| Research was conducted to evaluate the phytotoxicity and efficacy of tank mixtures of MCPP, 2,4-D, and HarmonyRTM Extra on southern turfgrass species and common broadleaf weed species. The objective was to devise a combination that provided lower phytotoxicity and comparable weed efficacy to TrimecRTM (MCPP+2,4-D+dicamba). The target turfgrass species was Floratam St. Augustinegrass [Stenotaphrum secundatum (Walt.) Ktze.], a particularly sensitive species to phenoxy herbicides. In addition to Floratam, other popular southern turfgrass species were assayed for phytotoxicity. These included common St. Augustinegrass [ Stenotaphrum secundatum (Walt.) Ktze.], common bermudagrass [ Cynodon dactylon (L.) Pers.], and common centipedegrass [ Eremochloa ophiuroides (Munro) Hack.]. Broadleaf weed species selected for efficacy included white clover (Trifolium repens L.), annual aster (Aster subulatus Michx.), lawn burweed [ Soliva pterosperma (Juss.) Less.], and bristly mallow [Modiola caroliniana (L.) G. Don]. After field evaluations, a tank mixture was applied consisting of MCPP plus 2,4-D plus HarmonyRTM Extra at the rate of 840+280+33 g ai ha-1. This provided lower phytotoxicity to selected southern turfgrass species and comparable weed efficacy to dicot weed species when compared to TrimecRTM. |
