Virginia Grape Disease Updates

Looks like we will likely to have another round of rain from Hurricane Irma sometimes next week. Just a reminder that we do not have any curative materials for Botrytis and other late season rots. In order to obtain better results, you need to protect your vines before the rain! Please see the previous post for disease management tips and the list of low PHI materials for each diseases. Also, it is very important to keep FRAC codes rotated!

At Winchester, night time temperature in recent few days is getting pretty low to the point that relative humidity during the night is close to 100%. In addition, we are looking at a thunderstorm forecast tonight that will bring high relative humidity. These conditions favor downy mildew development because downy mildew pathogen prefers to produce spores under dark, humid conditions. At this point, you do not need to worry about downy mildew infection on clusters; however, they can still infect leaves. Often time, you will initially see infection on the top of the canopy because younger leaves are more susceptible than older ones. Losing the top leaves and laterals are not a big deal; however, once the infection gets severe, it can defoliate many leaves rather quickly (as in the picture above), and that can affect maturing process. As usual, it is much better and easier to have a preventative program than trying to play the catch-up game. There are many good protective mater

In a typical year, the fourth of July weekend is the time the critical period for cluster infection by downy mildew, powdery mildew, and black rot will end for many of us because it will be about 5-6 weeks after bloom. (Bloom this year was about 1-2 weeks ahead of typical years, so, this week maybe it for 2017.)  This critical time varies by varieties, but in general, 4 to 6 weeks and 3 to 4 weeks from bloom for V. vinifera and V. labrusca species, respectively.  After this critical period, you should be able to relax a bit because these pathogens are no longer able to cause disease on berries. Plus, powdery mildew tends to slow down because it is not very active under hot condition (> 90F). So, what’s next?  As usual, disease dynamics depends on environmental conditions, cultivars, and cultural practices you employ, but in general, this is the moment when you will be thinking about late season diseases such as Botrytis, ripe rot, bitter rot, and sour rot.  The spray tim

As of today, it is about 10% bloom at our Chardonnay plots. Since bud break was about 2 weeks ahead of a typical year, things are moving along as we would expect. Of course, bloom in VA almost always has to happen in rain... As for bloom time disease management consideration, please refer to the previous post. From this point on, 4 to 5 weeks will be a critical period for management of downy mildew, powdery mildew, and black rot. Please make sure to keep your vines covered. Once again, providing a protection is much better and easier than playing a catch-up, especially if it comes to grape disease management in VA. You can use protective materials such as mancozeb, copper, and sulfur as your backbone, and add more specific (and often locally systemic) materials. Some of these materials have efficacy against multiple diseases (either by itself or through the combination of two materials). Examples are DMI, aka SI (FRAC = 3), e.g., Rally, tebuconazole, Mettle, etc. Inspire su

Some shoots of our vines are about to reach the second catch wire, but I saw many that were still about 10-12 inches too. It looks like series of rain during the month of April drove developments of black rot and Phomopsis. Although it was not severe, I found several vines with leaf lesions of black rot, and a few vines with Phomopsis. Tan-colored lesions are symptoms of black rot. If you click the image, it will open a larger file where you can observe fruiting bodies (tiny black specks) within these lesions. It is a bit difficult to see, but, please note the holes on the upper picture (in the blue circled area). The lower picture shows more characteristic leaf spots of Phomopsis cane and leaf spot. For management tips, please refer to my  around bloom disease management consideration post.  Please remember that clusters will be susceptible to black rot from bloom to 4-5 weeks after bloom. Looks like Winchester area is expecting chances of rain on Friday, Monday, and the

Many of our vines at VT's AHS AREC are about to reach the first catch wire and going strong. When shoots are about 10-12 inches long, downy mildew, powdery mildew, and black rot tend to show up. Then, at bloom time, flowers and young berries will be susceptible to these diseases until 4-6 weeks after bloom.  In addition, Botrytis, ripe rot, and bitter rot can cause infection on flowers.  Thus, you need to consider multiple diseases management. However, you probably do not need to manage all with expensive materials. What you need to think about is which disease(s) have been the major issues at your vineyards. The disease history of your vineyards tends to repeat itself because of the environmental conditions at your site and availability of spores from previous infections. Downy and black rot management depend on rains.  I have seen cases where downy or black rot developed before bloom under wet conditions. We receive a little fewer rains than last year, but it is always best to

