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Showing posts from 2020

Upcoming webinar on January 13th, 2021

Tremain and I will be participating in an upcoming webinar on January 13th, 2021, which is hosted by PSU. It will start at 10 AM, and we are planning a 2-hour meeting to cover pruning related topics. Please join us, if you have time. You need to register to receive an invitation. Also, please take some time to answer our survey on ripe rot!

Ripe rot (Colletotrichum) grower survey

Dear all,  If you have a moment, please fill in the survey below. A team of researchers, including myself, is working on a new grant proposal to develop management strategies against various fruit rots including grape ripe rot, which is caused by a series of Colletotrichum fungi.  The aim of this survey to determine what we need to focus our research effort. The project aims not only grapes, but other crops, so, please enter your input so that voices from grape growers will be heard. Thank you in advance for your time. It should not take more than 5 min. Best, Mizuho

In preparation for Hurricane Delta

Hurricane Delta seems to impact our regions, starting Saturday (10/10), and rain may last until Tuesday (10/13) or so . Depends on your location and cultivar selection, you may have some grapes that may need more time before harvest. ( A link to Hurricane Delta tracker from - will play a video. ) The target diseases right now are late-season fruit rots (Botrytis, ripe rot, bitter rot, etc.) and downy mildew (on leaves). The links here are  the presentation slides from the last viticulture meeting that covers some of the diseases mentioned above  and   a list of short PHI materials for Botrytis, powdery mildew, and downy mildew , which may help you decide what to do. If you decided to wait until the storm is over, there are several materials with a very short PHI that you may want to consider, such as Oso/Ph-D or Elevate for Botrytis and a phosphorous acid (Prohyt, Phostol, etc.) or Lifeguard for downy mildew. FYI: when we tested in the field, Oso plus Double Nickel combinat

Prepare for a potential rain event for this weekend.

Looks like a tropical storm Marco is moving westward, but Laura may hit our areas during this weekend. The current forecast shows (opens a new window with a link to potential movement to Virginia and surrounding states around this Saturday (8/29). Many white cultivars will be either ready to pick or getting very close to harvest, and red cultivars may have several weeks to go, depends on where you are what you grow. At this point in the season, the target diseases are late-season fruit rots (Botrytis, ripe rot, bitter rot, etc.) and downy mildew (on leaves). For whites, it may be a decision of when to pick, but not what to spray. If you decided to wait until the storm is over, there are several materials with a very short PHI that you may want to consider, such as Oso/Ph-D or Elevate for Botrytis and a phos acid for downy mildew. FYI: when we tested in the field, Oso plus Double Nickel combination worked well against sour rot. For reds, it will depend on when and what you

Downy, Botrytis, sulfur burn, and open house

With recent rain events and warm and humid nights, the risk of downy mildew and Botrytis are probably high in many areas of Virginia. For example, I counted seven days (at Winchester, VA) and eleven days (at Rustburg and Scottsville, VA), with downy mildew infection events in the past two weeks according to the NEWA model ( ). It is very important to keep your vines protected, and if you think you need to have a kick-back activity against downy mildew to counteract the recent rain event that your previous spray might not have provided good coverage, add a phosphorous acid material such as Prophyt or Phostrol.  Please refer to this list of materials with short PHI since some of the cultivars are getting very close to harvest. Note: although both sulfur and copper have a short PHI, we typically do not recommend spraying these materials within 3-4 weeks of harvest due to its potential negative impacts on the fermentation or wine quality.  When some of us ended up

Recent rain events and downy mildew spray

Central and northern VA received much-needed rains in the past two days. Looks like the chance of thunderstorm is high in today and tomorrow too. Several people asked me whether they need to jump on their tractor now and spray for downy mildew or not. Here are snapshots of downy mildew risk events in three locations during the past two weeks. Southwestern VA, Floyd: none Central VA, Afton: 7/11, 7/22, and 7/23 Northern VA, Winchester, 7/11 (a very short one) and 7/22 Since we have been experiencing a very dry season, I do not think we need to react to every rain event, especially if your previous spray was less than 7-10 days ago . If you are due to spray soon anyway, it may be a good idea to have a Phos acid material (e.g., Prophyt, Phostrol, Agri-Fos, etc.) in the tank-mix as insurance. For example, my previous spray (a fixed copper material) was on the 11th and my plan is to spray my vines this Saturday (the 25th) with a Phos acid, sulfur, and another PM material (Vivando,

