scholarly journals Effects of seasonal changes in cotton plants on the evolution of resistance to pyramided cotton producing the Bt toxins Cry1Ac and Cry1F in Helicoverpa zea

2017 ◽  
Vol 74 (3) ◽  
pp. 627-637 ◽  
Author(s):  
Yves Carrière ◽  
Ben A Degain ◽  
Gopalan C Unnithan ◽  
Virginia S Harpold ◽  
Shannon Heuberger ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Helicoverpa Zea ◽  
Bt Toxins ◽  
Cotton Plants ◽  
Evolution Of Resistance

scholarly journals Demographic Performance of Helicoverpa zea Populations on Dual and Triple-Gene Bt Cotton

Toxins ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 551 ◽  
Author(s):  
Marcelo M. Rabelo ◽  
Silvana V. Paula-Moraes ◽  
Eliseu Jose G. Pereira ◽  
Blair D. Siegfried
Keyword(s):  
Population Growth ◽  
Helicoverpa Zea ◽  
Agricultural Landscape ◽  
Insect Pests ◽  
Field Resistance ◽  
Corn Earworm ◽  
Bt Cotton ◽  
Bt Toxins ◽  
Cotton Plants ◽  
Demographic Performance

Insecticidal toxins from Bacillus thuringiensis (Bt) are valuable tools for pest management worldwide, contributing to the management of human disease insect vectors and phytophagous insect pests of agriculture and forestry. Here, we report the effects of dual and triple Bt toxins expressed in transgenic cotton cultivars on the fitness and demographic performance of Helicoverpa zea (Boddie)—a noctuid pest, known as cotton bollworm and corn earworm. Life-history traits were determined for individuals of three field populations from a region where H. zea overwintering is likely. Triple-gene Bt cotton cultivars that express Cry and Vip3Aa toxins killed 100% of the larvae in all populations tested. In contrast, dual-gene Bt cotton that express Cry1Ac+Cry1F and Cry1Ac+Cry2Ab allowed population growth with the intrinsic rate of population growth (rm) 38% lower than on non-Bt cotton. The insects feeding on Bt cotton plants that express Cry1Ac+Cry2Ab, Cry1Ac+Cry1F, or Cry1Ab+Cry2Ae exhibited reduced larval weight, survival rate, and increased development time. Additionally, fitness parameters varied significantly among the insect populations, even on non-Bt cotton plants, likely because of their different genetic background and/or previous Bt toxin exposure. This is the first report of the comparative fitness of H. zea field populations on dual-gene Bt cotton after the recent reports of field resistance to certain Bt toxins. These results document the population growth rates of H. zea from an agricultural landscape with 100% Bt cotton cultivars. Our results will contribute to the development and validation of resistance management recommendations.

scholarly journals Early Warning of Resistance to Bt Toxin Vip3Aa in Helicoverpa zea

Toxins ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 618
Author(s):  
Fei Yang ◽  
David L. Kerns ◽  
Nathan S. Little ◽  
José C. Santiago González ◽  
Bruce E. Tabashnik
Keyword(s):  
Early Warning ◽  
Helicoverpa Zea ◽  
The United States ◽  
Genetically Engineered ◽  
Bt Toxin ◽  
Bt Toxins ◽  
Evolution Of Resistance ◽  
Reported Data ◽  
Lepidopteran Pest ◽  
Urgent Action

Evolution of resistance by pests can reduce the benefits of crops genetically engineered to produce insecticidal proteins from Bacillus thuringiensis (Bt). Because of the widespread resistance of Helicoverpa zea to crystalline (Cry) Bt toxins in the United States, the vegetative insecticidal protein Vip3Aa is the only Bt toxin produced by Bt corn and cotton that remains effective against some populations of this polyphagous lepidopteran pest. Here we evaluated H. zea resistance to Vip3Aa using diet bioassays to test 42,218 larvae from three lab strains and 71 strains derived from the field during 2016 to 2020 in Arkansas, Louisiana, Mississippi, Tennessee, and Texas. Relative to the least susceptible of the three lab strains tested (BZ), susceptibility to Vip3Aa of the field-derived strains decreased significantly from 2016 to 2020. Relative to another lab strain (TM), 7 of 16 strains derived from the field in 2019 were significantly resistant to Vip3Aa, with up to 13-fold resistance. Susceptibility to Vip3Aa was significantly lower for strains derived from Vip3Aa plants than non-Vip3Aa plants, providing direct evidence of resistance evolving in response to selection by Vip3Aa plants in the field. Together with previously reported data, the results here convey an early warning of field-evolved resistance to Vip3Aa in H. zea that supports calls for urgent action to preserve the efficacy of this toxin.

scholarly journals Demographic Performance of Helicoverpa zea Populations on Dual and Triple-Gene Bt Cotton

