Q.What do I do about my spaghetti squash plants dying?
The plants are huge and were healthy and producing very well. Now suddenly they have a white, powdery coating on the leaves and they are drying up and dying. What is it? Is there anything I can do? The same thing happened last year, but quite a bit later than this.

Certified GKH Gardening Expert
This sounds like powdery mildew. It can be devastating if nothing is done about it. This can be quite easily treated luckily, though. Neem oil is safe for your plants and works very well, but there are many ways to control it.
This article will help: https://www.gardeningknowhow.com/edible/vegetables/squash/powdery-mildew-in-squash.htm