By Clint Thompson
Georgia’s grape vines were mostly dormant amid sub-freezing temperatures experienced in January. That benefited the state’s producers when temperatures plunged last month, according to Sarah Lowder, University of Georgia (UGA) viticulture Extension specialist.
“One of the benefits of this year compared to previous years is that the vines were able to go into dormancy. They were fully dormant by the time the cold weather came in. That doesn’t always happen with our variable temperature winters, but if they’re fully dormant, they’re going to be much more cold hardy than if they had not gone into dormancy yet,” Lowder said.
February has been mostly warm so far, though colder weather is expected next week. Lowder outlined in the UGA Extension Viticulture Blog what grape producers should be mindful of when surveying vines for cold damage.
Cold Damage
“A lot of times the first place that you’ll see damage is in the buds. I showed some pictures (on the blog) of healthy and dead buds, and it could take time for that healthy bud, if it does sustain damage, to die and look dead. It’s something that people can look out for if they suspect damage,” Lowder said. “I would guess that for the most part if we are seeing cold damage in any of the vines, it’s mostly going to be in vines that are already experiencing a lot of stress or potentially some of our cultivars like muscadines, a species that’s less cold hardy than others.
“If it was in some of those very cold areas of the mountains, we could potentially see more damage in some of those less cold hardy varieties.”
Lowder noted that colder temperatures can help growers overcome Pierce’s Disease. Pierce’s disease is caused by a bacterium that is usually transmitted by numerous sharpshooter insects, including the glassy-winged sharpshooter. It clogs the grape xylem, cutting off nutrient and water flow.