Field experiment was conducted during winter seasons of 1994–95 and 1996–97 to identify the critical period of crop-weed competition. Phalaris minor was dominant weed constituting 54% of total weed population at 30 days stage. Weed population in unweeded plots increased upto 60 days and decreased subsequently at later stages of crop growth. Weed-crop competition throughout the season reduced grain yield of pea by 77.2%. Magnitude of yield loss was more due to competition during initial 45 to 60 days period. The grain yield increased significantly with increasing initial weed-free period; however, increasing this period beyond 60 days did not cause further significant increase in yield. The critical period for crop-weed competition in tendril pea was 15–60 days.
