title: Evaluation of SmartStax and SmartStax PRO maize against western corn rootworm and northern corn rootworm: efficacy and resistance management.
abstract: BACKGROUND
  Cases of western corn rootworm (WCR) field-evolved resistance to Cry3Bb1 and other corn rootworm (CRW) control traits have been reported. Pyramid products expressing multiple CRW traits can delay resistance compared to single trait products. We used field studies to assess the pyramid CRW corn products, SmartStax (expressing Cry3Bb1 and Cry34Ab1/Cry35Ab1) and SmartStax PRO (expressing Cry3Bb1, Cry34Ab1/Cry35Ab1 and DvSnf7), at locations with high WCR densities and possible Cry3Bb1 resistance, and to assess the reduction in adult emergence attributable to DvSnf7 and other traits. Insect resistance models were used to assess durability of SmartStax and SmartStax PRO to WCR resistance.
  
  
  RESULTS
  SmartStax significantly reduced root injury compared to non-CRW-trait controls at all but one location with measurable WCR pressure, while SmartStax PRO significantly reduced root injury at all locations, despite evidence of Cry3Bb1 resistance at some locations. The advantage of SmartStax PRO over SmartStax in reducing root damage was positively correlated with root damage on non-CRW-trait controls. DvSnf7 was estimated to reduce WCR emergence by approximately 80-95%, which modeling indicated will improve durability of Cry3Bb1 and Cry34Ab1/Cry35Ab1 compared to SmartStax.
  
  
  CONCLUSIONS
  The addition of DvSnf7 in SmartStax PRO can reduce root damage under high WCR densities and prolong Cry3Bb1 and Cry34Ab1/Cry35Ab1 durability. © 2017 Society of Chemical Industry.
authors.affiliation: Monsanto LLC, St. Louis, MO, USA.
authors.forename: Graham P
authors.initials: GP
authors.lastname: Head
authors.affiliation: Monsanto LLC, St. Louis, MO, USA.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Carroll
authors.affiliation: Monsanto LLC, St. Louis, MO, USA.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Evans
authors.affiliation: Dow AgroSciences LLC, Indianapolis, IN, USA.
authors.forename: Dwain M
authors.initials: DM
authors.lastname: Rule
authors.affiliation: Monsanto LLC, St. Louis, MO, USA.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Willse
authors.affiliation: Monsanto LLC, St. Louis, MO, USA.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Clark
authors.affiliation: Dow AgroSciences LLC, Indianapolis, IN, USA.
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Storer
authors.affiliation: Monsanto LLC, St. Louis, MO, USA.
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Flannagan
authors.affiliation: Monsanto LLC, St. Louis, MO, USA.
authors.forename: Luke W
authors.initials: LW
authors.lastname: Samuel
authors.affiliation: Department of Entomology, University of Nebraska, Lincoln, NE, USA.
authors.forename: Lance J
authors.initials: LJ
authors.lastname: Meinke
mesh_terms: D000818:Animals; D001681:Biological Assay; D001517:Coleoptera / Q000502:physiology; D010935:Plant Diseases; D030821:Plants, Genetically Modified; D003313:Zea mays / Q000235:genetics* / Q000502:physiology*
keywords: RNA, DvSnf7; corn rootworm; insect resistance management; pyramids