I THINK borers usually attack at the base of a squash plant (not all borers may have read this info, however LOL)...But wilting sometimes is a plant's reaction to heat stress. By collapsing the leaves (i.e., closing the stomata), the plant conserves moisture. If the plant recovers after dark and looks normal in the morning, that is all it is. By the way, if this IS the reason for the wilting, it does not necessarily mean the plant needs water in the soil. (You may well know that over-watered plants also will wilt!) It is just a self-defense mechanism in very hot weather. (Mine are exhibiting this now, and I know it is not a water issue.)

Here is a link that might be useful: Photos of borer damage

Thank you. guys! In my reading last night I did figure out that it was squash bugs.

I understand that the threat from them is that they can chew the leaves or fruit and damage them. In this process. They can also be a vector for introducing bacterial wilt? I definitely have a few leaves that have been eaten and these guys are probably the culprits.

A few of the vines that are in full sun definitely do wilt during the day, but perk back up late in the day. I read that this is a sort of self-protective behavior and like you had said, not always caused by under-watering.

I cut off the end of the wilty vine and buried most of my vines. I read about the test for bacterial wilt, so I may attempt that - because if this plant DOES have BW, I need to remove it entirely, correct?

I'm evaluating my options for purging the squash bugs. I hate the idea of collateral damage.