Failing

My zucchini this year has been failing big time.  Last year we only got 1 big zucchini.  This year I was determined to do better.  However I have yet to get 1 zucchini and all of our different squash plants have a powdery mildew.  The summer squash is still producing despite the mildew but not the zucchini.  I have been cutting the foliage off that won't rebound from the mildew.  I have found one organic spray that seems to have been helping a little bit.  The plant has been flowering but I am afraid that this plant is a goner.  I read that squashes could be caged to reduce needed space I'm not sure if this has had an effect on the mildew.