By Esmaeil Nasrollahiazar and Mike Reinke el.at
Regional weather and seasonal progress
Seven-day forecasts for Michigan grape regions are as follows:
Weekly in-season weather updates are provided to the MSU Extension fruit team by Jeff Andresen, PhD, MSU agricultural meteorologist. These reports offer timely insights into weather conditions affecting fruit production across Michigan. You can watch recordings of these agricultural weather outlooks.
Growing degree day (GDD) report
You can track vine development using the MSU Enviroweather Growing Degree Day Map. Visit the Enviroweather site to find your nearest weather station, create a free account, and monitor GDDs daily.
Biweekly GDD summary (base 50 degrees Fahrenheit)
The following table summarizes current GDD accumulation, last week's totals and the biweekly increase for each monitored location across Michigan:
Vine development
Southwest and southeast Michigan
Grape bloom is finishing. Some early hybrids are at Buckshot Berry. Vinifera wine grapes are between immediate prebloom and completing bloom, depending on variety and location. Juice grape bloom is almost complete in locations not damaged by spring frosts/freezes. In vineyards damaged by the spring frosts, secondaries are now blooming. A line of storms moved through the region early evening on June 16. Several reports of hail in multiple grape production locations have resulted in damage. The extent of damage is still being assessed, but additional fungicide applications are recommended while the vines recover in these locations.
In southeast Michigan, most grape cultivars are at fruit set, including juice grapes, table grapes, and hybrid wine grapes. Later cultivars and vines in cooler parts of the region are still in bloom.
Source : msu.edu