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Calvin W, Yang F, Brown SA, Catchot AL, Crow WD, Cook DR, Gore J, Kurtz R, Lorenz GM, Seiter NJ, Stewart SD, Towles T, Kerns DL. Development of Economic Thresholds Toward Bollworm (Lepidoptera: Noctuidae), Management in Bt Cotton, and Assessment of the Benefits From Treating Bt Cotton With Insecticide. JOURNAL OF ECONOMIC ENTOMOLOGY 2021; 114:2493-2504. [PMID: 34625803 DOI: 10.1093/jee/toab173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Indexed: 06/13/2023]
Abstract
Widespread field-evolved resistance of bollworm [Helicoverpa zea (Boddie)] to Cry1 and Cry2 Bt proteins has threatened the utility of Bt cotton for managing bollworm. Consequently, foliar insecticide applications have been widely adopted to provide necessary additional control. Field experiments were conducted across the Mid-South and in Texas to devise economic thresholds for foliar insecticide applications targeting bollworm in cotton. Bt cotton technologies including TwinLink (TL; Cry1Ab+Cry2Ae), TwinLink Plus (TLP; Cry1Ab+Cry2Ae+Vip3Aa), Bollgard II (BG2; Cry1Ac+Cry2Ab), Bollgard 3 (BG3; Cry1Ac+Cry2Ab+Vip3Aa), WideStrike (WS; Cry1Ac+Cry1F), WideStrike 3 (WS3; Cry1Ac+Cry1F+Vip3Aa), and a non-Bt (NBT) variety were evaluated. Gain threshold, economic injury level, and economic thresholds were determined. A 6% fruiting form injury threshold was selected and compared with preventive treatments utilizing chlorantraniliprole. Additionally, the differences in yield from spraying bollworms was compared among Bt cotton technologies. The 6% fruiting form injury threshold resulted in a 25 and 75% reduction in insecticide applications relative to preventive sprays for WS and BG2, respectively. All Bt technologies tested in the current study exhibited a positive increase in yield from insecticide application. The frequency of yield increase from spraying WS was comparable to that of NBT. Significant yield increases due to insecticide application occurred less frequently in triple-gene Bt cotton. However, their frequencies were close to the dual-gene Bt cotton, except for WS. The results of our study suggest that 6% fruiting form injury is a viable threshold, and incorporating a vetted economic threshold into an Integrated Pest Management program targeting bollworm should improve the sustainability of cotton production.
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Affiliation(s)
- Wilfrid Calvin
- Department of Entomology, Texas A&M University, 2475 TAMU, College Station, TX 77843, USA
| | - Fei Yang
- Department of Entomology, Texas A&M University, 2475 TAMU, College Station, TX 77843, USA
| | - Sebe A Brown
- Dean Lee Research Station, Louisisana State University, 8105 Tom Bowman Drive, Alexandria, LA 71302, USA
| | - Angus L Catchot
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, P.O. Box 9775, Mississippi State, MS 39762, USA
| | - Whitney D Crow
- Delta REC, Mississippi State University, P.O. Box 197, Stoneville, MS 38776, USA
| | - Donald R Cook
- Delta REC, Mississippi State University, P.O. Box 197, Stoneville, MS 38776, USA
| | - Jeffrey Gore
- Delta REC, Mississippi State University, P.O. Box 197, Stoneville, MS 38776, USA
| | - Ryan Kurtz
- Cotton Incorporated, 6399 Weston Pkwy, Cary, NC 27513, USA
| | - Gustav M Lorenz
- Department of Entomology and Plant Pathology, University of Arkansas, 2001 Highway 70 E., Lonoke, AR 72086, USA
| | - Nicholas J Seiter
- Crop Sciences, 380 National Soybean Research Center, University of Illinois, 1101 W. Peabody Drive, Urbana, IL 61801, USA
| | - Scott D Stewart
- West Tennessee REC, University of Tennessee, 605 Airways Boulevard, Jackson, TN 38301, USA
| | - Tyler Towles
- Macon Ridge Research Station, Louisisana State University, 212A Macon Ridge Road, Winnsboro, LA 71295, USA
| | - David L Kerns
- Department of Entomology, Texas A&M University, 2475 TAMU, College Station, TX 77843, USA
