Q: Four years ago I installed Tifblair centipede sod. Last summer I noticed bermuda grass in it. How do I eliminate the bermuda in the centipede?
A: There are usually only two choices: dig out the offending bermudagrass or spray it repeatedly with glyphosate (click for sources). My personal choice would be to dig it out since glyphosate usually doesn’t kill bermudagrass completely with one application. Make the excavated area the same size as a piece of sod to make repair easy.
UGA turf expert Clint Waltz notes that another option for suppressing bermudagrass in centipedegrass is spot-spraying the bermudagrass with sethoxydim (click for sources). This is a selective option because centipedegrass is tolerant of sethoxydim but the process requires multiple sprays throughout the growing season (i.e. repeat applications every 21 to 28 days). Over the course of a couple years bermudagrass can actually be controlled with regular (don’t miss a month) applications.