title: F2 screening for resistance to pyramided Bacillus thuringiensis maize in Louisiana and Mississippi populations of Diatraea saccharalis (Lepidoptera: Crambidae).
abstract: BACKGROUND
  In the mid-southern region of the United States, sugarcane borer, Diatraea saccharalis (F.), is a major target pest of transgenic maize expressing Bacillus thuringiensis (Bt) proteins. Novel transgenic maize technologies containing two or more pyramided Bt genes for controlling lepidopteran pests have recently become commercially available. Insect resistance management (IRM) is an important issue in the sustainable use of Bt crop technologies. The objective of this study was to determine the frequency of resistance alleles in field populations of D. saccharalis to the new pyramided Bt maize technologies.
  
  
  RESULTS
  A total of 382 F(2) family lines derived from 735 feral larvae/pupae of D. saccharalis collected from six locations in Louisiana and Mississippi during 2008 and 2009 were screened for resistance to three new Bt maize technologies: MON 89034, Genuity™ VT Triple Pro™ and SmartStax™. None of the 382 F(2) isoline families survived on the Bt maize leaf tissue for ≥ 12 days in the F(2) screen. The joint frequency for two- or three-gene resistance models with 95% probability in these populations was estimated to be < 0.0063 to MON 89034 and < 0.003 to VT Triple Pro™ and SmartStax™.
  
  
  CONCLUSIONS
  These results suggest that the resistance allele frequency in D. saccharalis to the three pyramided Bt maize technologies is low in the mid-southern region of the United States, which should meet the rare resistance assumption of the currently used IRM strategy for Bt maize.
authors.affiliation: Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA, USA. fhuang@agcenter.lsu.edu
authors.forename: Fangneng
authors.initials: F
authors.lastname: Huang
authors.forename: Mukti N
authors.initials: MN
authors.lastname: Ghimire
authors.forename: Billy R
authors.initials: BR
authors.lastname: Leonard
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Chris
authors.initials: C
authors.lastname: Daves
authors.forename: Ronnie
authors.initials: R
authors.lastname: Levy
authors.forename: Don
authors.initials: D
authors.lastname: Cook
authors.forename: Graham P
authors.initials: GP
authors.lastname: Head
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Yang
authors.forename: Josh
authors.initials: J
authors.lastname: Temple
authors.forename: Rob
authors.initials: R
authors.lastname: Ferguson
mesh_terms: D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D005260:Female; D006460:Hemolysin Proteins; D007305:Insecticide Resistance / Q000235:genetics; D008145:Louisiana; D008297:Male; D008922:Mississippi; D009036:Moths / Q000235:genetics*; D003313:Zea mays / Q000235:genetics / Q000469:parasitology
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis