@article{jones_andres_owen_dunne_contreras_cahoon_jennings_leon_everman_2023, title={Confirmation of a five-way herbicide-resistant Amaranthus tuberculatus population in North Carolina}, volume={7}, ISSN={["1365-3180"]}, url={https://doi.org/10.1111/wre.12590}, DOI={10.1111/wre.12590}, abstractNote={Amaranthus tuberculatus (waterhemp) is a pervasive weed of the Mid-west and -south United States and is not native to North Carolina but infestations in crop fields have been reported recently. Amaranthus tuberculatus has evolved resistance to seven herbicide groups and multiple herbicide-resistant populations are common where the species is native. The reported A. tuberculatus infestations in North Carolina have not been controlled with herbicides but no formal herbicide resistance characterisation has been conducted to date. Glasshouse dose–response experiments were conducted to determine the susceptibility of a population collected from Surry County, North Carolina to commonly applied postemergence herbicides compared to a herbicide-susceptible population collected from Story County, Iowa. The Surry County population survived labelled rates of imazethapyr, atrazine, glyphosate, fomesafen, and mesotrione; the Story County population was controlled with these herbicides. Further, 2,4-D, dicamba, and glufosinate effectively controlled the Surry and Story County populations. Molecular sequencing assays were subsequently conducted to determine if altered target sites facilitated resistance in the acetolactate synthase (ALS), 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), photosystem II (psbA), and protoporphyrinogen oxidase (PPX2) genes. The Surry County population carried a Trp574Leu and ∆Gly210 mutations in the ALS and PPX2 gene, respectively. No mutations that would confer resistance were found in the EPSPS or psbA gene for either population. The results of both experiments provide evidence that a five-way herbicide-resistant A. tuberculatus population has encroached North Carolina. More research is needed to determine the mechanisms of resistance to atrazine, glyphosate, and mesotrione.}, journal={WEED RESEARCH}, author={Jones, Eric A. L. and Andres, Ryan J. and Owen, Micheal D. K. and Dunne, Jeffrey C. and Contreras, Diego J. and Cahoon, Charles W. and Jennings, Katherine M. and Leon, Ramon G. and Everman, Wesley J.}, year={2023}, month={Jul} } @article{clapp_vann_cahoon_jordan_fisher_inman_2022, title={Evaluations of S-Metolachlor in flue-cured tobacco weed management programs}, volume={114}, ISSN={["1435-0645"]}, url={https://doi.org/10.1002/agj2.20984}, DOI={10.1002/agj2.20984}, abstractNote={Effective weed control is critical to growth and development of flue-cured tobacco; however, current herbicide options are limited in commercial production. Field experiments were conducted from 2017 to 2018 to evaluate S-metolachlor for use in flue-cured tobacco weed management programs. Treatments included 10 herbicide programs: pretransplanted incorporated (PTI) applications of S-metolachlor (1.07 kg a.i. ha–1) alone or in various combinations with sulfentrazone (0.18 kg a.i. ha–1), clomazone (0.84 kg a.i. ha–1), and pendimethalin (0.79 kg a.i. ha–1). S-metolachlor and pendimethalin were also applied posttransplanting directed to row middles (POST-DIR) following PTI applications of sulfentrazone + clomazone. A single posttransplanting over-the-top (POST-OT) application of S-metolachlor and a non-treated control were included for comparison. The inclusion of S-metolachlor in PTI herbicide programs did not improve weed control beyond the combination of sulfentrazone + clomazone. However, weed control after final harvest was improved by 8%, when S-metolachlor was applied POST-DIR. S-metolachlor applied POST-OT caused injury to tobacco plants (12%), although symptoms were transient with less than 2% visual injury 6 wk after transplanting. Due to increased weed control through harvest and the low injury potential, our results suggest that POST-DIR applications of S-metolachlor are the best fit for flue-cured tobacco production when used in conjunction with recommended PTI herbicide programs.}, number={2}, journal={AGRONOMY JOURNAL}, publisher={Wiley}, author={Clapp, Andrew M. and Vann, Matthew C. and Cahoon, Charles W. and Jordan, David L. and Fisher, Loren R. and Inman, Matt D.}, year={2022}, month={Feb} } @article{joyner_cahoon_everman_collins_taylor_blythe_2022, title={HPPD-resistant cotton response to isoxaflutole applied preemergence and postemergence}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2022.6}, abstractNote={Abstract Studies were conducted in 2019 and 2020 at Lewiston, NC to determine the crop response of 4-hydroxyphenylpyrivate dioxygenase (HPPD)-resistant cotton to IFT and other cotton herbicides as part of a cotton weed management program, which included PRE, early-POST (EPOST), and mid-POST (MPOST) herbicides. Isoxaflutole (IFT) was applied PRE at 105 g ha -1 alone and in various combinations with acetochlor, diuron, fluometuron, fluometuron, fluridone, fomesafen, pendimethalin, and pyrithiobac. Early POST treatments included IFT at 53 or 105 g ha -1 alone or in combination with glyphosate or glufosinate, or dimethenamid- P + glufosinate. Glyphosate + glufosinate was applied mid-postemergenceT to all treatments except the nontreated control. Cotton injury from IFT PRE was minimal (0 to 3%). Injury following EPOST dimethenamid- P + glufosinate ranged 3 to 5% and 6 to 9% in 2019 and 2020, respectively. In both years, injury from IFT PRE followed by IFT EPOST never exceeded injury from IFT PRE followed by dimethenamid- P + glufosinate. Isoxaflutole fb IFT EPOST at 105 g ha -1 resulted in 0 to 2% cotton injury, indicating IFT can be applied PRE or EPOST with minimal risk to cotton. Late-season cotton height and cotton lint yield were not affected by any herbicide treatment. The experimental HPPD-resistant cotton cultivar was minimally injured by IFT PRE and EPOST, tolerated standard cotton herbicides, and yield loss was not observed. Given these results, HPPD-resistant cotton and IFT may be integrated into cotton weed management systems with minimal risk for cotton injury and provide an additional effective mechanism of action for managing troublesome weeds in cotton.}, journal={WEED TECHNOLOGY}, author={Joyner, Joshua D. and Cahoon, Charles W. and Everman, Wesley J. and Collins, Guy D. and Taylor, Zachary R. and Blythe, Andrew C.