Weeds pose one of the most important threats to crop production. Losses in both yield and quality
of crops due to weeds, as well as costs of weed control, constitute an enormous economic problem in crop production. Weeds have a major influence on the production decisions made by producers. Additional land, labor, equipment, fuel, herbicides, insecticides, fungicides, fertilizer, and irrigation water may be required to maintain economical production when weeds are present.
Weed control in commercial agriculture has depended heavily on herbicides for the last fifty years.
However, increased public and regulatory agency awareness regarding potential environmental and
health problems associated with pesticide use has paralleled our increased dependence upon pesticides.
Herbicides comprise 85% by weight of agricultural pesticides used in United States (21), and herbicide
residues have been detected in ground water in at least 33 states (16, 22). Therefore, there is great need to reevaluate weed control strategies that are currently dependent on chemicals (20).
Weed control is difficult when eliminating herbicides and integrating farming practices to lower
costs and reduce environmental impacts. However, strategies that might replace herbicides include: use
of green manure crops, cover crops, mulches, and competitive crops.