Question
Tom,
I have a strange question, but hopefully I can get it across well enough. I moved here to Memphis a year ago and knew nothing about grubs or lawn care. I treated for grubs last summer and this summer. Last fall I noticed the soil under the grass was becoming granulated or yeast-ish. It looks like those packages of instant yeast. I don't know how to explain it better. It even did this in the bare areas of the yard. Last year there was a bit of it and I found it to be weird. This year it covers both the front and backyard and it has become bothersome. Not a nuisance, just an unsightly annoyance. Mostly because my three little kids track the dirt everywhere.
I am just wondering what it could be. A pest? A result of the grub treatment? Or something else entirely? And if something does need to be done, what should I do?
I have searched everything I can think of online without success.
Thank you so much.
Shanda L.

Answer
Shanda:

I have observed such things also.  My guess, without seeing them, is that they are remains of a fertilizer or pesticide packet used to deliver the product to the lawn.

Another interpretation is that the soil, coated by salts, became colored under drought stress.  If you were able to remove grass on top, the plants were weakened by drought or disease.  I believe that, in Memphis, you suffered the same drought that we did in NC and that this diagnosis is probably correct.

To be sure, I would take a sample to your local ag agent for identification.  If there is a remedy, proper ID is necessary.

Best wishes.