}, year={2022}, month={Feb} } @article{cahoon_jordan_tranel_york_riggins_seagroves_inman_everman_leon_2022, title={In-field assessment of EPSPS amplification on fitness cost in mixed glyphosate-resistant and glyphosate-sensitive populations of Palmer amaranth (Amaranthus palmeri)}, volume={10}, ISSN={["1550-2759"]}, url={https://doi.org/10.1017/wsc.2022.60}, DOI={10.1017/wsc.2022.60}, abstractNote={Abstract Comparing fitness of herbicide-resistant and herbicide-susceptible weed biotypes is important for managing herbicide resistance. Previous research suggests there is little to no fitness penalty from amplification of the 5-enolpyruvylshikimate-3-phosphate synthase ( EPSPS ) gene (a mechanism of glyphosate resistance) in Palmer amaranth ( Amaranthus palmeri S. Watson) in controlled studies in the greenhouse or growth chamber. A field study was conducted in North Carolina at three locations naturally infested with A. palmeri to determine vegetative, reproductive, and germination fitness of plants with and without EPSPS amplification grown season-long with cotton ( Gossypium hirsutum L.). Seed number was not correlated with EPSPS copy number. However, when plants were binned into two groups, those having an EPSPS copy number ≥2 (relative to reference genes) and those having an EPSPS copy number <2, plant fresh weight and seed number were 1.4 and 1.6 times greater, respectively, for plants with fewer than 2 EPSPS copies. Amaranthus palmeri height and seed germination, and yield of cotton, did not differ when comparing the two binned groups. These data suggest that A. palmeri plants with EPSPS amplification are relatively less fit in the absence of glyphosate, but this reduced fitness does not translate into differences in interference with cotton.}, journal={WEED SCIENCE}, author={Cahoon, Charles W. and Jordan, David L. and Tranel, Patrick J. and York, Alan C. and Riggins, Chance and Seagroves, Richard and Inman, Matthew and Everman, Wesley and Leon, Ramon}, year={2022}, month={Oct} } @article{jones_cahoon_leon_everman_2022, title={Surveying stakeholder's perception of glufosinate and use in North Carolina}, volume={5}, ISSN={["1550-2740"]}, url={https://doi.org/10.1017/wet.2022.31}, DOI={10.1017/wet.2022.31}, abstractNote={Abstract Glufosinate is among the few remaining effective herbicides for postemergence weed control in North Carolina crops. The evolution of glufosinate resistance in key weeds is currently not widespread in North Carolina, but to better assess the current status of glufosinate effectiveness, surveys were distributed at Extension meetings in 2019 and 2020. The surveys were designed to provide information about North Carolina farmers’ perception of glufosinate and its use. Survey results indicate that many North Carolina farmers (≥26%) apply glufosinate at the correct timing (5- to 10-cm weeds). In addition, North Carolina farmers (≥22%) are applying glufosinate as a complementary herbicide to other efficacious herbicides and to control herbicide-resistant weeds, suggesting that glufosinate is part of a diverse chemical weed management plan. Conversely, survey findings indicated that some farmers (13% to 17%) rely exclusively on glufosinate for weed control. Additionally, 28% to 30% of farmers reported glufosinate control failures, and control failures were observed on several weed species among corn, cotton, and soybean crops. The results of the survey suggest that most North Carolina farmers are currently stewarding glufosinate, but they also support the need for Extension personnel to keep educating farmers on how to correctly use glufosinate to delay the evolution of glufosinate-resistant weeds. Semiannual surveys should be distributed to monitor where glufosinate control failures occur and the weed species not being controlled.}, journal={WEED TECHNOLOGY}, author={Jones, Eric A. L. and Cahoon, Charles W. and Leon, Ramon G. and Everman, Wesley J.}, year={2022}, month={May} } @article{jones_austin_dunne_cahoon_jennings_leon_everman_2022, title={Utilization of image-based spectral reflectance to detect herbicide resistance in glufosinate-resistant and glufosinate-susceptible plants: a proof of concept}, volume={12}, ISSN={["1550-2759"]}, url={https://doi.org/10.1017/wsc.2022.68}, DOI={10.1017/wsc.2022.68}, abstractNote={Abstract Glufosinate is an effective postemergence herbicide, and overreliance on this herbicide for weed control is likely to increase and select for glufosinate-resistant weeds. Common assays to confirm herbicide resistance are dose–response and molecular sequencing techniques; both can require significant time, labor, unique technical equipment, and a specialized skillset to perform. As an alternative, we propose an image-based approach that uses a relatively inexpensive multispectral sensor designed for unmanned aerial vehicles to measure and quantify surface reflectance from glufosinate-treated leaf disks. Leaf disks were excised from a glufosinate-resistant and glufosinate-susceptible corn ( Zea mays L.), cotton ( Gossypium hirsutum L.), and soybean [ Glycine max (L.) Merr.] varieties and placed into a 24-well plate containing eight different concentrations (0 to 10 mM) of glufosinate for 48 h. Multispectral images were collected after the 48-h incubation period across five discrete wave bands: blue (475 to 507 nm), green (560 to 587 nm), red (668to 682 nm), red edge (717 to 729 nm), and near infrared (842 to 899 nm). The green leaf index (GLI; a metric to measure chlorophyll content) was utilized to determine relationships between measured reflectance from the tested wave bands from the treated leaf disks and the glufosinate concentration. Clear differences of spectral reflectance were observed between the corn, cotton, and soybean leaf disks of the glufosinate-resistant and glufosinate-susceptible varieties at the 10 mM concentration for select wave bands and GLI. Leaf disks from two additional glufosinate-resistant and glufosinate-susceptible varieties of each crop were subjected to a similar assay with two concentrations: 0 and 10 mM. No differences of spectral reflectance were observed from the corn and soybean varieties in all wave bands and the GLI. The leaf disks of the glufosinate-resistant and glufosinate-susceptible cotton varieties were spectrally distinct in the green, blue, and red-edge wave bands. The results provide a basis for rapidly detecting glufosinate-resistant plants via spectral reflectance. Future research will need to determine the glufosinate concentrations, useful wave bands, and susceptible/resistant thresholds for weeds that evolve resistance.}, journal={WEED SCIENCE}, author={Jones, Eric A. L. and Austin, Robert and Dunne, Jeffrey C. and Cahoon, Charles W. and Jennings, Katherine M. and Leon, Ramon G. and Everman, Wesley J.