@article{mcknight_gannon_yelverton_2021, title={Phytoremediation of azoxystrobin and imidacloprid by wetland plant species Juncus effusus, Pontederia cordata and Sagittaria latifolia}, volume={6}, ISSN={["1549-7879"]}, DOI={10.1080/15226514.2021.1932726}, abstractNote={Abstract Azoxystrobin (strobilurin fungicide) and imidacloprid (neonicotinoid insecticide) have been detected in surface waters near treated agricultural, urban, and mixed landscapes. The hazards of pesticide runoff can be prevented through best management practices, including the establishment of diverse wetland plant barriers that can phytoremediate the chemicals in which they come into contact with. In this study, the wetland plant species softrush (Juncus effusus), pickerelweed (Pontederia cordata), and arrowhead (Sagittaria latifolia) were planted in sandy soil containers that were then placed in azoxystrobin or imidacloprid treated water. Every week for 2 months, water samples were collected for pesticide residue analysis using high-performance liquid chromatography (HPLC). At 14, 28, and 56 days after initiation, plants were destructively harvested and analyzed for pesticide residue in soil, above-ground vegetation, and below-ground vegetation. Results from this study report P. cordata reduced greater azoxystrobin (51.7% reduction compared to treated non-planted containers) compared to J. effusus and S. latifolia (24.9% and 28.7% reduction from non-planted containers) at 56 days. However, S. latifolia reduced greater imidacloprid (79.3% reduction compared to non-planted containers) compared to J. effusus and P. cordata (36.0% and 37.1% reduction from non-planted containers) at 56 days. Novelty statement: While research has found that wetland plants can absorb and remediate synthetic chemicals, this practice is only sustainable if used with native plants that require low maintenance and are tolerant to the applied substances. Various previous studies observe plants that are fast-growing, tolerant to environmental conditions, require low-maintenance, and are hardy. However, these plant species are not always suitable for any location and are often considered invasive and/or weed-like. The present research initiates a list of plant species which can be used within the southeastern United States and similar areas to phytoremediate commonly used pesticides azoxystrobin and imidacloprid and prevent off-target movement into sensitive water systems.}, journal={INTERNATIONAL JOURNAL OF PHYTOREMEDIATION}, author={McKnight, Alayne M. and Gannon, Travis W. and Yelverton, Fred}, year={2021}, month={Jun} }
 @article{mcknight_gannon_yelverton_2021, title={Phytoremediation potential of three terrestrial plant species for removal of atrazine, azoxystrobin, and imidacloprid}, volume={6}, ISSN={["1549-7879"]}, DOI={10.1080/15226514.2021.1932724}, abstractNote={Abstract Pesticides can move off-target resulting in contamination of sensitive water bodies and causing adverse effects on inhabiting species. Through best management practices, such as the implementation of vegetative buffer strips, off-target movement of pesticides can be decreased, and compound degradation can be increased via phytoremediation. In this study, blueflag iris (Iris versicolor), broomsedge (Andropogon virginicus) and switchgrass (Panicum virgatum) were planted in soil treated with one of three commonly used pesticides. At 28, 56 and 112 days after treatment (DAT), plants were destructively harvested and analyzed for pesticide residue in soil and above-ground and below-ground vegetation using high-performance liquid chromatography (HPLC). Relative to the amount of pesticide found in planted pots compared to non-planted pots, I. versicolor was found to reduce greater atrazine in soil compared to non-planted pots at 112 DAT by 58.7%. I. versicolor was also the most capable of reducing azoxystrobin, by 86.9% compared to non-planted pots, from the soil at 112 DAT. At the same sampling time, I. versicolor and P. virgatum reduced greater imidacloprid from soil by 62.5% and 64.3% compared to non-planted pots, respectively. This information supports the recommendation for establishment of diverse plant species for optimization of phytoremediation capacities. Novelty statement While research has found that plants can absorb and remediate synthetic chemicals, this practice is only sustainable if used with native plants that require low maintenance and are tolerant to the applied substances. Various previous studies observe plants that are fast-growing, tolerant to environmental conditions, require low-maintenance, and are hardy. However, these plant species are not always suitable for any location and are often considered invasive and/or weed-like. The present research initiates a list of plant species which can be used within the southeastern United States and similar areas to phytoremediate commonly used pesticides atrazine, azoxystrobin, and imidacloprid and prevent off-target movement.}, journal={INTERNATIONAL JOURNAL OF PHYTOREMEDIATION}, author={McKnight, Alayne M. and Gannon, Travis W. and Yelverton, Fred}, year={2021}, month={Jun} }
