A field experiment was conducted at BCKV, Mohanpur during the pre-Kharif season of 2010 and 2011 to observe the weed smothering ability of different crops and also to evaluate the bio-herbicidal potential of plant extracts on weeds. The study revealed that among the crops, significantly lowest population of different categories of weeds were found under black gram while highest population was recorded under sesame. Among the weed management practices, hand weeding at 20 DAS resulted in lowest population of all categories of weeds at 30 DAS. Among the botanical plant extracts, Ageratum conyzoides extract 5% (w/v) recorded lowest sedge and broad-leaved weed population while lowest grassy weed population was recorded under Ocimum sanctum extract 5% (w/v). The highest weed control efficiency was recorded under hand weeding treatment followed by fenoxaprop-p-ethyl while among the botanical plant extract, Ageratum conyzoides recorded the highest.