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Carrière Y, Degain BA, Tabashnik BE. Effects of gene flow between Bt and non-Bt plants in a seed mixture of Cry1A.105 + Cry2Ab corn on performance of corn earworm in Arizona. PEST MANAGEMENT SCIENCE 2021; 77:2106-2113. [PMID: 33350567 DOI: 10.1002/ps.6239] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/08/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND Using natural populations of Helicoverpa zea from Arizona, we tested the hypotheses that gene flow between Bacillus thuringiensis (Bt) plants and non-Bt plants in a seed mixture of 10% non-Bt corn and 90% Bt corn producing Cry1A.105 and Cry2Ab reduces larval performance on ears from non-Bt plants, or increases performance on ears from Bt plants. RESULTS Gene flow was not detected in blocks of non-Bt or Bt corn but was extensive in seed mixtures. Analyses of larval weight and abundance over a period of 3 to 4 weeks did not indicate consistent effects of gene flow on development rate and survival. However for non-Bt plants, the ear area damaged and percentage of ears with exit holes were significantly lower in the seed mixtures than blocks. By contrast, the percentage of ears with exit holes and ear damage did not differ significantly between the seed mixtures and blocks for Bt plants. Nearly 100% of the ears were damaged and the damaged area was substantial, showing that H. zea is a major ear-feeding pest in Arizona. Relative to non-Bt corn, the pyramided Bt corn did not significantly reduce the percentage of damaged ears and only reduced the ear area damaged by 21 to 39%, indicating that H. zea may have evolved resistance to Cry1A.105, Cry2Ab, or both. CONCLUSIONS Our results indicate that gene flow between Bt and non-Bt plants in seed mixtures reduced effective refuge size, and that block refuges may be needed to manage the evolution of H. zea resistance to Bt corn in Arizona. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Yves Carrière
- Department of Entomology, University of Arizona, Tucson, AZ, USA
| | - Ben A Degain
- Department of Entomology, University of Arizona, Tucson, AZ, USA
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Carrière Y, Degain BA, Harpold VS, Unnithan GC, Tabashnik BE. Gene Flow Between Bt and Non-Bt Plants in a Seed Mixture Increases Dominance of Resistance to Pyramided Bt Corn in Helicoverpa zea (Lepidoptera: Noctuidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2020; 113:2041-2051. [PMID: 32582955 DOI: 10.1093/jee/toaa138] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Indexed: 06/11/2023]
Abstract
For delaying evolution of pest resistance to transgenic corn producing Bacillus thuringiensis (Bt) toxins, limited data are available to compare the effectiveness of refuges of non-Bt corn planted in seed mixtures versus blocks. Here we addressed this issue in the ear-feeding pest Helicoverpa zea Boddie by measuring its survival and development in the laboratory on ears from field plots with 90% Cry1A.105 + Cry2Ab corn and 10% non-Bt corn planted in a seed mixture or blocks. We compared a strain of H. zea selected for resistance to Cry1Ac in the laboratory, its parent strain not selected in the laboratory, and their F1 progeny. The relative survival of the F1 progeny and dominance of resistance were higher on ears from Bt plants in the seed mixture than the block. Half of the kernels in ears from non-Bt plants in the seed mixture produced both Cry1A.105 and Cry2Ab. However, survival on ears from non-Bt plants did not differ between the block and seed mixture. In simulations based on the observed survival, resistance to Cry1A.105 + Cry2Ab corn evolved faster with the seed mixture than the blocks, because of the higher dominance of resistance in the seed mixture. Increasing the refuge percentage improved durability of Cry1A.105 + Cry2Ab corn more for the blocks than the seed mixture. These findings imply that, for a given percentage of non-Bt corn, resistance of H. zea and other ear-feeding pests to multi-toxin Bt corn is likely to evolve faster for seed mixtures than blocks.
