@article{kretschmar_cabrera_bradley_roe_2013, title={Novel adult feeding disruption test (FDT) to detect insecticide resistance of lepidopteran pests in cotton}, volume={69}, ISSN={["1526-4998"]}, DOI={10.1002/ps.3420}, abstractNote={Abstract}, number={5}, journal={PEST MANAGEMENT SCIENCE}, author={Kretschmar, B. and Cabrera, Ana R. and Bradley, Julius R. and Roe, R. Michael}, year={2013}, month={May}, pages={652–660} }
 @article{blinka_herbert_malone_van duyn_roberts_bradley_bacheler_2010, title={Relationship Between External Stink Bug (Hemiptera: Pentatomidae) Boll-Feeding Symptoms and Internal Boll Damage With Respect to Cotton Lint Gin-Out and Fiber Quality}, volume={103}, ISSN={["0022-0493"]}, DOI={10.1603/ec10122}, abstractNote={ABSTRACT 
 Cotton, Gossypium hirsutum L., bolls from 17 field locations in northeastern North Carolina and southeastern Virginia, having 20% or greater internal boll damage, were studied to determine the relationship between external feeding symptoms and internal damage caused by stink bug (Hemiptera: Pentatomidae) feeding. In 2006 and 2007, two cohorts of 100 bolls each were sampled at all field locations. The first cohort was removed as bolls reached approximately quarter size in diameter (2.4 cm). External and internal symptoms of stink bug feeding were assessed and tabulated. Concurrent to when the first cohort was collected, a second cohort of quarter-size-diameter bolls was identified, tagged, examined in situ for external feeding symptoms (sunken lesions), and harvested at the black seed coat stage. Harvested bolls were assessed for internal damage and locks were categorized (undamaged, minor damage, or major damage), dried, and ginned. Lint samples from each damage category were submitted for high volume instrument and advanced fiber information system quality analyses. Significant, moderately strong Pearson correlation coefficients existed between number of external stink bug feeding lesions and internal damage. Pearson correlation of total external lesions with total internal damage was stronger than any correlation among the other single components compared. Predictability plots indicated a rapid increase in relationship strength when relating external stink bug lesions to internal damage as the number of external lesions increased. Approximately 90% predictability of internal damage was achieved with four (2006) or six (2007) external lesions per boll. Gin-turnout and fiber quality decreased with increasing intensity of internal stink bug damage.}, number={6}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Blinka, Eric L. and Herbert, Ames and Malone, Sean and Van Duyn, John W. and Roberts, Phillip and Bradley, J. R. and Bacheler, Jack S.}, year={2010}, month={Dec}, pages={2236–2241} }
 @article{head_jackson_adamczyk_bradley_van duyn_gore_hardee_leonard_luttrell_ruberson_et al._2010, title={Spatial and temporal variability in host use by Helicoverpa zea as measured by analyses of stable carbon isotope ratios and gossypol residues}, volume={47}, ISSN={["0021-8901"]}, DOI={10.1111/j.1365-2664.2010.01796.x}, abstractNote={Summary 1. A high dose ⁄ refuge strategy has been adopted in the USA to manage the risk of Bacillus thuringiensis (Bt) resistance in target pests such as the cotton bollworm (CBW), Helicoverpa zea (Boddie) in transgenic Bt cotton Gossypium hirsutum L. Structured refuges, consisting of non-Bt cotton, have been a mandated part of this strategy to produce non-selected insects that are temporally and spatially synchronous with insects from the Bt crop, diluting Bt resistance alleles through mating. However, the bollworm is highly polyphagous and exploits a large number of crop and weedy hosts concurrently with Bt cotton.}, number={3}, journal={JOURNAL OF APPLIED ECOLOGY}, author={Head, Graham and Jackson, Ryan E. and Adamczyk, John and Bradley, Julius R. and Van Duyn, John and Gore, Jeff and Hardee, Dick D. and Leonard, B. Rogers and Luttrell, Randall and Ruberson, John and et al.}, year={2010}, month={Jun}, pages={583–592} }
 @article{outward_sorenson_bradley_2008, title={Effects of vegetated field borders on arthropods in cotton fields in eastern North Carolina}, volume={8}, DOI={10.1673/031.008.0901}, abstractNote={Abstract The influence, if any, of 5m wide, feral, herbaceous field borders on pest and beneficial arthropods in commercial cotton, Gossypium hirsutum (L.) (Malvales: Malvaceae), fields was measured through a variety of sampling techniques over three years. In each year, 5 fields with managed, feral vegetation borders and five fields without such borders were examined. Sampling was stratified from the field border or edge in each field in an attempt to elucidate any edge effects that might have occurred. Early season thrips populations appeared to be unaffected by the presence of a border. Pitfall sampling disclosed no differences in ground-dwelling predaceous arthropods but did detect increased populations of crickets around fields with borders. Cotton aphid (Aphis gossypii Glover) (Hemiptera: Aphididae) populations were too low during the study to adequately assess border effects. Heliothines, Heliothis virescens (F.) and Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), egg numbers and damage rates were largely unaffected by the presence or absence of a border, although in one instance egg numbers were significantly lower in fields with borders. Overall, foliage-dwelling predaceous arthropods were somewhat more abundant in fields with borders than in fields without borders. Tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois) (Heteroptera: Miridae) were significantly more abundant in fields with borders, but stink bugs, Acrosternum hilare (Say), and Euschistus servus (Say) (Hemiptera: Pentatomidae) numbers appeared to be largely unaffected by border treatment. Few taxa clearly exhibited distributional edge effects relative to the presence or absence of border vegetation. Field borders like those examined in this study likely will have little impact on insect pest management in cotton under current insect management regimens.}, journal={Journal of Insect Science (Ludhiana, India)}, author={Outward, R. and Sorenson, C. E. and Bradley, J. R.}, year={2008} }
 @article{siebert_nolting_leonard_braxton_all_van duyn_bradley_bacheler_huckaba_2008, title={Efficacy of Transgenic Cotton Expressing Cry1Ac and Cry1F Insecticidal Protein Against Heliothines (Lepidoptera: Noctuidae)}, volume={101}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493-101.6.1950}, abstractNote={Abstract Cotton, Gossypium hirsutum L, plants expressing Cry1Ac and Cry1F (Phytogen 440W) insecticidal crystal proteins of Bacillus thuringiensis (Bt) Berliner, were evaluated against natural populations of tobacco budworm, Heliothis virescens (F.), and bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), across 13 southern U.S. locations that sustained low, moderate, and high infestations. The intrinsic activity of Phytogen 440W was compared with nontreated non-Bt cotton (PSC355) and with management strategies in which supplemental insecticides targeting heliothines were applied to Phytogen 440W and to PSC355 cotton. Infestations were composed primarily of bollworm, which is the least sensitive of the heliothine complex to Cry toxins. Therefore, damage recorded in these studies was primarily due to bollworm. Greater than 75% of all test sites sustained heliothine infestations categorized as moderate to high (10.6–64.0% peak damaged bolls in nontreated PSC355). Phytogen 440W, alone or managed with supplemental insecticide applications, reduced heliothine-damaged plant terminals, squares (flower buds), flowers, and bolls equal to or better (1.0–79.0-fold) than managing a non-Bt cotton variety with foliar insecticides across all infestation environments. Rarely (frequency of ≤11% averaged across structures), sprayed Phytogen 440W reduced damaged structures compared with nontreated Phytogen 440W. Protection against heliothine-induced plant damage was similar across the three levels of infestation for each viable management strategy, with exception to damaged squares for nontreated Phytogen 440W. In situations of moderate to high heliothine infestations, cotton plants expressing Cry1Ac and Cry1F may sustain higher levels of damage compared with that same variety in low infestations. No significant difference in yield was observed among heliothine management strategies within each infestation level, indicating cotton plants may compensate for those levels of plant damage. These findings indicate Phytogen 440W containing Cry1Ac and Cry1F provided consistent control of heliothines across a range of environments and infestation levels.}, number={6}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Siebert, M. Willrich and Nolting, S. and Leonard, B. R. and Braxton, L. B. and All, J. N. and Van Duyn, J. W. and Bradley, J. R. and Bacheler, J. and Huckaba, R. M.}, year={2008}, month={Dec}, pages={1950–1959} }
 @article{abney_sorenson_gould_bradley_2008, title={Limitations of stable carbon isotope analysis for determining natal host origins of tobacco budworm, Heliothis virescens}, volume={126}, ISSN={["1570-7458"]}, DOI={10.1111/j.1570-7458.2007.00633.x}, abstractNote={Abstract}, number={1}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={Abney, M. R. and Sorenson, C. E. and Gould, F. and Bradley, J. R., Jr.}, year={2008}, month={Jan}, pages={46–52} }
 @article{jackson_bradley_van duyn_leonard_allen_luttrell_ruberson_adamczyk_gore_hardee_et al._2008, title={Regional assessment of Helicoverpa zea populations on cotton and non-cotton crop hosts}, volume={126}, ISSN={["1570-7458"]}, DOI={10.1111/j.1570-7458.2007.00653.x}, abstractNote={Abstract}, number={2}, journal={ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA}, author={Jackson, R. E. and Bradley, J. R. and Van Duyn, J. and Leonard, B. R. and Allen, K. C. and Luttrell, R. and Ruberson, J. and Adamczyk, J. and Gore, J. and Hardee, D. D. and et al.}, year={2008}, month={Feb}, pages={89–106} }
 @article{jackson_marcus_gould_bradley_van duyn_2007, title={Cross-resistance responses of Cry1Ac-selected Heliothis virescens (Lepidoptera : Noctuidae) to the Bacillus thuringiensis protein Vip3A}, volume={100}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493(2007)100[180:CROCHV]2.0.CO;2}, abstractNote={Abstract One susceptible and three Cry1Ac-resistant strains of tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), were used in laboratory studies to determine the level of cross-resistance between the Bacillus thuringiensis (Berliner) toxins Cry1Ac and Vip3A by using concentration–mortality and leaf tissue experiments. Concentration–mortality data demonstrated that the three Cry1Ac-resistant H. virescens strains, YHD2, KCBhyb, and CxC, were at least 215- to 316-fold resistant to Cry1Ac compared with the susceptible strain, YDK. Results from Vip3A concentration–mortality tests indicated that mortality was similar among all four H. virescens strains. Relative larval growth on Cry1Ac reflected concentration–mortality test results, because YHD2 larval growth was mostly unaffected by the Cry1Ac concentrations tested. Growth ratios for KCBhyb and CXC indicated that they had a more moderate level of resistance to Cry1Ac than did YHD2. Relative larval growth on Vip3A was highly variable at lower concentrations, but it was more consistent on concentrations of Vip3A above 25 &mgr;g/ml. Differences in larval growth among strains on Vip3A were not as pronounced as seen in Cry1Ac experiments. Mortality and larval growth also was assessed in leaf tissue bioassays in which YDK, CxC, and KCBhyb neonates were placed onto leaf disks from non-Bt and Bt cotton, Gossypium hirsutum L., for 5 d. Three Bt lines were used in an initial bioassay and consisted of two Vip3A-containing lines, COT203 and COT102, and a Cry1Ac-producing line. Mortality of KCBhyb and CXC was lower than that of YDK larvae in the presence of leaf tissue from the Cry1Ac-producing line. Additionally, increased larval growth and leaf tissue consumption on Cry1Ac-containing leaf disks was observed for KCBhyb and CXC. Mortality and larval weights were similar among strains when larvae were fed leaf tissue of either non-Bt, COT203, or COT102. A subsequent leaf tissue bioassay was conducted that evaluated four cotton lines: non-Bt, Cry1Ab-expressing, Vip3A-expressing, and pyramided-toxin plants that produced both Cry1Ab and Vip3A. Mortality levels were similar among strains when fed non-Bt, Vip3A-expressing, or pyramided-toxin leaf tissues. Mortality was higher for YDK than for KCBhyb or CXC on Cry1Ab-expressing leaf tissues. No differences in larval weights were observed among strains for any genotype tested. Results of these experiments demonstrate that cross-resistance is nonexistent between Cry1Ac and Vip3A in H. virescens. Thus, the introduction of Vip3A-producing lines could delay Cry1Ac-resistance evolution in H. virescens, if these lines gain a significant share of the market.}, number={1}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Jackson, R. E. and Marcus, M. A. and Gould, F. and Bradley, J. R., Jr. and Van Duyn, J. W.}, year={2007}, month={Feb}, pages={180–186} }
 @article{juba_bradley_notz_southern_sorenson_2007, title={Effect of tobacco budworm (Lepidoptera : Noctuidae) infestation level on budworm-resistant and susceptible varieties of flue-cured tobacco in north Carolina}, volume={100}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493(2007)100[801:EOTBLN]2.0.CO;2}, abstractNote={Abstract Field experiments were conducted from 1972 to 1978 and from 1998 to 1999 to evaluate tobacco budworm,Heliothis virescens (F.) (Lepidoptera: Noctuidae), larval feeding on flue-cured tobacco,Nicotiana tabacum (L.), yield in eastern North Carolina. In the earlier studies, using variety Coker 319, treatment plots were evaluated when either 0 or 100% of plants in a plot were infested withH.virescens larvae. Treatment differences based on actual yield loss (kilograms per hectare) were compared with estimations of yield loss based on leaf consumption and leaf loss. Results indicate actual yield loss when 100% of plants were infested was less than the corresponding estimates of yield loss. In the later experiments, two tobacco budworm-resistant lines, ‘CU 263′ and ‘CU 370′, were compared with a commercial susceptible variety, K 326, when 0, 10, 20, or 40% of plants were infested (1998) and 0, 10, 40, 75, or 100% of plants were infested (1999). Although significant increases in leaf equivalents consumed were associated with infestations exceeding the recommended threshold, differences were not detected for yield (kilograms per hectare), quality (dollars per kilogram), and value (dollars per hectare) within each tobacco line. Additionally, there was not a significant correlation between value and infestations level for any of the tobacco lines. These results provide economic support for tolerance of a higher treatment threshold. Although K 326 sustained more leaf equivalent loss than CU 263 and CU 370, the value of K 326 harvested was higher than that of CU 263 and CU 370. To justify use of resistant varieties, the combination of pest pressure and the benefit of host plant resistance must be greater than the capacity of a susceptible variety to produce competitive yields, despite sustaining significantly higher loss.}, number={3}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Juba, Thomas R. and Bradley, J. R., Jr. and Notz, Armando and Southern, P. Sterling and Sorenson, Clyde E.}, year={2007}, month={Jun}, pages={801–807} }