2020 ◽  
Author(s):  
Marcelo M. Rabelo ◽  
Silvana V. Paula-Moraes ◽  
Eliseu Jose G. Pereira ◽  
Blair D. Siegfried
Keyword(s):  
Population Growth ◽  
Helicoverpa Zea ◽  
Agricultural Landscape ◽  
Insect Pests ◽  
Field Resistance ◽  
Corn Earworm ◽  
Bt Cotton ◽  
Bt Toxins ◽  
Cotton Plants ◽  
Demographic Performance

Insecticidal toxins from Bacillus thuringiensis (Bt) are valuable tools for pest management worldwide, contributing to the management of human disease insect vectors and phytophagous insect pests of agriculture and forestry. Here, we report the effects of dual and triple Bt toxins expressed in transgenic cotton cultivars on the fitness and demographic performance of Helicoverpa zea (Boddie), a noctuid pest known as cotton bollworm and corn earworm. Life-history traits were determined for individuals of three field populations from a region where H. zea overwintering is likely. Triple-gene Bt cotton cultivars expressing Cry and Vip3Aa toxins killed 100% of the larvae in all populations tested. In contrast, dual-gene Bt cotton expressing Cry1Ac+Cry1F and Cry1Ac+Cry2Ab2 allowed population growth with the intrinsic rate of population growth (rm) 38% lower than on non-Bt cotton. The insects feeding on Bt cotton plants expressing Cry1Ac+Cry2Ab2, Cry1Ac+Cry1F, or Cry1Ab+Cry2Ae exhibited reduced larval weight, survival rate, and increased development time. Additionally, fitness parameters varied significantly among the insect populations, even on non-Bt cotton plants, likely because of their different genetic background and/or previous Bt toxin exposure. This is the first report of the comparative fitness of H. zea field populations on dual-gene Bt cotton after the recent reports of field resistance to certain Bt toxins. These results document the population growth rates of H. zea from an agricultural landscape with 100% Bt cotton cultivars. Our results will help to refine models designed to predict resistance evolution and improve insect resistance management for Bt crops.

scholarly journals Detection and Evolution of Resistance to the Pyrethroid Cypermethrin in Helicoverpa zea (Lepidoptera: Noctuidae) Populations in Texas

2007 ◽  
Vol 36 (5) ◽  
pp. 1174-1188 ◽  
Author(s):  
P. V. Pietrantonio ◽  
T. A. Junek ◽  
R. Parker ◽  
D. Mott ◽  
K. Siders ◽  
...  
Keyword(s):  
Helicoverpa Zea ◽  
Evolution Of Resistance ◽  
Lepidoptera Noctuidae

Long-Term Empirical and Observational Evidence of Practical Helicoverpa zea Resistance to Cotton With Pyramided Bt Toxins

2018 ◽  
Vol 111 (4) ◽  
pp. 1824-1833 ◽  
Author(s):  
Dominic D Reisig ◽  
Anders S Huseth ◽  
Jack S Bacheler ◽  
Mohammad-Amir Aghaee ◽  
Lewis Braswell ◽  
...  
Keyword(s):  
Helicoverpa Zea ◽  
Observational Evidence ◽  
Bt Toxins

Helicoverpa zea (Lepidoptera: Noctuidae) Preference for Plant Structures, and Their Location, Within Bt Cotton Under Different Nitrogen and Irrigation Regimes

2019 ◽  
Vol 112 (4) ◽  
pp. 1741-1751
Author(s):  
Lewis R Braswell ◽  
Dominic D Reisig ◽  
Clyde E Sorenson ◽  
Guy D Collins
Keyword(s):  
Helicoverpa Zea ◽  
Resistance Management ◽  
Larval Feeding ◽  
Bt Cotton ◽  
Larval Distribution ◽  
Cotton Plants ◽  
Small Plot ◽  
Nitrogen Treatments ◽  
Behavioral Resistance ◽  
Lepidoptera Noctuidae

Abstract Helicoverpa zea Boddie is a common economic pest of cotton (Gossypium hirsutum L.), including transgenic cotton varieties that express Bacillus thuringiensis (Bt). Helicoverpa zea oviposition is similar in Bt and non-Bt cotton, but behavior of H. zea larvae can be different in the presence of Bt, with neonates moving away from terminals faster in single-toxin Bt than non-Bt cotton or avoiding Bt-treated diet in the lab. We quantified H. zea oviposition and larval distribution on structures within cotton plants in small plot experiments of Cry1Ac + Cry1F cotton for 2 yr under different irrigation and nitrogen treatments. More eggs were oviposited on plants receiving nitrogen application during 2016 and on leaves in the top section of irrigated plants during 2017, but other treatment effects on eggs or larvae were minimal. Helicoverpa zea eggs were most common on leaves in the top third of plants at position zero and middle section of cotton plants throughout the season, but some oviposition occurred on fruiting structures as well. First and second instars were more common on squares in the top section of plants during 2016 and bolls in the middle and lower sections during 2017 due to oviposition lower in the canopy during 2017. During both years, third through fifth instars were more common on bolls in the middle and lower section of plants closer to the main stem. These findings have resistance management implications as extended larval feeding on bolls could optimize nutrition, decrease Bt susceptibility, and potentially influence behavioral resistance.

