Summary StatementThe presence of weed-reflected light during sugar beet emergence through
the two true-leaf stage (~16 d after emergence) had a
more detrimental impact on crop growth than the same environmental cue
beginning at the two true-leaf stage until harvest 50 d later. Sugar
beet responded irreversibly to the presence of early-season weed
presence, and therefore shade avoidance may be a major contributor to
sugar beet yield loss due to weeds.