Resistance Allele Frequency of Helicoverpa zea to Vip3Aa Bacillus thuringiensis Protein in the Southeastern US

Article Food Science & Technology

Resistance Allele Frequency to Cry1Ab and Vip3Aa20 in Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in Louisiana and Three Other Southeastern US States

Shucong Lin et al.

Summary: The study found that the resistance allele frequency (RAF) to Cry1Ab maize was high in H. zea populations, while no functional major resistance allele to Vip3Aa20 maize was detected, although functional minor alleles were not uncommon.

TOXINS (2022)

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Article Agronomy

Practical resistance to Cry toxins and efficacy of Vip3Aa in Bt cotton against Helicoverpa zea

Fei Yang et al.

Summary: This study evaluated the resistance of Helicoverpa zea, one of the most economically important pests, to Bt toxins and Bt cotton in the United States. The results showed widespread resistance of H. zea to certain Cry toxins produced by Bt cotton and corn, but not to Vip3Aa. The efficacy of Bt cotton decreased with higher survival rates in laboratory bioassays. Rigorous resistance management measures are needed to preserve the efficacy of Vip3Aa against this highly adaptable pest.

PEST MANAGEMENT SCIENCE (2022)

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Review Entomology

Mechanisms of Resistance to Insecticidal Proteins from Bacillus thuringiensis

Juan Luis Jurat-Fuentes et al.

Summary: Insecticidal proteins from Bt bacterium are widely used as successful alternatives to synthetic pesticides, but the evolution of resistance in target pests remains a major threat. High-level resistance to Bt sprays is limited in the field, but several lepidopteran and coleopteran species have developed practical resistance to Bt proteins produced in transgenic plants.

ANNUAL REVIEW OF ENTOMOLOGY, VOL 66, 2021 (2021)

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Article Entomology

Insecticidal activity of Bacillus thuringiensis Cry1, Cry2 and Vip3 toxin combinations in Spodoptera exigua control: highlights on synergism and data scoring

Jakub Baranek et al.

Summary: Bioinsecticides based on Bacillus thuringiensis toxins can be a safe alternative to chemical pesticides for controlling pests like Spodoptera exigua. Research shows synergistic interactions between certain Bt toxins, enhancing their insecticidal activity against S. exigua. Results indicate the potential for developing new bioinsecticides with high effectiveness against this pest species, but the timing of data collection may influence the estimation of interaction type.

ENTOMOLOGIA GENERALIS (2021)

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Article Entomology

Sweet Corn Sentinel Monitoring for Lepidopteran Field-Evolved Resistance to Bt Toxins

G. P. Dively et al.

Summary: This study improves resistance monitoring for Bt crops by monitoring changes in H. zea susceptibility to Cry and Vip3A toxins. The sentinel plot approach effectively detects field-evolved resistance and provides evidence for resistance within populations.

JOURNAL OF ECONOMIC ENTOMOLOGY (2021)

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Article Agronomy

Genetic basis of resistance to the Vip3Aa Bt protein in Helicoverpa zea

Fei Yang et al.

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)

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Article Agronomy

No positive cross-resistance to Cry1 and Cry2 proteins favors pyramiding strategy for management of Vip3Aa resistance in Spodoptera frugiperda

Ryan T. Gilreath et al.

Summary: The study evaluated the cross-resistance of Vip3Aa-resistant Spodoptera frugiperda to Bt cotton and corn plants, as well as purified Bt proteins. Results showed that resistance to Vip3Aa did not confer any positive cross-resistance to other Bt proteins in S. frugiperda. This indicates that pyramiding strategy may be an effective approach for managing resistance to Vip3Aa protein in S. frugiperda.

PEST MANAGEMENT SCIENCE (2021)

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Article Food Science & Technology

Populations of Helicoverpa zea (Boddie) in the Southeastern United States are Commonly Resistant to Cry1Ab, but Still Susceptible to Vip3Aa20 Expressed in MIR 162 Corn

Ying Niu et al.

Summary: The study revealed that resistance to Cry1Ab is widely distributed in H. zea across the region, but populations resistant to Cry1Ab are not cross-resistant to Vip3Aa20. Additionally, H. zea in the region remains susceptible to the Vip3Aa20 toxin.

TOXINS (2021)

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Article Agronomy

Multiple and non-recessive resistance to Bt proteins in a Cry2Ab2-resistant population of Helicoverpa zea

Fei Yang et al.

Summary: This study evaluated the responses of Cry2Ab2-resistant H. zea to Cry1Ac, Cry1A.105, Cry2Ab2, and Vip3Aa39 proteins using diet-overlay bioassays. The resistant H. zea showed high levels of resistance to Cry1Ac and Cry1A.105, but were susceptible to Vip3Aa, with resistance levels varying depending on the protein concentration. The data suggest that RR H. zea possess multiple non-recessive resistances to Cry1 and Cry2 proteins.

CROP PROTECTION (2021)

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Article Food Science & Technology

Early Warning of Resistance to Bt Toxin Vip3Aa in Helicoverpa zea

Fei Yang et al.

Summary: The study evaluated resistance of H. zea to Vip3Aa and found that susceptibility of field-derived strains to the toxin decreased significantly, with some strains showing significant resistance. Additionally, strains derived from Vip3Aa plants exhibited significantly lower susceptibility to Vip3Aa, indicating evolving resistance in the field.

TOXINS (2021)

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Article Entomology