Article
Entomology
Joseph L. Black, Gus M. Lorenz, Aaron J. Cato, Nick R. Bateman, Nicholas J. Seiter
Summary: This study examined the effectiveness of Helicoverpa armigera nucleopolyhedrovirus (HearNPV) in controlling different larval instars of the soybean pest Helicoverpa zea, as well as the potential for cross-generational infection. The results showed that HearNPV was effective in controlling 1st-3rd instar larvae, but not 4th or 5th instar larvae. Additionally, the second generation of larvae infected by HearNPV died faster than the first generation, indicating the potential for cross-generational infection. These findings suggest that HearNPV could be a useful tool in managing H. zea.
Article
Entomology
Khouloud Klai, Marwa Zidi, Benoit Chenais, Francoise Denis, Aurore Caruso, Nathalie Casse, Maha Mezghani Khemakhem
Summary: MITEs are ubiquitous, non-autonomous class II transposable elements. The moths Helicoverpa armigera and Helicoverpa zea are recognized as the two most serious pest species within the genus. Moreover, these pests have the ability to develop insecticide resistance. In this study, a genome-wide analysis of MITEs present in H. armigera and H. zea genomes was conducted using the bioinformatics tool MITE tracker. A total of 3570 and 7405 MITE sequences were identified in the H. armigera and H. zea genomes, respectively. Comparative analysis of the identified MITE sequences led to the identification of 18 families, comprising 140 MITE members in H. armigera and 161 MITE members in H. zea. The analysis of MITE insertion sites in defensome genes showed intronic insertions of 11 MITEs in H. armigera and one MITE in H. zea. These insertions could be involved in the insecticide resistance observed in these pests.
Article
Agronomy
Fei Yang, Jose C. Santiago Gonzalez, Gregory A. Sword, David L. Kerns
Summary: The study revealed that resistance to Vip3Aa in H. zea is monogenic, autosomal, and recessive, with no maternal effects or sex linkage observed. Resistance is largely determined by a single gene, providing valuable insights for understanding the resistance mechanism and developing effective resistance management strategies.
PEST MANAGEMENT SCIENCE
(2021)
Article
Agronomy
Dawson D. Kerns, Fei Yang, David L. Kerns, Scott D. Stewart
Summary: The study aimed to determine if plant tissue overlays could detect resistance by using Bt proteins and Bt cotton plant tissue in diet-overlay bioassays. Results showed that overlays using lyophilized tissue from white flowers were most ideal, while tissue from non-Bt bolls and leaves affected larval health and behavior, affecting assay results.
PEST MANAGEMENT SCIENCE
(2022)
Article
Entomology
Jose C. Santiago-Gonzalez, David L. Kerns, Fei Yang
Summary: This study aims to determine the frequency of alleles conferring resistance to Vip3Aa in Helicoverpa zea. The research found that the major resistance allele frequency for Vip3Aa in H. zea collected from four southern states during 2019-2020 was 0.0155, indicating that the frequency of Vip3Aa resistance alleles in H. zea is not rare in the field.
Article
Entomology
K. C. Allen, N. S. Little, O. P. Perera
Summary: The corn earworm, a major pest in the Southern United States, has been controlled through the use of insecticidal transgenic crops and synthetic insecticides, including chlorantraniliprole. A study conducted from 2016 to 2021 found no significant reduction in susceptibility to chlorantraniliprole among corn earworm populations in the Mississippi Delta.
JOURNAL OF ECONOMIC ENTOMOLOGY
(2023)
Article
Agronomy
Seth J. Dorman, Kristen A. Hopperstad, Brian J. Reich, Suman Majumder, George Kennedy, Dominic D. Reisig, Jeremy K. Greene, Francis P. F. Reay-Jones, Guy Collins, Jack S. Bacheler, Anders S. Huseth
Summary: The study found significant year effects of Helicoverpa zea damage frequency in commercial cotton throughout the Bt adoption period in the USA, with a recent increase in damage after 2012. Landscape-level Bt crop production intensity over time was positively associated with the risk of Helicoverpa zea damage in two- and three-toxin pyramided Bt cotton. Damage from Helicoverpa zea also varied across Bt toxin types in spatially replicated on-farm studies.
