Never had a problem with squash or cucumbers when I lived in RI. When I moved to Illinois my squash was just wilted and died one day. Thought I was being heavy handed with watering. Four years ago I moved to Texas and the same thing happened. Someone on this thread mentioned moths that lay their eggs on the underside of the squash and cucumber leaves and then the lava burrow into the stem of the plants. One day the plant “appears” perfect then the next day it wilts and dies. Evidently the moth will winter over in the soil so I emptied the raise bed completely and will refill with Miracle Grow. I bought row covers to keep out insects and someone suggested covering the stems with aluminum foil. We’ll see if that works.
I am thinking we have cucumber beetles and/or some sort of soil borne fungus/bacterial disease.
The aluminum foil will prevent cut-worms , looks sorta like a grub that girdles the plant at soil level, or just below.
If the problem is borers, they leave a 'frass' that looks like brown/yellowed sawdust at the point of entry .
Actually , you can save the plant if its borers, by using a sharp knife and slitting the stem until you find the borer, remove it,
and then bury the slit under some soil. Chances are the plant will recover, and possibly form new roots in the soil mound.
Squash Borers and squash bugs will both impact cukes, melons, squash, and other curcubits .
The squash borer attcks the stem near a leaf ; squash bugs (beetle like) generally lay eggs on the underside of leaves
The borer is the pupal stage ; the adult is a gey/white moth which attacks plants May /June generally at night .
Timely administration of insecticidal controls (and insecticidal soaps), and totally clean up in the fall are the best controls to prevent next years problems.