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Affiliation(s)
- Yves Carrière
- Department of Entomology, University of Arizona, Tucson, AZ
| | - Ben A Degain
- Department of Entomology, University of Arizona, Tucson, AZ
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Coates BS, Abel CA, Swoboda-Bhattarai KA, Palmquist DE, Montezano DG, Zukoff SN, Wang Y, Bradshaw JD, DiFonzo CD, Shields E, Tilmon KJ, Hunt TE, Peterson JA. Geographic Distribution of Bacillus thuringiensis Cry1F Toxin Resistance in Western Bean Cutworm (Lepidoptera: Noctuidae) Populations in the United States. JOURNAL OF ECONOMIC ENTOMOLOGY 2020; 113:2465-2472. [PMID: 32740653 DOI: 10.1093/jee/toaa136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Indexed: 06/11/2023]
Abstract
The western bean cutworm (WBC), Striacosta albicosta (Lepidoptera: Noctuidae), can be a severe pest of transgenic corn in the western Plains and Great Lakes regions of North America, including on hybrids expressing the Bacillus thuringiensis (Bt) Cry1F toxin. The level and geographic distribution of Cry1F resistance are not completely known. Neonate S. albicosta from 10 locations between Nebraska and New York state were subjected to dose-response trypsin-activated native Cry1F toxin overlay bioassays. In 2017, the mean estimated lethal concentration causing 50% larval mortality (LC50) ranged from 15.1 to 18.4 µg Cry1F cm-2, and were not significantly different among locations. In 2018, LC50 estimates at Scottsbluff, NE (22.0 µg Cry1F cm-2) and Watertown, NY (21.7 µg Cry1F cm-2) were significantly higher when compared to locations in Michigan (15.8 µg Cry1F cm-2). Significantly lower 14-day larval weight among survivors was correlated with higher Cry1F dose. Results from this study indicate that S. albicosta survivorship on purified Bt Cry1F toxin shows a relatively even distribution across the native and range expansion areas where seasonal field infestations typically occur.
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Affiliation(s)
- Brad S Coates
- USDA-ARS, Corn Insects & Crop Genetics Research Unit, Ames, IA
| | - Craig A Abel
- USDA-ARS, Corn Insects & Crop Genetics Research Unit, Ames, IA
| | - Katharine A Swoboda-Bhattarai
- University of Nebraska-Lincoln, Department of Entomology, West Central Research and Extension Center, North Platte, NE
| | | | - Débora G Montezano
- University of Nebraska-Lincoln, Department of Entomology, West Central Research and Extension Center, North Platte, NE
| | - Sarah N Zukoff
- Kansas State University, Department of Entomology, Southwest Research and Extension Center, Garden City, KS
| | - Yangzhou Wang
- Jilin Academy of Agricultural Sciences, Plant Protection Institute, Changchun, Jilin Province, China
| | - Jeffrey D Bradshaw
- University of Nebraska-Lincoln, Department of Entomology, Panhandle Research and Extension Center, Scottsbluff, NE
| | | | - Elson Shields
- Cornell University, Department of Entomology, Ithaca, NY
| | | | - Thomas E Hunt
- University of Nebraska-Lincoln, Department of Entomology, Haskell Agricultural Laboratory, Concord, NE
| | - Julie A Peterson
- University of Nebraska-Lincoln, Department of Entomology, West Central Research and Extension Center, North Platte, NE
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5
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Caprio MA, Kurtz R, Catchot A, Kerns D, Reisig D, Gore J, Reay-Jones FPF. The Corn-Cotton Agroecosystem in the Mid-Southern United States: What Insecticidal Event Pyramids Should be Used in Each Crop to Extend Vip3A Durability. JOURNAL OF ECONOMIC ENTOMOLOGY 2019; 112:2894-2906. [PMID: 31375824 DOI: 10.1093/jee/toz208] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Indexed: 06/10/2023]
Abstract
Recent studies suggest that resistance in Helicoverpa zea (Boddie) (Lepidoptera, Noctuidae) to Cry1A(b/c) and Cry2Ab2 toxins from the bacterium Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) has increased and field efficacy is impacted in transgenic corn and cotton expressing these toxins. A third toxin, Vip3A, is available in pyramids expressing two or more Bt toxins in corn hybrids and cotton varieties, but uncertainty exists regarding deployment strategies. During a growing season, H. zea infests corn and cotton, and debate arises over use of Vip3A toxin in corn where H. zea is not an economic pest. We used a three-locus, spatially explicit simulation model to evaluate when using Vip3A in corn might hasten evolution of resistance to Vip3A, with implications in cotton where H. zea is a key pest. When using a conventional refuge in corn and initial resistance allele frequencies of Cry1A and Cry2A were 10%, transforming corn with Vip3A slowed resistance to these toxins and delayed resistance evolution to the three-toxin pyramid as a whole. When Cry resistance allele frequencies exceeded 30%, transforming corn with Vip3A hastened the evolution of resistance to the three-toxin pyramid in cotton. When using a seed blend refuge strategy, resistance was delayed longest when Vip3A was not incorporated into corn and used only in cotton. Simulations of conventional refuges were generally more durable than seed blends, even when 75% of the required refuge was not planted. Extended durability of conventional refuges compared to other models of resistance evolution are discussed as well as causes for unusual survivorship in seed blends.