 @article{jackson_gould_bradley_duyn_2006, title={Genetic variation for resistance to Bacillus thuringiensis toxins in Helicoverpa zea (Lepidoptera : Noctuidae) in eastern North Carolina}, volume={99}, DOI={10.1603/0022-0493-99.5.1790}, abstractNote={Abstract To evaluate resistance to Bacillus thuringiensis Berliner (Bt) toxins, adult female bollworms, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), were collected from four light trap locations in two eastern North Carolina counties from August to October during 2001 and 2002. Females were allowed to oviposit, and upon hatching, 24 neonates from each female (F1 lines) were screened for survival and growth rate on each of three diets: non-Bt diet, diet containing 5.0 &mgr;g/ml Cry1Ac toxin, or diet containing 5.0 &mgr;g/ml Cry2Ab toxin. These screens were designed to identify nonrecessive Bt resistance alleles present in field populations of bollworm. Of 561 and 691 families screened with both Cry1Ac- and Cry2Ab-containing diets in 2001 and 2002, respectively, no F1 lines were identified that seemed to carry a gene conferring substantial resistance to either Cry1Ac or Cry2Ab. Adults from F1 lines with growth scores in the highest (R) and lowest (S) quartiles were mated in four combinations, RxR, SxR, RxS, and SxS. Differences in growth rates of larvae from these crosses demonstrated that there is substantial quantitative genetic variation in eastern North Carolina populations for resistance to both Cry1Ac and Cry2Ab toxins. These findings, in addition to results suggesting partially dominant inheritance of resistance to Cry1Ac and Cry2Ab, are critically important for determining appropriate resistance management strategies that impact the sustainability of transgenic cotton, Gossypium hirsutum (L.).}, number={5}, journal={Journal of Economic Entomology}, author={Jackson, R. E. and Gould, Fred and Bradley, J. R. and Duyn, J. W. Van}, year={2006}, pages={1790–1797} }
 @article{jackson_mahaffey_bradley_van duyn_sorenson_2005, title={The impact of transgenic cottons expressing one or two proteins from Bacillus thuringiensis on survival and damage potential of first and second instars of Ostrinia nubilalis (Lepidoptera: Crambidae)}, volume={9}, ISBN={1524-3303}, number={4}, journal={Journal of Cotton Science (Online)}, author={Jackson, R. E. and Mahaffey, J. S. and Bradley, J. R., Jr. and Van Duyn, J. W. and Sorenson, C. E.}, year={2005}, pages={199} }
 @article{jackson_bradley_van duyn_gould_2004, title={Comparative production of Helicoverpa zea (Lepidoptera : Noctuidae) from transgenic cotton expressing either one or two Bacillus thuringiensis proteins with and without insecticide oversprays}, volume={97}, ISSN={["1938-291X"]}, DOI={10.1603/0022-0493-97.5.1719}, abstractNote={Abstract Transgenic cotton, Gossypium hirsutum (L.), expressing either one or two Bacillus thuringiensis ssp. kurstaki Berliner (Bt) proteins was compared with the conventional sister line in field experiments with regard to production of bollworm, Helicoverpa zea (Boddie), and bolls damaged by bollworm. The relative numbers of bollworms that developed on Bollgard (Monsanto Co., St. Louis, MO), Bollgard II (Monsanto Co.), and conventional cotton were estimated under nontreated conditions in 2000 and both insecticide-treated and nontreated conditions in 2001–2002 in North Carolina tests. Averaged across seven field studies under nontreated conditions, Bollgard cotton generated statistically similar numbers of large (L4–L5) bollworm larvae compared with the conventional variety; however, Bollgard cotton produced significantly fewer damaged bolls and bollworm adults than the conventional variety. Production of large larvae, damaged bolls, and adults was decreased dramatically by Bollgard II cotton as compared with Bollgard and conventional varieties. When comparing insecticide-treated and nontreated cotton genotypes, both Bt cotton sustained less boll damage than the conventional variety averaged across insecticide regimes; furthermore, Bollgard II cotton had fewer damaged bolls than the Bollgard variety. When averaged across cotton genotypes, pyrethroid oversprays reduced the numbers of damaged bolls compared with the nontreated cotton. Insecticide-treated Bollgard cotton, along with insecticide-treated and nontreated Bollgard II cotton reduced production of bollworm larvae, pupae, and adults. However, the addition of pyrethroid oversprays to Bollgard II cotton seemed to be the best resistance management strategy available for bollworm because no bollworms were capable of completing development under these conditions.}, number={5}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Jackson, RE and Bradley, JR and Van Duyn, JW and Gould, F}, year={2004}, month={Oct}, pages={1719–1725} }
 @article{jackson_bradley_van duyn_2004, title={Performance of feral and Cry1Ac-selected Helicoverpa zea (Lepidoptera : Noctuidae) strains on transgenic cottons expressing one or two Bacillus thuringiensis ssp kurstaki proteins under greenhouse conditions}, volume={39}, ISSN={["0749-8004"]}, DOI={10.18474/0749-8004-39.1.46}, abstractNote={Efficacy of Bollgard (DP50B) and Bollgard II (DP50BX) cottons that express either one or two Bacillus thuringiensis Berliner proteins, respectively, along with the conventional sister genotype (DP50), was determined for a feral strain of bollworm, Helicoverpa zea (Boddie), and a Cry1Ac-selected bollworm strain in 1999. In 2000, a greenhouse study was designed to compare the efficacy of three transgenic cottons expressing either the Cry1Ac endotoxin alone (DP50B), the Cry2Ab endotoxin alone (DP50X), or both the CrylAc and Cry2Ab endotoxins (DP50BX) against a feral and a Cry1Ac-selected bollworm strain. Results from the 1999 greenhouse study evaluating both a feral and a Cry1Ac-selected bollworm strain demonstrated that when averaged across bollworm strains, the Bollgard II genotype significantly reduced larval survival and fruit penetration by bollworm compared to the Bollgard variety. Also, the Cry1Ac-selected bollworm strain displayed increased larval survival, superficial fruit damage, and fruit penetration compared to the feral strain when averaged across genotypes. In the 2000 study, the Bollgard II genotype significantly reduced fruit penetration by bollworm below that of the Bollgard variety when averaged across strains; however, the single Cry2Ab-producing genotype performed similarly to both Bollgard and Bollgard II with respect to fruit penetration. The Cry1Ac-selected bollworm strain exhibited significantly greater larval survival and superficial fruit damage on the Bollgard variety compared to the feral strain, but no differences among larval strains were evident for other genotypes. Also, when averaged across genotypes, the Cry1Ac-selected bollworm strain penetrated a higher proportion of cotton fruit compared to the feral strain. These results suggest that commercialization of Bollgard II cottons would significantly reduce bollworm survival and damage compared to that experienced by current Bollgard varieties. Bollgard II plantings also should have a positive impact on Bt resistance management of bollworm.}, number={1}, journal={JOURNAL OF ENTOMOLOGICAL SCIENCE}, author={Jackson, RE and Bradley, JR and Van Duyn, JW}, year={2004}, month={Jan}, pages={46–55} }
 @article{burd_gould_bradley_van duyn_moar_2003, title={Estimated frequency of nonrecessive Bt resistance genes in bollworm, Helicoverpa zea (Boddie) (Lepidoptera : Noctuidae) in eastern North Carolina}, volume={96}, ISSN={["0022-0493"]}, DOI={10.1603/0022-0493-96.1.137}, abstractNote={Abstract In summer 2000, adult female bollworm moths, Helicoverpa zea (Boddie), were collected from light-traps at four locations near the Tidewater Research Station, Plymouth, NC. Female moths were allowed to lay eggs, and at hatch, 72 larvae from each female were screened for growth rate on normal artificial diet and on diets containing 5.0 μg of either Cry1Ac or Cry2Aa Bt toxin per milliliter of diet. The growth rate bioassays were performed to isolate nonrecessive Bt resistance genes present in field populations of bollworm. We found one individual out of 583 screened that appeared to carry a major gene for resistance to Cry1Ac. Assuming four alleles per individual, the gene frequency is 1/2332 or 0.00043. Other females appeared to have minor genes for Cry1Ac resistance or major genes with lower levels of dominance. We also found one individual out of 646 screened that appeared to carry a major gene for resistance to Cry2Aa. The gene frequency for Cry2Aa resistance was estimated at 1/2584 or 0.00039. Again, other females seemed to carry additional minor resistance genes. Along with other results that indicate partially dominant inheritance of Cry1Ac resistance in bollworm, these allele frequency estimates are important for determining the rate of resistance evolution in H. zea to specific Bt toxins.}, number={1}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Burd, AD and Gould, F and Bradley, JR and Van Duyn, JW and Moar, WJ}, year={2003}, month={Feb}, pages={137–142} }
 @article{faircloth_edmisten_bradley_2003, title={Whitefringed beetles (Graphognathus spp.) damage to North Carolina cotton}, volume={38}, ISSN={["0749-8004"]}, DOI={10.18474/0749-8004-38.1.140}, abstractNote={Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Joel C. Faircloth, Keith L. Edmisten, J. R. Bradley; Whitefringed Beetles (Graphognathus spp.) Damage to North Carolina Cotton. Journal of Entomological Science 1 January 2003; 38 (1): 140. doi: https://doi.org/10.18474/0749-8004-38.1.140 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest Search}, number={1}, journal={JOURNAL OF ENTOMOLOGICAL SCIENCE}, author={Faircloth, JC and Edmisten, KL and Bradley, JR}, year={2003}, month={Jan}, pages={140–140} }
