For cool season grasses, you shouldn't fertilize in the summer, as it can lead to fungal disease, which is what I suspect you have. Where do you live? Do you know what kind of grass you have? How often do you water? Overwatering can also lead to fungal issues and weakly rooted turf. Aerating shouldn't be done in summer either, and if your turf isn't compacted it probably shouldn't be done at all.

Have you checked to see how wet it gets? If you dig down a little at the edge you can tell. It may have a fungus. In some areas it has been cool this year, so if you are watering too much you could be encouraging a rust or something. Other things that kill grass are grub infestations, but I think we're mostly past that now: they are all ready to hatch at this time of year. Perhaps if you post some photos you can get better answers. I hope it's something easily cured. Renee

The grass is dry. That can happen from not enough moisture or from rotten roots not letting the water up. Are you getting puddles of water in the dry areas? Puddles can allow fungal rot to set in. If no puddles then the areas are not getting enough water. That could be due to sprinklers not adjusted right, runoff from hydrophobic soils, sandy soils allowing moisture to run through, or simply the idea that you need more than 1 inch per week this time of year. My guess is your sprinklers are not adjusted right. That's more of an educated guess because I can see what appears to be a circular shape on the grass in your big picture. Mid way up from center to the right side of the picture is a nice colored circle(ish) green. Outside of that is the dry area. If you put cat food cans perpendicular to the circle and turn on the sprinklers, you will probably see that the cans are not filling evenly.

I live in the hot Tri Valley area east of San Francisco. I was given a grass tree from a fellow gardener. The tree is about 10 years and had flowered for them. We dug it up in February and took alot of soil with it however, it's roots went through a ginko tree and so in getting it out, some of it's middle roots were severed-to get it free from the Ginko. I planted it in a very sunny spot-all day sun. It looked good but the last month it has been having more and more dying fronds. The trunk is about knee high. Today I went to investigate and found that the top of the tree is rotted, Near the soil level on one side there is an outshoot of some fronds. That was there when I got the tree. Also when I got the tree there were two pony tails of fronds on the top opposite where the flower stem was. Is my tree a goner? Is there anything that I can try. Right now I am hoping the sun will dry the rot. Is there anything that can save this tree? Sondra