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Affiliation(s)
- Michael A Caprio
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS
| | | | - Angus Catchot
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS
| | - David Kerns
- Department of Entomology, Texas A&M University, TAMU, College Station, TX
| | - Dominic Reisig
- Department of Entomology and Plant Pathology, North Carolina State University, Vernon G. James Research and Extension Center, Plymouth, NC
| | - Jeff Gore
- Delta Research & Extension Center, Mississippi State University, Stoneville, MS
| | - Francis P F Reay-Jones
- Department of Plant and Environmental Sciences, Pee Dee Research and Education Center, Clemson University, Florence, SC
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6
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Fleming D, Musser F, Reisig D, Greene J, Taylor S, Parajulee M, Lorenz G, Catchot A, Gore J, Kerns D, Stewart S, Boykin D, Caprio M, Little N. Effects of transgenic Bacillus thuringiensis cotton on insecticide use, heliothine counts, plant damage, and cotton yield: A meta-analysis, 1996-2015. PLoS One 2018; 13:e0200131. [PMID: 30024919 PMCID: PMC6053876 DOI: 10.1371/journal.pone.0200131] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 06/20/2018] [Indexed: 01/03/2023] Open
Abstract
The primary management tactic for lepidopteran pests of cotton in the United
States of America (USA) is the use of transgenic cotton that produces
Bacillus thuringiensis Berliner (Bt)
toxins. The primary target pests of this technology are Helicoverpa
zea (Boddie) and Heliothis virescens (F.) in the
eastern and central Cotton Belt of the USA. Concerns over the evolution of
resistance in H. zea to Bt
toxins and scrutiny of the necessity of Bt crops has escalated.
We reviewed published and unpublished data from field trials of
Bt cotton in the eastern and central Cotton Belt of the USA
through 2015 to evaluate the effectiveness of Bt cotton
(Bollgard, Bollgard II, WideStrike, WideStrike 3, and TwinLink).
Bt cotton reduced insecticide usage, reduced heliothine
pest numbers and damage, and provided a yield benefit, but Bollgard II and
WideStrike efficacy declined in the Midsouth over the period evaluated. In the
Southeastern region, heliothine damage remained constant through 2015, but yield
benefits declined from 2010 until 2015. Resistance of H.
zea to several Bt toxins is the most
plausible explanation for the observed changes in Bt cotton
efficacy. The introduction of new Bt toxins such as found in
Widestrike 3 and Twinlink may preserve the benefits of Bt
crops. However, while both Widestrike 3 and Twinlink had less damage than
Widestrike, damage levels of both were similar to Bollgard II.
