George Levitt

SULFONYLUREAS: NEW HIGH POTENCY HERBICIDES

Abstract The sulfonylureas are new herbicides which exhibit both preemergence and postemergence activity at extraordinarily low rates of application. Two of these compounds are being commercialized by DuPont. Glean™ weed killer controls most broadleaf weeds and some grasses in wheat at 5-35 g a.i./ha. The active ingredient in this product is chlorsulfuron, formerly DPX-W4189. Oust™ weed killer is a potent herbicide, especially useful for control of seedling and rhizome johnsongrass (Sorghum halepense) at rates of 210-835 g a.i./ha with safety to Bermudagrass. The active component of this product is sulfometuron methyl (Note a), formerly DPX-T5648. The discovery, mode of action, and empirical structure-activity relationships of these new herbicides will be reviewed.