Postemergence Tropical Signalgrass Control.

With the loss of MSMA in the state of Florida Tropical Signalgrass (Urochloa distachya) is becoming an even hard to control weed issue. Therefore in the fall of 2013 several studies were initiated in South Florida to evaluate a fall timing using various herbicide and herbicide combinations for the control of Tropical Signalgrass. Herbicides used in the first series of trials included Tribute Total, Xonerate, Dismiss South, Revolver, and Celsius. These herbicides were applied alone and in combination with one another. Treatments were initiated on October 23, 2013 with a sequential treatment applied two weeks after the initial. Specticle was applied to all plots on October 21, 2013 at 9 oz/A. Best results from were seen with a single application of Xonerate at 10 and 14 oz/A,; sequential applications of Tribute Total at 3.2 oz/A, Xonerate at 7.25 oz/A, Celsuis at 3.7 oz/A, Revolver at 26 oz/A and Dismiss South at 7.25 oz/A,; combinations with sequential applications of Tribute Total + Xonerate, Tribute Total + Celsius, Tribute Total + Revolver, Dismiss South + Tribute Total, and Dismiss South + Xonerate. Future research will include evaluating fall versus spring applications of various herbicides and combinations of for improved long term Tropical Signalgrass control.