HERBICIDE TANK-MIXING FOR POST-EMERGENCE WEED-CONTROL IN SUGAR-BEETS

Tank-mixtures of selective herbicides were evaluated for 2 yr on field-grown sugarbeets under 2 weed flora situations: mixed floras of broad-leaved and grass weeds and weed floras of broadleaves grown beyond their stages of greatest sensitivity to herbicides. In these situations, single herbicides usually fail to provide satisfactory post-emergence weed control in sugarbeets. Of several tank-mixtures, which could be divided for use in the 1st situation, ethofumesate + Betanal AM 11, diclofop-methyl + Betanal AM 11 and diclofop-methyl + metamitron gave synergistic phytotoxicity to sugarbeet seedlings. Synergism in weed control, becoming apparent by an accelerated appearance of the herbicidal effects, was obtained with the mixture alloxydimeton + Betanal AM 11. This mixture was not phytotoxic and appears to be the most efficient for simultaneous control of broad-leaved and grass weeds. From trials in the 2nd situation it became apparent that the activity of metamitron, which was reduced on older weeds, could be restored by mixing with a non-phytotoxic oil or a low dose of Betanal AM 11. These mixtures should be useful when growth of sugarbeets has been retarded by carried-over herbicides, drought, frost, etc.