Control of Weeds in Sugarbeets (Beta vulgaris) with Handhoeing and Herbicides

Abstract

Handweeding sugarbeets (Beta vulgarisL. ‘Mono Hy D2’) for 8 weeks after planting prevented sugarbeet yield losses. Weeds invading sugarbeet plots at the two-leaf stage (4 weeks after planting) reduced sugarbeet yields 26%. Cycloate (S-ethylN-ethylthiocyclohexanecarbamate) caused more visual sugarbeet injury and stand reduction than did ethofumesate [(±)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate]. Broadleaf and grass weeds differed in their response to cycloate and ethofumesate, but overall, total weed yields were lower in plots treated with cycloate. Ethofumesate injured sugarbeets more when applied before planting and incorporated into the soil than when applied preemergence. Herbicides applied when sugarbeets had four to six leaves generally injured sugarbeets less, but controlled weeds less effectively, than when sugarbeets had two to four leaves. None of these herbicide treatments were as effective as handweeding in providing season-long weed control. Every 1120 kg/ha of oven dry weeds present in sugarbeet fields corresponded to a decrease in sugarbeet root yields of 10 000 to 11 500 kg/ha.