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Affiliation(s)
- Daniel Fleming
- Mississippi State University, Department of Biochemistry, Molecular
Biology, Entomology, and Plant Pathology, Mississippi State, MS, United States
of America
- * E-mail: (DF); (FM)
| | - Fred Musser
- Mississippi State University, Department of Biochemistry, Molecular
Biology, Entomology, and Plant Pathology, Mississippi State, MS, United States
of America
- * E-mail: (DF); (FM)
| | - Dominic Reisig
- North Carolina State University, Vernon G. James Research and Extension
Center, Plymouth, NC, United States of America
| | - Jeremy Greene
- Clemson University, Edisto Research and Education Center, Blackville, SC,
United States of America
| | - Sally Taylor
- Virginia Tech, Tidewater Agricultural Research and Extension Center,
Suffolk, VA, United States of America
| | - Megha Parajulee
- Texas A&M University, AgriLife Research and Extension Center,
Lubbock, TX, United States of America
| | - Gus Lorenz
- University of Arkansas Cooperative Extension Service, Lonoke Extension
Center, Lonoke, AR, United States of America
| | - Angus Catchot
- Mississippi State University, Department of Biochemistry, Molecular
Biology, Entomology, and Plant Pathology, Mississippi State, MS, United States
of America
| | - Jeffrey Gore
- Mississippi State University Delta Research and Extension Center,
Stoneville, MS, United States of America
| | - David Kerns
- Texas A&M University Department of Entomology, College Station, TX,
United States of America
| | - Scott Stewart
- The University of Tennessee, West Tennessee Research and Education
Center, Jackson, TN, United States of America
| | - Deborah Boykin
- United States Department of Agriculture–Agricultural Research Service,
James Whitten Delta States Research Center, Stoneville, MS, United States of
America
| | - Michael Caprio
- Mississippi State University, Department of Biochemistry, Molecular
Biology, Entomology, and Plant Pathology, Mississippi State, MS, United States
of America
| | - Nathan Little
- United States Department of Agriculture–Agricultural Research Service,
Southern Insect Management Research Unit, Stoneville, MS, United States of
America
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Onstad DW, Crespo ALB, Pan Z, Crain PR, Thompson SD, Pilcher CD, Sethi A. Blended Refuge and Insect Resistance Management for Insecticidal Corn. ENVIRONMENTAL ENTOMOLOGY 2018; 47:210-219. [PMID: 29220481 PMCID: PMC5850660 DOI: 10.1093/ee/nvx172] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Indexed: 06/07/2023]
Abstract
In this review, we evaluate the intentional mixing or blending of insecticidal seed with refuge seed for managing resistance by insects to insecticidal corn (Zea mays). We first describe the pest biology and farming practices that will contribute to weighing trade-offs between using block refuges and blended refuges. Case studies are presented to demonstrate how the trade-offs will differ in different systems. We compare biological aspects of several abstract models to guide the reader through the history of modeling, which has played a key role in the promotion or denigration of blending in various scientific debates about insect resistance management for insecticidal crops. We conclude that the use of blended refuge should be considered on a case-by-case basis after evaluation of insect biology, environment, and farmer behavior. For Diabrotica virgifera virgifera, Ostrinia nubilalis, and Helicoverpa zea in the United States, blended refuge provides similar, if not longer, delays in the evolution of resistance compared to separate block refuges.
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8
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Reay-Jones FPF, Bessin RT, Brewer MJ, Buntin DG, Catchot AL, Cook DR, Flanders KL, Kerns DL, Porter RP, Reisig DD, Stewart SD, Rice ME. Impact of Lepidoptera (Crambidae, Noctuidae, and Pyralidae) Pests on Corn Containing Pyramided Bt Traits and a Blended Refuge in the Southern United States. JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:1859-1871. [PMID: 27329627 DOI: 10.1093/jee/tow109] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 04/27/2016] [Indexed: 06/06/2023]
Abstract
Blended refuge for transgenic plants expressing Bacillus thuringiensis (Bt) toxins has been approved in the northern United States as a resistance management strategy alternative to a structured refuge. A three-year study (2012-2014) was conducted with 54 trials across nine states in the southern United States to evaluate plant injury from lepidopteran pests of corn and yield in a corn hybrid expressing Cry1F × Cry1Ab × Vip3Aa20 (Pioneer Brand Optimum Leptra) planted as a pure stand and in refuge blends of 5, 10, and 20% in both early and late plantings. Injury by corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), and fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), was generally proportional to the percentage of non-Bt corn within each refuge blend. Across locations, ear injury in plots with 100% Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra) corn ranged from no injury to a maximum of 0.42 cm(2) per ear in Mississippi in 2013. Leaf injury ratings in 100% non-Bt plots in early and late planted trials in 2014 were 86- and 70-fold greater than in 100% Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra) plots. Plants in plots with blended refuges had significantly greater leaf injury in 2012 (5, 10, and 20% refuge blends), in the early-planted corn in 2013 (10 and 20% only), and in both early- and late-planted corn in 2014 (20% only) as compared with leaf injury in a pure stand of Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra) seen during these years. Corn ears in plots with blended refuges also had significantly greater area of kernels injured in 2012 (5, 10, and 20%), in early- and late-planted corn in 2013 (5, 10, and 20%), and in early (10 and 20% only)- and late-planted corn (5, 10, and 20%) in 2014 as compared with ear injury in a pure stand of Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra) seen during these years. Infestations of southwestern corn borer, Diatraea grandiosella Dyar (Lepidoptera: Crambidae), were also significantly reduced by Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra). Despite these differences in injury, yield averaged across locations varied among refuge blends only in the late-planted trials in 2013, with greater yields in the 0% refuge blend than in the 20% blend; however, when examining yield separately by location, only two of nine locations had higher yields in the 100% Bt plots than in any of the blended refuge plots. As a complement to studying the contribution of blended refuge to delaying resistance, quantifying injury and yield in a range of refuge blends is a necessary step to provide management information on the range of lepidopteran pests that occur in the southern United States.
