Response of Sugarbeet (<i>Beta vulgaris</i>) to Herbicide Residues in Soil

Abstract

Herbicides can persist in the soil and injure sensitive crops planted in the years following herbicide application. The response of sugarbeet to clomazone, imazaquin, imazethapyr, and chlorimuron residues in soil was examined. Clomazone at 1.1 or 2.2 kg ai ha -1 did not reduce yield of sugarbeet planted 1 or 2 yr after application. Imazaquin at 0.07 to 0.28 kg ai ha -1 , and imazethapyr at 0.09 to 0.14 kg ai ha -1 , can reduce yield of sugarbeet planted 1 yr after application. Imazaquin at 0.07 to 0.14 kg ha -1 caused 28 to 47% sugarbeet injury and imazethapyr at 0.09 kg ha -1 caused 54% injury 2 yr after application in soybean. A 25% yield loss occurred from the imazethapyr treatment. Sugarbeet injury 2 yr after application was greatest when sugarbeet also was planted the year following soybean. Chlorimuron at 0.02 to 0.08 kg ai ha -1 plus linuron at 0.4 to 0.9 kg ai ha -1 reduced yield of sugarbeet planted 1 yr after application when compared with linuron alone, regardless of soil pH. Visible sugarbeet injury of 38 to 66% was still evident from chlorimuron plus linuron treatments 2 yr after application. Sugarbeet should not be planted less than 25 mo following imazaquin, imazethapyr, or chlorimuron application.