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The fall armyworm, Spodoptera frugiperda (J.E. Smith), is an economically important crop pest and a major target of transgenic crops expressing Cry and/or Vip3Aa proteins. Widespread adoption of Bt crops has placed a strong selection pressure on the insect populations. Till now, seven lepidopteran and two coleopteran insect species have developed the field-evolved resistance to a Bt crop with practical consequences. Understanding the genetic basis of insect resistance to a Bt protein is essential for designing appropriate resistance management strategies. In this study, we firstly characterized the genetic basis of Vip3Aa resistance in S. frugiperda derived from Texas. Then, we compared the genetic basis of Vip3Aa resistance of this Texas population with a known Vip3Aa resistant population of S. frugiperda collected from Louisiana to determine whether the genetic basis of the resistance in these two resistant populations was the same. Finally, we evaluated the responses of the Vip3Aa-resistant population of S. frugiperda collected from Texas against Cry1F and Cry2Ab2 purified proteins. The results showed that the resistance to Vip3Aa protein in S. frugiperda collected from Texas was likely controlled by a single, functionally recessive and autosomal gene. In addition, the resistance to Vip3Aa in the Texas population of S. frugiperda was not cross-resistant to Cry1F and Cry2Ab2 proteins. The interstrain complementation tests between the Texas and Louisiana resistant populations indicated the genetic basis of the resistance to Vip3Aa in these two populations are different. Considering the rapid invasion of S. frugiperda and the adoption of Vip3Aa Bt crops in the United States and other countries, results generated from this study should provide important information for management of Vip3Aa resistance in S. frugiperda worldwide.
Fei Yang; Jayme Williams; Fangneng Huang; David L. Kerns. Genetic basis and cross-resistance of Vip3Aa resistance in Spodoptera frugiperda (lepidoptera: Noctuidae) derived from Texas, USA. Crop Protection 2021, 147, 105702 .
AMA StyleFei Yang, Jayme Williams, Fangneng Huang, David L. Kerns. Genetic basis and cross-resistance of Vip3Aa resistance in Spodoptera frugiperda (lepidoptera: Noctuidae) derived from Texas, USA. Crop Protection. 2021; 147 ():105702.
Chicago/Turabian StyleFei Yang; Jayme Williams; Fangneng Huang; David L. Kerns. 2021. "Genetic basis and cross-resistance of Vip3Aa resistance in Spodoptera frugiperda (lepidoptera: Noctuidae) derived from Texas, USA." Crop Protection 147, no. : 105702.
BACKGROUND Helicoverpa zea is a destructive pest and target of maize and cotton expressing Cry and Vip3Aa proteins in North America. The efficacy of Cry proteins against H. zea in the U.S. has been largely compromised by resistance. A rapid shift towards planting Bt cotton and maize producing Vip3Aa will accelerate evolution of resistance to Vip3Aa in H. zea. Research on the genetic basis of Vip3Aa resistance in H. zea is urgently needed, and can provide fundamental information for managing resistance of this pest. Here, we characterize the inheritance of Vip3Aa resistance in H. zea. RESULTS Susceptibility of a Vip3Aa‐susceptible strain (SS), a resistant strain (RR), and progeny from different crosses against Vip3Aa39 was determined. RR was established from an F2 screening of a population sampled from Texas in 2019. RR had a resistance ratio of 45,194.1‐fold against Vip3Aa39 relative to SS. Maternal effects and sex linkage were absent in RR. The dominance D value calculated based on LC50 values was ‐1.0, and the effective dominance (DML) calculated based on a given Vip3Aa39 concentration was ≤ 0.0 at the concentrations of 0.1‐31.6 μg/cm2. The test using a monogenic mode of inheritance showed that the resistance to Vip3Aa in H. zea was largely due to a single gene. CONCLUSION Results of this study indicate that the Vip3Aa resistance in H. zea is monogenic, autosomal and recessive. This information is valuable for studying the mechanism of Vip3Aa resistance, monitoring of resistance development, and designing appropriate strategies for preventive management of Vip3Aa resistance.
