TY - JOUR
T1 - Demographic performance of helicoverpa zea populations on dual and triple-gene Bt cotton
AU - Rabelo, Marcelo M.
AU - Paula-Moraes, Silvana V.
AU - Pereira, Eliseu Jose G.
AU - Siegfried, Blair D.
N1 - Funding Information:
Funding: This research was funded by USDA National Institute of Food and Agriculture, Hatch project 005643, and CPPM EIP FLA-ENY-005649.
Funding Information:
Acknowledgments: We thank the extension agent Ethan Carter, the Entomology team at WFREC for the help collecting the insects, and Barry Brecke for the English proofreading. We also acknowledge the farmers from the Florida Panhandle who provided access to their commercial fields and the companies Bayer, BASF, and Corteva for providing the cotton seeds. MMR received a scholarship from CAPES (Brazilian Ministry of Education, Finance code 001).
Publisher Copyright:
© 2020 by the authors.
PY - 2020/9
Y1 - 2020/9
N2 - 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.
AB - 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.
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U2 - 10.3390/toxins12090551
DO - 10.3390/toxins12090551
M3 - Article
C2 - 32872277
AN - SCOPUS:85090179402
SN - 2072-6651
VL - 12
JO - Toxins
JF - Toxins
IS - 9
M1 - 551
ER -