Working Model for Assessing Integrated Weed-Management Strategies
Highly efficacious pesticides often mask the complexity of a cropping system-pest relationship. Many crop producers and scientists are just beginning to understand the relationships between biological and agronomic practices and the impacts of a pest on a crop. Herbicides, in particular, have made the recognition and integration of more biologically based alternatives difficult. Commodity-grain producers now use highly efficacious and fast-acting herbicides as time- and labor-management tools, giving less regard to the biological and agronomic principles that can increase or decrease a herbicides effectiveness and durability (see box 5-1).
For more than 30 years, herbicide use has been the dominant tactic for weed management. Over this period, herbicide technology has been a primary focal point of the agrochemical industry-university relationship. Historically, university herbicide-evaluation trials were established to demonstrate the efficacy of individual products and to promote weed-management research. In its technology-transfer role, the University Extension Service also provided a public service by offering a third-party neutral perspective to this manufacturer-crop producer relationship.
During the 1990s major changes occurred in both institutions. As agrochemical markets became saturated, herbicides were differentiated more by marketing and product endorsements than by efficacy. Past agrochemical and university relationships were centered around basic and applied research and technology transfer. The current economic climate has resulted in agrochemical industries doing more of their own basic and applied herbicide research and has tended to push university herbicide evaluation and technology transfer to more of a marketing and product-endorsement focus. Although a marketing perspective might address attributes of a single herbicide, this approach to weed management does not address the complexities of integrating a pesticide into a cropping system of an individual producer.
The University of Minnesota is responding to public demand for alternatives to herbicide weed-control technology by adopting a biological and ecological research strategy with a goal of developing integrated weed-management systems, including herbicides as a component. University of Minnesota Extension and Branch Station personnel have formed a weed-management working group. The group focuses on evaluating weed management systems rather than individual herbicides. Its goals are as follows: