Please help. My lawn is in trouble, it seems to be turning white over the last week

Question

The lawn was looking very healthy, then I noticed some lighter patches, over 3 days these are turning whiter and spreading

Answer 1

It looks like a case of powdery mildew. These articles should help:

https://www.gardeningknowhow.com/lawn-care/lgen/powdery-mildew-on-grass.htm

https://www.gardeningknowhow.com/plant-problems/disease/get-the-cure-for-powdery-mildew.htm