Field studies in 1988 and 1989 evaluated POST herbicides alone and in tank-mixtures for tropic croton control in peanut. Acifluorfen + 2,4-DB, acifluorfen + bentazon, acifluorfen + bentazon + 2,4-DB controlled > 90% of tropic croton when applied at 2 or 4 wk after crop emergence. Paraquat + bentazon controlled 55% at 2 wk and 24% at 4 wk after crop emergence. Imazethapyr and imazethapyr + 2,4-DB controlled < 24% tropic croton at either 2 or 4 wk after crop emergence. Acifluorfen + 2,4-DB, acifluorfen + bentazon, and acifluorfen + bentazon + 2,4-DB controlled at least 90% of the common lambsquarters, common ragweed, and morningglory species. Greatest yields and net returns were obtained with acifluorfen + bentazon + 2,4-DB applied 2 wk after crop emergence. Yields were higher with acifluorfen + bentazon + 2,4-DB and imazethapyr applied at 2 wk after crop emergence than at 4 wk after crop emergence. All other herbicide treatments provided equivalent yields among application timings. Only acifluorfen + 2,4-DB provided equivalent net returns at either application timing. All other herbicide treatments provided lower net returns with applications made at 4 wk than at 2 wk after crop emergence.

Field experiments conducted in 1988 and 1989 evaluated clomazone alone and in a systems approach for weed control in peanut. Clomazone PPI at 0.8 kg ai/ha controlled common ragweed, prickly sida, spurred anoda, and tropic croton better than ethalfluralin and/or metolachlor applied PPI. POST application of acifluorfen plus bentazon was not needed to control these weeds when clomazone was used. Acifluorfen plus bentazon improved control of these weeds when clomazone was not used and generally were necessary to obtain peanut yields regardless of the soil-applied herbicides. Alachlor PRE did not improve clomazone control of any weed species evaluated. Fall panicum and large crabgrass control was similar with clomazone or clomazone plus ethalfluralin.