The benefits and risks of carefully applying glyphosate to large redroot pigweed (Amaranthus retroflexus L.) plants without contacting sugarbeet were evaluated. Glyphosate applied to redroot pigweed growing in close association with sugarbeet reduced or tended to reduce sugarbeet (Beta vulgaris L.) root yield and extractable sucrose yield when compared to handweeding. Glyphosate injury to sugarbeet was observed despite careful application and plastic bagging of redroot pigweed to prevent the herbicide from dripping onto sugarbeet during or following application. Results suggested that sugarbeet injury was caused by movement of glyphosate from roots of treated redroot pigweed to roots of untreated sugarbeet.