Our reds broke buds, and whites have about 1-inch shoot growth on it today, and more rains in the weather forecast. It is time to think about Phomopsis! What happen from this point to pre-bloom is a relatively simple spray program to manage Phomopsis, downy mildew, and powdery mildew. During the early part of the season, I typically recommend a mix of mancozeb and sulfur or copper by itself. The reason why I recommend mancozeb now is because it works on so many different diseases (including Phomopsis which is the main target for us), plus, mancozeb has a 66-day PHI and a limit on the amount of mancozeb to be used in a year (e.g., 24 lb (or 18 lb of a.i) if you Dithane DF). Thus, I would like to use mancozeb-based product early in the season. I have been often asked whether you should include sulfur or not. If your vineyard has a history of powdery mildew outbreak, it would be a good idea to have a sulfur in your tank mix, even at early part of the season. Although you may not abl

It looks like the 2017 season for us has officially begun. Our 8 years old Chardonnay at Virginia Tech's Winchester AREC was about 10% bud break as of yesterday. Despite a warm winter, a colder spring might have kept things slow (I am not complaining!) Once again, the important disease at this point is Phomopsis cane and leaf spot. Please refer to my previous post about Phomopsis management. Also for our Chardonnay plot, we have a chronic issue with climbing cutworms. Since we know the location of our vineyard where we always see some damages, we typically apply an insecticide to the panels of vines that is facing a wooded area. Without spraying the whole vineyard, it seems to provide adequate control. Good luck with the 2017 season. I will post key disease management tips as the season moves along.

Our Chardonnay and some of the hybrid vines are in bud swell stage as of this week, and others are tagging along.  It looks like we will see bud break very soon with warmer temperature coming up next week. One of the diseases you need to consider this time of the year is   Phomopsis cane and leaf spot .  It causes minor leaf spots, which is more obvious to our eyes, but the more important 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. Materials for black rot and downy mildew are often effective against Phomopsis. Thus, the fungicide coverage for these diseases is also working as management of Phomopsis, especially later in the spring and early summer. Some cultivars, such as Viognier and Seyval Blanc, are more susceptible to Phomopsis than the others. Phomopsis takes a while to establish in the vineyard. It may take 5-6 years for Phomopsis to become noticeable if you

It was very nice to see you all at the Weekend Warrior Grape IPM workshop. I think we had a very good time with lots of discussions. Hopefully to see you at other meetings. Here is a list of materials that we covered during the meeting. Prioritization in vineyards (Tremain Hatch) VCE overview (Mark Sutphin) Grape weed management (Tremain Hatch on behalf of Dr. Jeff Derr) Interactive grape disease management (Mizuho Nita) Fungicide application template (will open a Google Drive spreadsheet, in order to save, click "file" and select "download as..." Please remember that this one is just an example. You need to come up with your own!) Please note that there is another version, under "Resources" on the right-hand side of this blog. It is in a different format, but essentially the same type of tool. Template used in the exercise (pdf) List of chemical with FRAC codes  (pdf)

The meeting tomorrow is called "Weekend warrior workshop". This is our first attempt to target growers who have very limited time to manage their vineyard. What we originally imagined as the target audience was someone who has another job during the week and can only spend time during the weekends, but it can be applicable for someone who has several operations.  We will discuss time management and prioritization of tasks, and develop a template for disease weed, and insect management. It will be held at Winchester AREC (595 Laurel Grove Rd., Winchester, VA) on 4/1 (Sat), starting 10 AM and probably goes on until 2 or 3 PM. If you are interested in,  please RSVP using this link , or just show up. Our station is a bit far from restaurants, so, you do need to bring your own lunch.

We are looking for an agricultural technician position in my lab, which is located in Winchester, VA. The main duty is assisting various vineyard and experimental operations in our vineyards and other field plots, such as canopy management, weed management, and treatment applications. It is a part-time position, but the position will be held year around. During the winter months, duties will be mostly inside, assisting vine propagations, pruning, etc. We are looking for someone who enjoys working in vineyards and with good communication skills. The other requirements are: valid driver license, basic computer (Word, Excel, etc.) skills, and willingness to learn new things. If you know someone who is interested in, please let them know to apply for this position through the link below. The posting will close on 4/1. https://listings.jobs.vt.edu/postings/74676

Thank you all for coming to our IPM workshop today. Here are my slides from today (it will open a new window for Google Drive). As I mentioned at the workshop, this exercise is to help you developing a backbone of your program. You need to adjust it for your vineyard(s). Our next meeting is called "Weekend warrior workshop". This is our first attempt to target growers who have very limited time to manage their vineyard. What we originally imagined as the target audience was someone who has another job during the week and can only spend time during the weekends, but it can be applicable for someone who has several operations. We will discuss time management and prioritization of tasks, and develop a template for disease and insect management. It will be held at Winchester AREC on 4/1 (Sat), starting 10 AM. If you are interested in, please RSVP using this link.

