Utilizing Topramezone for Goosegrass Control.

Goosegrass (Eleusine indica) is one of the most problematic grassy weeds of manicured turfgrass. Management can be very difficult, due to the ability of goosegrass to thrive in extreme environments and the lack of herbicides available offering acceptable control. Previous research has shown that topramezone (Pylex, BASF, Research Triangle Park, NC) offers excellent control of goosegrass, but turfgrass injury is an issue. Field trials were conducted in the summer of 2015 to determine the safening effects that chelated iron (Sprint 330, BASF, Research Triangle Park, NC) has on topramezone injury of bermudagrass. Results of this previous work showed that topramezone (12.3 g ai/ha) used in combination with chelated iron (1.22 kg ai/ha,) significantly reduced the bleaching effects associated with topramezone on bermudagrass. In order to determine whether the addition of chelated iron to the mixture affected herbicide efficacy of goosegrass, greenhouse trial were conducted. Two rates of topramezone (6.15 and 12.3 g ai/ha), five rates of chelated iron (0.1525, 0.305, 0.610, 1.22, 2.44 kg ai/ha), and MSO (0.5% v/v) were applied sequentially (initial, 3 weeks after initial) to two goosegrass biotypes. The results of the trials performed showed that both rates of topramezone, with or without the addition of chelated iron, yielded complete control of both goosegrass populations for all topramezone treatments. Complete control came 45 days after initial (DAI) for trial one, and 26 DAI for trial two, respectively. These data suggest that the addition of chelated iron to combinations of topramezone and MSO may offer another herbicide option for goosegrass control in bermudagrass.