Abstract: Field experiments were conducted in 1996 and 1997 to evaluate weed control and dry bean response to mechanical tillage and herbicide treatments. Herbicide treatments were EPTC plus ethalfluralin, dimethenamid, and imazethapyr plus bentazon. Herbicides were applied alone or combined with rotary hoeing and in-row cultivation. Differences in dry bean yields between years were due to differences in weed density. Weed species included redroot pigweed, common lambsquarters, hairy nightshade, wild proso millet, and green foxtail. Weed density in the untreated check plots at the end of the growing season was 35 plants/m2 in 1996 and 134 plants/m2 in 1997. Dry bean stands were not reduced by rotary hoeing, in-row cultivation, and herbicides in 1996, but in-row cultivation reduced dry bean populations 27% compared to the hand-weeded check in 1997. In-row cultivation and rotary hoeing provided similar weed control in both years. At low weed densities, either mechanical tillage or herbicides alone were effective in suppressing weeds, whereas at higher densities, herbicides combined with mechanical tillage were required for effective control.
Nomenclature: Bentazon; dimethenamid; EPTC; ethalfluralin; imazethapyr; common lambsquarters, Chenopodium album L. #3 CHEAL; dry bean, Phaseolus vulgaris, Great Northern ‘Beryl’; green foxtail, Setaria viridis L. Beauv. # SETVI; hairy nightshade, Solanum sarrachoides Sendt. # SOLSA; redroot pigweed, Amaranthus retroflexus L. # AMARE; wild proso millet, Panicum miliaceum L. # PANMI.
Additional index words: Combinations, herbicides and mechanical tillage, postemergence herbicides, preemergence herbicides, preplant-incorporated herbicides.
Abbreviations: DAP, days after planting; IR, in-row cultivation; POST, postemergence; PRE, preemergence; RH, rotary hoeing.