Any idea what might be causing this and what I an do about it? The vine has been producing some cucumbers but this problem has been getting worse and I think I may have to pull the plants out and start over.

I am in south central Florida and we are in the high 80s now during the day.

Thanks to any who respond.

Hi,
You will have to pull and start over. I don't see miraculous recovery in their future. Mine do that often. I am not sure.. there's a virus spread by cucumber beetles, I believe. And I used to crowd mine and cause them to be weaker. I read to plant a foot apart..

I am wondering it it would help to sprinkle some Sevin powder on the news plants when they are still small...

It does look like a lot of insect damage. A liquid spray would better than a dust on cucumbers. Downy mildew is a major problem in the southeast, but your plants are so chewed up I can't tell if that is the problem. Only real solution to DM is plants with built in resistance. Sometimes a fungicide will help.