Q.Large spaghetti squash plant
Some of the leaves on my spaghetti squash are turning brown and dying. What is causing that and what should I do?
Leaves can become injured and damaged as the plant gets larger. Inspect the plant for signs of insects or disease.
A more serious issue to watch for is Squash Wilt. Links below will help you identify this.
I would treat it with Neem Oil as this acts as both an insecticide and fungicide.
Refresh yourself on the care requirements and watering.
https://www.gardeningknowhow.com/edible/vegetables/squash/growing-spaghetti-squash.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
https://www.gardeningknowhow.com/edible/vegetables/squash/signs-and-treatments-of-squash-wilt.htm