Another cucumber suggestion.
I've recently read that you should always pick cucumbers before they develop any yellow on them. Keep them picked. The logic goes that yellow indicates that the cucumber fruit is sufficiently mature to have viable seed. Having reached that point with one fruit, the plant has done it's job, and starts to die.
This seems to follow what I have observed on plants where I've gotten lazy or too busy to keep up with picking. The vines start looking horrible, then die.
