Field experiments were conducted from 1994 through 1996 to evaluate the effects of imazapic applied postemergence (POST) at 0.05 and 0.07 kg ai/ha, imazethapyr applied preplant incorporated (PPI) or POST at 0.07 kg ai/ha, and metolachlor applied PPI at 1.7 kg ai/ha on yellow nutsedge control, nutsedge tuber density, and peanut yield. All herbicides controlled yellow nutsedge at least 75% after 3 yr. Imazapic at 0.05 and 0.07 kg/ha controlled yellow nutsedge more consistently than did imazethapyr or metolachlor. Imazethapyr applied POST controlled yellow nutsedge more effectively than did imazethapyr applied PPI. Yellow nutsedge tuber densities in herbicide-treated plots were 51 to 75% less than in untreated control plots. Plots treated with imazapic, imazethapyr applied POST, and metolachlor resulted in higher peanut yields than did untreated control plots.

Few herbicides are used in carrot production in the United States, and none suppress volunteer potato, a serious weed where the two crops are grown in rotation. Hand-weeding is the primary method of controlling emerged volunteer potato within carrot. The objective of this work was to evaluate carrot tolerance and volunteer potato control with single or sequential applications of prometryn, prometryn plus fluroxypyr, and ethofumesate. The treatment with fluroxypyr resulted in malformed carrots with numerous root hairs and reduced carrot yield. Treatments with prometryn, either as single or sequential POST applications at 2.23 kg ai/ha, were safe on carrot and frequently controlled volunteer potato similar to the hand-weeded treatment. Ethofumesate applied as single or sequential PRE or POST at 2.2 kg ai/ha proved safe on carrot, but higher rates reduced yield. Ethofumesate applied POST or PRE followed by POST consistently reduced volunteer potato tuber mass. If registered for use in carrot, prometryn and ethofumesate would help modernize weed management in carrot and reduce or eliminate the need for hand-weeding volunteer potato.