Yellowing Pumpkin Leaves

A pumpkin vine sprawls across the tiny front lawn,growing a single pumpkin and lots of blossoms.
The leaves are starting to yellow and die.
I read else were to use pesticide or fungicide,but I am cheap,lazy AND against poisoning my food,so I am asking for help here.

It's tough to advise without knowing exactly what is wrong.  It could be overwatering, nutrient deficency, disease or pests.  If you can post some pictures we can try to diagnose.  I would recommend starting with looking at pictures of nutrient deficiencies and also powdery mildew.  If those don't match what you are seeing you can also try squash vine borer though I think that makes the whole plant wilt at once.  Once you know what is wrong it will be easier to offer suggestions to fix things.