The influence of weeds on yield and quality were studied in sugar beet stan
ds kept mechanically weedless for different periods in small-plot. Plots wh
ich were weeded early in the season (1(st) May or 15(th) May) and were kept
clean to the end of the growing period (30(th) September) gave significant
ly higher and better quality yield than plots where weed killing started la
ter (1(st) June) or where the weeds were allowed to reappear after 15(th) M
ay or 1(st) June.
Trials proved that weed control in sugar beet has to be started early and t
hat the stand has to be kept weedless to the end of the growing period. The
late spread of weeds is an important yield-reducing factor.