Help! North Houston I have lost the grass in my entire back yard

Due to the crazy spring weather (rain and heat) my st. Augustine weakened (we think we had chinch bugs too) and has been taken over by what I call "crazy grass" that is actually a weed -- we're going to get new sod but I don't know how to kill this stuff without endangering my new sod. Also, I want to know if I can put kraft paper under the new soil prep before the sod is laid as a weed barrier. This is so bad. :(

Here is the pic of the weed -- I was told it has a white flower at some point. The sod guy said he didn't recommend a weed killer as it may kill the new grass as well.

I'm not sure I've seen that before. You might try the plant ID forum to see if they can help if someone from the Houston area doesn't chime in soon.

The floods. Water grasses spreading. Yeah, poisoning for old growth will kill new grass. Cinch bugs and others can kill out St Augustine. Sometimes it's a losing fight trying to get bare ground to plant as so many seeds then think its their turn. Have you done anything to the base sod at all?