Abstract
The corn earworm, Helicoverpa zea (Boddie), is a major pest of Bacillus thuringiensis (Bt) maize and cotton in the U.S. Reduced efficacy of Bt plants expressing Cry1 and Cry2 against H. zea has been reported in some areas of the U.S. In this study, we evaluated the occurrence and ear damage of H. zea on transgenic Bt maize expressing Cry proteins or a combination of Vip3A and Cry proteins in the field in Texas in 2018. We found that the occurrence of H. zea larvae and the viable kernel damage area on the ear were not different between non-Bt maize and Bt maize expressing Cry1A.105+Cry2Ab2 and Cry1Ab+Cry1F proteins. A total of 67.5% of the pyramided Bt maize expressing Cry1Ab+Cry1F+Vip3A was damaged by 2nd–4th instar larvae of H. zea. Diet bioassays showed that the resistance ratio against Vip3Aa51 for H. zea obtained from Cry1Ab+Cry1F+Vip3A maize was 20.4 compared to a field population collected from Cry1F+Cry1A.105+Cry2Ab2 maize. Leaf tissue bioassays showed that 7-day survivorship on WideStrike3 (Cry1F+Cry1Ac+Vip3A) cotton leaves was significantly higher for the H. zea population collected from Cry1Ab+Cry1F+Vip3A maize than for a Bt-susceptible laboratory population. The results generated from this study suggest that H. zea has evolved practical resistance to Cry1 and Cry2 proteins. Therefore, it is crucial to ensure the sustainable use of the Vip3A technology in Bt maize and cotton.
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Claims 6
Claim · model-written summary
Helicoverpa zea larval occurrence and viable kernel damage area on the ear did not differ between non-Bt maize and Bt maize expressing Cry1A.105+Cry2Ab2 and Cry1Ab+Cry1F proteins.
- Organ / stage
- eare0
- Treatment
- Bt maize expressing Cry1A.105+Cry2Ab2 and Cry1Ab+Cry1F proteinse0
- Interactor
- H. zea
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Helicoverpa zeae0pest - Outcome
- occurrence of H. zea larvae and the viable kernel damage areae0
- Direction
- no_changeinferrede0
- Comparator
- non-Bt maizee0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“the occurrence of H. zea larvae and the viable kernel damage area on the ear were not different between non-Bt maize and Bt maize expressing Cry1A.105+Cry2Ab2 and Cry1Ab+Cry1F proteins”
Claim · model-written summary
A total of 67.5% of the pyramided Bt maize expressing Cry1Ab+Cry1F+Vip3A was damaged by H. zea larvae.
- Material
- Cry1Ab+Cry1F+Vip3Ae1
- Interactor
- H. zeaHelicoverpa zeae1pest
- Outcome
- damagede1
- Value
- 67.5%e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“A total of 67.5% of the pyramided Bt maize expressing Cry1Ab+Cry1F+Vip3A was damaged by 2nd–4th instar larvae of H. zea”
Claim · model-written summary
H. zea resistance ratio against Vip3Aa51 was 20.4 for the population from Cry1Ab+Cry1F+Vip3A maize, compared with a field population from Cry1F+Cry1A.105+Cry2Ab2 maize.
- Interactor
- H. zeaHelicoverpa zeae2pest
- Gene
- Vip3Aa51e2
- Outcome
- resistance ratio against Vip3Aa51e2
- Value
- 20.4e2
- Comparator
- a field population collected from Cry1F+Cry1A.105+Cry2Ab2 maizee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“Diet bioassays showed that the resistance ratio against Vip3Aa51 for H. zea obtained from Cry1Ab+Cry1F+Vip3A maize was 20.4 compared to a field population collected from Cry1F+Cry1A.105+Cry2Ab2 maize”
Claim · model-written summary
The 7-day survivorship of H. zea on WideStrike3 cotton leaves was significantly higher for the population from Cry1Ab+Cry1F+Vip3A maize than for a Bt-susceptible laboratory population.
- Taxon
- cotton
Gossypium hirsutume3 - Material
- H. zea population collected from Cry1Ab+Cry1F+Vip3A maizee3
- Treatment
- WideStrike3 (Cry1F+Cry1Ac+Vip3A) cotton leavese3
- Interactor
- H. zeaHelicoverpa zeae3pest
- Outcome
- 7-day survivorshipe3
- Direction
- highere3
- Comparator
- a Bt-susceptible laboratory populatione3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“7-day survivorship on WideStrike3 (Cry1F+Cry1Ac+Vip3A) cotton leaves was significantly higher for the H. zea population collected from Cry1Ab+Cry1F+Vip3A maize than for a Bt-susceptible laboratory population”
Claim · model-written summary
H. zea has evolved practical resistance to Cry1 and Cry2 proteins in maize.
- Interactor
- H. zeaHelicoverpa zeae4pest
- Gene
- Cry1 and Cry2 proteinse4
- Outcome
- practical resistancee4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“The results generated from this study suggest that H. zea has evolved practical resistance to Cry1 and Cry2 proteins”
e0“the occurrence of H. zea larvae and the viable kernel damage area on the ear were not different between non-Bt maize and Bt maize expressing Cry1A.105+Cry2Ab2 and Cry1Ab+Cry1F proteins”
Claim · model-written summary
Ensuring the sustainable use of the Vip3A technology in maize is crucial.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“it is crucial to ensure the sustainable use of the Vip3A technology in Bt maize and cotton”
The same questions in other papers
transgenic · Helicoverpa zea · Zea mays (maize)Positive and negative results
3 papers in the same direction as this paper · 18 reporting no difference from an alternative
- positive
- 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.