title: Resistance to HPPD-inhibiting herbicides in a population of waterhemp (Amaranthus tuberculatus) from Illinois, United States.
abstract: BACKGROUND
  A population of waterhemp in a seed maize production field in central Illinois, United States, was not adequately controlled after post-emergence applications of herbicides that inhibit 4-hydroxyphenylpyruvate dioxygenase (HPPD).
  
  
  RESULTS
  Progeny from the field population survived following treatment with mesotrione, tembotrione or topramezone applied to the foliage either alone or in combination with atrazine in greenhouse experiments. Dose-response experiments indicated that the level of resistance to the HPPD inhibitor mesotrione is at least tenfold relative to sensitive biotypes.
  
  
  CONCLUSIONS
  These studies confirm that waterhemp has evolved resistance to HPPD-inhibiting herbicides.
authors.affiliation: Department of Crop Sciences, University of Illinois, Urbana, IL, USA.
authors.forename: Nicholas E
authors.initials: NE
authors.lastname: Hausman
authors.forename: Sukhvinder
authors.initials: S
authors.lastname: Singh
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Tranel
authors.forename: Dean E
authors.initials: DE
authors.lastname: Riechers
authors.forename: Shiv S
authors.initials: SS
authors.lastname: Kaundun
authors.forename: Nicholas D
authors.initials: ND
authors.lastname: Polge
authors.forename: David A
authors.initials: DA
authors.lastname: Thomas
authors.forename: Aaron G
authors.initials: AG
authors.lastname: Hager
mesh_terms: D015111:4-Hydroxyphenylpyruvate Dioxygenase / Q000037:antagonists & inhibitors*; D027721:Amaranthus / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D001280:Atrazine / Q000737:chemistry / Q000494:pharmacology; D005075:Biological Evolution; D003512:Cyclohexanones / Q000737:chemistry / Q000494:pharmacology*; D004351:Drug Resistance; D006540:Herbicides / Q000737:chemistry / Q000494:pharmacology*; D007087:Illinois; D011720:Pyrazoles / Q000737:chemistry / Q000494:pharmacology; D013450:Sulfones / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D003512:Cyclohexanones; D006540:Herbicides; D011720:Pyrazoles; D013450:Sulfones; C432907:mesotrione; D015111:4-Hydroxyphenylpyruvate Dioxygenase; D001280:Atrazine; C521377:topramezone; C585552:tembotrione