 @article{jeffries_gannon_reynolds_yelverton_silcox_2017, title={Herbicide Applications and Incorporation Methods Affect Dazomet Efficacy on Bermudagrass}, volume={27}, ISSN={["1943-7714"]}, DOI={10.21273/horttech03564-16}, abstractNote={Turfgrass renovations commonly involve changing cultivars or species that are better suited for a given setting. Common bermudagrass [Cynodon dactylon (L.) Pers.] is a perennial turfgrass that is difficult to eradicate before renovations, and poses contaminant concerns for the subsequent stand. Dazomet is a granular soil fumigant that has activity on various pests, including common bermudagrass. Field research was conducted from 2015 to 2016 in Raleigh, NC and College Station, TX to evaluate dazomet treatments including various combinations of soil incorporation (irrigationor tillage-incorporated) and sealing (tarp or no tarp) methods, application rates [291, 291 followed by (fb) 291, 468, or 583 kg ha], and fluazifop-P [fluazifop (0.4 kg ha)] D glyphosate (2.8 kg ha acid equivalent) application(s) for established common bermudagrass control. Overall, treatments required fluazifopD glyphosate before dazomet application for acceptable control (>90% cover reduction) at 42 and 46 weeks after initial treatment (WAIT) in Texas and North Carolina, respectively. Soil-incorporation results varied by location, with dazomet application (583 kg ha) fb tillage resulting in ‡88% cover reduction across locations, while acceptable control from irrigation incorporation was only observed in North Carolina. Tarping did not improve efficacy when tillage incorporation at the maximum label application rate provided acceptable control, suggesting practitioners may eliminate this procedure. Information from this research will aid turfgrass managers in developing cost-effective, ecologically sound common bermudagrass eradication programs before renovations.}, number={1}, journal={HORTTECHNOLOGY}, author={Jeffries, Matthew D. and Gannon, Travis W. and Reynolds, W. Casey and Yelverton, Fred H. and Silcox, Charles A.}, year={2017}, month={Feb}, pages={24–29} }
 @article{jeffries_gannon_yelverton_2017, title={Herbicide Inputs and Mowing Affect Vaseygrass (Paspalum urvillei) Control}, volume={31}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-16-00072.1}, abstractNote={Vaseygrass is an invasive, perennial C4-grass commonly found on roadsides in areas with poorly drained soils. Due to its upright growth habit and seedhead production, vaseygrass can impair motorist sightlines and subsequently, require increased management inputs to maintain vegetation at an acceptable height. Two field experiments were conducted from 2012 to 2015 on North Carolina roadsides to evaluate the effect of mowing and mowing timing with respect to applications of various herbicides on vaseygrass control. Both experiments evaluated clethodim (280 g ai ha−1), foramsulfuron+halosulfuron+thiencarbazone-methyl (44+69+22 g ai ha−1), imazapic (140 g ai ha−1), metsulfuron+nicosulfuron (16+59 g ai ha−1), and sulfosulfuron (105 g ai ha−1) with a nonionic surfactant at 0.25% v/v. Experiment one focused on the effect of mowing (routinely mowed or nonmowed) and herbicide application timing (fall-only, fall-plus-spring, or spring-only), while experiment two focused on pre-herbicide application mowing intervals (6, 4, 3, 2, 1, or 0 wk before treatment [WBT]). From experiment one, routine mowing reduced vaseygrass cover in nontreated plots 55% at 52 wk after fall treatment (WAFT), suggesting this cultural practice should be employed where possible. Additionally, routine mowing and herbicide application season affected herbicide efficacy. Treatments providing >70% vaseygrass cover reduction at 52 WAFT included routinely mowed fall-only clethodim and fall-plus-spring imazapic, and fall-plus-spring metsulfuron+nicosulfuron across mowing regimens. Within clethodim, mowing vaseygrass 2 or 1 WBT resulted in the