Thursday, June 4, 2020

Presentation slides from 4 June 2020 virtual meeting

Thanks for all who were able to make it to our virtual meeting this afternoon.

The file below is the slide set I used today, the link will open a pdf file in a new window.

Wednesday, May 27, 2020

Presentation slides from PSU webinar

Thank you for those of you who were able to join the webinar today. You can access the slides from today from the link below (will open a new window with a pdf file).

PSU Grape management reminders from bloom through bunch closure (5/27/20)

Please see this posting for how to access the Google sheet that I showed during the webinar.

Friday, May 22, 2020

Video recordings from recent online grape pathology workshops

It took a while, but I think I figured out how to share the recodings. If you click the line below, each opens a new window with the video recording of the workshop. If you are wondering why I am pausing here and there, I was reading questions from the chatbox.

Thursday, May 21, 2020

Presentation slides and how to download the spreadsheet.

Thank you for participating in our bi-weekly meeting!
Here's a slide set from my portion of the meeting (will open a pdf file).

The spreadsheet examples I showed during my presentation can be accessed from the "Resources" tab on your right-hand side (or at the bottom, if you are accessing using a tablet or phone). (or click here) You can edit it after downloading it onto your device (file > Download >, please see the picture below) (and then you may upload it to Google, if you choose to do so).

Wednesday, May 13, 2020

Disease management after bad frost events?

Unfortunately, many of our vines suffered from frost events that happened over the past weekend (and this morning for some of us). I think I lost about 30-40% of Chardonnay shoots. :( 
Here are some disease management tips for dealing with frost-damaged vines, especially if your vines have shoots with several to many leaves open.

  • Minor damage: E.g., < 15% of shoots affected.
    • You probably do not need to alter your spray schedule.
  • Moderate damage: E.g., 20-50% sporadic damage throughout a block. Some shoots are heavily damaged, but others are OK.
    • You may keep your regular spray schedule. If we have an extensive rain event(s), there is some risk of Botrytis infection on the damaged shoots. This pathogen can produce spores on the dead tissues. If you are concerned about a potential Botrytis infection (i.e., you have a Botrytis-prone cultivar and the weather forecast says there will be a big rain event coming soon), you may want to use either captain or copper instead of mancozeb for next spray, since these two have some efficacy against Botrytis.
    • If you keep using either captan or copper as one of your backbone material, please keep in your mind that you need to add a QoI (i.e., strobilurin) or DMI (i.e., sterol inhibitor) for black rot management, when we get close to blooming time because these two materials won't work against black rot. 
    • In addition, it is probably a good idea to plan for good protection against Botrytis at bloom. In addition to the risk of Botrytis infection on dead shoots, inflorescences on shoots from the secondary buds may make the blooming period last longer than usual. 
      • E.g., You can use two Botrytis materials with different FRAC groups to protect flowers, maybe use one group at trace bloom, and the second group at 50% bloom. Plus, make sure to mix a Botrytis material with either captan or fixed copper for the fungicide resistance management. 
    • Also, you probably need to spend more time on canopy management to avoid crowded canopy due to extensive lateral shoot development from the damaged shoots. 
    • As of today (5/13/20), I do not see any extensive rain events (crossing fingers). It looks like we will have showers here and there in the next 3-4 days, and we are expecting days above 80F, thus, I am hoping that damaged shoots desiccate soon so that we don't need to worry about Botrytis too much. We will see... 
  • Severe damage: widespread and extensive. E.g., >50%
    • If you think there is a chance of having fruits, please see the comment above. You will most likely have more dead tissues remaining in the canopy, thus, the risk of Botrytis can be high. 
      • Whether you can expect fruit or not depends on the location of the damage and other factors. E.g., If you see more damages on the upper part of the shoots and clusters/inflorescences seem to be intact, you may get lucky, but I must say that the damage on the inflorescence is very difficult to see.
    • Even if you think it will be a total loss (sorry), you still need to protect your vines. Once shoots start to develop from the secondary buds, you need to protect them. If you are not planning to have any crop, you can have a lean disease management program. E.g. use mancozeb plus sulfur, or captan plus sulfur, or fixed copper for the rest of the season. (plus you do not need to spray for grape berry moth) 
      • Spraying every 10 to 14 days may be enough, but it also depends on the weather. If there are many rain events, you may need to either shorten the spray interval or add a phosphorous acid product or another downy mildew material. (note: do not mix a phosphorous acid and copper, which cause phytotoxicity)
      • You do not need to worry about the 66-day PHI of mancozeb since you do not have harvest; thus, you can use mancozeb late in the season. However, keep eye on the limit of total mancozeb used, which is 19.2 lb a.i./acre/year, but please see the label for your product to make sure.
  • I can only cover potential disease management, and I understand that there is more to it. For more frost-damage related information, I found a note from Dr. David Lockwood (University of Tennessee), which he posted last month, very useful (this link will open a new window with a pdf file).
Now I am hoping that the periodical cicada in our area won't be so bad...

    Thursday, May 7, 2020

    Thank you for your participation today!

    Thank you for joining our virtual vineyard meeting today. Let's hope that we won't see a bad frost event over this weekend...

    Please find the link below for my portion of the presentation. 

    As Tony mentioned at the meeting, if you have any questions, please send me an email, which is the best way to contact me right now.

    Friday, May 1, 2020

    Virtual vineyard meeting on 7 May from 12 PM!

    Here's a snip from Tony's Viticulture Note newsletter: If you wish to have a link to the meeting, please send me an email. (Due to the security concern, I prefer not posting the link on the website.) Looking forward to seeing you virtually!

    Virginia Cooperative Extension will host a series of virtual vineyard meetings using Zoom video conferencing starting Thursday, 7 May. We are planning for the meetings to run about 90 minutes and will feature updates from Virginia Tech specialists, with ample time allowed for questions, answers/discussion. The meeting on 7 May will start at noon and meeting invitation details are shown below. If you are new to using Zoom, you can access the meeting with desktop or mobile devices by clicking the link after "Join Zoom Meeting". You may also call in using phone numbers shown below in the invitation, but be advised that these are NOT toll-free calls.

    Planned topics for Thursday, May 7th include:
    - frost updates and early season vineyard management considerations in light of a cool start to season (T. Wolf)
    - early-season disease management (M. Nita)
    - early-season pest management considerations (D. Pfeiffer)
    - Review of recent questions from the field (T. Hatch)
    In advance of next week's meeting, we would like to invite you to submit digital photos of things that you might be seeing in your vineyards and that you might have questions about. Along with our updates, we could discuss these pictures together and try to provide relevant feedback and recommendations. This could include pictures of disease, insects or insect injury, or other vineyard issues. If you submit photos of any issues you are seeing, please include any pertinent information and your specific question(s). We will keep these photos anonymous, but read your question/comments about each image to the group. Of course, sharp and clear images will work best for this, and it would be ideal to receive photos by 10:00 am on Thursday the 7th. You may also submit questions in advance or ask them during the course of the meeting via the Chat feature within Zoom.
    We look forward to your participation next Thursday, and please mark your calendars for similar meetings on 21 May, and 4 and 18 June. Additional meetings will be scheduled as interest or need dictate. Presenters and topics will vary from meeting to meeting. We are pleased to partner with the Virginia Vineyards Association in hosting these meetings. Please note that the meeting on the 7th of May was originally listed as May 4th on the VVA website.