Southern crabgrass is a major weed in turfgrass and it primarily is controlled through preemergence herbicide application. Separate studies were conducted to evaluate the efficacy of trifloxysulfuron and flazasulfuron alone and in tank mixtures for southern crabgrass control in bermudagrass as MSMA alternatives. In 2001, two applications of trifloxysulfuron at 0.03 kg ai/ha 6 wk apart controlled southern crabgrass equal to MSMA applied twice at 2.2 kg ai/ha 7 d apart (91% compared to 90%, respectively) 90 d after initial treatment (DAIT), but provided greater control than MSMA in 2002 (80 versus 74%, respectively) 90 DAIT. Two applications of trifloxysulfuron at 0.02 kg/ha tank mixed with MSMA at 1.1 kg/ha controlled southern crabgrass 90%, greater than either two applications of trifloxysulfuron or MSMA applied alone (80% and 74%, respectively). In the second study, flazasulfuron applied at 0.05 kg ai/ha tank mixed with prodiamine at 1.1 kg ai/ha, pendimethalin at 1.6 kg ai/ha, or quinclorac at 0.84 kg ai/ha controlled southern crabgrass greater than a single application of MSMA at 2.2 kg/ha 60 DAT. In both 2005 and 2006 flazasulfuron applied alone provided similar or greater southern crabgrass control compared to a single application of MSMA at 2.2 kg/ha 60 DAT. At the conclusion of these studies, trifloxysulfuron and flazasulfuron alone or in tank mixtures controlled southern crabgrass similar to or better than MSMA; therefore these would be effective alternatives to MSMA in bermudagrass.

Nomenclature: flazasulfuron, trifloxysulfuron. bermudagrass, Cynodon dactylon Pers. (L.) x. transvaalensis Burtt-Davy, ‘Tifway 419’, southern crabgrass, Digitaria ciliaris L. DIGSP