lowest cover at 40 (1 to 2%) and 52 (4 to 6%) wk after treatment (WAT) compared to other intervals, which aligns with current label vegetation height at treatment recommendation. Vaseygrass persisted across all treatments evaluated through 52 WAT, suggesting eradication of this species will require inputs over multiple growing seasons. Nomenclature: Clethodim; foramsulfuron; halosulfuron; imazapic; metsulfuron; nicosulfuron; sulfosulfuron; thiencarbazone; vaseygrass, Paspalum urvillei Steud. Paspalum urvillei es una gramínea C4 perenne invasiva que se encuentra comúnmente a las orillas de caminos y en áreas con suelos con poco drenaje. Debido a su hábito de crecimiento vertical y producción de espigas, P. urvillei puede limitar la visibilidad de vehículos y subsecuentemente incrementar los insumos de manejo para mantener la vegetación a una altura aceptable. Se realizaron dos experimentos de campo desde 2012 a 2015 en orillas de caminos en North Carolina para evaluar los efectos de la chapia y el momento de chapia con respecto a las aplicaciones de varios herbicidas sobre el control de P. urvillei. Ambos experimentos evaluaron clethodim (280 g ai ha−1), foramsulfuron+halosulfuron+thiencarbazone-methyl (44+69+22 g ai ha−1), imazapic (140 g ai ha−1), metsulfuron+nicosulfuron (16+59 g ai ha−1), y sulfosulfuron (105 g ai ha−1) con un surfactante no iónico a 0,25% v/v. El experimento uno se enfocó en el efecto de la chapia (chapia rutinaria o sin chapia) y el momento de aplicación de herbicidas (sólo otoño, otoño más primavera, o sólo primavera), mientras que el experimento dos se enfocó en el intervalo entre la chapia y la aplicación de herbicidas (6, 4, 3, 2, 1, ó 0 semanas antes del tratamiento [WBT]). En el experimento uno, la chapia rutinaria redujo 55%la cobertura de P. urvillei en parcelas sin tratamiento con herbicidas a 52 semanas después del tratamiento de otoño (WAFT), sugiriendo que esta práctica cultural debería ser empleada cuando sea posible. Adicionalmente, la chapia rutinaria y la temporada de aplicación de herbicida afectaron la eficacia del herbicida. Los tratamientos que proveyeron >70% de reducción en la cobertura de P. urvillei a 52 WAFT incluyeron chapia rutinaria y clethodim sólo en el otoño e imazapic en el otoño más la primavera, y metsulfuron+nicosulfuron en el otoño más la primavera para todos los regímenes de chapia. Dentro de los tratamientos con clethodim, la chapia 2 ó 1 WBT resultó en la menor cobertura a 40 (1 a 2%) y 52 (4 a 6%) semanas después del tratamiento (WAT) al compararse con otros intervalos, lo que se alinea con la actual recomendación de la etiqueta de tratamiento según la altura de la vegetación. P. urvillei persistió en todos los tratamientos evaluados hasta 52 WAT, lo que sugiere que la erradicación de esta especie requerirá insumos a lo largo de múltiples temporadas de crecimiento.}, number={1}, journal={WEED TECHNOLOGY}, author={Jeffries, Matthew D. and Gannon, Travis W. and Yelverton, Fred H.}, year={2017}, pages={120–129} }
 @article{atkinson_mccarty_powell_mcelroy_yelverton_estes_2017, title={Postemergence Control and Glyphosate Tolerance of Doveweed (Murdannia nudiflora)}, volume={31}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2017.31}, abstractNote={Doveweed is a problematic weed of lawns and sod production, as well as golf course roughs, fairways, and tees. End-user reports of selective POST control options are inconsistent and control is often short-lived. In addition, inconsistent control with non-selective herbicides such as glyphosate is common. The goals of this research were: (1) evaluate selective POST doveweed control options in ‘Tifway’ hybrid bermudagrass turf; (2) compare efficacy of single vs. sequential applications of selective POST herbicides; (3) quantify doveweed tolerance to glyphosate; and (4) quantify recovery of foliar applied glyphosate following treatment with a C14-glyphosate solution. A single application of sulfentrazone + metsulfuron; thiencarbazone + iodosulfuron + dicamba or 2,4-D + MCPP + dicamba + carfentrazone; or thiencarbazone + foramsulfuron + halosulfuron provided >60% control 2 weeks after initial treatment (WAIT). A second application of these treatments 3 WAIT improved control 6 WAIT. Two applications of 2,4-D + MCPP + dicamba + carfentrazone or thiencarbazone + foramsulfuron + halosulfuron provided ~80% control 6 WAIT. Doveweed was tolerant to glyphosate application up to 5.68 kg ae ha-1. Absorption of 14C-glyphosate was compared between doveweed with cuticle intact, doveweed with a disturbed cuticle, and smooth crabgrass. 