Disease risk events from last two weeks and quick reminders

Here are snapshots from the NEWA risk models from the past two weeks. Floyd: no black rot or downy mildew infection events Afton: black rot and downy mildew infection event on 7/1-2. Winchester: downy mildew infection event on 7/8 Looks like we are having relatively dry conditions. Depends on where you are and which cultivar you grow, you may not need to worry too much about downy mildew or black rot for a while. Also, most of our vines are done with the critical period of cluster susceptibility to black rot, downy mildew, and powdery mildew. What I would keep eye on will be powder mildew, since the pathogen does not require water for infection. Sulfur is a good material, and you can add powdery mildew materials, such as Quitec, Vivando, Torino, DMI, and SDHI to provide extra protection. When you spray a sulfur product, make sure the sprayed material will be dried up before temperature gets above mid-90F. If the leaf surface is wet with sulfur when the temperature gets high, it

Rains and fungicide sprays

It looks like we will see a series of rain events in the next few days. As noted in the previous virtual viticulture meetings, we had several black rot and downy mildew infection events in the past two weeks, and some people start to see the development of these diseases. Some growers asked me how long does it take for fungicide materials to be dry enough to be rainfast. It depends on your sprayer, droplet size, weather conditions, etc., but typically, I hear 1.5 hours to 2 hours are required. Some fungicide labels show the expected dry time. The other common question is about how much rain is enough to wash off fungicide materials from the plant surface. Please check the excellent articles from Dr. Annemiek Shielder ( link 1 , link 2 ). She talks about the rain fastness of some products using a rain simulator. It looks like there is a sharp drop only after 0.04 inches of rain, but after that, the material tends to stay on the surface, even if there are more precipitations. In the art

Slides from a virtual vineyard meeting, 18 June 2020

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. Critical time *very quick* grape disease management reminders  - please see the previous two presentation slides for more information! 1) June 4th meeting , 2) PSU meeting .

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.

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. 1) short training and Q and A (10 April 2020). 2) Grape fungicide planning workshop (24 March 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).

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 nex

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.  Nita - Early season disease management 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.

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

Quick reminders on Phomopsis and a virtual meeting

It looks like we will have another wet week coming up. Our Chardonnay is about 50% bud break at this point, thus, I think that many folks south of us are seeing 1-3 inches growth. Once again, a 1-3 inch shoot growth is the timing for Phomopsis management. The forecast tomorrow and this weekend seems to be OK for spraying ( but watch out for the wind! Saturday seems to be a better day ). Also, if it is too windy to spray tomorrow and looking for things to do, we have a short workshop/Q&A session on , which is created to help your spray management, from 3 to 4 PM. Please join us in a virtual meeting.

Working at home? Please join our online workshop: 4/10 (Friday) from 3 PM.

Grape Pathology lab will hold an online workshop on, which is a new online database to help you track, manage, plan, record, and report your pesticide usage. You may remember my presentation at the VVA meeting in February.  It will be a 20-min presentation followed with a 40-min Q and A. We will help you set up an account, enter your vineyards and blocks information in the system, and go through basic functions to kick start the season. It will be on next Friday (4/10) from 3 PM. Please use the URL below to register by 4/8 so that we can send you a Zoom link for the meeting. In addition, if you find your vineyard management in a bind related to the pandemic, please keep records- a paper trail- of the details. This may be helpful if there is assistance available after the pandemic.