PEST MANAGEMENT SCIENCE
(2021)
Article
Microbiology
Jean M. Deguenon, Anirudh Dhammi, Loganathan Ponnusamy, Nicholas Travanty, Grayson Cave, Roger Lawrie, Dan Mott, Dominic Reisig, Ryan Kurtz, R. Michael Roe
Summary: Research shows that internal bacterial density and diversity of H. zea insects in Bt cotton are higher than those in non-Bt cotton, possibly due to bacteria like Enterococcus which can acidify the environment and reduce the activation of Bt toxins. This highlights the need for further exploration into cotton-bollworm-bacteria interactions and their impact on caterpillar susceptibility to Bt toxins.
Article
Entomology
Mitchell Rich, Enoch Noh, Hehe Wang, Jeremy Greene, Todd Gilligan, Francis P. F. Reay-Jones, Matt Turnbull, Frida Zink
Summary: This study developed a field-based recombinase polymerase amplification (RPA) assay combined with a lateral flow strip and qPCR melt curve assay to specifically detect Helicoverpa armigera DNA in pooled moth samples. These newly developed molecular assays will contribute to large-scale surveillance programs of H. armigera.
JOURNAL OF ECONOMIC ENTOMOLOGY
(2023)
Article
Agronomy
Benjamin R. Arends, Dominic D. Reisig, Shawnee Gundry, Jeremy K. Greene, George G. Kennedy, Francis P. F. Reay-Jones, Anders S. Huseth
Summary: Despite the widespread occurrence of resistance to Cry toxins in maize, Bt maize continues to provide a measurable reduction in damage. There are negative relationships between kernel injury and ears with larval exit holes in both Bt and non-Bt maize, as well as the proportion of maize in the landscape during the current year.
PEST MANAGEMENT SCIENCE
(2022)
Article
Entomology
Jose C. Santiago Gonzalez, David L. Kerns, Graham P. Head, Fei Yang
Summary: Using mass mating and light trap strategy, the study found high frequency of resistance alleles to Cry1Ac and Cry2Ab2 in Helicoverpa zea in Texas. The resistance to Cry1 and Cry2 proteins in H. zea varied from recessive to dominant in the screened families.
Article
Biotechnology & Applied Microbiology
Dawson D. Kerns, Fei Yang, David L. Kerns, Scott D. Stewart, Juan Luis Jurat-Fuentes
Summary: This study identified a Vip3Aa-resistant strain of Helicoverpa zea and revealed that the resistance is associated with altered Vip3Aa receptor. Understanding this resistance mechanism is important for managing current commercial Bt traits and developing future transgenic traits.
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
(2023)
Article
Agronomy
Haley Kennedy, David L. Kerns, Graham P. Head, Fei Yang
Summary: Our findings show that Vip3Aa-resistant H. zea does not exhibit positive cross-resistance to Cry1 or Cry2 proteins. Furthermore, most pyramided Bt crops have a complete or nearly complete redundant killing effect on Vip3Aa-resistant H. zea. These results suggest that the pyramiding strategy is often effective for managing Vip3Aa resistance in regions of the United States where H. zea has not developed resistance to Cry1 and Cry2 toxins. (c) 2023 Society of Chemical Industry.
PEST MANAGEMENT SCIENCE
(2023)
Article
Entomology
Haoxiang Zhao, Xiaoqing Xian, Zihua Zhao, Guifen Zhang, Wanxue Liu, Fanghao Wan
Summary: This study predicts the potential geographical distributions of Helicoverpa zea in China using a calibrated MaxEnt model and finds that China is an important distribution area for the pest under current climate conditions. Future climate changes will facilitate its expansion in the country. Customs ports need to strengthen monitoring and quarantine measures for host plants and containers harboring this pest.
Article
Ecology
Qinjian Pan, Ikkei Shikano, Tong-Xian Liu, Gary W. Felton
Summary: Insect-associated bacteria play a crucial role in modulating the interactions between insects and plants. This study demonstrates the significance of gut-associated bacteria in inducing herbivore-induced defenses in tomato. The findings suggest that certain bacterial isolates or communities can trigger plant defense responses and affect the development of herbivorous insects.