Cultivation and Reduced-Rate Herbicides Weed Control in Sugarbeet Grown for Biofuel

Sugarbeet, grown for biofuel, is being considered as an alternate cool-season crop in the southeastern United States. Previous research identified ethofumesate PRE and phenmedipham + desmedipham POST as herbicides that controlled troublesome cool-season weeds in the region, specifically cutleaf evening-primrose. Research trials were conducted from 2014 through 2016 to evaluate an integrated system of sweep cultivation and reduced rates of ethofumesate PRE and/or phenmedipham+desmedipham POST for weed control in sugarbeet grown for biofuel. There were no interactions between the main effects of cultivation and herbicides for control of cutleaf evening-primrose and other cool-season species in two out of three years. Cultivation improved control of cool-season weeds, but the effect was largely independent of control provided by herbicides. Of the herbicide combinations evaluated, the best overall cool-season weed control was from systems that included either a 1/2X or 1X rate of phenmedipham+desmedipham POST. Either rate of ethofumesate PRE was less effective than phenmedipham+desmedipham POST. Despite improved cool-season weed control, sugarbeet yield was not affected by cultivation each year of the study. Sugarbeet yields were greater when treated with any herbicide combination that included either a 1/2X or 1X rate of phenmedipham+desmedipham POST compared with either rate of ethofumesate PRE alone or the nontreated control. These results indicate that cultivation has a very limited role in sugarbeet grown for biofuel. The premise of effective weed control based on an integration of cultivation and reduced herbicide rates does not appear to be viable for sugarbeet grown for biofuel.

Isoglucose: what are its prospects post-quotas?

After the end of the EU sugar quota system from 1 October 2017, expansion of isoglucose production will be possible. Currently production is limited to 720,000 t in nine EU countries, which is divided among six producers. Production is concentrated in Central and Southeastern Europe, far away from the main consumption areas, where high sugarbeet yields make sugar production very competitive. The possibilities for isoglucose production expansion are discussed. An 1 mn t production increase, to about 2 mn t of sugar equivalent, seems likely after 2017 despite the high beet sugar production surplus currently seen on the EU market.

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

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.