Texas panicum is considered to be the most troublesome weed of field corn in the Southeast. Field trials were conducted in Georgia in 2003 and 2004 to compare pendimethalin, nicosulfuron, foramsulfuron, and glyphosate for Texas panicum control in irrigated field corn and to determine which herbicide provided the greatest economic returns. Pendimethalin applied early POST (EPOST), 10 to 12 d after planting (DAP), controlled Texas panicum less than 35% late in the season and resulted in reduced corn yield and net returns in 2004. Glyphosate applied sequentially POST at 21 to 24 DAP and again late POST (LPOST) at 35 to 38 DAP controlled Texas panicum 82 to 94% late in the season compared with 43 to 80% control by nicosulfuron and foramsulfuron applied POST. Texas panicum control, corn yield, and net returns were similar with glyphosate applied POST and LPOST at 0.53 or 1.1 kg ai/ha. Glyphosate applied POST and LPOST was more effective than glyphosate POST, but net returns were greater only in 2004.
Nomenclature: Atrazine, foramsulfuron, nicosulfuron, pendimethalin, potassium salt of glyphosate, Texas panicum, Panicum texanum L. #3 PANTE, corn, Zea mays L. ‘DeKalb 67-60RR’.
Additional index words: Economics, herbicide-resistant crops, postemergence.
Abbreviations: AMS, ammonium sulfate; COC, crop oil concentrate; GR, glyphosate resistant; MSO, methylated seed oil.