 @article{faircloth_bradley_van duyn_2002, title={Effect of insecticide treatments and environmental factors on thrips populations, plant growth and yield of cotton}, volume={37}, ISSN={["0749-8004"]}, DOI={10.18474/0749-8004-37.4.308}, abstractNote={Field experiments were conducted in 1997–1999 in Washington Co., NC, to examine how cotton, Gossypium hirsutum, is affected by thrips species composition and abundance, environmental factors, and insecticide applications. Populations of adult and juvenile thrips were monitored in seedling cotton treated with insecticide applications of either imidacloprid as a seed treatment, acephate as a foliar spray, or aldicarb applied in-furrow. The number of plants per 3.05 row-m, location of the first fruiting branch, number of open bolls per 1.52 row-m, yields, accumulated degree-d 60′s (DD60′s), and accumulated rainfall were recorded each year the studies were conducted. Aldicarb and acephate provided better thrips control than did imidacloprid in all 3 yrs. Thrips species ratios differed among years. In 1997, the aldicarb treatment resulted in a better “earliness profile” (lower fruit set and more early opening bolls) than either acephate or imidacloprid, while in 1998 and 1999 there were few differences in these plant parameters. In 1997, all insecticide treatments resulted in statistically higher yields compared with the untreated check. Accumulated DD60′s were consistently higher in 1998 and 1999 than in 1997 after the first thrips sampling date. Cumulative rainfall appeared to be inversely associated with juvenile thrips populations.}, number={4}, journal={JOURNAL OF ENTOMOLOGICAL SCIENCE}, author={Faircloth, JC and Bradley, JR and Van Duyn, JW}, year={2002}, month={Oct}, pages={308–316} }
 @article{agi_burd_bradley_van duyn_2001, title={Planting date effects on hellothine larval numbers, fruit damage, and yield of transgenic B.t. cotton in North Carolina}, volume={36}, ISSN={["0749-8004"]}, DOI={10.18474/0749-8004-36.4.402}, abstractNote={The susceptibility of Bollgard® cotton and non-B.t. cotton to bollworm, Helicoverpa zea (Boddie), was examined under contrasting crop management strategies in northeastern North Carolina in 1995, 1996, and 1998. Specifically, planting date effects were observed in Edgecombe Co. in 1995 and 1996, in Martin Co. in 1996, and in Washington Co. in 1998. The bollworm was the only lepidopterous pest which occurred at damaging levels in these tests. Although no significant differences were detected in mean percent egg deposition, mean percent larval infestation, and mean percent damaged fruit between early-planted and late-planted plots in 1995 and 1996, yields were higher in early-planted cotton than in late-planted cotton. In 1998 mean percent damaged fruit was higher in early-planted cotton than in late-planted cotton, but early-planted cotton had significantly higher yields than late-planted cotton. Early planting may be an effective management strategy for Bollgard® cotton in northeastern North Carolina.}, number={4}, journal={JOURNAL OF ENTOMOLOGICAL SCIENCE}, author={Agi, AL and Burd, A and Bradley, JR and Van Duyn, JW}, year={2001}, month={Oct}, pages={402–410} }
 @article{faircloth_bradley_van duyn_groves_2001, title={Reproductive success and damage potential of tobacco thrips and western flower thrips on cotton seedlings in a greenhouse environment}, volume={18}, number={3}, journal={Journal of Agricultural and Urban Entomology}, author={Faircloth, J. C. and Bradley, J. R. and Van Duyn, J. W. and Groves, R. L.}, year={2001}, pages={179–185} }
 @article{bradley_2000, title={Integrating new insecticide technologies in IPM}, ISBN={0890542465}, journal={Emerging technologies for integrated pest management : concepts, research, and implementation}, publisher={St. Paul, MN : APS Press,}, author={Bradley, J. R., Jr.}, year={2000}, pages={384} }
 @article{performance of selected bt cotton genotypes against bollworm in north carolina_1999, volume={2}, number={1999}, journal={Beltwide Cotton Conferences. Proceedings}, year={1999}, pages={931–934} }
 @article{lambert_bradley_gould_van duyn_1998, title={Bollworm (Helicoverpa zea): adaptation to BT toxin?}, volume={2}, number={1998}, journal={Beltwide Cotton Conferences. Proceedings}, author={Lambert, A. L. and Bradley, J. R., Jr. and Gould, F. and Van Duyn, J. W.}, year={1998}, pages={1033–1037} }
 @article{koenning_coble_bradley_barker_schmitt_1998, title={Effects of a low rate, of aldicarb on soybean and associated pest interactions in fields infested with Heterodera glycines}, volume={28}, number={2}, journal={Nematropica}, author={Koenning, S. R. and Coble, H. D. and Bradley, J. R. and Barker, K. R. and Schmitt, D. P.}, year={1998}, pages={205–211} }
 @article{bradley_1998, title={New approaches to insect control}, volume={1}, number={1998}, journal={Beltwide Cotton Conferences. Proceedings}, author={Bradley, J. R.}, year={1998}, pages={17–18} }
 @article{interactions of helicoverpa zea and bt cotton in north carolina_1997, volume={2}, number={1997}, journal={Beltwide Cotton Conferences. Proceedings}, year={1997}, pages={870–873} }
 @article{bradley_1996, title={Boll weevil eradication: Economic benefits to North Carolina and program status}, number={178}, journal={Special Report (University of Arkansas, Fayetteville. Agricultural Experiment Station)}, author={Bradley, J. R., Jr.}, year={1996}, pages={40} }
 @article{bradley_1996, title={Controlling cotton pests}, volume={273}, DOI={10.1126/science.273.5282.1642a}, abstractNote={Letters from: 

[ W. Randy Deaton ][1] 

[ Marvin K. Harris ][1] 

[ J. R. Bradley Jr. ][1] 

Contrary to the characterization in Jocelyn Kaiser's article “Pests overwhelm Bt cotton crop” (News & Comment, [26 July, p. 423][2]), the Bollgard Bacillus thuringiensis ( Bt ) gene by Monsanto is providing economic and environmental benefits to cotton growers and is performing as expected given this year's severe pest conditions.

Bollgard was evaluated in 6 years of field tests before commercialization. The vast majority of these tests were done in full public view by scientists at the U.S. Department of Agriculture, universities, and extension facilities. Control of the pests targeted for this product—tobacco budworm, pink bollworm, and bollworm—was excellent. In a few of the field tests, high infestation levels have required application of pesticides to supplement the control provided by the Bt gene.

Monsanto is well aware of the potential for pests to adapt to the Bt protein. Because we—along with many others—have much to lose if this happens, we have worked long and hard with resistance management experts to develop strategies to delay the onset of resistance. Strategies vary depending on the insect involved. With the bollworm, the key strategy is refugia, host plants where the insect can escape exposure to the Bt protein. Nonselected populations that develop on these refuges help dilute and suppress any resistance genes that may develop in the Bollgard fields. The bollworm has a multitude of hosts—both wild and crop plants. With Bollgard, resistance management is taken even further by requiring growers to plant refuges with cotton that does not contain the Bollgard gene. When both the natural and mandated refuges are combined, resistance development in the bollworm can be delayed significantly.

