The Continued Evolution of Herbicide Resistant Weed Populations Implications and Potential Economic Consequences to Iowa Crop Production

Micheal D. K. Owen, Faculty, Agronomy

 
Situation

Weeds continue to remain the principle pest problem plaguing Iowa production agriculture.  Adoption of transgenic crops represents an unprecedented change in corn and soybean production.  Specifically one herbicide (glyphosate) now plays the primary, if not singular role in managing weeds.  This has dramatically increased the risk of selection pressure which will result in weed population shifts or the evolution of glyphosate resistant weed biotypes.  ISU Extension has an obligation to provide clientele with information about risks related to various agricultural technologies and the adoption of these technologies.  ISU Extension is the sole source of objective information for Iowa agricultural endeavors and thus has an obligation to develop and deliver information that is important to the well being of Iowa Agriculture.
 
Objective

Develop and deliver objective information describing the implications of various crop production and weed management technologies on the evolution of herbicide resistant weed populations.  Specifically, the implications of transgenic crops and the use of glyphosate will be the focus of these efforts.  Glyphosate resistant weed populations can impact crop yield and crop production expenditures, and potentially can depreciate land values.
 
Activities/Output

The dissemination of information will be via traditional strategies (grower meetings, AgChem dealer meetings, short courses, conferences, publications, and popular press/radio offerings) and via web-based education tactics.  Also, a national glyphosate stewardship forum was held to address issues of stewardship and IPM practices.  This national stewardship forum was organized by ISU Extension Weed Science and provided valuable information for Iowa growers.
 
Impact/Outcomes

Growers will demonstrate a high knowledge level about the implications of the evolution of glyphosate resistant weed populations.  However, the implications of the risk of glyphosate resistant weed populations are longer term.  In the current economic climate, Iowa Agriculture may not be in a position to adopt practices that are less convenient and possibly more costly even if these practices are arguably better from an IPM perspective.  Thus, while it is apparent that ISU Extension is highly successful in making Iowa Agriculture aware of the significance of the evolution of glyphosate resistant weed populations and the subsequent economic implications of this ecological shift in weed communities, growers are reticent to make significant changes.  However, it is apparent that changes within the agricultural industry are occurring in response to information provided by ISU Extension.


2005
142 Integrated Pest Management/Integrated Crops Management

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