more pics

bottom of the vine

Doesn't really look like it. Bacterial wilt causes the vine to wilt from the tip, while at first remaining green. I don't see any droopy green vines there, and the leaves seem to be yellowing without drooping.

My cuke lower leaves do the same thing, but they are producing cucumbers, so I've not done anything about it. I suspect the soil dries out a bit more than they'd like especially during our windy afternoons, so I've just been giving them a bit more water than before.

I have the same thing happening to mine here in NY. I think from another post here that it my be a mildew.

If it's not bacterial wilt, and perhaps instead it is a mildew, should I remove this vine in case whatever the problem is won't spread?

I have the same problem. They seem to die. I was spraying Serenade, but it really didn't do much (I probably should have given them a once over about six weeks ago before all the rain came). Lately I have been spraying milk, which actually does seem to help. I did an initial spray with about 50% milk and a bit of liquid seaweed and it did wonders. It came back after some more rain so I did it again yesterday, and poof-- it's not gone but it looks a lot better.

Yeah I've used a 20% milk solution reapplied multiple times to a squash plant and it seems to effectively curb the spread of powdery mildew. Although I really don't think that these cuc's are affected by a mildew. The leaves don't have spores growing on them. But I have been spraying milk on the leaves as a preventative measure since the squash with the mildew is kinda close by.