}, year={2022}, month={Dec} } @article{askew_cahoon_york_flessner_langston_ferebee_2021, title={Comparison of 2,4-D, dicamba and halauxifen-methyl alone or in combination with glyphosate for preplant weed control}, volume={35}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2020.83}, abstractNote={Abstract A field study was conducted in 2017 and 2018 to determine foliar efficacy of halauxifen-methyl, 2,4-D, or dicamba applied alone and in combination with glyphosate at preplant burndown timing. Experiments were conducted near Painter, VA; Rocky Mount, NC; Jackson, NC; and Gates, NC. Control of horseweed, henbit, purple deadnettle, cutleaf evening primrose, curly dock, purple cudweed, and common chickweed were evaluated. Halauxifen-methyl applied at 5 g ae ha −1 controlled small and large horseweed 89% and 79%, respectively, and was similar to control by dicamba applied at 280 g ae ha −1 . Both rates of 2,4-D—533 g ae ha −1 (low rate [LR]) or 1,066 g ae ha −1 (high rate [HR])—were less effective than halauxifen-methyl and dicamba for controlling horseweed. Halauxifen-methyl was the only auxin herbicide to control henbit (90%) and purple deadnettle (99%). Cutleaf evening primrose was controlled 74% to 85%, 51%, and 4% by 2,4-D, dicamba, and halauxifen-methyl, respectively. Dicamba and 2,4-D controlled curly dock 59% to 70% and were more effective than halauxifen-methyl (5%). Auxin herbicides applied alone controlled purple cudweed and common chickweed 21% or less. With the exception of cutleaf evening primrose (35%) and curly dock (37%), glyphosate alone provided 95% or greater control of all weeds evaluated. These experiments demonstrate halauxifen-methyl effectively (≥79%) controls horseweed, henbit, and purple deadnettle, whereas common chickweed, curly dock, cutleaf evening primrose, and purple cudweed control by the herbicide is inadequate (≤7%).}, number={1}, journal={WEED TECHNOLOGY}, author={Askew, M. Carter and Cahoon, Charles W., Jr. and York, Alan C. and Flessner, Michael L. and Langston, David B., Jr. and Ferebee, J. Harrison}, year={2021}, month={Feb}, pages={93–98} } @article{mahoney_jordan_hare_leon_roma-burgos_vann_jennings_everman_cahoon_2021, title={Palmer Amaranth (Amaranthus palmeri) Growth and Seed Production When in Competition with Peanut and Other Crops in North Carolina}, volume={11}, ISSN={["2073-4395"]}, url={https://doi.org/10.3390/agronomy11091734}, DOI={10.3390/agronomy11091734}, abstractNote={Palmer amaranth (Amaranthus palmeri S. Wats.) is a highly competitive weed that can be difficult to manage in many cropping systems. Research to date has not quantified the growth and development of A. palmeri in a manner that allows direct comparisons across cropping systems. Research was conducted to compare the growth, development, and seed production of A. palmeri when competing with corn (Zea mays L.), cotton (Gossypium hirsutum L.), peanut (Arachis hypogaea L.), and soybean [Glycine max (L.) Merr.] when emerging with crops or emerging three weeks after crops emerge. Regardless of when A. palmeri emerged, seed production was greatest and similar in cotton and peanut and exceeded that of corn and soybean; seed production in soybean exceeded that of corn. However, seed production was approximately 10-fold greater when A. palmeri emerged with crops compared with emergence three weeks later. These results illustrate the importance of controlling weeds during the first three weeks of the season relative to contributions of A. palmeri to the weed seed bank and is the first report comparing seed production in presence of these crops in a manner allowing a statistical comparison of seed production and highlighting the importance of crop sequence for seed bank management.}, number={9}, journal={AGRONOMY-BASEL}, publisher={MDPI AG}, author={Mahoney, Denis J. and Jordan, David L. and Hare, Andrew T. and Leon, Ramon G. and Roma-Burgos, Nilda and Vann, Matthew C. and Jennings, Katherine M. and Everman, Wesley J. and Cahoon, Charles W.}, year={2021}, month={Sep} } @article{moore_jennings_monks_jordan_boyette_leon_mahoney_everman_cahoon_2021, title={Susceptibility of Palmer amaranth accessions in North Carolina to atrazine, dicamba, S-metolachlor, and 2,4-D}, volume={11}, ISSN={["2374-3832"]}, url={https://doi.org/10.1002/cft2.20136}, DOI={10.1002/cft2.20136}, abstractNote={Core Ideas All of the 120 accessions of Palmer amaranth collected in the Coastal Plain of North Carolina were controlled by atrazine and dicamba applied at field use rates in the greenhouse. Reduced sensitivity among accessions was noted when S ‐metolachlor and 2,4‐D were applied to Palmer amaranth at field use rates in the greenhouse. Additional research is needed to determine if reduced sensitivity of Palmer amaranth to S ‐metolachlor and 2,4‐D is associated with evolved resistance.}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, publisher={Wiley}, author={Moore, Levi D. and Jennings, Katherine M. and Monks, David W. and Jordan, David L. and Boyette, Michael D. and Leon, Ramon G. and Mahoney, Dennis J. and Everman, Wesley J. and Cahoon, Charles W.}, year={2021}, month={Nov} } @article{mahoney_jordan_hare_roma-burgos_jennings_leon_vann_everman_cahoon_2021, title={The influence of soybean population and POST herbicide application timing on in-season and subsequent-season Palmer amaranth (Amaranthus palmeri) control and economic returns}, volume={35}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2020.87}, abstractNote={Abstract Overreliance on herbicides for weed control has led to the evolution of herbicide-resistant Palmer amaranth populations. Farm managers should consider the long-term consequences of their short-term management decisions, especially when considering the soil weed seedbank. The objectives of this research were to (1) determine how soybean population and POST herbicide application timing affects in-season Palmer amaranth control and soybean yield, and (2) how those variables influence Palmer amaranth densities and cotton yields the following season. Soybeans were planted (19-cm row spacing) at a low-, medium-, and high-density population (268,000, 546,000, and 778,000 plants ha –1 , respectively). Fomesafen and clethodim (280 and 210 g ai ha –1 , respectively) were applied at the VE, V1, or V2 to V3 soybean growth stage. Nontreated plots were also included to assess the effect of soybean population alone. The following season, cotton was planted into these plots so as to understand the effects of soybean planting population on Palmer amaranth densities in the subsequent crop. When an herbicide application occurred at the V1 or V2 to V3 soybean stage, weed control in the high-density soybean population increased 17% to 23% compared to the low-density population. Economic return was not influenced by soybean population and was increased 72% to 94% with herbicide application compared to no treatment. In the subsequent cotton crop, Palmer amaranth densities were 24% to 39% lower 3 wk after planting when following soybean sprayed with herbicides compared to soybean without herbicides. Additionally, Palmer amaranth densities in cotton were 19% lower when soybean was treated at the VE stage compared to later stages. Thus, increasing soybean population can improve Palmer amaranth control without adversely affecting economic returns and can reduce future weed densities. Reducing the weed seedbank and selection pressure from herbicides are critical in mitigating resistance evolution.