Crop Manipulation in Integrated Weed Management Systems

Integrated weed management (IWM) became an accepted, and frequently used, term by weed scientists in the early 1970's. It has been argued by some that IWM is simply new terminology for a system that was previously called "weed control". In any event, the acceptance of the "management concept" has assured the grower that chemicals for weed control are merely a component part of a total system for managing weeds in crops (9, 65). Even with this discord, there is common agreement among weed scientists that farmers should not rely as heavily on herbicides for weed control in the future as in the past. Therefore, the primary objective in integrated weed management in a crop-weed relationship is to exert such pressure that growth of the crop is favored over that of the weeds. Techniques proposed to accomplish this shift are apparent in the definition of integrated weed management: "the application of many kinds of technologies in a mutually supportive manner. It involves the deliberate selection, integration, and implementation of effective weed control measures with due consideration of economic, ecological, and sociological consequences" (6, 7).