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An error on yesterday's slide: Vivando should not be on Downy mildew table!

I mistakingly placed Vivando, which does not work on downy mildew, on the downy mildew table. Please strike it out or use the updated version below. 1)  List of short PHI fungicides for late-season diseases (will open a pdf file) 2)  Updated presentation from the last virtual field day (will open a pdf file).
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List of short PHI fungicides for late season diseases and today's presentation

Thank you again for participating in our meeting. Please find two materials from today's presentation. 1) List of short PHI fungicides for late-season diseases (will open a pdf file) 2) Today's presentation (will open a pdf file). Have a good rest of the season, and hope to see you next week at the VVA summer technical meeting!!

Recent downy mildew risk events.

This is another reminder about downy mildew. This post is probably more applicable to those of us who are in northern VA. We received several rain events in the past two weeks. Not all of them accounted for downy mildew infection risk events; however, recent warm and humid nighttime weather probably encouraged the downy mildew pathogen to produce spores.  Here are recent downy mildew infection risks based on the NEWA's DMCast. Floyd, VA: Downy mildew risk events on 7/6, 11, and 15. (note: the temperature sensor has been fixed recently, and that's why it shows records from mid-June.) Red Hill, VA and Olympic Lake: If you are in central VA, please check your local weather station. It seems that the numbers vary quite a bit among them. Red Hill: downy mildew risk events on 7/2 and 8. Olympic Lake, downy mildew risk events on 7/2, 6, 8, 11, 12, 15, and 16. Winchester, VA: downy mildew risk events on 7/1, 5, 9, and 13. Protective materials for downy mildew are Ziram (FRAC M3, 21-day

Another reminder on downy mildew

It looks like many of us received some rain in the past few days, and we may see another rain toward the end of this week. Here are recent downy mildew infection risks based on the NEWA's DMCast. Floyd, VA (note: the temperature sensor has been fixed recently, and that's why it shows records from mid-June.) Crozet, VA (note: the precipitation sensor has been fixed recently! We really appreciate the willingness and commitment of the personal weather station owners!) Winchester, VA Protective materials for downy mildew are Ziram (FRAC M3), Captan (FRAC M4), Fixed copper (FRAC M1), Revus or Forum (FRAC 40), or Zampro (FRAC 40 + 45), or Ranman (FRAC 21)). There are increasing cases of Revus resistant downy mildew isolates in VA. Plus, resistance to Ranman is known among downy mildew pathogens of other crops. Make sure to spray before the rain and rotate the FRAC codes! Materials with kick-back activities are Phosphorous acids (Prophyt, Phostrol, etc, FRAC P07), and Ridomil products

Slides from today's presentation, meetings, and newsletters (email subscription)

Presentation slides Thank you to those of you who were able to make it to the meeting today. Here are slides from today's presentation (open PDF).  Up-coming meetings Eastern Section American Society for Enology and Viticulture annual meeting (7 – 8 July): The ASEV/ES meeting will occur on-line this summer. See https://www.asev-es.org/ for details on the meeting, which will include research presentations and a panel discussion entitled “Future Grape Cultivars for Eastern North American Growers”. Eastern Viticulture and Enology Forum (13 July): The July 13th meeting is the next of a series of 4 virtual meetings organized by viticulture and enology extension specialists at Penn State, Cornell, and Virginia Tech. In addition to regional round-ups of seasonal progress, specialists from around the eastern US address pre-submitted questions from participants. Registration instructions and additional information about the meetings can be found on the attached Word document. Virginia Viney

Recent grape disease risk events

It looks like we all received much-needed rains, which is good for vine growth. However, since most of our vines are still within the critical period for cluster infection by downy mildew, powdery mildew, and black rot (~ until 6 weeks after bloom for V. vinifera , ~ 4 weeks for V. labrusca ), it also means that we may have had risk events for disease infection. Since the month of May was dry, I think the overall disease risk is low for downy, black rot, and other diseases that are driven by rain (e.g., ripe rot and Botrytis), but I just want to go over recent NEWA outputs.  Disease risks from the recent rain events Westfield (Close to Bristol, VA) It seems that the southwest VA received quite a bit of rain over the past two weeks! I would think many cultivars are close to the end of the critical period, but if you are concerned, a DMI fungicide and a Ridomil or Phos-acid product are effective for black rot and downy mildew, respectively. These materials can be applied a few days after

A quick reminder about downy mildew

Just a quick note that recent rain events were risk events for downy mildew based on the NEWA DMCast model. It seems that northern VA received more and longer rain events. In addition, we may see more rain toward the end of next week. DMCast results at Crozet station (green cells indicate downy mildew infection events) DMCast results from Winchester station Since we have been experiencing a very dry season, I was not really thinking about downy mildew. However, during recent vineyard visits, I have noticed downy mildew on leaves, and sure enough, I saw some downy mildew lesions on leaves in one of my research blocks too. Early downy mildew lesions may not be very obvious. If you are due to spray soon, grow downy mildew susceptible cultivars (e.g., Chardonnay, Vidal, etc.), and/or have seen a considerable amount (or duration) of rain recently, it may be a good idea to include a Phos acid material (e.g., Prophyt, Phostrol, Agri-Fos, etc.) in the tank mix as insurance. Please note that if