We have four vines in our back yard that are three years old. This year, one of the vines has severely curled leaves. They are curled upward, and seem just a little dry. Could this be due to overwatering?
Yes, if you drown the roots they die, leaving a reduced root system and reduced ability to take up water and nutrients. There are other possible causes as well; can you post a picture? Ralph
Thanks for the thoughts. I think it may be insect related. The affected parts seem to be spreading and there are affected and healty parts on the same vines. Here are a couple of pics.
The second photo in particular looks like 2-4-D damage. This is commonly found in grass weed preparations like "Weed-n-feed" fertilizer or broadleaf selective herbicides. The source can be a considerable distance from the vines as grapes are very sensitive to it. There is no particular treatment but recovery should begin within a few months unless it is a very severe case. The effects are typically random in a vinyard, depending on the wind eddies at the time of exposure. On the other hand, the first photo looks like a potassium deficiency. Ralph