An investigation to study the comparative efficiency of manual, mechanical and chemical methods of weed control and identification of critical stage in crop-wc d competition in upland rice was conducted at Research Farm, Banaras Hindu University, Varanasi during Kharif, 1972. It revealed that hand weeding is the most effective method in controlling weeds as compared to chemical and mechanical methods. Among the weedicides, Alachlor and Butachlor sprayed as pre-emergence at the rate of 25 kg (a.i.) per hectare proved equally effective and were found superior to Propanil (2.5 lit. per hectare) sprayed as post-emergence weedicide. Weed infestation for the first 20 days or more after seeding reduced the crop yield significantly as compared to clean check.
