Does anybody know what this is?

[flhiker]

I had some of that in my yard. And I also tried Scotts weed and feed. I have to say I will never use Scotts again. I used Vigaro from Home Depot and I have not seen it since. You can be a little heavy handed with it. Now, Vigaro is the only lawn fertilizer I use. If you have recently fertilized, I wouldn't do it again til the fall. Good Luck