title: Insecticide resistance and cross-resistance development in Colorado potato beetle Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae) populations in Canada 2008-2011.
abstract: BACKGROUND
  A survey of insecticide resistance in over 150 Canadian populations of Colorado potato beetle was completed between 2008 and 2011. Three neonicotinoid and two anthranilic diamide insecticides were tested at a discriminating concentration (DC) with second-instar larvae in a leaf-disc bioassay.
  
  
  RESULTS
  The mean mortality for the imidacloprid (Admire) DC was 46-67% between 2008 and 2011 respectively. Over the 4 years, 10-46% and 26-40% of the populations were classified as resistant or showed reduced susceptibility to imidacloprid. The mean mortality for thiamethoxam (Actara) and clothianidin (Poncho/Titan) ranged from 56-76% in 2008 to 81-84% in 2010 for each insecticide respectively, indicating continuous susceptibility to clothianidin but reduced susceptibility to thiamethoxam. In 2008 and 2009, susceptibility to chlorantraniliprole (Coragen) was observed in 85% of populations. Similarly, cyantraniliprole (Cyazypyr) affected 93% of the 2009 and 74% of the 2010 populations. There was a significant (P < 0.05) and high positive correlation (R = 0.4-0.84) between the three neonicotinoids, indicating the potential for cross-resistance.
  
  
  CONCLUSIONS
  The trend observed in decreasing susceptibility for thiamethoxam and clothianidin will continue unless resistance management practices are followed.
authors.affiliation: Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, London, Ontario, Canada.
authors.forename: Ian M
authors.initials: IM
authors.lastname: Scott
authors.forename: Jeff H
authors.initials: JH
authors.lastname: Tolman
authors.forename: Dale C
authors.initials: DC
authors.lastname: MacArthur
mesh_terms: D000818:Animals; D002170:Canada; D001517:Coleoptera / Q000502:physiology*; D006146:Guanidines; D007093:Imidazoles; D007305:Insecticide Resistance; D007306:Insecticides; D007814:Larva / Q000502:physiology; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010078:Oxazines; D011720:Pyrazoles; D000077922:Thiamethoxam; D013844:Thiazoles; D062367:ortho-Aminobenzoates
chemical_list: D006146:Guanidines; D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010078:Oxazines; D011720:Pyrazoles; D013844:Thiazoles; D062367:ortho-Aminobenzoates; C480342:clothianidin; C082359:imidacloprid; C517733:chlorantranilipole; D000077922:Thiamethoxam; C558219:cyantraniliprole
keywords: Colorado potato beetle; anthranilic diamides; insecticide resistance; neonicotinoids