Preemergence Lespedeza Control with Dithiopyr and Indaziflam.

Annual lespedeza is a troublesome weed in turfgrasses in the southern U.S. and multiple applications of postemergence herbicides are often required for control.  The objective of this research was to evaluate efficacy of dithiopyr and indaziflam for preemergence lespedeza control in a bermudagrass lawn in Griffin, GA.   Two applications of dithiopyr at 0.42 or 0.56 kg a.i./ha provided excellent (>90%) lespedeza control at 180 days after applications.  Single applications of dithiopyr at 0.42 or 0.56 kg a.i./ha at an early postemergence crabgrass timing provided excellent control of lespedeza and was better than indaziflam at 35 or 53 g a.i./ha at this timing.  Lespedeza control was poor (<70%) from indaziflam applied twice at preemergence timings at 35 or 53 g a.i/ha. Overall, dithiopyr appears to have potential for controlling lespedeza in bermudagrass lawns but indaziflam was ineffective.