard and at first I thought I was fighting Downey Mildew, but these leaves didn't really look like the Downy Mildew pictures in my IPM Scouting Guide. I took pictures and was going to try and find someone that could identify what's going on. I marked the infected shoots and have been observing that there doesn't seem to be any spread to adjacent non-infected shoots on the same vine cordon. I would like to learn more and hopefully there is a way to not loose the vines or at least learn how to best manage and prevent the spread. Can you point me in the right direction to get some assistance? My vines are located in the Catlett, Virginia area.

  2. Hi Michael,
    The best way is to send some samples (unfortunately, it has to be trunk tissue to isolate the pathogen) to VT's plant disease clinic. If you contact your local extension agent, they will assist for the submission of your sample. If you do, please put my name, along with your extension agent's name on the form so that I will also receive a report from them.

    If it is indeed Esca (aka Petri disease, black goo), chances are you can re-train the vine by cutting the infected area and promote basal buds to come out. (I.e., if you notice suckers coming out this year, you may want to keep it.) This pathogen is relatively slow growing, thus, if you rotate your trunk every 4-5 years, I think you can manage the vine. If you have further questions, please shoot me an email.


Post a Comment

Please leave your comment here. In order to avoid spam messages, l moderate comments, thus it may take a few hours for your comment to be posted on the page.

Popular posts from this blog

Season's Greetings!

I hope you and your family have a good holiday season and a Happy (and safe) New Year! Thanks again for your support of our programs. Here are some recent media highlights. 😉 The link will open a new window. AHS AREC promotional video  that highlights some of our activities. The link did not work... It asks you to log in to VT. I will request the IT people to change the setting, but in a meantime, here's the same video. We also appeared in  the Library of Congress project “Winery Workers of Virginia”. One more announcement: I will be moving this blog to a new location ( ) early next year. I had to make a change due to the email subscription service, which has been terminated.  You do not need to change your bookmark or your email subscription. The URL will be forwarded to a new site and your email subscription has been moved to a new site already. 

Downy mildew gallery

At Winchester, we had light rain events during the night of 6/12/09, but it was short events and the relative humidity was low (80% or so), thus it probably did not promote any infections. However, we are experiencing continuing favorable nights for downy mildew sporulation (average T>55F, high RH (80-100%)) for 10 days now. Yesterday, we conducted a formal disease assessment, and observed first incidence of powdery mildew for this season. We had plenty of infection events in last two months, so it was not surprising. At this point, it is a trace level of infection on untreated vines. Downy mildew was the major disease so far. We had up to 40% incidence on untreated vines. Next runner-up was black rot. It varies vine to vine, but some of vine had 10-15% incidence. Phomopsis was omnipresent as I expected from early May rain falls, but severity was low overall. We will examine diseases again in the near future, and I will update as the season goes. Here is downy mildew ga

Recent downy mildew risk events

 It seems that several rain events have happened over the course of the past two weeks or so. Here is a summary of recent downy mildew risk events, based on the NEWA stations and DMCast. Bristol, VA Fifteen days with potential DM infection event(s) since Sept 1. The latest event happened last Sunday. Floyd, VA Eleven days with potential DM infection event(s) since Sept 1. The last event happened last Friday. Charles City, VA Twelve days with potential DM infection event(s) since Sept 1. The latest event happened yesterday. Central VA Since there was a wide variation among stations, I am listing several around Central VA. Tyro, VA Nine days with potential DM infection event(s) since Sept 1. The latest event happened yesterday. Red Hill and Crozet, VA Only one day with potential DM infection event(s) since Sept 1. Olympic Lake Thirteen days with potential DM infection event(s) since Sept 1. The latest event happened last Sunday. Washington, VA Eight days with potential DM infection event