Economic Importance of Weeds: A Review

Weeds are plants that are unwanted in a given situation and may be harmful, dangerous or economically detrimental. They are responsible for substantial losses of farm production and extensive damage to the environment. Weeds, through competition with other plants, would almost always have deleterious effects on them and can have a lethal effect on livestock through consumption of weeds containing poisonous chemicals in the pasture. Weed invasion has become the most dreaded and deleterious impact of weeds in nature; it adversely affects agriculture, alters the balance of ecological communities, disrupts the natural diversity and interferes in the aesthetic value of the environment. Weeds can interfere in water management, thereby reducing the economic value of water. Weeds, however, besides their deleterious impacts in nature, have many beneficial properties, which include, but not limited to benefits of weeds to companion plants, ethnomedical and ethnopharmaceutical uses of weeds, ethnobotanical uses of wild edible weeds, and the use of weeds as feed for livestock. In the light of myriads of deleterious effects and benefits accompanying weeds, it is suggested that more studies should be carried out on weed control and weed management. Also, further explorations on the potential uses of weeds to man, his environments and livestock should be undertaken.