Fei Yang; José C. Santiago González; Gregory A. Sword; David L. Kerns. Genetic basis of resistance to the Vip3Aa Bt protein in Helicoverpa zea. Pest Management Science 2020, 77, 1530 -1535.
AMA StyleFei Yang, José C. Santiago González, Gregory A. Sword, David L. Kerns. Genetic basis of resistance to the Vip3Aa Bt protein in Helicoverpa zea. Pest Management Science. 2020; 77 (3):1530-1535.
Chicago/Turabian StyleFei Yang; José C. Santiago González; Gregory A. Sword; David L. Kerns. 2020. "Genetic basis of resistance to the Vip3Aa Bt protein in Helicoverpa zea." Pest Management Science 77, no. 3: 1530-1535.
The repetitive release of Eretmocerus eremicus (Mercet) (Hymenoptera: Aphelinidae) to manage Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a promising strategy on poinsettias in protected culture. Management of B. tabaci, however, may be improved if releases include multiple natural enemy species that attack different B. tabaci life stages. In this study, we investigate whether suppression of B. tabaci on poinsettias is improved by the combination of E. eremicus and Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) compared to either natural enemy alone at release rates 1.2 – 2.7-fold the cost of conventional insecticide inputs. We found that all natural enemy treatments provided significant suppression when starting whitefly populations were below 13.7 ± 1.7 immatures per plant. The combination of E. eremicus and A. swirskii performed equally well compared to either natural enemy alone, in both a substitutive and additive design. These effects, however, were density dependent; neither natural enemy alone nor the combination of natural enemies suppressed whiteflies if initial whitefly density was above 40.8 ± 2.5 immature whiteflies per plant.
Erfan K. Vafaie; H. Brent Pemberton; Mengmeng Gu; David Kerns; Micky D. Eubanks; Kevin M. Heinz. A comparison of repetitive releases of single or multiple natural enemy species on the suppression of Bemisia tabaci infesting poinsettias. Biological Control 2020, 151, 104407 .
AMA StyleErfan K. Vafaie, H. Brent Pemberton, Mengmeng Gu, David Kerns, Micky D. Eubanks, Kevin M. Heinz. A comparison of repetitive releases of single or multiple natural enemy species on the suppression of Bemisia tabaci infesting poinsettias. Biological Control. 2020; 151 ():104407.
Chicago/Turabian StyleErfan K. Vafaie; H. Brent Pemberton; Mengmeng Gu; David Kerns; Micky D. Eubanks; Kevin M. Heinz. 2020. "A comparison of repetitive releases of single or multiple natural enemy species on the suppression of Bemisia tabaci infesting poinsettias." Biological Control 151, no. : 104407.
BACKGROUND The corn earworm, Helicoverpa zea (Boddie), is a major target pest of pyramided Bt corn and cotton in the U.S. Field‐evolved practical resistance to Cry1 and Cry2 proteins in H. zea has been documented in multiple locations in the U.S. Understanding the genetic basis of Bt resistance is essential in developing insect resistance management (IRM) strategies for the sustainable use of the Bt crop technology. In this study, we characterized the genetic bases of Cry2Ab2 resistance in H. zea using diet‐overlay bioassays with two different forms of Cry2Ab2 protein. RESULTS Laboratory bioassays using a Cry2Ab2‐resistant (RR) strain, a susceptible (SS) strain, as well as cross and backcross strains, revealed that resistance to Cry2Ab2 was autosomally inherited and controlled by more than one locus. In diet bioassays, the dominance of Cry2Ab2 resistance in H. zea varied from incompletely recessive to incompletely dominant across all tested Cry2Ab2 concentrations of either Bt corn leaf powder or solubilized protein. On leaf tissue of TwinLink cotton (expressing Cry1Ab and Cry2Ae), Cry2Ab2 resistance in H. zea was completely dominant. CONCLUSION These results have significant implications for understanding the widespread field‐evolved resistance of H. zea against Cry1 and Cry2 proteins in Bt corn and cotton and should be useful in developing effective IRM strategies for H. zea. This article is protected by copyright. All rights reserved.
