An undesirable bermudagrass [Cynodon dacytlon (L.) Pers. # CYNDA] often must be removed before converting to an improved bermudagrass turf or to a different turfgrass species. Because bermudagrass control with glyphosate [N-(phosphonomethyl)glycine] has been inconsistent, an experiment was initiated to determine the necessary application rates and frequency for glyphosate and SC-0224 (trimethylsulfonium carboxymethylaminomethylphosphonate) to control bermudagrass. Both glyphosate and SC-0224 applied in three applications (May, June, and August) had controlled three bermudagrass hybrids [Cynodon transvaalensis Burtt-Davy # CYNTR x C. dactylon (L.) Pers. Tifway’, Tifgreen’, and ‘Tifdwarf’] and ‘Ormond’ bermudagrasses when evaluated the next June. None of the cultivars were controlled effectively with either herbicide applied in one (May) or two (May and June) applications regardless of rate. Control with glyphosate and SC-0224 was similar.

Herbicide applications prior to turf renovation often fail to provide complete control of perennial warm-season turfgrass species like seashore paspalum. Surface applications of dazomet at 506 kg/ha provided > 90% POST control of ‘SeaDwarf’ seashore paspalum turf in 2008. Although applications of glyphosate at 5.6 kg/ha or fluazifop-P-butyl at 0.42 kg/ha induced significant injury, these treatments provided < 40% POST control of SeaDwarf seashore paspalum turf 10 wk after initial treatment (WAIT) in 2008. A similar response was noted following applications of glyphosate plus fluazifop-P-butyl at rates of 5.6 kg/ha and 0.42 kg/ha, respectively. POST control following applications of glyphosate at 5.6 kg/ha plus fluazifop-P-butyl at 0.42 kg/ha, prior to applying dazomet at 506 kg/ha, was not different from that which was observed following applications of dazomet alone at 506 kg/ha. These data suggest that granular applications of dazomet alone, at 506 kg/ha, can be used to provide effective control of SeaDwarf seashore paspalum prior to renovation.

Field experiments were conducted to evaluate the efficacy of herbicides and soil sterilants for the fairway conversion of ‘Tifway’ bermudagrass to ‘Zorro’ zoysiagrass. Treatments included glyphosate (4.48 kg ae ha−1), EPTC (7.84 kg ai ha−1), dazomet (338 kg ai ha−1), siduron (13.4 kg ai ha−1), glyphosate plus ETPC (4.48 + 7.84 kg ha−1), glyphosate plus dazomet (4.48 + 338 kg ha−1), EPTC plus siduron (7.84 + 13.4 kg ha−1), and dazomet plus siduron (338 + 13.4 kg ha−1). Glyphosate treatments were applied 5 wk prior to establishment (WPE), dazomet and EPTC treatments were applied 3 WPE, and siduron was applied at establishment. Dazomet and EPTC treatments were incorporated to a depth of 10 to 15 cm with a rotary tiller and rolled with a weighted roller to reduce losses from volatilization after application. Zorro zoysiagrass was established in June 2008 and 2009 using a mixture of rhizomes and stolons at a rate of 76 cm3 m−2. Results indicate that glyphosate + dazomet, glyphosate + EPTC, dazomet + siduron, and EPTC + siduron were equally effective at controlling Tifway bermudagrass. EPTC and dazomet controlled bermudagrass more effectively when used in combination with glyphosate or siduron. There were no significant differences in bermudagrass cover between the EPTC combinations with glyphosate or siduron and dazomet applied with glyphosate or siduron. Comparing EPTC- and dazomet-alone, EPTC yielded less bermudagrass cover (32%) than dazomet (71%). At present, research is limited on using EPTC for controlling perennial grasses in turfgrass systems. Data from these studies demonstrate the potential use of EPTC as a preplant soil herbicide to control hybrid bermudagrass during zoysiagrass renovation.