scholarly journals Differences between two populations of bollworm, Helicoverpa zea (Lepidoptera: Noctuidae), with variable measurements of laboratory susceptibilities to Bt toxins exposed to non-Bt and Bt cottons in large field cages

PLoS ONE ◽  
2019 ◽  
Vol 14 (3) ◽  
pp. e0212567 ◽  
Author(s):  
Nathan S. Little ◽  
Blake H. Elkins ◽  
R. Michelle Mullen ◽  
Omaththage P. Perera ◽  
Katherine A. Parys ◽  
...  
Keyword(s):  
Helicoverpa Zea ◽  
Large Field ◽  
Bt Toxins ◽  
Lepidoptera Noctuidae ◽  
Two Populations

scholarly journals Evolution of Asian Corn Borer Resistance to Bt Toxins Used Singly or in Pairs

Toxins ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 461 ◽  
Author(s):  
Yueqin Wang ◽  
Yudong Quan ◽  
Jing Yang ◽  
Changlong Shu ◽  
Zhenying Wang ◽  
...  
Keyword(s):  
Transgenic Crops ◽  
Model System ◽  
Cross Resistance ◽  
Ostrinia Furnacalis ◽  
Worst Case ◽  
Corn Borer ◽  
Laboratory Selection ◽  
Bt Toxins ◽  
Asian Corn Borer ◽  
Evolution Of Resistance

Transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) have revolutionized pest control, but the benefits of this approach have been reduced by the evolution of resistance in pests. The widely adopted ’pyramid strategy’ for delaying resistance entails transgenic crops producing two or more distinct toxins that kill the same pest. The limited experimental evidence supporting this strategy comes primarily from a model system under ideal conditions. Here we tested the pyramid strategy under nearly worst-case conditions, including some cross-resistance between the toxins in the pyramid. In a laboratory selection experiment with an artificial diet, we used Bt toxins Cry1Ab, Cry1F, and Cry1Ie singly or in pairs against Ostrinia furnacalis, one of the most destructive pests of corn in Asia. Under the conditions evaluated, pairs of toxins did not consistently delay the evolution of resistance relative to single toxins.

Volatiles released from cotton plants in response to Helicoverpa zea feeding damage on cotton flower buds

Planta ◽  
2004 ◽  
Vol 218 (5) ◽  
pp. 824-832 ◽  
Author(s):  
Ursula S. R. R�se ◽  
James H. Tumlinson
Keyword(s):  
Helicoverpa Zea ◽  
Feeding Damage ◽  
Flower Buds ◽  
Cotton Plants

scholarly journals Hybridizing transgenic Bt cotton with non-Bt cotton counters resistance in pink bollworm

2017 ◽  
Vol 114 (21) ◽  
pp. 5413-5418 ◽  
Author(s):  
Peng Wan ◽  
Dong Xu ◽  
Shengbo Cong ◽  
Yuying Jiang ◽  
Yunxin Huang ◽  
...  
Keyword(s):  
First Generation ◽  
Resistance Management ◽  
Genetically Engineered ◽  
Pink Bollworm ◽  
Bt Cotton ◽  
Bt Toxin ◽  
Random Mixture ◽  
Cotton Plants ◽  
Evolution Of Resistance ◽  
Insecticide Sprays

Extensive cultivation of crops genetically engineered to produce insecticidal proteins from the bacteriumBacillus thuringiensis(Bt) has suppressed some major pests, reduced insecticide sprays, enhanced pest control by natural enemies, and increased grower profits. However, these benefits are being eroded by evolution of resistance in pests. We report a strategy for combating resistance by crossing transgenic Bt plants with conventional non-Bt plants and then crossing the resulting first-generation (F1) hybrid progeny and sowing the second-generation (F2) seeds. This strategy yields a random mixture within fields of three-quarters of plants that produce Bt toxin and one-quarter that does not. We hypothesized that the non-Bt plants in this mixture promote survival of susceptible insects, thereby delaying evolution of resistance. To test this hypothesis, we compared predictions from computer modeling with data monitoring pink bollworm (Pectinophora gossypiella) resistance to Bt toxin Cry1Ac produced by transgenic cotton in an 11-y study at 17 field sites in six provinces of China. The frequency of resistant individuals in the field increased before this strategy was widely deployed and then declined after its widespread adoption boosted the percentage of non-Bt cotton plants in the region. The correspondence between the predicted and observed outcomes implies that this strategy countered evolution of resistance. Despite the increased percentage of non-Bt cotton, suppression of pink bollworm was sustained. Unlike other resistance management tactics that require regulatory intervention, growers adopted this strategy voluntarily, apparently because of advantages that may include better performance as well as lower costs for seeds and insecticides.

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