Q: I have a centipede grass lawn and have been noticing some dallisgrass scattered around the yard. I have been using sethoxydim broadcasted and it has been somewhat effective. But do you know of a better post-emergent alternative? Also, can you recommend any effective pre-emergent herbicides I can use on the dallisgrass that won’t hurt the other grasses in the lawn?
A: Dallisgrass is very hard to control with a post emergent herbicide. The professional product Revolver has some effect but I doubt you can find it to buy at homeowner quantities. I think spraying Roundup to kill clumps is your best bet.
Notes from Dr. Tim Murphy
Sethoxydim G-Pro is the only selective option for dallisgrass control in centipede. Dallisgrass is only moderately sensitive to sethoxydim and repeat applications are necessary.
Research at Clemson University showed that 3 applications of sethoxydim at intervals of 2 to 6 weeks apart gave about 85% control. I would suggest that sethoxydim be applied at the high rate on about at 3 week intervals. Use 3 applications per year during the summer months.
Treat when there is good soil moisture and dallisgrass is actively growing. Plan on doing this program for 2 to 3 years. This program will also suppress bermudagrass in centipedegrass. Other than this, glyphosate is the only other option for dallisgrass control in centipede.
My advice: If there are a few dallisgrass plants, dig them up, or spot spray glyphosate. It is very difficult to selectively control dallisgrass in centipede.