It looks like wilting caused by squash vine borer infestation. Check the base of the vines for holes, and for frass (the sawdust-like excrement from the caterpillars).

If you find these signs, there are several ways you can kill the caterpillars (there have been recent threads on that topic) but if wilting has already started, then the damage to the vine is probably already too great for it to survive. Check all the rest of your vines carefully, even if they still appear healthy. They too might be infested, but it could be possible to save them.

I will look. I thought those darn bugs didn't exist west of the Rockies. I live in Eastern Washington. I've never grown pumpkins so I am very unfamiliar with bugs that like pumpkins. SVBs sound like a nightmare I was hoping to avoid. Might do a little surgery to search for them. My garden plot is rented away from my house but as soon as I can I will be hunting them down! Thanks for your help :)!

This post was edited by gardengal13 on Thu, Aug 22, 13 at 1:46

If those leaves happen to be on the same plant, the same vine/branch, then it is root or stem related. However, if the are scattered on different plants, branched, may be they are just old aborted leaves.

Another possibility is that they WILL perk up.

Beside the obvious leaf wilting, they appear to be a bit under fed. Leaves should be darker green. I was going to ask about PM, but you already mentoned that. Whatever vine the leaves are attached to is definitely in trouble. Possibly SVBs. I'd inspect the stem carefully.

Thank you! I am going to search for bugs. I think I know why and when it got underfed. I will try to fix that. So far, it is just in that one area of the vine. The rest of the vine looks healthy. Should I bury that portion of the vine so it is stronger and more rooted?