Lawn dying in spots
Put in a new lawn last fall. Looked great all spring. Now dying in some spots. A few facts.
Lawn is 'Enviroturf' from Turfmaster Sod farms in nearby Ft. Collins.
3" top soil put down
Sprinkler system. Watered 1.5" per week. Dead areas not in particularly dry or wet parts (i.e. where heads don't overlap as well as they maybe should or where they really do overlap extra well).
Description : Patches that started to go from a good green to a 'dark green' but dry. Then turned brown and essentially disappeared. (rub it with foot and brown grass disintergrates down to dirt. Patches are in a long line on one side. a few patches here and there.
Does not pull up easily (as I've read grub damage should). No noticable mold or other discoloration at soil or on grass. Soil at roots looks 'reasonably' but I just dug in with finger.
I do keep the grass long (as long as my mower can cut it).
There are some kind of bug flying up when I walk around. But they are everywhere. I imagine that is is just because the grass makes a nice home. I don't think they are doing the damage, but maybe?
Also it is a new built. Lot might have been treated with weed killer, but then pushed around. Plus 3" of topsoil. But maybe the grass just now found the weedkiller in the ground?
Thanks for any help!