The people of the world required from the dawn of time until 1830 to reach a population of 1 billion. By 1960, we reached 3 billion and by 1980 we had a population of about 4 billion. It is estimated that by the year 2000 there will be 7 billion people in the world. Just 30 yr from now the world's population will have doubled. This means that within the next 30 yr we must produce as much food as we have produced since the beginning of history. Can we feed this many people? Yes, but expanded research to develop improved technology will be required to meet the challenge.

In a special symposium on weed biology presented at the 1975 annual meeting of the Weed Science Society of America, Parka (37) reviewed the trend of published papers in WEED SCIENCE related to weed biology over the 20-yr period, 1952 to 1972. His data indicated a steady increase from 9.2 to 17.2% of published papers directly related to weed growth and development. My recent assessment of similarly classified papers in 1978, 1979, and 1980 showed a remarkable increase to 21.9, 24.3, and 27.2%, respectively. Further, the more recent papers on weed growth and development also include crop-effect data, i.e., the association of weed growth with crop competition.

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).

Little effort has been directed toward integrating biological control; that is, the use of living natural enemies to control weeds, with more conventional weed control practices. The usual focus of biological control has been on the introduction of weed insects and pathogens from foreign areas to control naturalized range, pasture, and/or aquatic weeds, principally single species that had become dominant over a plant community. The released natural enemies were allowed to reach their own balance with the target weed without added assistance. As economic and environmental perspectives change along with our knowledge and technological capability, however, it becomes worthwhile to review periodically if and how biological control might be integrated with other farming practices. Because my biological control experience has centered on the use of weed-feeding insects, this discussion will focus on methods of enhancing and integrating insect impact on weeds with other weed-control activities.

A need exists to manage or manipulate plant pathogens for biocontrol of weeds in row crops. Many weed species remain refractory to conventional weed-control technology. Some of these weeds occur in the same families as important crops and are resistant or tolerant to many of the herbicides that are applied for weed control within those crops. Preemergence treatments are needed for some weed species for which only postemergence treatments are now available. The cost of controlling some weeds is so prohibitive that many farmers will not spend the necessary money; therefore, more economical control is needed.

I am honored by your invitation to participate in a symposium on this timely topic. Our twenty-first annual meeting on weed science and technology comes during a critical period of challenging readjustment for agricultural production in the world, especially in the United States. To focus perspective on this subject, I have compiled a list of factors, trends, and economic forces that can exert a strong impact on the future of agriculture, food production, herbicide technology, and integrated crop-management programs during the next 20 yr.

Producers of food have always been troubled with weeds. Hand labor was the primary source of weed control for centuries, and selective weed control was not achieved until copper sulphate was used to control mustard (Brassica spp.) in wheat (Triticum aestivum L.) in 1896 (4, 42). Adequate crop selectivity was usually difficult to obtain with herbicides during the first 40 yr of the 20th century and the cost of the early herbicides was high.

Integrated Pest Management (IPM) has been defined as an interdisciplinary science (3). IPM has become popular this past decade; however, integrated pest management has been practiced by farmers and growers for decades. As nonfarming agricultural professionals become more specialized they tend to become “reductionists” or ever-narrower in their perspective base. From this evolution into disciplines has arisen the necessity to redirect thought and effort to addressing the total or whole such as is commonly done by the farmer or grower. IPM has been considered an effort in this direction, although unanimity in definition of IPM has been notably absent. Some have considered it synonymous with integrated pest control; in contrast, others have viewed it as a means to reduce the use of pesticides. Nevertheless, IPM has received considerable attention in the pest-related disciplines. Its implementation has been addressed in Presidential messages to Congress in 1977 and 1979 (7, 8).

A considerable amount of scientific time has been spent defining Integrated Pest Management (IPM). The following is quoted from an Extension Committee on Organization and Policy publication (4): “Integrated Pest Management (IPM) is a system that utilizes all suitable pest control techniques and methods to keep pest populations below economically injurious levels. Each pest control technique must be environmentally sound and compatible with production and user objectives. Integrated Pest Management is more than chemical pesticide management. In many cases it includes biological, cultural, and sanitary control practices for all pest complexes.”