14C-glyphosate recovery from the leaf surface of doveweed plants with an intact cuticle was 93.6%. In comparison, 14C-glyphosate recovery from the leaf surface of doveweed plants with a disrupted cuticle and the leaf surface of crabgrass plants was 79.1 and 70.5%, respectively. Nomenclature: Bromoxynil; carfentrazone; dicamba; foramsulfuron; glyphosate; halosulfuron; iodosulfuron; mecoprop; metsulfuron; MSMA; quinclorac; sulfentrazone; thiencarbazone; 2,4-D; doveweed, Murdannia nudiflora (L.) Brenan; smooth crabgrass, Digitaria ischaemum (Schreb.) Schreb. ex Muhl.; ‘Tifway’ bermudagrass, Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt-Davy.}, number={4}, journal={WEED TECHNOLOGY}, author={Atkinson, Jeffrey L. and McCarty, Lambert B. and Powell, Brian A. and McElroy, Scott and Yelverton, Fred and Estes, Alan G.}, year={2017}, pages={582–589} }
 @article{jeffries_gannon_yelverton_2017, title={Tall Fescue Roadside Right-of-Way Mowing Reduction from Imazapic}, volume={109}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2016.04.0246}, abstractNote={Core Ideas Imazapic provided 100% tall fescue seedhead suppression through 56 d after treatment. Imazapic reduced tall fescue mowing requirements by two cycles across 23‐ and 30‐cm intervention heights. Imazapic application to tall fescue mown at 30‐cm intervention height required one mowing event through 70 d after treatment. Tall fescue [ Lolium arundinaceum (Schreb.) S.J. Darbyshire] is commonly established along roadside rights‐of‐way in adapted zones due to its tolerance of drought, heat, and wear; however, its upright growth habit coupled with seedhead production can impair motorist vision. Field research was conducted in 2013 and 2014 to quantify tall fescue mowing requirements following imazapic {(±)‐2‐[4,5‐dihydro‐4‐methyl‐4‐(1‐methylethyl)‐5‐oxo‐1 H ‐imidazol‐2‐yl]‐5‐methyl‐3‐pyridinecarboxylic acid}, an herbicide commonly used for plant growth regulation, application (53 g a.i. ha −1 ) alone, as well as tank‐mixed with clopyralid (3,6‐dichloro‐2‐pyridinecarboxylic acid) + triclopyr {[(3,5,6‐trichloro‐2‐pyridinyl)oxy]acetic acid} (158 + 473 g a.i. ha −1 ). Plots were mown at a 23‐ or 30‐cm foliage intervention height following treatment. Nontreated‐mown and nontreated‐nonmown controls were included for comparisons. Evaluated herbicide treatments caused 0 to 20% tall fescue injury, which recovered following mowing. Additionally, imazapic provided 100% tall fescue seedhead suppression through 56 days after treatment (DAT). Imazapic reduced tall fescue mowing requirements at both intervention heights through 70 DAT. Two mowing cycles were reduced across intervention heights in 2013, while three and two cycles were reduced at 23 and 30 cm heights, respectively, in 2014. Lastly, imazapic + clopyralid + triclopyr application increased tall fescue cover 84 DAT. This information will allow vegetation managers to more efficiently allocate resources to maintain clear motorist sightlines on tall fescue roadside rights‐of‐way.}, number={4}, journal={AGRONOMY JOURNAL}, author={Jeffries, Matthew D. and Gannon, Travis W. and Yelverton, Fred H.}, year={2017}, pages={1765–1770} }
 @article{jeffries_gannon_yelverton_2017, title={Zoysiagrass Sod Establishment along Guardrails: Evaluation of Cultivars, Soil Preparation Techniques, and Planting Timings}, volume={57}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2016.09.0740}, abstractNote={Appropriately designed and installed guardrails are structures that enhance motorist safety; however, their inherent design requires additional vegetation management inputs to maintain safe, acceptable driving conditions. Establishing low‐growing, perennial vegetation under guardrails may reduce long‐term management inputs. Field research was initiated 17 Dec. 2012 and 3 Dec. 2013 along guardrails in Chatham, Lee, and Yadkin Counties, NC, to evaluate the effect of establishment timing (December, March, April, or May) and soil preparation technique (tillage alone, tillage + bed preparation, or vegetation strip) on ‘El Toro’ ( Zoysia japonica Steud.) and ‘Zeon’ [ Zoysia matrella (L.) Merr.] zoysiagrass sod establishment and spread along guardrails. Sod establishment in year 1 was successful (>60% cover) across cultivars, locations, and techniques at December and March timings, with cover ranging from 64 to 90% at 90 wk after initial establishment. April and May timings resulted in inconsistent establishment success and are not