}, number={1}, journal={WEED TECHNOLOGY}, author={Mahoney, Denis J. and Jordan, David L. and Hare, Andrew T. and Roma-Burgos, Nilda and Jennings, Katherine M. and Leon, Ramon G. and Vann, Matthew C. and Everman, Wesley J. and Cahoon, Charles W.}, year={2021}, month={Feb}, pages={106–112} } @article{rector_pittman_beam_bamber_cahoon_frame_flessner_2020, title={Herbicide carryover to various fall-planted cover crop species}, volume={34}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2019.79}, abstractNote={Abstract Residual herbicides applied to summer cash crops have the potential to injure subsequent winter annual cover crops, yet little information is available to guide growers’ choices. Field studies were conducted in 2016 and 2017 in Blacksburg and Suffolk, Virginia, to determine carryover of 30 herbicides commonly used in corn, soybean, or cotton on wheat, barley, cereal rye, oats, annual ryegrass, forage radish, Austrian winter pea, crimson clover, hairy vetch, and rapeseed cover crops. Herbicides were applied to bare ground either 14 wk before cover crop planting for a PRE timing or 10 wk for a POST timing. Visible injury was recorded 3 and 6 wk after planting (WAP), and cover crop biomass was collected 6 WAP. There were no differences observed in cover crop biomass among herbicide treatments, despite visible injury that suggested some residual herbicides have the potential to effect cover crop establishment. Visible injury on grass cover crop species did not exceed 20% from any herbicide. Fomesafen resulted in the greatest injury recorded on forage radish, with greater than 50% injury in 1 site-year. Trifloxysulfuron and atrazine resulted in greater than 20% visible injury on forage radish. Trifloxysulfuron resulted in the greatest injury (30%) observed on crimson clover in 1 site-year. Prosulfuron and isoxaflutole significantly injured rapeseed (17% to 21%). Results indicate that commonly used residual herbicides applied in the previous cash crop growing season result in little injury on grass cover crop species, and only a few residual herbicides could potentially affect the establishment of a forage radish, crimson clover, or rapeseed cover crop.}, number={1}, journal={WEED TECHNOLOGY}, author={Rector, Lucas S. and Pittman, Kara B. and Beam, Shawn C. and Bamber, Kevin W. and Cahoon, Charles W. and Frame, William H. and Flessner, Michael L.}, year={2020}, month={Feb}, pages={25–34} } @article{pittman_cahoon_bamber_rector_flessner_2020, title={Herbicide selection to terminate grass, legume, and brassica cover crop species}, volume={34}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2019.107}, abstractNote={Abstract Cover crops provide a number of agronomic benefits, including weed suppression, which is important as cases of herbicide resistance continue to rise. To effectively suppress weeds, high cover crop biomass is needed, which necessitates later termination timing. Cover crop termination is important to mitigate potential planting issues and prevent surviving cover crop competition with cash crops. Field studies were conducted in Virginia to determine the most effective herbicide options alone or combined with glyphosate or paraquat to terminate a range of cover crop species. Results revealed that grass cover crop species were controlled (94% to 98%) by glyphosate alone 4 wk after application (WAA). Overall, legume species varied in response to the single active-ingredient treatments, and control increased with the addition of glyphosate or paraquat. Mixes with glyphosate provided better control of crimson clover and hairy vetch by 7% to 8% compared with mixes containing paraquat 4 WAA. Mix partner did not influence control of Austrian winter pea. No treatment adequately controlled rapeseed in this study, with a maximum of 58% control observed with single active-ingredient treatments and 62% control with mixes. Height reduction for all cover crop species supports visible rating data. Rapeseed should be terminated when smaller, which could negate weed suppressive benefits from this cover crop species. Growers should consider herbicide selection and termination timing in their cover crop plan to ensure effective termination.}, number={1}, journal={WEED TECHNOLOGY}, author={Pittman, Kara B. and Cahoon, Charles W. and Bamber, Kevin W. and Rector, Lucas S. and Flessner, Michael L.}, year={2020}, month={Feb}, pages={48–54} } @article{hare_jordan_leon_edmisten_post_cahoon_everman_mahoney_inman_2020, title={Influence of timing and intensity of weed management on crop yield and contribution to weed emergence in cotton the following year}, volume={6}, ISSN={["2374-3832"]}, url={https://doi.org/10.1002/cft2.20021}, DOI={10.1002/cft2.20021}, abstractNote={Abstract Adequate weed control is important in protecting crop yield and allowing efficient harvest in North Carolina. Data in the literature are limited with respect to direct comparisons of weed control and yield across multiple crops. Research is also limited in terms of documenting the impact of weed control in one crop on weed populations in the crop planted the following season. Experiments were conducted in North Carolina to determine weed control and yield of corn ( Zea mays L.), cotton ( Gossypium hirsutum L.), and soybean [ Glycine max (L.) Merr.] in the same experiment when herbicides were applied postemergence at different timings (Year 1) and to determine how weed control translated into weed populations and cotton yield the following year (Year 2). Herbicides were applied 2 or 6 wk after planting (WAP); 2 and 4 WAP; 4 and 6 WAP; and 2, 4, and 6 WAP. At Lewiston‐Woodville, common ragweed ( Ambrosia artemisiifolia L.) and Texas millet ( Urochloa texana L.) were present. At Rocky Mount, Palmer amaranth ( Amanthus palmeri S. Wats) and large crabgrass ( Digitaria sanguinalis L.) were present. A single postemergence application of herbicide protected yield from weed interference in corn, whereas in most instances multiple herbicide applications were needed in cotton and to a degree in soybean. Weed densities in Year 2 in cotton were negatively correlated with weed control the previous year in corn, cotton, and soybean. Densities of common ragweed and Palmer amaranth 3 WAP in Year 2 were higher in cotton when the preceding crop was cotton or soybean rather than corn when herbicides were not applied; no difference was noted when comparing cotton and soybean. In some instances, sequential applications of herbicides resulted in lower weed densities the following year in cotton. These results demonstrate the importance of timely, sequential herbicide applications for weed control in cotton and soybean and in some instances the positive benefits on weed populations the following year in cotton.