I am in the Milwaukee area just 10 miles west of Lake Michigan. Our lawn has had relatively few disease problems this summer. Let me say, though, that despite the drought I have watered very little, only two days all summer. Sure there was a bit of the dormancy experience, but not as much as you'd expect.
On the other hand I have a few spots of low
growing grass which I suppose is creeping bent. I know the only way to cure it is via Roundup and re-seeding, but it's not been spreading so I'm leaving it alone for another year.