Due to simultaneous decrease in the labor supply and increase in the cost of available labour for physical methods of weed control, the demand for herbicides increased all over, especially in the United States.

Need for the integrated weed control

Because almost all weed-control efforts are directed toward many weed species, which often exhibit highly diverse growth habits and characteristics, more than one control method is commonly required to maintain weed populations below the economic threshold. The best method for each set of circumstances should be selected. However, the best control of weeds most often results from the use of two or more different methods in appropriate sequence or combination. The use of multiple methods of weed control in a given area or crop is more common than use of a single method alone. For example, tillage of the soil is practiced primarily for weed control, but the use of an herbicide as an additional method of weed control in the same area, either in conjunction with tillage or at a different period during the growing season, is especially common in the production of many important crops. Such appropriate use of multiple methods is referred to as integrated weed control.

The advantages of managerial practices, such as planting a crop as early as possible to give it a competitive edge over weeds that appear later, are well known. But that procedure alone does not provide enough weed control to allow satisfactory crop yields; other procedures are essential. Mechanical control, or cultivation, is usually required, often in combination with one or more herbicide treatments. The primary objective of integrated weed control is to provide effective control as economically as possible without adverse effects to the crop. Integration is possible by applying the various available methods to each weed-control problem. Such application may be made on either a small scale or a large scale on agricultural lands, on aquatic or industrial sites, or wherever control of weeds is desirable. Although integrated weed control has been used traditionally, new advances apparently can and should be made. Such advances can come, considering all available control methods and all factors involved. Progress is also possible in the integration of weed-control procedures with methods of controlling other pests. Additional emphasis, for example, may be given in controlling a weed that not only competes with the crop, but also serves as an alternate host to a particular fungus, virus, or insect that severely affects that crop. Integration of all procedures that are required to control existing pests with minimum cost and maximum efficiency is the objective of integrated pest management.

Ag.
Technologies
(Weed Control)