title: Managing the evolution of herbicide resistance.
abstract: BACKGROUND
  Understanding and managing the evolutionary responses of pests and pathogens to control efforts is essential to human health and survival. Herbicide-resistant (HR) weeds undermine agricultural sustainability, productivity and profitability, yet the epidemiology of resistance evolution - particularly at landscape scales - is poorly understood. We studied glyphosate resistance in a major agricultural weed, Amaranthus tuberculatus (common waterhemp), using landscape, weed and management data from 105 central Illinois grain farms, including over 500 site-years of herbicide application records.
  
  
  RESULTS
  Glyphosate-resistant (GR) A. tuberculatus occurrence was greatest in fields with frequent glyphosate applications, high annual rates of herbicide mechanism of action (MOA) turnover and few MOAs field(-1) year(-1) . Combining herbicide MOAs at the time of application by herbicide mixing reduced the likelihood of GR A. tuberculatus.
  
  
  CONCLUSIONS
  These findings illustrate the importance of examining large-scale evolutionary processes at relevant spatial scales. Although measures such as herbicide mixing may delay GR or other HR weed traits, they are unlikely to prevent them. Long-term weed management will require truly diversified management practices that minimize selection for herbicide resistance traits.
authors: USDA-ARS Global Change and Photosynthesis Research Unit, Urbana, IL, USA.
authors: Jeffrey A
authors: JA
authors: Evans
authors: Department of Crop Sciences, University of Illinois, Urbana, IL, USA.
authors: Patrick J
authors: PJ
authors: Tranel
authors: Department of Crop Sciences, University of Illinois, Urbana, IL, USA.
authors: Aaron G
authors: AG
authors: Hager
authors: Department of Entomology, Plant Pathology and Weed Science, New Mexico State University, Las Cruces, NM, USA.
authors: Brian
authors: B
authors: Schutte
authors: Department of Crop Sciences, University of Illinois, Urbana, IL, USA.
authors: Chenxi
authors: C
authors: Wu
authors: Department of Crop Sciences, University of Illinois, Urbana, IL, USA.
authors: Laura A
authors: LA
authors: Chatham
authors: USDA-ARS Global Change and Photosynthesis Research Unit, Urbana, IL, USA.
authors: Adam S
authors: AS
authors: Davis
mesh_terms: D027721:Amaranthus / Q000187:drug effects*; D005075:Biological Evolution; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D053209:Herbicide Resistance; D006540:Herbicides / Q000494:pharmacology*; D007087:Illinois; D057685:Plant Weeds / Q000187:drug effects*; D012307:Risk Factors; D000097797:Glyphosate
chemical_list: D005998:Glycine; D006540:Herbicides; D000097797:Glyphosate
keywords: Amaranthus tuberculatus; common waterhemp; glyphosate resistance; herbicide mixing; herbicide rotation; modes of action; resistance evolution