Scotty said:

Every winter I get a type of winter mold that kills off large patches of my
grass. Its is a sun and shade mixture for the northeast. I understand how to
prevent the mold by putting down expensive amounts of systemic fungicide
just before the grass goes dormant. If I don't put it down as I didn't last
year the mold returns and my lawn is very damaged. I want to know how to
cure it once and for all. Even if its an expensive cure, in the long run it
would be cheap compared to the 120 $ application of fungicide every fall.

I get a little of this, mostly where the soil is more compressed (commonly used
routes across the lawn) or where extra snow was piled on the lawn from clearing
walks or the driveway. The spots are small and fill in quickly. They were worse
this year when I didn't get my usual fall aeration.

My suggestions:
Have the lawn aerated in the fall.

As the growing season ends, gradually lower the mowing height. Your last cut
should be just tall enough that you aren't scalping the lawn anywhere.

Avoid walking on the snowy lawn.
--
Pat K. ('someplace.net' is comcast)

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)