Efficacy and economic evaluation of weed management systems in sugarbeets

Irrigated field studies were conducted at the Research and Extension Centers at Torrington, Wyoming in 1999 and 2000, and at Powell, Wyoming in 2000 to evaluate weed control and economic returns for glyphosate tolerant, glufosinate tolerant, and conventional weed management systems in sugarbeets. The effect of either 0, l, or 2 cultivation operations on sugarbeet yield was also evaluated within each system at both locations in 2000. Weed control at Torrington over both years was excellent (98 to 99%) with all glyphosate treatments regardless of application timing or number of applications. Adequate (82 to 86%) weed control was achieved with glufosinate only when applied as three separate applications at both locations and when applied as an early two-application program at Powell. The conventional treatments provided good (81 to 91%) overall weed control at both locations but were less consistent than the glyphosate treatments at Torrington. Sugarbeet yields were different among treatments and were generally related to weed control. Cultivation had a significant impact on extractable sucrose yield with the glufosinate system at Powell. Glufosinate applied as three separate applications and glyphosate applied twice late produced the highest net returns at Torrington and Powell, respectively. The micro-rate program produced the highest net returns in the conventional system and was similar to the two-application program with glyphosate.