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Affiliation(s)
- F P F Reay-Jones
- Department of Agricultural and Environmental Sciences, Pee Dee Research and Education Center, Clemson University, 2200 Pocket Rd., Florence, SC 29506-9727
| | - R T Bessin
- Department of Entomology, University of Kentucky, S-225 Ag North, Lexington, KY 40546
| | - M J Brewer
- Texas A&M AgriLife Research & Extension Center, 10345 State Hwy 44, Corpus Christi, TX 78406
| | - D G Buntin
- Department of Entomology, UGA-Griffin Campus, 1109 Experiment Street, Griffin, GA 30223
| | - A L Catchot
- Department of Entomology & Plant Pathology, Mississippi State University, Mississippi State, MS 39762
| | - D R Cook
- Delta Research & Extension Center, Mississippi State University, P.O. Box 197, Stoneville, MS 38776
| | | | - D L Kerns
- LSU AgCenter, Macon Ridge Station, 212A Macon Ridge Rd., Winnsboro, LA 71295
| | - R P Porter
- Texas AgriLife Research & Extension Center, Lubbock, TX 79403
| | - D D Reisig
- Department of Entomology, North Carolina State University, Vernon G. James Research and Extension Center, Plymouth, NC 27962
| | - S D Stewart
- West Tennessee Research and Education Center, 605 Airways Blvd., Jackson, TN 38301
| | - M E Rice
- DuPont Pioneer, P. O. Box 1150, Johnston, IA 50131 , and
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Pan Z, Onstad D, Crain P, Crespo A, Hutchison W, Buntin D, Porter P, Catchot A, Cook D, Pilcher C, Flexner L, Higgins L. Evolution of Resistance by Helicoverpa zea (Lepidoptera: Noctuidae) Infesting Insecticidal Crops in the Southern United States. JOURNAL OF ECONOMIC ENTOMOLOGY 2016; 109:821-831. [PMID: 26637533 PMCID: PMC4821455 DOI: 10.1093/jee/tov340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 11/04/2015] [Indexed: 06/05/2023]
Abstract
We created a deterministic, frequency-based model of the evolution of resistance by corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), to insecticidal traits expressed in crops planted in the heterogeneous landscapes of the southern United States. The model accounts for four generations of selection by insecticidal traits each year. We used the model results to investigate the influence of three factors on insect resistance management (IRM): 1) how does adding a third insecticidal trait to both corn and cotton affect durability of the products, 2) how does unstructured corn refuge influence IRM, and 3) how do block refuges (50% compliance) and blended refuges compare with regard to IRM? When Bt cotton expresses the same number of insecticidal traits, Bt corn with three insecticidal traits provides longer durability than Bt corn with two pyramided traits. Blended refuge provides similar durability for corn products compared with the same level of required block refuge when the rate of refuge compliance by farmers is 50%. Results for Mississippi and Texas are similar, but durabilities for corn traits are surprisingly lower in Georgia, where unstructured corn refuge is the highest of the three states, but refuge for Bt cotton is the lowest of the three states. Thus, unstructured corn refuge can be valuable for IRM but its influence is determined by selection for resistance by Bt cotton.
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Affiliation(s)
- Zaiqi Pan
- DuPont Pioneer, Wilmington, DE 19803 (; ; ; )
| | | | | | | | - William Hutchison
- Department of Entomology, University of Minnesota, St. Paul, MN 55108
| | - David Buntin
- Department of Entomology, University of Georgia, Griffin, GA 30223
| | - Pat Porter
- Department of Entomology, Texas A & M AgriLife Extension, Lubbock, TX 79403
| | - Angus Catchot
- Department of Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS 39762 , and
| | - Don Cook
- Delta Research and Extension Center, Mississippi State University, Stoneville, MS 38756
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