Every year I get a handful of grapes that look like they have scabs on them. I'll get a pic tomorrow when the sun is out, but imagine a green, immature grape, with a patch of what looks like .... ok if you get a really bad sunburn, you know how the skin goes brown and cracks just before it peels? That's what these little patches look like. I don't think it's sunscald because the ones that get it are not the ones that get the most sun. I googled for scabby grapes but never found any photos like it. I'm seeing it exclusively on the Marquis, if that helps. Could it be some sort of fungus causing that? I don't think I have an issue with dampness; hot dry winds tend to keep everything aired out well. Added: photo. not the greatest, the phone dislikes closeups. The scabby part doesn't spread and it doesn't appear on the vine or leaves.
This would be bad: Black rot (grape) - Wikipedia, the free encyclopedia but I don't think you have this problem (thankfully). I might have seen what you described, a long time ago. I am trying to picture where I was at the time. I am thinking something benevolent like noble rot: Noble rot - Wikipedia, the free encyclopedia But I am only guessing. A picture would help. Also, how frequent it occurs and how many grapes? If it is a very small number to the point of it being almost non-existent, it might just be nothing at all -the results of a skin gone bad. No big deal.
It's just a couple here and there. Of 11 vines I only see it on a few bunches, and only on a couple of grapes total per bunch. Again, I'm only seeing it on the Marquis. Every other variety is fine. It's probably nothing but I've only had grapes for about 3 years now and I'm paranoid I guess.
