The UGA Extension Viticulture Team harvested our first research plot on Tuesday, August 22. The plots were a part of a leaf removal trial in Chardonnay which evaluated leaf pulling at to different magnitudes and at two different stages – both pre-bloom and post-fruit set. On each vine, clusters were picked, counted, and weighed (140 total vines across the entire experiment), and evaluated for sour rot and botrytis incidence. Weather conditions were clear and perfect for harvesting.
Primary chemistry data were also evaluated. There were some preliminary differences in fruit chemistry, most notably reduced titratable acidity in well-exposed compared to shaded grape clusters, and increased Brix in the pre-bloom leaf removal plots. While not formally evaluated with statistics as of yet, Botrytis incidence and severity appeared to be lower in well-exposed compared to shaded clusters, but this did not appear to be the case for sour rot.
Below are some pictures from the day.
Nathan Eason, White County Extension Agent, weighs Chardonnay crop weight while Clark MacAllister, Lumpkin County Extension Agent, records data.
Sour rot infestation in a Chardonnay cluster.
Lumpkin County Extension Agent Clark MacAllister and UGA viticulture graduate student Rachael White prepare for harvesting.
This is the first of many harvests the UGA Extension Viticulture Team will complete this year, and complete results from our research trials will be evaluated and shared later in the year at grower meetings, extension meetings, and state and regional viticulture conferences. The first of these conferences very well may be at Georgia Wine Producers Conference on January 23 and 24 at Chateau Elan.
Thanks, and a brief note from Cain, below:
Please let any of the team members know if you have questions as you approach harvest. We understand that many are seeing downy mildew in the canopy and likely some botrytis and sour rot crop up in the fruit. It has been a battle out there this year with many spraying in the short dry intervals that were experienced between long bouts of rain. If you plan on using chemicals to control fungal diseases in the vineyard, please be aware of the labelled pre-harvest interval. Use your best judgment on when to pick – Brix is far from the only compositional attribute that makes wine, and you must account for the integrity (or lack thereof) of the fruit when making harvest decisions. That said, it looks like a high pressure system is predicted for the next couple weeks, which could provide some nice ripening “power” if things look to be holding up pretty well in your vineyard. Pam Knox, UGA Climatology Specialist, will be posting more about the weather either today or tomorrow.
Good luck out there – Clark and Cain