Although previous cases of herbicide-resistant biotypes are typically controlled by unrelated herbicide families, more recent examples involve weedy biotypes with metabolism-based resistance.  These biotypes have evolved enhanced capabilities to metabolize or inactivate the herbicide before it accumulates to toxic intercellular levels.  Enhanced metabolism mediated by cytochrome P450 enzymes often confers resistance to additional, unrelated herbicide families, thus creating serious management challenges for producers.  In 2006 we detected the first Avena fatua (wild oat) biotype with enhanced metabolism in the Northern Great Plains.  Preliminary evaluation of this A. fatua biotype indicates resistance to at least four different mechanisms of herbicide action.  In this project and we are: 1) Characterizing the molecular regulation of metabolism-based resistance A. fatua, 2) Evaluating biological and environmental stressors determining fitness costs associated with enhanced herbicide metabolism in the resistant A. fatuabiotype, and 3) Developing and delivering an extension program to educate producers and land managers about preventing and managing metabolism-based herbicide resistance.   We will develop and deliver research based material in on- and off-farm presentations, as well as creating technical bulletins of straightforward approaches to 1) prevent the selection of enhanced metabolism herbicide resistance and 2) manage metabolism-based resistant A. fatua biotypes in small grain fields. This material will be presented at numerous local and regional stakeholder activities, including periodic Pest Management Schools, Grain Grower Association Meetings, and Agri-Business Conventions.

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