Fei Yang; Graham P. Head; Paula A. Price; José C. Santiago González; David L. Kerns. Inheritance of Bacillus thuringiensis Cry2Ab2 protein resistance in Helicoverpa zea (Lepidoptera: Noctuidae). Pest Management Science 2020, 76, 3676 -3684.
AMA StyleFei Yang, Graham P. Head, Paula A. Price, José C. Santiago González, David L. Kerns. Inheritance of Bacillus thuringiensis Cry2Ab2 protein resistance in Helicoverpa zea (Lepidoptera: Noctuidae). Pest Management Science. 2020; 76 (11):3676-3684.
Chicago/Turabian StyleFei Yang; Graham P. Head; Paula A. Price; José C. Santiago González; David L. Kerns. 2020. "Inheritance of Bacillus thuringiensis Cry2Ab2 protein resistance in Helicoverpa zea (Lepidoptera: Noctuidae)." Pest Management Science 76, no. 11: 3676-3684.
The corn earworm, Helicoverpa zea, is a major target pest of the insecticidal Vip3Aa protein used in pyramided transgenic Bt corn and cotton with Cry1 and Cry2 proteins in the U.S. The widespread resistance to Cry1 and Cry2 proteins in H. zea will challenge the long-term efficacy of Vip3Aa technology. Determining the frequency of resistant alleles to Vip3Aa in field populations of H. zea is critically important for resistance management. Here, we provided the first F2 screen study to estimate the resistance allele frequency for Vip3Aa in H. zea populations in Texas, U.S. In 2019, 128 H. zea neonates per isofamily for a total of 114 F2 families were screened with a diagnostic concentration of 3.0 μg/cm2 of Vip3Aa39 protein in diet-overlay bioassays. The F2 screen detected two families carrying a major Vip3Aa resistance allele. The estimated frequency of major resistance alleles against Vip3Aa39 in H. zea in Texas from this study was 0.0065 with a 95% CI of 0.0014–0.0157. A Vip3Aa-resistant strain (RR) derived from the F2 screen showed a high level of resistance to Vip3Aa39 protein, with a resistance ratio of >588.0-fold relative to a susceptible population (SS) based on diet-overlay bioassays. We provide the first documentation of a major resistance allele conferring high levels of Vip3Aa resistance in a field-derived strain of H. zea in the U.S. Data generated from this study contribute to development of management strategies for the sustainable use of the Vip3Aa technology to control H. zea in the U.S.
Fei Yang; José C. Santiago González; Nathan Little; Dominic Reisig; Gregory Payne; Rafael Ferreira Dos Santos; Juan Luis Jurat-Fuentes; Ryan Kurtz; David L. Kerns. First documentation of major Vip3Aa resistance alleles in field populations of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in Texas, USA. Scientific Reports 2020, 10, 1 -8.
AMA StyleFei Yang, José C. Santiago González, Nathan Little, Dominic Reisig, Gregory Payne, Rafael Ferreira Dos Santos, Juan Luis Jurat-Fuentes, Ryan Kurtz, David L. Kerns. First documentation of major Vip3Aa resistance alleles in field populations of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in Texas, USA. Scientific Reports. 2020; 10 (1):1-8.
Chicago/Turabian StyleFei Yang; José C. Santiago González; Nathan Little; Dominic Reisig; Gregory Payne; Rafael Ferreira Dos Santos; Juan Luis Jurat-Fuentes; Ryan Kurtz; David L. Kerns. 2020. "First documentation of major Vip3Aa resistance alleles in field populations of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in Texas, USA." Scientific Reports 10, no. 1: 1-8.
