title: Lepidoptera (Crambidae, Noctuidae, and Pyralidae) Injury to Corn Containing Single and Pyramided Bt Traits, and Blended or Block Refuge, in the Southern United States.
abstract: Fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae); corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae); southwestern corn borer, Diatraea grandiosella Dyar (Lepidoptera: Crambidae); sugarcane borer, Diatraea saccharalis F. (Lepidoptera: Crambidae); and lesser cornstalk borer, Elasmopalpus lignosellus Zeller (Lepidoptera: Pyralidae), are lepidopteran pests of corn, Zea mays L., in the southern United States. Blended refuge for transgenic plants expressing the insecticidal protein derivative from Bacillus thuringiensis (Bt) has recently been approved as an alternative resistance management strategy in the northern United States. We conducted a two-year study with 39 experiments across 12 states in the southern United States to evaluate plant injury from these five species of Lepidoptera to corn expressing Cry1F and Cry1Ab, as both single and pyramided traits, a pyramid of Cry1Ab×Vip3Aa20, and a pyramid of Cry1F×Cry1Ab plus non-Bt in a blended refuge. Leaf injury and kernel damage from corn earworm and fall armyworm, and stalking tunneling by southwestern corn borer, were similar in Cry1F×Cry1Ab plants compared with the Cry1F×Cry1Ab plus non-Bt blended refuge averaged across five-plant clusters. When measured on an individual plant basis, leaf injury, kernel damage, stalk tunneling (southwestern corn borer), and dead or injured plants (lesser cornstalk borer) were greater in the blended non-Bt refuge plants compared to Cry1F×Cry1Ab plants in the non-Bt and pyramided Cry1F×Cry1Ab blended refuge treatment. When non-Bt blended refuge plants were compared to a structured refuge of non-Bt plants, no significant difference was detected in leaf injury, kernel damage, or stalk tunneling (southwestern corn borer). Plant stands in the non-Bt and pyramided Cry1F×Cry1Ab blended refuge treatment had more stalk tunneling from sugarcane borer and plant death from lesser cornstalk borer compared to a pyramided Cry1F×Cry1Ab structured refuge treatment. Hybrid plants containing Cry1F×Cry1Ab within the pyramided Cry1F×Cry1Ab blended refuge treatment had significantly less kernel damage than non-Bt structured refuge treatments. Both single and pyramided Bt traits were effective against southwestern corn borer, sugarcane borer, and lesser cornstalk borer.
authors.affiliation: Department of Entomology, North Carolina State University, Vernon G. James Research and Extension Center, 207 Research Station Rd., Plymouth, NC 27962.
authors.forename: D D
authors.initials: DD
authors.lastname: Reisig
authors.affiliation: University Arkansas, Cooperative Extension Service, Monticello, AR 71656; currently, FMC Corporation, 1672 Hwy 138, Monticello, AR 71655.
authors.forename: D S
authors.initials: DS
authors.lastname: Akin
authors.affiliation: Department of Entomology, University of Georgia, Athens, GA 30602.
authors.forename: J N
authors.initials: JN
authors.lastname: All
authors.affiliation: Department of Entomology, S-225 Ag North, Lexington, KY 40546.
authors.forename: R T
authors.initials: RT
authors.lastname: Bessin
authors.affiliation: Texas A&M AgriLife Research & Extension Center, 10345 State Hwy 44, Corpus Christi, TX 78406.
authors.forename: M J
authors.initials: MJ
authors.lastname: Brewer
authors.affiliation: Department of Entomology, UGA-Griffin Campus, 1109 Experiment Street, Griffin, GA 30223.
authors.forename: D G
authors.initials: DG
authors.lastname: Buntin
authors.affiliation: Department of Entomology & Plant Pathology, Mississippi State University, Mississippi State, MS 39762.
authors.forename: A L
authors.initials: AL
authors.lastname: Catchot
authors.affiliation: Delta Research & Extension Center, Mississippi State University, P.O. Box 197, Stoneville, MS 38776.
authors.forename: D
authors.initials: D
authors.lastname: Cook
authors.affiliation: 201 Extension Hall, Auburn University, AL 36849.
authors.forename: K L
authors.initials: KL
authors.lastname: Flanders
authors.affiliation: Department of Entomology, 404 Life Sciences Bldg., LSU AgCenter, Baton Rouge, LA 70803.
authors.forename: F-N
authors.initials: FN
authors.lastname: Huang
authors.affiliation: UK-REC, 1205 Hopkinsville Street, Princeton, KY 42445.
authors.forename: D W
authors.initials: DW
authors.lastname: Johnson
authors.affiliation: LSU AgCenter, Macon Ridge Station, 212A Macon Ridge Rd., Winnsboro, LA 71295.
authors.forename: B R
authors.initials: BR
authors.lastname: Leonard
authors.affiliation: Cralley-Warren Lab, 2601 N. Young Ave., Fayetteville, AR 72704.
authors.forename: P J
authors.initials: PJ
authors.lastname: Mcleod
authors.affiliation: Texas AgriLife Research & Extension Center, Lubbock, TX 79403.
authors.forename: R P
authors.initials: RP
authors.lastname: Porter
authors.affiliation: School of Agricultural, Forest, and Environmental Sciences, Pee Dee Research & Education Center, Clemson University, 2200 Pocket Rd., Florence, SC 29506.
authors.forename: F P F
authors.initials: FP
authors.lastname: Reay-Jones
authors.affiliation: Division of Plant Sciences, University of Missouri, Portageville, MO 63873.
authors.forename: K V
authors.initials: KV
authors.lastname: Tindall
authors.affiliation: West Tennessee Research and Education Center, 605 Airways Blvd., Jackson, TN 38301.
authors.forename: S D
authors.initials: SD
authors.lastname: Stewart
authors.affiliation: Texas AgriLife Research & Extension Center, P.O. Box 1849, Uvalde, TX 78802.
authors.forename: N N
authors.initials: NN
authors.lastname: Troxclair
authors.affiliation: Department of Entomology, 216-A Price Hall, MC 0319, Virginia Tech University, Blacksburg, VA 24061.
authors.forename: R R
authors.initials: RR
authors.lastname: Youngman
authors.affiliation: DuPont Pioneer, P. O. Box 1004, Johnston, IA 50131. marlin.rice@pioneer.com.
authors.forename: M E
authors.initials: ME
authors.lastname: Rice
mesh_terms: D000383:Agriculture / Q000379:methods*; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D060434:Herbivory; D007915:Lepidoptera; D018411:Spodoptera
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Helicoverpa zea; Spodoptera frugiperda; blended refuge; structured refuge