Sugarbeet (Beta vulgarisL.) Response to Simulated Herbicide Spray Drift

Abstract

Dicamba (3,6-dichloro-o-anisic acid), 2,4-D [(2,4-dichlorophenoxy)acetic acid], and picloram (4-amino-3,5,6-trichloropicolinic acid) were applied as simulated spray drift to sugarbeets at several growth stages. When applied at early growth stages 2,4-D tended to decrease root yield but decreased purity and extractable sucrose content by as much as 54% when applied at later growth stages. Dicamba at 0.14 kg ae/ha and 2,4-D at 0.28 kg ae/ha decreased extractable sucrose/ha and tended to decrease root yield at harvest while picloram at 0.028 kg ae/ha did not significantly reduce root yield or sucrose content at harvest compared to the control. All rates of 2,4-D from 0.035 to 0.28 kg ae/ha increased sucrose losses during post-harvest storage at 5 C and 95% relative humidity. Dicamba and picloram at 0.14 and 0.028 kg ae/ha, respectively, caused similar storage losses. Sugarbeets that are inadvertently exposed to 2,4-D, dicamba, or picloram spray drift during the growing season should be processed immediately after harvest.