recommended for North Carolina. Year 2 sodding generally resulted in unsuccessful establishment, which may be due in part to colder winter and dryer spring–summer conditions compared with year 1. Overall, El Toro sod more readily established and spread than Zeon, suggesting that it is a better species for establishment along guardrails. Tillage alone resulted in equivalent or greater sod establishment and spread than tillage + bed preparation and vegetation stripping, and it also requires fewer equipment and personnel inputs. Results suggest that El Toro sod planted in March following soil tillage is the most promising practice for establishment along North Carolina guardrails; however, water inputs may be required during moisture‐deficient periods following planting.}, number={2}, journal={CROP SCIENCE}, author={Jeffries, Matthew D. and Gannon, Travis W. and Yelverton, Fred H.}, year={2017}, pages={993–1000} }
 @article{jeffries_yelverton_ahmed_gannon_2016, title={Persistence in and Release of 2,4-D and Azoxystrobin from Turfgrass Clippings}, volume={45}, ISSN={["1537-2537"]}, DOI={10.2134/jeq2016.03.0081}, abstractNote={Research has shown that pesticide residue in clippings from previously treated turfgrass may become bioavailable as grass decomposes, adversely affecting off-target organisms. We conducted a field study to quantify 2,4-D (2,4-dichlorophenoxyacetic acid) and azoxystrobin (methyl(E)-2-{2[6-(2-cyanophenoxy)pyrmidin-4-yloxy]phenyl}-3-methoxyacrylate) residues in turfgrass clippings collected from hybrid bermudagrass [ (L.) Pers. × Burtt-Davy], tall fescue [ (Schreb.) S.J. Darbyshire], and zoysiagrass ( Steud.). A subsequent greenhouse experiment was conducted to measure pesticide release from clippings into water. 2,4-D (1.6 kg a.i. ha) and azoxystrobin (0.6 kg a.i. ha) were applied to field plots at 32, 16, 8, 4, 2, 1, or 0 d before collection of the clippings. Clippings were collected from each experimental unit to quantify pesticide release from clippings into water. Both 2,4-D and azoxystrobin were detected when turfgrass was treated over the 32-d experimental period, suggesting that clipping management should be implemented for an extended period of time after application. Pesticide residue was detected in all water samples collected, confirming 2,4-D and azoxystrobin release from turfgrass clippings; however, pesticide release varied between compounds. Two days after clippings were incorporated in water, 39 and 10% of 2,4-D and azoxystrobin were released from clippings, respectively. Our research supports the currently recommended practice of returning clippings to the turfgrass stand when mowing because removal of 2,4-D and azoxystrobin in clippings may reduce pest control and cause adverse off-target impacts.}, number={6}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Jeffries, Matthew D. and Yelverton, Fred H. and Ahmed, Khalied A. and Gannon, Travis W.}, year={2016}, pages={2030–2037} }
 @article{dunne_reynolds_miller_arellano_brandenburg_schoeman_yelyerton_milla-lewis_2015, title={Identification of South African bermudagrass germplasm with shade tolerance}, volume={50}, number={10}, journal={HortScience}, author={Dunne, J. C. and Reynolds, W. C. and Miller, G. L. and Arellano, C. and Brandenburg, R. L. and Schoeman, A. and Yelyerton, F. H. and Milla-Lewis, S. R.}, year={2015}, pages={1419–1425} }
 @article{lewis_jeffries_gannon_richardson_yelverton_2014, title={Persistence and Bioavailability of Aminocyclopyrachlor and Clopyralid in Turfgrass Clippings: Recycling Clippings for Additional Weed Control}, volume={62}, ISSN={["1550-2759"]}, DOI={10.1614/ws-d-13-00119.1}, abstractNote={Abstract The synthetic auxin herbicides, aminocyclopyrachlor and clopyralid, control dicotyledonous weeds in turf. Clippings of turfgrass treated with synthetic auxin herbicides have injured off-target plants exposed to herbicide-laden clippings. Labels of aminocyclopyrachlor and clopyralid recommend that clippings of treated turfgrass remain on the turf following a mowing event. Alternative uses for synthetic auxin-treated turfgrass clippings are needed because large quantities of clippings on the turf surface interfere with the functionality and aesthetics of golf courses, athletic fields, and residential turf. A white clover bioassay was conducted to determine the persistence and bioavailability of aminocyclopyrachlor and clopyralid in turfgrass clippings. Aminocyclopyrachlor and clopyralid were each applied at 79 g ae ha−1 to mature tall fescue at 56, 28, 