Field and greenhouse experiments were conducted at Southern Illinois University-Carbondale in 2006 and 2007 to evaluate the herbicide tembotrione for postemergence grass control. Tembotrione inhibits the p-hydroxyphenylpyruvate dioxygenase (HPPD) enzyme, which aids in the formation of essential plant constituents for photosynthesis. Tembotrione efficacy was examined in the greenhouse on large crabgrass, giant foxtail, shattercane, and fall panicum. Significant activity that could translate to commercial levels of weed control in the field was found on all species except fall panicum. Greenhouse studies also compared the efficacy of tembotrione, mesotrione, and topramezone which represent the three HPPD-inhibiting herbicides commercially available in U.S. corn production. Tembotrione and topramezone have more activity on these grasses than mesotrione. Tembotrione was also tank-mixed with either nicosulfuron or foramsulfuron to evaluate fall panicum response. Activity on fall panicum was similar weather nicosulfuron or foramsulfuron was applied alone or with tembotrione. In the field, it was also determined that nicosulfuron or foramsulfuron could be added to tembotrione to control fall panicum. The addition of atrazine to nicosulfuron and tembotrione did not negatively effect fall panicum control. It was also observed in both the field and greenhouse that utilizing methylated seed oil provided more activity than crop oil concentrate.