KIH-485 and <i>S</i>-metolachlor Efficacy Comparisons in Conventional and No-Tillage Corn

Abstract

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.