Vine growth is flushing out rapidly in Vermont vineyards, with many vines at or approaching 5-8” shoot growth. We are entering a critical window of disease management when anthracnose, black rot, Phomopsis, and powdery mildew can all be active. There isn’t a lot of rain in the forecast, but showers mid-week may cause enough wetting to initiate infections. Vineyards should be covered with your fungicide(s) of choice this week.
This is also a great time to apply any ground-applied fertilizers, as this period of rapid shoot growth is when plants need nutrients the most. Nitrogen need in Vermont vineyards is relatively low (but not non-existent), but most vineyards need some potassium and often magnesium. Please base your fertility applications on soil and foliar analyses (more on that next week) or visual symptoms, especially for magnesium.