Can you grab a close up of the blades? It's fungus season around here now, but bugs are a possibility with all your trees. Are you somewhere on the north side? Worst case scenario is you grab some new sod squares over at Houston garden.

I'm in magnolia someone also suggested web worms. They sent me some links from the news.

It's possible, the moths are definitely out right now. How old is the lawn? Young St. Augustine isn't a fan of all this dry weather the last 2 months, but if it's older than 1 year, I think fungus will still be the prime suspect.

Could be webworms. It has been reported to be a bad year for them.
Sod Weborms

The yard was laid in march of this year. I got lazy in watering with all the rain we had previously but my backyard is perfectly fine. I do think it is web worms. I saw tons of moths the other day when watering some trees. I had no idea they indicated worms. Thanks for all the responses. I just laid a 2nd dose of insecticide.

Almost nothing looks good about that lawn. Need a picture taken from 3 inches away from the blades on a cloudy day (or in the shade) without the flash to see if it might be a disease.

Try this, dig up one square foot of grass in the bad area and see if there are any grubs. If you see fewer than a dozen grubs, then don't do anything. If you have more than a dozen, at this time of year they have stopped feeding, so killing them would be a waste of time and money. They have done their damage and that would be what you see at the surface. The damage was done months ago.

Check your insecticide to see if it works on caterpillars. The best thing for caterpillars is a product called BT Worm Killer. It only kills caterpillars. It takes about 48 hours, but it stops them from feeding immediately.