The radar is showing thunderstorms for tonight (now I heard the thunder...); however, in the past few days, there is only one night when the condition was favorable for downy mildew sporulation. Since we are approaching the end of critical period, those of you who has not seen much downy mildew can relax a bit once the 4-5 week window has past. If you are concerned about downy mildew based on your assessment of the vineyard and if the vines are not protected, then you can apply Phosphorus acid or Ridomil products after the rain. (The forecast is showing chances of rains coming later in this week.)
We visited a vineyard at Southern Piedmont AREC yesterday. This vineyard is set to test a relatively low input practice (14-day schedule of mancozeb+sulfur is the backbone). This year, they did not experience extensive rains as Northern part. In addition, they managed the canopy very well. As the result, we could not find major outbreak of disease. It tells you that the importance of canopy management (= air circulation) and the incorporation of weather information in your spray schedule. We will monitor the vineyard and see how it holds toward the harvest.