}, number={1}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, publisher={Wiley}, author={Hare, Andrew T. and Jordan, David L. and Leon, Ramon G. and Edmisten, Keith L. and Post, Angela R. and Cahoon, Charles W. and Everman, Wesley J. and Mahoney, Denis J. and Inman, Matthew D.}, year={2020} } @article{mahoney_jordan_roma-burgos_jennings_leon_vann_everman_cahoon_2020, title={Susceptibility of Palmer amaranth (Amaranthus palmeri) to herbicides in accessions collected from the North Carolina Coastal Plain}, volume={68}, ISSN={["1550-2759"]}, url={http://dx.doi.org/10.1017/wsc.2020.67}, DOI={10.1017/wsc.2020.67}, abstractNote={Abstract Palmer amaranth ( Amaranthus palmeri S. Watson) populations resistant to acetolactate synthase (ALS)-inhibiting herbicides and glyphosate are fairly common throughout the state of North Carolina (NC). This has led farm managers to rely more heavily on herbicides with other sites of action (SOA) for A. palmeri control, especially protoporphyrinogen oxidase and glutamine synthetase inhibitors. In the fall of 2016, seeds from A. palmeri populations were collected from the NC Coastal Plain, the state’s most prominent agricultural region. In separate experiments, plants with 2 to 4 leaves from the 110 populations were treated with field use rates of glyphosate, glufosinate-ammonium, fomesafen, mesotrione, or thifensulfuron-methyl. Percent visible control and survival were evaluated 3 wk after treatment. Survival frequencies were highest following glyphosate (99%) or thifensulfuron-methyl (96%) treatment. Known mutations conferring resistance to ALS inhibitors were found in populations surviving thifensulfuron-methyl application (Ala-122-Ser, Pro-197-Ser, Trp-574-Leu, and/or Ser-653-Asn), in addition to a new mutation (Ala-282-Asp) that requires further investigation. Forty-two populations had survivors after mesotrione application, with one population having 17% survival. Four populations survived fomesafen treatment, while none survived glufosinate. Dose–response studies showed an increase in fomesafen needed to kill 50% of two populations (LD 50 ); however, these rates were far below the field use rate (less than 5 g ha −1 ). In two populations following mesotrione dose–response studies, a 2.4- to 3.3-fold increase was noted, with LD 90 values approaching the field use rate (72.8 and 89.8 g ha −1 ). Screening of the progeny of individuals surviving mesotrione confirmed the presence of resistance alleles, as there were a higher number of survivors at the 1X rate compared with the parent population, confirming resistance to mesotrione. These data suggest A. palmeri resistant to chemistries other than glyphosate and thifensulfuron-methyl are present in NC, which highlights the need for weed management approaches to mitigate the evolution and spread of herbicide-resistant populations.}, number={6}, journal={WEED SCIENCE}, publisher={Cambridge University Press (CUP)}, author={Mahoney, Denis J. and Jordan, David L. and Roma-Burgos, Nilda and Jennings, Katherine M. and Leon, Ramon G. and Vann, Matthew C. and Everman, Wesley J. and Cahoon, Charles W.}, year={2020}, month={Nov}, pages={582–593} } @article{askew_cahoon_flessner_vangessel_langston_ferebee_2019, title={Chemical termination of cover crop rapeseed}, volume={33}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2019.50}, abstractNote={Abstract Rapeseed is a popular cover crop choice due to its deep-growing taproot, which creates soil macropores and increases water infiltration. Brassicaceae spp. that are mature or at later growth stages can be troublesome to control. Experiments were conducted in Delaware and Virginia to evaluate herbicides for terminating rapeseed cover crops. Two separate experiments, adjacent to each other, were established to evaluate rapeseed termination by 14 herbicide treatments at two timings. Termination timings included an early and late termination to simulate rapeseed termination prior to planting corn and soybean, respectively, for the region. At three locations where rapeseed height averaged 12 cm at early termination and 52 cm at late termination, glyphosate + 2,4-D was most effective, controlling rapeseed 96% 28 d after early termination (DAET). Paraquat + atrazine + mesotrione (92%), glyphosate + saflufenacil (91%), glyphosate + dicamba (91%), and glyphosate (86%) all provided at least 80% control 28 DAET. Rapeseed biomass followed a similar trend. Paraquat + 2,4-D (85%), glyphosate + 2,4-D (82%), and paraquat + atrazine + mesotrione (81%) were the only treatments that provided at least 80% control 28 d after late termination (DALT). Herbicide efficacy was less at Painter in 2017, where rapeseed height was 41 cm at early termination, and 107 cm at late termination. No herbicide treatments controlled rapeseed >80% 28 DAET or 28 DALT at this location. Herbicide termination of rapeseed is best when the plant is small; termination of large rapeseed plants may require mechanical of other methods beyond herbicides.}, number={5}, journal={WEED TECHNOLOGY}, author={Askew, M. Carter and Cahoon, Charles W., Jr. and Flessner, Michael L. and VanGessel, Mark J. and Langston, David B., Jr. and Ferebee, J. Harrison}, year={2019}, month={Oct}, pages={686–692} } @article{ferebee_cahoon_flessner_langston_arancibia_hines_blake_askew_2019, title={Comparison of Diquat, Glufosinate, and Saflufenacil for Desiccation of 'Dark Red Norland' Potato}, volume={29}, ISSN={["1943-7714"]}, DOI={10.21273/HORTTECH04327-19}, abstractNote={Chemical desiccants are commonly used to regulate tuber size, strengthen skin, and facilitate harvest for potato ( Solanum tuberosum ) production. Glufosinate is labeled for potato vine desiccation; however, limited data are available. Saflufenacil, a protoporphyrinogen oxidase–inhibiting herbicide, is an effective desiccant in other crops. Field research was conducted to evaluate glufosinate and saflufenacil as desiccants applied to ‘Dark Red Norland’ potato. Desiccants consisted of diquat, glufosinate, saflufenacil, glufosinate plus carfentrazone, and glufosinate plus saflufenacil applied at three timings, DESIC-1, DESIC-2, and DESIC-3, when size B potatoes averaged 43%, 31%, and 17% of total potato weight. Potato vine desiccation was more difficult at DESIC-1 and DESIC-2 because of immature vines. Diquat was the most effective desiccant 7 days after treatment (DAT), desiccating potato vines 88% at DESIC-1 7 DAT. Glufosinate alone desiccated potato vines 65% at the same timing; however, carfentrazone and saflufenacil added to glufosinate increased vine desiccation 8% and 16% compared with glufosinate alone, respectively. Vine desiccation by all treatments ranged 99% to 100% at 14 DAT. Desiccant and timing effects on skin set were determined using a torque meter before harvest. Skin set resulting from all desiccants and timings ranged between 1.88 and 2 lb-inch, and no significant differences were observed. No significant differences in yield were noted among desiccants. This research indicates that glufosinate and saflufenacil are suitable alternatives to diquat for potato vine desiccation; however, safety of saflufenacil applied to potatoes before harvest has not been determined.