@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{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{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} }