In India, weeds are responsible for about 33% of total yield losses caused by pests, whereas insects and diseases are responsible for 26% and 20%, respectively. Weeds interfere with crops by competing for light, water, nutrients and space resulting in reduction of crop yield and quality. The yield reduction in any crop through weed competition depends on several factors such as weed flora and density, duration of competition, management practices and climatic conditions. Therefore, timely weed management is crucial for attaining optimal grain yield of a crop. However, none of the single weed control methods are effective for all weeds and to manage weeds effectively and sustainably in the long run, it is essential to develop and deploy flexible integrated weed management (IWM) practices for organic farm. IWM consists of physical, cultural, bio-herbicides, and biological means developed on knowledge of weed ecology and biology.