}, number={5}, journal={HORTTECHNOLOGY}, author={Ferebee, J. Harrison and Cahoon, Charles W. and Flessner, Michael L. and Langston, David B. and Arancibia, Ramon and Hines, Thomas E. and Blake, Hunter B. and Askew, M. Carter}, year={2019}, month={Oct}, pages={643–648} } @article{askew_cahoon_york_flessner_langston_ferebee_2019, title={Cotton tolerance to halauxifen-methyl applied preplant}, volume={33}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2019.41}, abstractNote={Abstract Auxin herbicides are used in combinations to control glyphosate-resistant horseweed preplant burndown. Herbicide labels for 2,4-D–containing products require a 30-d rotation interval for planting cotton cultivars not resistant to 2,4-D. Dicamba labels require an accumulation of 2.5 cm of rain plus 21 d per 280 g ae ha –1 rotation interval for planting cotton cultivars not resistant to dicamba. Previous research has shown that cotton injury caused by dicamba applied 14 d before planting was transient with little effect on cotton yield, whereas 2,4-D has little effect on cotton when applied 7 d prior to planting. Injury caused by dicamba and 2,4-D is inversely related to rainfall received between herbicide application and cotton planting. Experiments were conducted to evaluate cotton tolerance to halauxifen-methyl, a new Group 4 herbicide, applied at intervals shorter than labeled requirements. Experiments were established near Painter and Suffolk, VA, and Belvidere, Clayton, Eure, Lewiston, and Rocky Mount, NC, during the 2017 and 2018 growing seasons. Herbicide treatments included halauxifen, dicamba, and 2,4-D applied 4, 3, 2, 1, and 0 wk before planting (WBP). Visible estimates of cotton growth reduction and total injury were collected 1, 2, and 4 wk after cotton emergence (WAE). Cotton stand and percentage of plants with distorted leaves were recorded 2 and 4 WAE. Cotton plant heights were recorded 4 and 8 WAE. Halauxifen was less injurious (9%) than dicamba (26%) or 2,4-D (21%) 2 WAE when herbicides were applied 0 WBP. Cotton stand reduction 2 WAE by halauxifen was less than 2,4-D and dicamba when applied 0 WBP. Injury observed from herbicides applied 1, 2, 3, and 4 WBP was minor, and no significant differences in cotton stand were observed. Early-season cotton injury was transient, and seed cotton yield was unaffected by any treatment.}, number={4}, journal={WEED TECHNOLOGY}, author={Askew, M. Carter and Cahoon, Charles W., Jr. and York, Alan C. and Flessner, Michael L. and Langston, David B., Jr. and Ferebee, J. Harrison}, year={2019}, month={Aug}, pages={620–626} } @article{ferebee_cahoon_besancon_flessner_langston_hines_blake_askew_2019, title={Fluridone and acetochlor cause unacceptable injury to pumpkin}, volume={33}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2019.42}, abstractNote={Abstract Residual herbicides are routinely applied to control troublesome weeds in pumpkin production. Fluridone and acetochlor, Groups 12 and 15 herbicides, respectively, provide broad-spectrum PRE weed control. Field research was conducted in Virginia and New Jersey to evaluate pumpkin tolerance and weed control to PRE herbicides. Treatments consisted of fomesafen at two rates, ethalfluralin, clomazone, halosulfuron, fluridone, S -metolachlor, acetochlor emulsifiable concentrate (EC), acetochlor microencapsulated (ME), and no herbicide. At one site, fluridone, acetochlor EC, acetochlor ME, and halosulfuron injured pumpkin 81%, 39%, 34%, and 35%, respectively, at 14 d after planting (DAP); crop injury at the second site was 40%, 8%, 19%, and 33%, respectively. Differences in injury between the two sites may have been due to the amount and timing of rainfall after herbicides were applied. Fluridone provided 91% control of ivyleaf morningglory and 100% control of common ragweed at 28 DAP. Acetochlor EC controlled redroot pigweed 100%. Pumpkin treated with S -metolachlor produced the most yield (10,764 fruits ha –1 ) despite broadcasting over the planted row; labeling requires a directed application to row-middles. A separate study specifically evaluated fluridone applied PRE at 42, 84, 126, 168, 252, 336, and 672 g ai ha –1 . Fluridone resulted in pumpkin injury ≥95% when applied at rates of ≥168 g ai ha –1 ; significant yield loss was noted when the herbicide was applied at rates >42 g ai ha –1 . We concluded that fluridone and acetochlor formulations are unacceptable candidates for pumpkin production.}, number={5}, journal={WEED TECHNOLOGY}, author={Ferebee, J. Harrison and Cahoon, Charles W., Jr. and Besancon, Thierry E. and Flessner, Michael L. and Langston, David B. and Hines, Thomas E. and Blake, Hunter B. and Askew, M. Carter}, year={2019}, month={Oct}, pages={748–756} } @article{beam_mirsky_cahoon_haak_flessner_2019, title={Harvest weed seed control of Italian ryegrass [Lolium perenne L. ssp. multiflorum (Lam.) Husnot], common ragweed (Ambrosia artemisiifolia L.), and Palmer amaranth (Amaranthus palmeri S. Watson)}, volume={33}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2019.46}, abstractNote={Abstract Herbicide resistance is a major problem in United States and global agriculture, driving farmers to consider other methods of weed control. One of these methods is harvest weed seed control (HWSC), which has been demonstrated to be effective in Australia. HWSC studies were conducted across Virginia in 2017 and 2018, targeting Italian ryegrass in continuous winter wheat as well as common ragweed and Palmer amaranth in continuous soybean. These studies assessed the impact of HWSC (via weed seed removal) on weed populations in the next year’s crop compared with conventional harvest (weed seeds returned). HWSC reduced Italian ryegrass tillers compared with the conventional harvest at two locations in April (29% and 69%), but no difference was observed at a third location. At wheat harvest, HWSC at one location reduced Italian ryegrass seed heads (41 seed heads m −2 ) compared with conventional harvest (125 seed heads m −2 ). In soybean, before preplant herbicide applications and POST herbicide applications, HWSC reduced common ragweed densities by 22% and 26%, respectively, compared with the conventional harvest plots. By soybean harvest, no differences in common ragweed density, seed retention, or crop yield were observed, because of effectiveness of POST herbicides. No treatment differences were observed at any evaluation timing for Palmer amaranth, which is attributed to farmer weed management (i.e., effective herbicides) and low weed densities making any potential treatment differences difficult to detect. Across wheat and soybean, there were no differences observed in crop yield between treatments. Overall, HWSC was demonstrated to be a viable method to reduce Italian ryegrass and common ragweed populations.