Several new herbicides which inhibit acetolactate synthase (ALS) have recently been marketed in the turfgrass industry. These herbicides vary in weed control spectrum and the types of weeds (broadleaf, grasses, and sedges) that are controlled. Such diversity suggests these herbicides will be useful in many weed control situations. Since weeds are seldom found in monocultures, it is desirable to apply treatments that control many types of weeds at once. Mixing different herbicides is the best way to increase weed control spectrum but can be a costly risk that could injure desirable turfgrass or reduce control of certain weeds due to antagonism of the mixture.

Field trials were conducted in 2005 at the Hanover Country Club in Hanover, VA on Vamont bermudagrass to evaluate Certainty (sulfosulfuron), Monument (trifloxysulfuron), Revolver (foramsulfuron), and flazasulfuron for broadleaf, grass, and sedge control when mixed with herbicides such as 3-way blends, Drive (quinclorac), Quicksilver (carfentrazone), Manor (metsulfuron), and Confront (triclopyr plus clopyralid). Effects on bermudagrass injury at greenup, control of prostrate knotweed, and false green kyllinga were evaluated. Treatments for prostrate knotweed (Polygonum aviculare) were applied during bermudagrass greenup and treatments for false green kyllinga (Kyllinga gracillima) control were applied in late June.

Treatments of prostrate knotweed included Revolver at 0.2 and 0.4 fl oz/1000 sq ft, flazasulfuron at 1 and 1.5 oz/A, Certainty at 1 and 1.5 oz/A, and Monument at 0.33 and 0.56 oz/A each alone or mixed with Drive at 1.0 lb/A, SpeedZone at 4 pt/A, Confront at 1.5 pt/A, Manor at 0.5 oz/A, Quicksilver at 1.5 fl oz/A, or primisulfuron at 1 oz/A. Treatments for false green kyllinga control included flazasulfuron at 1.5 or 3.0 oz/A alone or mixed with Acclaim at 3.5 oz/A, Drive at 1 lb/A, Dimension Ultra at 20 oz/A, Barricade at 2.3 lb/A, or Pendulum Aquacap at 4.2 pt/A.

Treatments containing Confront, SpeedZone, and Drive injured bermudagrass turf at greenup, but eventually recovered. Prostrate knotweed control was increased from 75% to 100% when flazasulfuron was mixed with Quicksilver or SpeedZone. Speed of prostrate knotweed control was also increased with these mixtures. False green kyllinga was completely controlled by flazasulfuron regardless of tank mixture.