Significantly higher bulb yield was obtained when crop was kept weed-free for initial 60 days after transplanting (DAT) compared to 20 and 40 DAT where weeds remerged at later stages and accumulated higher weed dry matter and reduced the bulb yield. Bulb yield remain.ed at par with weed-free check when weeds were allowed to grow with the onion crop upto 20 DAT; however, weedy period beyond 20 days was detrimental to bulb yield. There was 53.4% reduction in bulb yield under season long unweeded conditions. Critical period of crop-weed competition was found to be 20–60 DAT.