Fall armyworm, Spodoptera frugiperda, is a major target pest of pyramided Bt (Bacillus thuringiensis) corn and cotton in the U.S. In this study, we used a well-established F2 screening method to detect resistance alleles to Vip3Aa51 protein in field populations of S. frugiperda in Texas. In 2018, a total of 95 F2 two-parent families of S. frugiperda were established using single-pair mating of field individuals collected from two sorghum fields in two locations in Texas. For each F2 family, 128 neonates were screened on a diagnostic concentration of 3.0 μg/cm2 Vip3Aa51 protein using diet-overlay bioassays. The results showed that two out of 95 two-parent families possessed a major resistance allele against Vip3Aa51 protein. The estimated frequency of major resistance alleles against Vip3Aa51 in S. frugiperda in Texas was 0.0078 with a 95% CI of 0.0016–0.0188. The Vip3Aa51-resistant strain (TX-RR) derived from the F2 screening showed a high level of resistance to Vip3Aa51 protein, with a resistance ratio of >395.0-fold relative to a susceptible population (SS). Information generated from this study should be useful in studying mechanisms of Vip3Aa resistance in S. frugiperda, resistance monitoring, and resistance management of the Vip3Aa technology.
Fei Yang; Jayme Williams; Pat Porter; Fangneng Huang; David L. Kerns. F2 screen for resistance to Bacillus thuringiensis Vip3Aa51 protein in field populations of Spodoptera frugiperda (Lepidoptera: Noctuidae) from Texas, USA. Crop Protection 2019, 126, 104915 .
AMA StyleFei Yang, Jayme Williams, Pat Porter, Fangneng Huang, David L. Kerns. F2 screen for resistance to Bacillus thuringiensis Vip3Aa51 protein in field populations of Spodoptera frugiperda (Lepidoptera: Noctuidae) from Texas, USA. Crop Protection. 2019; 126 ():104915.
Chicago/Turabian StyleFei Yang; Jayme Williams; Pat Porter; Fangneng Huang; David L. Kerns. 2019. "F2 screen for resistance to Bacillus thuringiensis Vip3Aa51 protein in field populations of Spodoptera frugiperda (Lepidoptera: Noctuidae) from Texas, USA." Crop Protection 126, no. : 104915.
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.
Fei Yang; José C. Santiago González; Jayme Williams; Donald C. Cook; Ryan T. Gilreath; And David L. Kerns; David L. Kerns. Occurrence and Ear Damage of Helicoverpa zea on Transgenic Bacillus thuringiensis Maize in the Field in Texas, U.S. and Its Susceptibility to Vip3A Protein. Toxins 2019, 11, 102 .
AMA StyleFei Yang, José C. Santiago González, Jayme Williams, Donald C. Cook, Ryan T. Gilreath, And David L. Kerns, David L. Kerns. Occurrence and Ear Damage of Helicoverpa zea on Transgenic Bacillus thuringiensis Maize in the Field in Texas, U.S. and Its Susceptibility to Vip3A Protein. Toxins. 2019; 11 (2):102.
Chicago/Turabian StyleFei Yang; José C. Santiago González; Jayme Williams; Donald C. Cook; Ryan T. Gilreath; And David L. Kerns; David L. Kerns. 2019. "Occurrence and Ear Damage of Helicoverpa zea on Transgenic Bacillus thuringiensis Maize in the Field in Texas, U.S. and Its Susceptibility to Vip3A Protein." Toxins 11, no. 2: 102.
