On Fri, 14 Jul 2017 13:42:32 -0400, "Kurt V. Ullman"
wrote:

Have some things on my yard that I am not sure what it is. I have gone
to two garden shops and got two mutually exclusive responses.
After rains the last couple of weeks, I have a cottony cover on my
grass (I thought originally it was stuff from the cottonwood or some
weed sticking to the wet grass (see picture). However, soon I realized
that the grass in the area was turning brown in roughly the outline of
the cottony cover. One guy suggested fungicide and another just thought
I should fertilize and it would come back.
Any suggestion?
http://imgur.com/M3roAaC
http://imgur.com/3MsIWYL

_Cotton-Like Fungus in the Grass _

http://www.ehow.com/facts_7706464_cottonlike-fungus-grass.html

"Pythium blight is a fungal disease also known as cottony blight. This
disease affects all types of turfgrass and is most common during hot,
humid weather. Pythium blight spreads rapidly and can kill large
portions of grass in a short time. Powdery mildew is another fungal
disease that affects lawn grass, especially in shaded areas. Shade,
high humidity and and improper aeration favors the development of
powdery mildew."

Try some aeration if the ground is heavy in clay?