}, number={4}, journal={WEED TECHNOLOGY}, author={Beam, Shawn C. and Mirsky, Steven and Cahoon, Charlie and Haak, David and Flessner, Michael}, year={2019}, month={Aug}, pages={627–632} } @article{pittman_barney_cahoon_flessner_2019, title={Influence of hairy vetch seed germination and maturation on weediness in subsequent crops}, volume={59}, ISSN={["1365-3180"]}, DOI={10.1111/wre.12380}, abstractNote={Summary Hairy vetch is a widely adopted cover crop in the United States. However, hairy vetch can become weedy in subsequent crops as seeds germinate after the cover crop growing season, which is largely attributed to seed dormancy. We conducted two field experiments to determine seed germination, viability and seed production phenology of two common hairy vetch cultivars in Blacksburg and Blackstone, Virginia, US. ‘Groff’ and ‘Purple Bounty’ seed were sown in October 2015 and May 2016 and germination was tracked until June 2017. Subsequently, ungerminated seeds were tested for viability. Both cultivars had <2% germination after the initial germination period, and <1% of seed recovered was still viable at the end of the experiments. We also conducted experiments to determine when these cultivars produce viable seed. Hairy vetch seeds were counted and tested for germination in the spring. Both cultivars produced seed beginning in late‐May, but most seed were not viable until mid‐June in Virginia. Our results indicate that seed dormancy is not the primary cause of hairy vetch weediness in subsequent crops as nearly all germination, 99% of the total germinated seed, occurred during the cover crop growing season. Also, if complete termination occurs before mid‐June in Virginia, it is unlikely viable seed will be added to the seed bank. To better utilise this cover crop species, cultivar selection and proper termination are important to prevent weediness.}, number={6}, journal={WEED RESEARCH}, author={Pittman, K. B. and Barney, J. N. and Cahoon, C. W. and Flessner, M. L.}, year={2019}, month={Dec}, pages={427–436} } @article{braswell_cahoon_seagroves_jordan_york_2016, title={Integrating fluridone into a glufosinate-based program for Palmer amaranth control in cotton}, volume={20}, number={4}, journal={Journal of Cotton Science}, author={Braswell, L. R. and Cahoon, C. W. and Seagroves, R. W. and Jordan, D. L. and York, A. C.}, year={2016}, pages={394–402} } @article{soltani_dille_burke_everman_vangessel_davis_sikkema_2016, title={Potential Corn Yield Losses from Weeds in North America}, volume={30}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-16-00046.1}, abstractNote={Crop losses from weed interference have a significant effect on net returns for producers. Herein, potential corn yield loss because of weed interference across the primary corn-producing regions of the United States and Canada are documented. Yield-loss estimates were determined from comparative, quantitative observations of corn yields between nontreated and treatments providing greater than 95% weed control in studies conducted from 2007 to 2013. Researchers from each state and province provided data from replicated, small-plot studies from at least 3 and up to 10 individual comparisons per year, which were then averaged within a year, and then averaged over the seven years. The resulting percent yield-loss values were used to determine potential total corn yield loss in t ha −1 and bu acre −1 based on average corn yield for each state or province, as well as corn commodity price for each year as summarized by USDA-NASS (2014) and Statistics Canada (2015). Averaged across the seven years, weed interference in corn in the United States and Canada caused an average of 50% yield loss, which equates to a loss of 148 million tonnes of corn valued at over U.S.$26.7 billion annually.}, number={4}, journal={WEED TECHNOLOGY}, author={Soltani, Nader and Dille, J. Anita and Burke, Ian C. and Everman, Wesley J. and VanGessel, Mark J. and Davis, Vince M. and Sikkema, Peter H.}, year={2016}, pages={979–984} } @article{cahoon_york_jordan_seagroves_2015, title={Cotton response and Palmer amaranth control with mixtures of glufosinate and residual herbicides}, volume={19}, number={3}, journal={Journal of Cotton Science}, author={Cahoon, C. W. and York, A. C. and Jordan, D. L. and Seagroves, R. W.}, year={2015}, pages={622–630} } @article{cahoon_york_jordan_seagroves_everman_jennings_2015, title={Cotton response and Palmer amaranth control with pyroxasulfone applied preemergence and postemergence}, volume={19}, number={1}, journal={Journal of Cotton Science}, author={Cahoon, C. W. and York, A. C. and Jordan, D. L. and Seagroves, R. W. and Everman, W. J. and Jennings, K. M.}, year={2015}, pages={212–223} } @article{cahoon_york_jordan_seagroves_everman_jennings_2015, title={Fluridone carryover to rotational crops following application to cotton}, volume={19}, number={3}, journal={Journal of Cotton Science}, author={Cahoon, C. W. and York, A. C. and Jordan, D. L. and Seagroves, R. W. and Everman, W. J. and Jennings, K. M.}, year={2015}, pages={631–640} } @article{cahoon_york_jordan_everman_seagroves_culpepper_eure_2015, title={Palmer Amaranth (Amaranthus palmeri) Management in Dicamba-Resistant Cotton}, volume={29}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-15-00041.1}, abstractNote={Cotton growers rely heavily upon glufosinate and various residual herbicides applied preplant, PRE, and POST to control Palmer amaranth resistant to glyphosate and acetolactate synthase-inhibiting herbicides. Recently deregulated in the United States, cotton resistant to dicamba, glufosinate, and glyphosate (B2XF cotton) offers a new platform for controlling herbicide-resistant Palmer amaranth. A field experiment was conducted in North Carolina and Georgia to determine B2XF cotton tolerance to dicamba, glufosinate, and glyphosate and to compare Palmer amaranth control by dicamba to a currently used, nondicamba program in both glufosinate- and glyphosate-based systems. Treatments consisted of glyphosate or glufosinate applied early POST (EPOST) and mid-POST (MPOST) in a factorial arrangement of treatments with seven dicamba options (no dicamba, PRE, EPOST, MPOST, PRE followed by [fb] EPOST, PRE fb MPOST, and EPOST fb MPOST) and a nondicamba standard. The nondicamba standard consisted of fomesafen PRE, pyrithiobac EPOST, and acetochlor MPOST. Dicamba caused no injury when applied PRE and only minor, transient injury when applied POST. At time of EPOST application, Palmer amaranth control by dicamba or fomesafen applied PRE, in combination with acetochlor, was similar and 13 to 17% greater than acetochlor alone. Dicamba was generally more effective on Palmer amaranth applied POST rather than PRE, and two applications were usually more effective than one. In glyphosate-based systems, greater Palmer amaranth control and cotton yield were obtained with dicamba applied EPOST, MPOST, or EPOST fb MPOST compared with the standard herbicides in North Carolina. In contrast, dicamba was no more effective than the standard herbicides in the glufosinate-based systems. In Georgia, dicamba was as effective as the standard herbicides in a glyphosate-based system only when dicamba was applied EPOST fb MPOST. In glufosinate-based systems in Georgia, dicamba was as effective as standard herbicides only when dicamba was applied twice.