Field experiments were conducted during 2003 and 2004 to compare the effectiveness of KIH-485 and S-metolachlor for PRE weed control in no-tillage and conventional-tillage corn. Longspine sandbur control increased as KIH-485 or S-metolachlor rates increased in conventional-tillage corn, but control did not exceed 75% when averaged over experiments. Both herbicides controlled at least 87% of green foxtail with the exception of no-tillage corn in 2004, when KIH-485 was more effective than S-metolachlor at lower rates. Palmer amaranth control ranged from 85 to 100% in 2003 and 80 to 100% in 2004, with the exception of only 57 to 76% control at the lowest two S-metolachlor rates in 2004. Puncturevine control exceeded 94% with all treatments in 2003. In 2004, KIH-485 controlled 86 to 96% of the puncturevine, whereas S-metolachlor controlled only 70 to 81%. Mixtures of atrazine with KIH-485 or S-metolachlor generally provided the most effective control of broadleaf weeds studied.
Nomenclature: Atrazine; KIH-485; S-metolachlor; Palmer amaranth, Amaranthus palmeri S. Wats. #3 AMAPA; green foxtail, Setaria viridis (L.) Beauv. # SETVI; puncturevine, Tribulus terrestris L. # TRBTE; longspine sandbur, Cenchrus longispinus (Hack.) Fern. # CCHPA; corn, Zea mays L.
Additional index words: Tillage systems, best management practices.
Abbreviations: BMP, best management practices; DAT, days after herbicide treatment; Kow, herbicide adsorption coefficient.
