Weeds are one of the main limiting factors in crop production, causing billions of dollars in annual global losses through degraded agricultural and silvicultural productivity. Weeds also reduce access to land and water, impair aesthetics, and disrupt human activities and well-being. The number of positions devoted to weed science teaching, research, and extension at 76 land-grant institutions across the United States and its territories was determined and compared with that for plant pathology and entomology. The number of classes and graduate students in these disciplines at those institutions was also determined. There are more than four times as many entomologists and more than three times as many plant pathologists as weed scientists at land-grant institutions. There are approximately five times as many graduate students currently in entomology and almost three times as many in plant pathology compared with weed science. There are approximately five times as many entomology and two and a half times as many plant pathology undergraduate classes compared with weed science classes. These differences increase when graduate courses are considered. Most land-grant universities have either none or few graduate classes in weed science. There are more than six times as many graduate entomology courses and more than five times as many plant pathology courses compared with weed science graduate classes. There are no departments devoted solely to weed science, whereas entomology and plant pathology departments are both common. Most universities have little to no faculty assigned to ornamental, fruit, aquatic, or forestry weed control. Number of faculty assigned to vegetable, turf, non-crop, ecology, and basic/laboratory studies in weed science are also limited. Additional university resources are needed if weed science research, teaching, and extension efforts are to meet the priority needs for the management of weeds in the agricultural, natural resources, and urban ecosystems.

Plant model systems have contributed greatly to the dramatic progress in understanding the fundamental aspects of plant biology. Using model weeds will also help facilitate focused funding and research in the weed science community. Criteria for developing model weeds require attention to weedy characteristics that impart economic losses and a wide geographic distribution, attributes that present the potential for political and scientific support. Expressed sequence tag (EST) databases for model weeds are the most practical approach to identifying new genes and obtaining data on the gene expression underlying weedy characteristics. Weeds such as Canada thistle, eastern black nightshade, johnsongrass, jointed goatgrass, leafy spurge, waterhemp, and weedy rice are proposed as model systems.

Two broad aims drive weed science research: improved management and improved understanding of weed biology and ecology. In recent years, agricultural weed research addressing these two aims has effectively split into separate subdisciplines despite repeated calls for greater integration. Although some excellent work is being done, agricultural weed research has developed a very high level of repetitiveness, a preponderance of purely descriptive studies, and has failed to clearly articulate novel hypotheses linked to established bodies of ecological and evolutionary theory. In contrast, invasive plant research attracts a diverse cadre of nonweed scientists using invasions to explore broader and more integrated biological questions grounded in theory. We propose that although studies focused on weed management remain vitally important, agricultural weed research would benefit from deeper theoretical justification, a broader vision, and increased collaboration across diverse disciplines. To initiate change in this direction, we call for more emphasis on interdisciplinary training for weed scientists, and for focused workshops and working groups to develop specific areas of research and promote interactions among weed scientists and with the wider scientific community.

The increased effort by Congress to reduce agriculture's adverse consequences on the environment has been focused almost entirely on changing agricultural production practices at the farm level Because the agricultural sector is highly integrated, attempts to change a specific industry within the sector, such as production, input supply, or processing, may have undesirable effects. Programs designed to achieve society's environmental objectives by forcing change in agricultural production practices will lead to increased frustration, new programs and regulations, and further conflict between society and farmers. To guarantee sustainability of U.S. agriculture into the next century, efforts to incorporate new social needs into production agriculture should include changes in the research agendas of public and private institutions, marketing grades and standards, and the institutions that support the agricultural producer.