}, number={4}, journal={WEED TECHNOLOGY}, author={Cahoon, Charles W. and York, Alan C. and Jordan, David L. and Everman, Wesley J. and Seagroves, Richard W. and Culpepper, A. Stanley and Eure, Peter M.}, year={2015}, pages={758–770} } @misc{cahoon_york_jordan_seagroves_everman_jennings_2015, title={Sequential and co-application of glyphosate and glufosinate in cotton}, volume={19}, number={2}, journal={Journal of Cotton Science}, author={Cahoon, C. W. and York, A. C. and Jordan, D. L. and Seagroves, R. W. and Everman, W. J. and Jennings, K. M.}, year={2015}, pages={337–350} } @article{cahoon_york_jordan_everman_seagroves_braswell_jennings_2015, title={Weed Control in Cotton by Combinations of Microencapsulated Acetochlor and Various Residual Herbicides Applied Preemergence}, volume={29}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-15-00061.1}, abstractNote={Residual herbicides are routinely recommended to aid in control of glyphosate-resistant (GR) Palmer amaranth in cotton. Acetochlor, a chloroacetamide herbicide, applied PRE, controls Palmer amaranth. A microencapsulated (ME) formulation of acetochlor is now registered for PRE application in cotton. Field research was conducted in North Carolina to evaluate cotton tolerance and Palmer amaranth control by acetochlor ME alone and in various combinations. Treatments, applied PRE, consisted of acetochlor ME, pendimethalin, or no herbicide arranged factorially with diuron, fluometuron, fomesafen, diuron plus fomesafen, and no herbicide. The PRE herbicides were followed by glufosinate applied twice POST and diuron plus MSMA directed at layby. Acetochlor ME was less injurious to cotton than pendimethalin. Acetochlor ME alone or in combination with other herbicides reduced early season cotton growth 5 to 8%, whereas pendimethalin alone or in combinations injured cotton 11 to 13%. Early season injury was transitory, and by 65 to 84 d after PRE treatment, injury was no longer noticeable. Before the first POST application of glufosinate, acetochlor ME and pendimethalin controlled Palmer amaranth 84 and 64%, respectively. Control by acetochlor ME was similar to control by diuron plus fomesafen and greater than control by diuron, fluometuron, or fomesafen alone. Greater than 90% control was obtained with acetochlor ME mixed with diuron or fomesafen. Palmer amaranth control was similar with acetochlor ME plus a full or reduced rate of fomesafen. Acetochlor ME controlled large crabgrass and goosegrass at 91 and 100% compared with control at 83 and 91%, respectively, by pendimethalin. Following glufosinate, applied twice POST, and diuron plus MSMA, at layby, 96 to 99% control was obtained late in the season by all treatments, and no differences among herbicide treatments were noted for cotton yield. This research demonstrated that acetochlor ME can be safely and effectively used in cotton weed management programs.}, number={4}, journal={WEED TECHNOLOGY}, author={Cahoon, Charles W. and York, Alan C. and Jordan, David L. and Everman, Wesley J. and Seagroves, Richard W. and Braswell, Lewis R. and Jennings, Katherine M.}, year={2015}, pages={740–750} } @article{cahoon_york_jordan_everman_seagroves_2014, title={An Alternative to Multiple Protoporphyrinogen Oxidase Inhibitor Applications in No-Till Cotton}, volume={28}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-13-00078.1}, abstractNote={Glyphosate-resistant (GR) Palmer amaranth is a widespread problem in southeastern cotton production areas. Herbicide programs to control this weed in no-till cotton commonly include flumioxazin applied with preplant burndown herbicides approximately 3 wk before planting followed by fomesafen applied PRE and then glufosinate or glyphosate applied POST. Flumioxazin and fomesafen are both protoporphyrinogen oxidase (PPO) inhibitors. Multiple yearly applications of PPO inhibitors in cotton, along with widespread use of PPO inhibitors in rotational crops, raise concerns over possible selection for PPO resistance in Palmer amaranth. An experiment was conducted to determine the potential to substitute diuron for one of the PPO inhibitors in no-till cotton. Palmer amaranth control by diuron and fomesafen applied PRE varied by location, but fomesafen was generally more effective. Control by both herbicides was inadequate when timely rainfall was not received for activation. Palmer amaranth control was more consistent when programs included a preplant residual herbicide. Applied preplant, flumioxazin was more effective than diuron. Programs with diuron preplant followed by fomesafen PRE were as effective as flumioxazin preplant followed by fomesafen only if fomesafen was activated in a timely manner. Programs with flumioxazin preplant followed by diuron PRE were as effective as flumioxazin preplant followed by fomesafen PRE at all locations, regardless of timely activation of the PRE herbicide. As opposed to flumioxazin preplant followed by fomesafen PRE, which exposes Palmer amaranth to two PPO-inhibiting herbicides, one could reduce selection pressure by using flumioxazin preplant followed by diuron PRE without sacrificing Palmer amaranth control or cotton yield.}, number={1}, journal={WEED TECHNOLOGY}, author={Cahoon, Charles W. and York, Alan C. and Jordan, David L. and Everman, Wesley J. and Seagroves, Richard W.}, year={2014}, pages={58–71} } @article{graves_liwimbi_israel_heugten_robinson_cahoon_lubbers_2011, title={Distribution of ten antibiotic resistance genes in E. coli isolates from swine manure, lagoon effluent and soil collected from a lagoon waste application field}, volume={56}, ISSN={["0015-5632"]}, DOI={10.1007/s12223-011-0019-z}, number={2}, journal={FOLIA MICROBIOLOGICA}, author={Graves, A. K. and Liwimbi, L. and Israel, D. W. and Heugten, E. and Robinson, B. and Cahoon, C. W. and Lubbers, J. F.}, year={2011}, month={Mar}, pages={131–137} }