Field experiments were conducted in 2006, 2007, and 2008 at the Louisiana State University Agricultural Center's Northeast Research Station near St. Joseph, LA, to evaluate imazosulfuron programs involving rate, application timings, and tank mixes for PRE and POST broadleaf weed control in drill-seeded rice. Imazosulfuron showed residual activity against both Texasweed and hemp sesbania. PRE-applied imazosulfuron at 168 g ai ha⁻¹ and higher rates provided 83 to 93% Texasweed control at 4 WAP. At 12 WAP, Texasweed control with 168 g ha⁻¹ and higher rates was 92%. Hemp sesbania control with 168 g ha⁻¹ and higher rates was 86 to 89% at 4 WAP and 65 to 86% at 12 WAP. Imazosulfuron at 224 g ha⁻¹ applied EPOST provided 84 to 93% Texasweed control and 82 to 87% hemp sesbania control, and it was as effective as its tank mixture with bispyribac-sodium. When applied LPOST, four- to five-leaf Texasweed, imazosulfuron alone at 224 g ha⁻¹ was not effective against Texasweed and hemp sesbania, but did improve weed control when mixed with bispyribac-sodium at 17.6 g ai ha⁻¹.

Nomenclature: Imazosulfuron; bispyribac-sodium; hemp sesbania, Sesbania herbacia (L.) SESEX; Texasweed, Caperonia palustris (L.) St. Hil. CNPPA; rice, Oryza sativa L. ORYSA.