Two field experiments were conducted at the Agronomy Research Station near Stillwater, OK in 2004 and 2005 to identify and evaluate herbicides applied preplant incorporated, preemergence, early postemergence, or late postemergence for the control of seedling sericea lespedeza. Trifluralin, applied preplant incorporated, controlled seedlings 77 (15 wk after emergence [WAE]) and 63% (16 WAE) in 2004 and 2005, respectively. Flumioxazin, imazapic, fluometuron, diuron, sulfentrazone, atrazine, metribuzin, and metolachlor applied preemergence all provided greater than 86% seedling control at 15 and 16 WAE in both years. Diclosulam, applied preemergent, controlled seedlings 47% at 15 WAE in 2004 and 91% control at 16 WAE in 2005. In 2004, triclopyr, metsulfuron-methyl, glyphosate, picloram, dicamba, and 2,4-D amine plus picloram (tank-mix) applied early postemergence controlled 90 to 100% of the sericea lespedeza seedlings at 15 WAE. However, in 2005, only triclopyr, metsulfuron-methyl, glyphosate, and 2,4-D amine plus picloram (tank-mix) showed greater than 80% control at 16 WAE. Triclopyr, applied late postemergence, controlled seedlings 100% at 15 and 16 WAE, in both years. In 2004, dicamba plus 2,4-D (premix) and glyphosate were the only other herbicides which provided greater than 75% control at 15 WAE. These data suggest that there were preemergence-applied herbicides that were effective for the control of seedling sericea lespedeza. These data also suggest that triclopyr was the most effective postemergence-applied herbicide for the control of seedling sericea lespedeza. The data also showed that the overall level of control of seedling sericea lespedeza decreased as the season progressed and the plant matured.

Nomenclature: 2,4-D amine; atrazine; dicamba; diclosulam; diuron; flumioxazin; fluometuron; glyphosate; imazapic; metolachlor; metribuzin; metsulfuron-methyl; picloram; sulfentrazone; triclopyr; trifluralin; Sericea lespedeza, Lespedeza cuneata (Dumont) G. Don LESCU.