Bud break and Phomopsis

Our Chardonnay is about to break buds. It is about 2 weeks ahead of "normal" year, whatever it means at this point... One of the diseases you need to consider soon after bud break is Phomopsis cane and leaf spot. It causes minor leaf spots, which is more evident to our eyes, but the more critical damage is caused by necrotic lesions on shoots and rachis. It also causes berry rot; however, it is not common with wine grapes because of our spray programs.  (Typical shoot symptoms) Phomopsis spores can cause infection under the relatively cooler environment (the upper 40s). Thus, springtime rain events are ideal for Phomopsis to produce spores and cause infection. Unfortunately, we do not have curative fungicides for Phomopsis management. Therefore, it is vital to protect young tissues when they come out from the older canes and trunks. Since shoots will proliferate quickly, you may need to spray 1-2 times against Phomopsis, depending on how much rains we receive

Slide sets from recent extension meetings.

It looks like I forgot to upload my slides from recent extension meetings. So here you go! 1) Slides from VVA meeting on grape pathology research projects and grapeIPM 2) Slides from pruning workshop 3) Slides from IPM workshop 25 March 2020  Note: for #3, I am posting one from yesterday (but not the one from Tuesday) since this one is more up-to-date. As Tony mentioned yesterday, although we do not have a plan for face-to-face meetings at this point, we are available through email. Send me an email if you have questions regarding grape disease management. It would work better if you can send me pictures of affected grapevines. ;)

Reminder: online grape disease workshop tomorrow (3/24) from 1PM!

We will have an online grape disease management workshop tomorrow from 1 PM. Thank you for those of you who registered already. You should have received an email this morning. For those of you who registered today, I will send you an invitation email tonight.  We will use the Zoom application ( ), which you can connect via a computer or smartphone, or tablet. In order for us to organize the event, please register using the form below: Registration form for grape disease management workshop on 3/24/2020 Once you receive an invitation to join the conference, please click on the link in the invitation before the meeting. It may ask you to install Zoom application on your computer or smartphone or tablet. Guest Account and upcoming grape disease management workshop

As I presented at the VVA meeting in February, our team has been working on an online disease management aid called The main functions of the system are to help you keep track of your fungicide (and other pesticides) inventory, planning, usage, record-keeping, and reporting. We are in the last stage of the developmental phase, and are welcoming users to test it out. There are some details to be polished, but most of the functions are available. I have been using it in the past two seasons, and I am surprised how it made my spray preparation and record-keeping easier. If you wish to participate, please go to and request a new account. It is free for now. If you just want to see how it works, we created a guest account. Username: guestvineyard Password: VitisGu3st If you find some errors or have some comments or suggestions, please let me know. With all the restrictions on the gathering of people, I think it is a very good time for you to think ab

Changes in upcoming grape disease management workshop on the 24th and 26th

The meetings on the 24th and 26th of this month will be consolidated into one ONLINE meeting on the 24th from 1 PM. We will use Zoom application ( ), which you can connect via a computer or smartphone. In order for us to organize the event, please register using the form below: Registration form for grape disease management workshop on 3/24/2020  If you have registered with Ms. Beth Sastre, we already have your name. Once you register, we will send an invitation to the meeting. Please click on the link in the invitation before the meeting. It may ask you to install Zoom application on your computer or smartphone or tablet. Sorry for any inconvenience it may cause.

Upcoming VCE Vineyard meetings

Upcoming Vineyard Meetings a)    17-18 Feb      Central Virginia UvaSapians (fee) b)    19-21 Feb.     VVA Winter Technical (fee) c)    27 Feb.          VT/VCE Vineyard Pruning Workshop – Winchester, VA d)    10-12 March Eastern Wine Exposition – Lancaster PA (fee) e)    14 March      Pruning Competition  -Abingdon, VA f)     24 March      Interactive grape disease management planning workshop (in English) g)    25 March       VT/VCE Vineyard IPM workshop– Charlottesville, VA h)    26 March      Interactive grape disease management planning workshop (in Spanish) __________________________________________________________________ More Information a)    17-18 Feb      Central Virginia UvaSapians (fee) Hosted by the Monticello Wine Trail Association, but growers from across the mid-Atlantic are welcome to register.  Dates and the registration link are below. Monday, Feb. 17, 2020 - 8:00 AM-4:00 PM (Winter Pruning) Tuesday, Feb. 18, 2020 - 8:00 AM-4:00 PM (Winter