I would cut one of the patches out and send it to your county extension. Someone said here recently that they will analyze lawn disease for free. If that is true, then it is a great deal.

In your first 3 photos, I'm almost positive it a disease called Fairy Rings. look it up.

I'm not sure about the other photos, but I would apply cornmeal immediately at 20lbs per 1000 on your entire lawn. Then again in 3 weeks.

Along with the above: you could poking holes with a pitch fork around the effected area and then drench the soil with cornmeal tea. This should get things working a little faster.

I agree with skoot_cat. The circles are easily recognizable as a fungal disease. The corn meal should kill it and fertilize at the same time. Apply to your entire lawn so you don't have tall green spots where the fungus was.

Thanks for the fairy ring id. My plan was to pick up some corn meal for the lawn soon anyway, so I'll just go get it today. Up until today, I could not find any around here (Western suburb of St. Louis). I just found it at a small feed and grain store in a small town -- for $4.50 for a 50/lb bag. Not too bad!

$4.50! Jeepers! That's a deal. I think i pay twenty something per 50 pound back of corn gluten meal. Maybe the gluten part makes it more costly. :)

"$4.50! Jeepers! That's a deal. I think i pay twenty something per 50 pound back of corn gluten meal."

Keep in mind that CGM has about five times the nitrogen of corn meal. That means that you need five times as much corn meal for the same fertilizer effect.

-Deerslayer

Well that's a comfort. Does it have similar anti-fungal properties?

"Does it have similar anti-fungal properties?"

No, it doesn't. CGM is used as a fertilizer and preemergent herbicide.

-Deerslayer

The last 3 photos look like dollar spot disease. Very common and hard to treat (both organically and chemically). Should calm down soon with the cooler weather. Here is a link to check out:

http://turfgrassmanagement.psu.edu/turfdis3.cfm