Fall armyworm, Spodoptera frugiperda, is a target pest of the Vip3A protein used in pyramided Bt corn and cotton in the U.S. In this study, we provide the first documentation of a resistance allele conferring Vip3A resistance in a field-derived population of S. frugiperda from U.S., and characterize its inheritance and cross-resistance. An F2 screen with 104 two-parent families generated from a field collection of S. frugiperda in Louisiana, U.S., resulted in one family carrying a Vip3A resistance allele. The Vip3A-resistant strain (RR) derived from the two-parent family showed a high level of resistance to Vip3A in both diet and whole plant bioassays, with a resistance ratio of >632.0-fold relative to a susceptible population (SS) based on diet-overlay bioassays. The inheritance of Vip3A resistance was monogenic, autosomal and recessive. Furthermore, the Vip3A resistance conferred no cross-resistance to Cry1F, Cry2Ab2 or Cry2Ae purified proteins, with resistance ratios of 3.5, 5.0 and 1.1, respectively. These findings provide valuable information for characterizing Vip3A resistance, resistance monitoring, and developing effective resistance management strategies for the sustainable use of the Vip3A technology.
Fei Yang; Shannon Morsello; Graham P. Head; Chris Sansone; Fangneng Huang; Ryan T. Gilreath; David L. Kerns. F2screen, inheritance and cross-resistance of field-derived Vip3A resistance inSpodoptera frugiperda(Lepidoptera: Noctuidae) collected from Louisiana, USA. Pest Management Science 2018, 74, 1769 -1778.
AMA StyleFei Yang, Shannon Morsello, Graham P. Head, Chris Sansone, Fangneng Huang, Ryan T. Gilreath, David L. Kerns. F2screen, inheritance and cross-resistance of field-derived Vip3A resistance inSpodoptera frugiperda(Lepidoptera: Noctuidae) collected from Louisiana, USA. Pest Management Science. 2018; 74 (8):1769-1778.
Chicago/Turabian StyleFei Yang; Shannon Morsello; Graham P. Head; Chris Sansone; Fangneng Huang; Ryan T. Gilreath; David L. Kerns. 2018. "F2screen, inheritance and cross-resistance of field-derived Vip3A resistance inSpodoptera frugiperda(Lepidoptera: Noctuidae) collected from Louisiana, USA." Pest Management Science 74, no. 8: 1769-1778.
Gene-pyramiding by combining two or more dissimilar Bt proteins into a crop has been used to delay insect resistance. The durability of gene-pyramiding can be reduced by cross-resistance. Fall armyworm, Spodoptera frugiperda, is a major target pest of the Cry2Ab2 protein used in pyramided Bt corn and cotton. Here, we provide the first experimental evaluation of cross-resistance in S. frugiperda selected with Cry2Ab2 corn to multiple Bt sources including purified Bt proteins, Bt corn and Bt cotton. Concentration-response bioassays showed that resistance ratios for Cry2Ab2-resistant (RR) relative to -susceptible (SS) S. frugiperda were −1.4 for Cry1F, 1.2 for Cry1A.105, >26.7 for Cry2Ab2, > 10.0 for Cry2Ae, and −1.1 for Vip3A. Larvae of Cry2Ab2-heterozygous (RS), SS, and RR S. frugiperda were all susceptible to Bt corn and Bt cotton containing Cry1 (Cry1F or Cry1A.105) and/or Vip3A proteins. Pyramided Bt cotton containing Cry1Ac+Cry2Ab2 or Cry1Ab+Cry2Ae were also effective against SS and RS, but not RR. These findings suggest that Cry2Ab2-corn selected S. frugiperda is not cross-resistant to Cry1F, Cry1A.105, or Vip3A protein, or corn and cotton plants containing these Bt proteins, but it can cause strong cross-resistance to Cry2Ae and Bt crops expressing similar Bt proteins.
Fei Yang; Paula Price; Fangneng Huang; David L. Kerns; Graham P. Head. Cross-resistance to purified Bt proteins, Bt corn and Bt cotton in a Cry2Ab2-corn resistant strain of Spodoptera frugiperda. Pest Management Science 2017, 73, 2495 -2503.
AMA StyleFei Yang, Paula Price, Fangneng Huang, David L. Kerns, Graham P. Head. Cross-resistance to purified Bt proteins, Bt corn and Bt cotton in a Cry2Ab2-corn resistant strain of Spodoptera frugiperda. Pest Management Science. 2017; 73 (12):2495-2503.
