I recently resodded in S FL. I put in new St Aug. It is bedding in nicely. In one area, I had something like Bermuda that would take over. The sun would hit that spot and the Bermuda would take over.
Before resodding - I weed whacked down to dirt and tried to take the top layer off. I probably should have used grass killer but could not wait 2 weeks.
So the Bermuda is peeking through again. The suggestions I have seen is cut as high as possible, keep St Aug water well and try Atrzine. It is safe on St Aug and will not kill BErmuda but will weaken it.
Agree with canary. Also, dont worry too much about a different grass in your intended monoculture. Almost impossible to maintain without dumping pesticides/pre-emergents/fungicides/etc. Who needs it. Insanity.
be thankful you dont have torpedo grass.
Alexander Pope: [a little knowledge can be a dangerous thing]