ABSTRACT
Weed science is concerned with understanding and preventing the adverse effects of weeds on crop production. Weeds have been a constant companion of crop plants in croplands since man replaced native vegetation with more nutritious, productive, and economical plants to meet the needs of an ever-increasing human population. Weeds cause economic losses in crop production. Weeds growing among crop plants adversely affect yield and quality of the harvested commodity and increase production costs, resulting in economic loss. Weeds reduce crop yields by decreasing the amount of the desired commodity produced. Weed species infesting croplands are primarily herbaceous grass and broadleaf plants. Weeds commonly arise and infest croplands from seeds and asexual propagules already present in or on the soil when a crop is planted.
