Me again. Some of my leaves, far back from the growing tips, are yellowing especially around the edges. Anyone recognize this as anything besides heat stress? (I'm growing in Phoenix so that can only be helped so much.) And no, the light leaves aren't powdery mildew, they just turn pale when it's hot. This is a Jack Be Little, but I have a Connecticut Field vine behaving similarly. Both have fruits set and they seem to be growing fine, but if this is a disease or something that might spread down the vine I'd like to keep ahead of it.