dry patchy grass

Grab the turf and pull on it, if it comes up like carpet keep pulling it back and look for little white grubs as seen in the middle of the picture.

These are Bill Bugs - they eat the grass root off just below the stem.

You can use Grub killer from the local store. Be sure and water it in. The retail products are slow to kill the larvea - if it is a serious infestation call a professional and ask for Areana.

Watering at this point is very important. Remember the grass root is very short so it has to have water constantly to try and recover.