# {#article-title-2}

The bollworm outbreak on Bt cotton is not a manifestation of physiological resistance predicted in 1991 ([1][3]); rather, the epidemic apparently arises from extant populations that have the inherent ability to discriminate among tissues with varying concentrations of the toxin within a plant. Whereas physiological resistance in insects to pesticides and plant resistance (biotypes) is well documented ([2][4]), inherent behavioral capabilities of insects to discriminate in a toxin mosaic superimposed on their host or habitat is not well understood ([3][5]). Insect-resistant transgenic plants appear to provide an ideal substrate in which entomologists can explore this previously recalcitrant and otherwise neglected subject. Nonlethal repellency of preadapted populations from human-valued resource tissues to yield insensitive tissues offers the prospect of conserving the extant insect genome by these intraplant refugia and of increasing mortality in cannibalistic species by concentrating populations in smaller areas. Realization of such possibilities would be accelerated if prepared minds were combined with proprietary technology in a context of production agriculture.

1. 1.[↵][6] 1. M. K. Harris
 , Science 253, 1075 (1991).
 [OpenUrl][7][CrossRef][8][PubMed][9][Web of Science][10]

2. 2.[↵][11] 1. R. L. Metcalf, 2. R. A. Metcalf
 , Destructive and Useful Insects McGraw-Hill New York 1993 7.42 7.47; Biology and Breeding for Resistance M. Harris, Ed. (Texas Department of Agriculture Commission, Texas A&M University, College Station, TX, 1980).
 

3. 3.[↵][12] 1. A. Brown, 2. J. Haworth, 3. A. Zahar
 , J. Med. Entomol. 13, 4 (1976).
 [OpenUrl][13]

# {#article-title-3}

It is regrettable, but not surprising, that Bt cotton in its initial year of commercialization has fallen victim to the bollworm. During 1994, when bollworm numbers were extremely high in North Carolina, peak boll damage and yield reductions in two of our Bt cotton tests exceeded 20% ([1][3]).

Our data ([1][3], [2][4]) were summarily ignored in favor of data acquired when there were low numbers of “wild” bollworms or from test sites artificially infested with laboratory-cultured larvae. The wave of euphoria created by Bt cotton swept across the cottonbelt and carried many entomologists with it.

In Bt cotton, biotechnology has provided cotton farmers with a most powerful tool to assist in the management of insect pests; however, for success and sustainability the tool must be strategically integrated with other management tactics into systems designed for specific areas.

1. 1. 1. J. S. Mahaffey, 2. J. R. Bradley Jr., 3. J. W. Van Duyn
 , Proc. 1995 Beltwide Cotton Conf. 2, 795 (1995).
 [OpenUrl][14]

2. 2. 1. J. S. Mahaffey, 2. J. S. Bacheler, 3. J. R. Bradley Jr., 4. J. W. Van Duyn
 , Proc. 1994 Beltwide Cotton Conf. 2, 1061 (1994);
 [OpenUrl][15]
 1. A. L. Lambert, 2. J. R. Bradley Jr., 3. J. W. Van Duyn
 , Proc. 1996 Beltwide Cotton Conf. 1, 931 (1996).

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 @inbook{bradley_vab duyn_1980, title={Insect pest management in North Carolina soybeans}, ISBN={0891586784}, booktitle={World Soybean Research Conference II: Proceeding}, publisher={Boulder, Colorado:  Westview Press Inc}, author={Bradley, J. R., Jr. and Vab Duyn, J. W.}, year={1980}, pages={343} }