In my pruning time disease considerations  (this link opens Google Drive with this year's recommendation for trunk disease management), I refer to Topsin-M as a choice of trunk disease management, especially for Botryosphaeria canker, which is very common in our area. The product has been transferred to a new company this year, and hence, there are changes in the label. [The US distributor is still the same (UPI), thus, I do not think it will affect where you can purchase the product.] If you are using Topsin-M for pruning wound protection, please update your label. You can download the new label by clicking this link  (will open Google Drive). Also, speaking of trunk diseases, I have been involved in a big research effort to develop management strategies for various trunk diseases. Please check our project page which contains not only research reports, but also extension information, such as disease keys, management guides, and economic tools to estimate the benefit of trunk

I think many of you have received Tony's newsletter about upcoming vineyard IPM workshops. Here's the same information about workshops, just in case you are not a recipient of the newsletter. (hint: if you have not, I recommend getting touch with Tremain (thatch at vt.edu) so that he can sign you up for Tony's newsletter.) I hope to see you in one of these two meetings. Hopefully, we don't get as much snow as the original forecast... 2017 Upcoming meetings *Please register at the link provided for these upcoming meetings if you plan to attend, this will give us a headcount for printing purposes as well as a means to contact you if the meeting schedule changes due to road conditions. Program name Location Meeting details and registration* information 15-Mar IPM meeting – Pre-season training for vineyard pest management Early Mountain Vineyards, Central Virginia Virginia Cooperative Extension htt

I have updated my fungicide application template that I have been using for my fungicide guides. If you are interested in, it can be  downloaded from this link . (will open a new Google Doc page) Many thanks to Mr. Bob Romsey who shared the original template to me! NOTE (8 march 2017): It says it is "View Only", but you can download the file. If you select "File" from the top menu of Google Drive, you will see "Download As" submenu which has several options for the file type. (I should have mentioned it when I posted. Sorry!) Please note that this is just a template. Your program will differ based on what you see in your vineyard(s). Please use it with VCE's Pest Management guide (linked under "Resouces"). I have been migrating my fungicide guide to an online database, but it won't come alive until late this year or 2018, thus, refer to either the PMG or Southeastern IPM guides (also linked under "Resources") for your refere

It's bit off-topic for this blog, but we have a series of presentations at a local Master Gardener class tonight. Here are slides and handouts for the meeting. The major topic is plant pathology and we cover signs and symptoms of diseases, abiotic disorders, nutrient management, plant disease management, and plant sample submission tips. Thus, some of regular audiences of this blog maybe interested in too. If you click on the link, it will open a new window for Google Drive that contains a PDF file of each presentation. Introduction to Plant Pathology, and Plant Disease Management Fundamentals (Two presentations in one)  by Mizuho Nita A table of over-the-counter fungicides and their target grape diseases Plant Abiotic Disorders  by Charlotte Oliver  Nutrient Management  by Amanda Bly  Explanation of Soil Tests (a link to VCE publication) Plant disease Clinic Sample Preparation and submission  by Charlotte Oliver  If you are attending the meeting, see you tonight!

I have several presentations at the upcoming VVA meeting. Here are handouts for my presentations. If click the link, it will open a new window for Google Drive that contains the handouts. All files are in PDF format. 1) Fundamentals of integrated grape disease management 2) Grape pathology updates 3) Low input fungicide regimen and cultivar selection for disease management in southeast VA The last presentation is based on my recent book chapter, which is free for you to download. Please click the link here to visit the publisher's website. Unfortunately, I won't present these talks, but Tony and Charlotte (my PhD student) will present them on my behalf. I will be at each presentation to answer any questions you may have. I will also be around throughout the meeting. I am looking forward to see you during the meeting!

First of all, Happy New Year! I hope you had a nice holiday season. Here's a table of upcoming vineyard meetings. 2017 Upcoming Virginia Vineyard Extension Meetings Program name Location Meeting details and registration information 24-Jan Pruning Workshop Honah Lee Vineyard, Central Virginia https://goo.gl/forms/J48R5RKwlFg76ckw2 23-Feb New Grower Workshop Charlottesville http://www.virginiavineyardsassociation.com/2016/12/winter-technical-meeting-registration-opens/ 24-Feb VVA Winter Technical Meeting Charlottesville http://www.virginiavineyardsassociation.com/2016/12/winter-technical-meeting-registration-opens/ 7-Mar Pruning workshop Breaux Vineyards, Northern Virginia More information coming soon 16-Mar IPM meeting – Pre-season training for vineyard