Bacterial Wilt courtesy of Cornell University
One of our members has been bothered by squash plants dying suddenly, with blackened leaves. We ran through the normal suspects like disease, squash bugs feeding as well as spreading a disease and of course the beautiful but deadly vine borer. Nothing seemed to match exactly so we decided to do some research.
Turns out there are more blights, spots, wilts, mildews etc that can affect a squash plant than I ever thought. However, I found an excellent resource from Cornell University. Why excellent? Because it has a lot of picture examples of what they are talking about.
After you find a leaf that looks "sort of" like what you have, click on the particular cucurbit in your garden and you may see more examples, close-ups, etc.
See if this helps narrow in on the culprit. If it does, we can then pursue the solution.