I've noticed this rather hard protrusion coming out of only a few of my Concord grapes (see below picture). It doesn't seem to affect the grape, and they are only on one per cluster and only a few clusters. Definitely not widespread. A google search gave me completely unrelated suggestions. It has been there since at least July. I can't remember seeing it earlier, but I wasn't looking specifically either. I've sprayed with Manzate / Stylet according to schedule, and haven't seen much of anything but a small amount of Japanese Beetles on the vines. Any suggestions about where I can look? Thank you much...