St Augustine is not on the label. However refer to the section of the label stating: "other warm season turf species and cultivars may be tolerant". I do know that well fertilized and watered st augustine will handle 20 oz Revolver. Do not try this on bahia, centipede or seashore paspalum. I use Revolver to remove those grasses from other warm season species.
Using carfentrazone to burn down sedges was a tip I got from the Monsanto Rep when I was discussing how slowly Certainty worked. He suggested Quicksilver + Certainty. Dismiss is not an option for me, it is illegal in Hawaii.
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety.
Benjamin Franklin 1775
Sell not virtue to purchase wealth, nor Liberty to purchase power.
Benjamin Franklin Poor Richard's Almanac1738