Grape Variety Developmental Stages: August 2, 2019
At the West Madison Agricultural Research Station (WMARS) in Madison, WI, shoot development across most cultivars has reached E-L* stage 33 (“Berries still hard and green”). At this point, vines are still behind in development compared to 2017 and 2018 growing seasons, in part due to the cooler temperatures we experienced this spring. Similarly, at the Peninsular Agricultural Research Station (PARS), all varieties are at E-L stage 32 (“Beginning of bunch closure, berries touching (if bunches are tight)”) to E-L stage33 (“Berries still hard and green”).
The following photos were taken on July 29 at West Madison Agricultural Research Station.
Brianna E-L stage 33 
Crimson Pearl
E-L stage 33
Frontenac E-L stage 33 
Itasca E-L stage 33 
LaCrescent E-L stage 33 
Marquette E-L stage 33 
Petite Pearl E-L stage 33
The following photos were taken on July 30 at Peninsular Agricultural Research Station.
Brianna E-L stage 33 
Frontenac E-L stage 32 
Marquette E-L stage 33 
LaCrescent E-L stage 32 
LaCrosse E-L stage 32 
St. Croix E-L stage 33
Date: April 1-August 2, 2019 Growing Degree Days (Base 50°F)
| | 2019 | 2018 | 2017 |
| Location: WMARS | 1543 | 1769 | 1549 |
| Location: PARS | 1058 | 1281 | 1132 |
Growing degree-day accumulation from April 1 to July 19 for the past three seasons. Currently, the 2019 season is running behind in GDD accumulation compared to 2017 and 2018 seasons. Degree-days were calculated using a base 50°F, starting on April 1 as a biofix. We calculated degree days using the NEWA website, and you can visit their “About degree days” page to learn more about the degree days and the formulas used for their respective calculations (http://newa.cornell.edu/index.php?page=about-degree-days).
*E-L stands for Eichhorn-Lorenz Phenological stages to describe grapevine development
This article was posted in Grapes.