What is this stuff in my yard?

I 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. These are seen only after a rain, it seems to be only in areas that are full or near full sun. And it has been high temperatures in the high 80s and 90s F. Then rain, immediate cool down and these little buggers appear. Any suggestion? http://imgur.com/M3roAaC http://imgur.com/3MsIWYL
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 7/14/2017 2:29 PM, Kurt V. Ullman wrote:

You're in the right place. May take a while but I'm betting answers will be better than you got from the garden centers. Mine have been.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.