The UGA bulletin (link below) covers the subject in much detail. Available in PDF, if you wish to print it or pick up a copy at your County Extension office.
You might also look up treatment of pest and diseases for St Augustine grass while on their site. I have lost 2 St.Augustine lawns in the past due to diseases, one was infected when the contractor laid the sod and prompthy died.
Doesn't say much for Ag inspection, does it? But that load came from out of state.
Rb

Here is a link that might be useful: Fertilization for lawns