In years past we lost many zucchini plants to various types of rot. I believe the rot was often caused by wilting and rotting leaves that created an environment of wet, mushy mess. Wet, mushy mess is a breeding ground for plant ailments. A couple of years ago I began to carefully experiment with trimming off single leaves and their stems from the main stem of the plant. This can be a risky move because pruning a zucchini plant leaves the plant vulnerable at the spot where you made a cut.
In my experience the risk was worth taking. The video below shows how I prune my zucchini and what they look like in late September.