Squash Vine Borers. The beetle looking mamas lay their eggs at the base of the plant. The eggs hatch and the larvae bore into the vine and eat it from the inside out. Usually your first clue is the brownish gooey looking frass on the outside of the vine. The plant is a goner. Don't compost it. Put it in the trash. One of the great plagues of squash, cucumbers, pumpkins, and melons. Makes you sick, doesn't it?

Your location indicates California. Only folks in the Eastern half of the U.S. get to enjoy the challenges of the Squash Vine Borer. So, it's most likely not your culprit.

Unfortunately, I cannot tell from your pics what bug is invading your cucumber. Some close-up photos maybe?

In the mean time, here's a couple guesses:

Squash Bug

Sow/Pill bugs

Perhaps someone from the West Coast can chime in and be of further assistance.

Rick

Yes, I am from California. Thanks for your replies. After posting the question here, I looked at other sites and I seem to think it is sowbug - it does curl into a ball when touched. I am going to try diatomaceous earth to see if that will help. Right now, I just have the peas sprouting and I hope they grow well. Thanks once again.

Purnima