I’m not quite sure what’s going on? We try to be more natural and not use chemicals so we have not sprayed anything but lavender, tea tree and lemongrass for bugs twice this year. I noticed in my garden my green bean leaves are doing the same thing. It only seems to be on a few leaves out of 200 grapevines. So not all of the plants are doing this. We are in North Texas with lots of rain this year. Zone 8. I’ve tried contacting A&M plant pathology no answer and I’m waiting on a phone call from the Tarleton Horticulture Dept too.