Abstract
The corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), is only moderately susceptible to most toxins from the bacterium Bacillus thuringiensis (Bt) expressed in transgenic corn. To better understand the impact of Bt corn on the life cycle of H. zea, we collected pupae of H. zea during 2014-2016 in North Carolina, South Carolina, and Mississippi from corn hybrids expressing Cry1Ab, Cry1F, Cry1F + Cry1Ab, Cry1F + Cry1Ab + Vip3Aa20, Cry1A.105 + Cry2Ab2, and Cry1A.105 + Cry2Ab2 + Cry1F, as well as from non-Bt near-isolines. We investigated the effect of Bt corn on pupal weight, fecundity, and egg viability of H. zea. Pupal weights were significantly reduced for males and females from all Bt hybrids compared with non-Bt near-isolines. Female pupae from the hybrid expressing Cry1F + Cry1Ab were also significantly lighter relative to those from the near-isolines expressing only Cry1F. Reductions in pupal weight did not result in any detectable effects on fecundity or egg viability. The reduction in pupal weight in the hybrids expressing Cry1F and Cry1F + Cry1Ab significantly declined over time in South Carolina, possibly indicating developing resistance to these Bt toxins. These data can be incorporated into insect resistance management models used to improve risk management decisions regarding H. zea in Bt crops in the complex landscapes of the southern United States.
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Claims 6
Claim · model-written summary
Pupal weights of male and female corn earworms were lower on all Bt hybrids than non-Bt near-isolines.
- Taxon
- Corn
Zea mays subsp. mayst0 - Treatment
- all Bt hybridse0
- Interactor
- Helicoverpa zea (Boddie)
.jpg?width=60)
Helicoverpa zeae1pest - Outcome
- Pupal weightse0
- Direction
- reducede0
- Comparator
- non-Bt near-isolinese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
t0“Bt Corn”
e0“Pupal weights were significantly reduced for males and females from all Bt hybrids compared with non-Bt near-isolines.”
e1“The corn earworm, Helicoverpa zea (Boddie)”
Claim · model-written summary
Female pupae from the Cry1F + Cry1Ab hybrid were lighter than those from Cry1F near-isolines.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- hybrid expressing Cry1F + Cry1Abe0
- Interactor
- H. zeaHelicoverpa zeae1pest
- Outcome
- Female pupaee0
- Direction
- lightere0
- Comparator
- near-isolines expressing only Cry1Fe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Bt Corn”
e0“Female pupae from the hybrid expressing Cry1F + Cry1Ab were also significantly lighter relative to those from the near-isolines expressing only Cry1F.”
e1“life cycle of H. zea”
Claim · model-written summary
Pupal weight reductions had no detectable effect on fecundity.
- Taxon
- CornZea mays subsp. mayst0
- Organ / stage
- pupale0
- Interactor
- H. zeaHelicoverpa zeae1pest
- Outcome
- fecunditye0
- Direction
- did not result in any detectable effectse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Bt Corn”
e0“Reductions in pupal weight did not result in any detectable effects on fecundity or egg viability.”
e1“life cycle of H. zea”
Claim · model-written summary
Pupal weight reductions had no detectable effect on egg viability.
- Taxon
- CornZea mays subsp. mayst0
- Organ / stage
- pupale0
- Interactor
- H. zeaHelicoverpa zeae1pest
- Outcome
- egg viabilitye0
- Direction
- did not result in any detectable effectse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Bt Corn”
e0“Reductions in pupal weight did not result in any detectable effects on fecundity or egg viability.”
e1“life cycle of H. zea”
Claim · model-written summary
The pupal weight reduction associated with Cry1F declined over time in South Carolina.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- Cry1Fe0
- Interactor
- H. zeaHelicoverpa zeae1pest
- Outcome
- reduction in pupal weighte0
- Direction
- declinede0
- Setting
- South Carolinae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Bt Corn”
e0“The reduction in pupal weight in the hybrids expressing Cry1F and Cry1F + Cry1Ab significantly declined over time in South Carolina, possibly indicating developing resistance to these Bt toxins.”
e1“life cycle of H. zea”
Claim · model-written summary
The pupal weight reduction associated with Cry1F + Cry1Ab declined over time in South Carolina.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- Cry1F + Cry1Abe0
- Interactor
- H. zeaHelicoverpa zeae1pest
- Outcome
- reduction in pupal weighte0
- Direction
- declinede0
- Setting
- South Carolinae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Bt Corn”
e0“The reduction in pupal weight in the hybrids expressing Cry1F and Cry1F + Cry1Ab significantly declined over time in South Carolina, possibly indicating developing resistance to these Bt toxins.”
e1“life cycle of H. zea”
The same questions in other papers
transgenic · Helicoverpa zea · Zea mays (maize)Positive and negative results
17 papers in the same direction as this paper · 1 in the opposite direction · 3 reporting no difference from an alternative
- no effect
- positive
- negative
18 papers more in this group
See all 22 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.