Chicago/Turabian StyleFei Yang; Paula Price; Fangneng Huang; David L. Kerns; Graham P. Head. 2017. "Cross-resistance to purified Bt proteins, Bt corn and Bt cotton in a Cry2Ab2-corn resistant strain of Spodoptera frugiperda." Pest Management Science 73, no. 12: 2495-2503.
Seed mixture, also called ‘RIB’, has been used to provide refuge populations for delaying insect resistance. Pollen contamination in RIB could result in refuge kernels of non-Bt maize expressing variable Bt proteins. Data are lacking regarding the impact of pollen contamination on evolution of resistance for ear-feeding insects. Here, we used Spodoptera frugiperda and Cry1F-maize as a model to examine if pollen contamination in RIB increases the dominance of insect resistance. Pollen contamination caused >66% refuge kernels in 5:95% (non-Bt:Bt) and 20:80% RIBs to express Cry1F protein. Survival at adult stage on pure non-Bt ears was similar (54.4–63.3%) among Cry1F-susceptible (SS), Cry1F-resistant (RR) and Cry1F-heterozygous (RS) S. frugiperda. On Bt ears, survival was similar between SS and RS (0.0–1.7%), but it was significantly less than that of RR (59.2%). On the two RIB refuge ears, survival at adult stage for RS (42.3% in 5:95% RIB; 50.0% in 20:80% RIB) was significantly higher than for SS (8.7% in 5:95% RIB; 10.0% in 20:80% RIB). The results suggest that pollen contamination in RIB could increase the dominance of resistance for ear-feeding insects by significantly reducing susceptible refuge populations and supporting higher survival of heterozygotes relative to homozygous susceptible insects. © 2017 Society of Chemical Industry
Fei Yang; David L Kerns; Sebe Brown; Graham P Head; Fangneng Huang. Pollen contamination in seed mixture increases the dominance of resistance to Bt maize in Spodoptera frugiperda (Lepidoptera: Noctuidae). Pest Management Science 2017, 73, 2379 -2385.
AMA StyleFei Yang, David L Kerns, Sebe Brown, Graham P Head, Fangneng Huang. Pollen contamination in seed mixture increases the dominance of resistance to Bt maize in Spodoptera frugiperda (Lepidoptera: Noctuidae). Pest Management Science. 2017; 73 (11):2379-2385.
Chicago/Turabian StyleFei Yang; David L Kerns; Sebe Brown; Graham P Head; Fangneng Huang. 2017. "Pollen contamination in seed mixture increases the dominance of resistance to Bt maize in Spodoptera frugiperda (Lepidoptera: Noctuidae)." Pest Management Science 73, no. 11: 2379-2385.
Fei Yang; David L. Kerns; B.Rogers Leonard; Isaac Oyediran; Tony Burd; Ying Niu; Fangneng Huang. Performance of Agrisure®Viptera™ 3111 corn against Helicoverpa zea (Lepidoptera: Noctuidae) in seed mixed plantings. Crop Protection 2015, 69, 77 -82.
AMA StyleFei Yang, David L. Kerns, B.Rogers Leonard, Isaac Oyediran, Tony Burd, Ying Niu, Fangneng Huang. Performance of Agrisure®Viptera™ 3111 corn against Helicoverpa zea (Lepidoptera: Noctuidae) in seed mixed plantings. Crop Protection. 2015; 69 ():77-82.
Chicago/Turabian StyleFei Yang; David L. Kerns; B.Rogers Leonard; Isaac Oyediran; Tony Burd; Ying Niu; Fangneng Huang. 2015. "Performance of Agrisure®Viptera™ 3111 corn against Helicoverpa zea (Lepidoptera: Noctuidae) in seed mixed plantings." Crop Protection 69, no. : 77-82.