14, 7, 3.5, and 1.75 d before clipping collection (DBCC). Clippings were collected, and the treated clippings were recycled onto adjacent white clover plots to determine herbicidal persistence and potential for additional weed control. Clippings of tall fescue treated with aminocyclopyrachlor produced a nonlinear regression pattern of response on white clover. Calculated values for 50% response (GR50) for visual control, for normalized difference vegetative index (NDVI), and for reduction in harvested biomass were 20.5, 17.3, and 18.7 DBCC, respectively, 8 wk after clippings were applied. Clippings of tall fescue treated with clopyralid did not demonstrate a significant pattern for white clover control, presumably because clopyralid was applied at a less-than-label rate. The persistence and bioavailability of synthetic auxin herbicides in clippings harvested from previously treated turfgrass creates the opportunity to recycle clippings for additional weed control. Nomenclature: Aminocyclopyrachlor; clopyralid; tall fescue, Lolium arundinaceum (Schreb.) S.J. Darbyshire; white clover, Trifolium repens L. ‘Dutch’.}, number={3}, journal={WEED SCIENCE}, author={Lewis, Dustin F. and Jeffries, Matthew D. and Gannon, Travis W. and Richardson, Robert J. and Yelverton, Fred H.}, year={2014}, pages={493–500} }
 @article{gannon_hixson_keller_weber_knezevic_yelverton_2014, title={Soil Properties Influence Saflufenacil Phytotoxicity}, volume={62}, ISSN={["1550-2759"]}, DOI={10.1614/ws-d-13-00171.1}, abstractNote={Abstract Saflufenacil, a pyrimidinedione herbicide, is used for contact and residual broadleaf weed control in various crops. Bioactivity of saflufenacil in soil was tested in greenhouse and laboratory studies on 29 soils representing a wide range of soil properties and geographic areas across the United States. A greenhouse bioassay method was developed using various concentrations of saflufenacil applied PPI to each soil. Whole canola plants were harvested 14 d after treatment, and fresh and dry weights were recorded. Nonlinear regression analysis was used to determine the effective saflufenacil doses for 50% (ED50,), 80% (ED80), and 90% (ED90) inhibition of total plant fresh weight. Bioactivity of saflufenacil in soil was strongly correlated to soil organic (R  =  0.85) and humic matter (R  =  0.81), and less correlated to cation exchange capacity (R  =  0.49) and sand content (R  =  −0.32). Stepwise regression analysis indicated that organic matter was the major soil constituent controlling bioactivity in soil and could be used to predict the bioactivity of saflufenacil. Saflufenacil phytotoxicity was found to be dependent on soil property; therefore, efficacy and crop tolerance from PRE and PPI applications may vary based on soil organic matter content and texture classification. Nomenclature: Saflufenacil; canola, Brassica napus L.}, number={4}, journal={WEED SCIENCE}, author={Gannon, Travis W. and Hixson, Adam C. and Keller, Kyle E. and Weber, Jerome B. and Knezevic, Stevan Z. and Yelverton, Fred H.}, year={2014}, pages={657–663} }
 @article{lewis_roten_everman_gannon_richardson_yelverton_2013, title={Absorption, Translocation, and Metabolism of Aminocyclopyrachlor in Tall Fescue (Lolium arundinaceum)}, volume={61}, ISSN={["1550-2759"]}, DOI={10.1614/ws-d-12-00189.1}, abstractNote={Abstract Synthetic auxin herbicides are commonly used in forage, pasture, range, and turfgrass settings for dicotyledonous weed control. Aminocyclopyrachlor (AMCP) is a newly developed pyrimidine carboxylic acid with a chemical structure and mode of action similar to the pyridine carboxylic acids—aminopyralid, clopyralid, and picloram. Injury to sensitive dicotyledonous plants has been observed following exposure to monocotyledonous plant material previously treated with pyridine compounds. The absorption, translocation, and metabolism of AMCP has been documented in susceptible broadleaf weeds; however, no information is available, to our knowledge, regarding AMCP fate in tolerant Poaceae, which may serve as the vector for off-target plant injury. Based on this premise, research was conducted to characterize absorption, translocation, and metabolism of AMCP in tall fescue. 14C-AMCP was applied to single tiller tall fescue plant foliage under controlled laboratory conditions at North Carolina State University (Raleigh, NC). Radiation was quantified in leaf wash, treated leaf, foliage, crown, roots, and root exudates at 3, 12, 24, 48, 96, and 192 h after treatment (HAT). 14C-AMCP was rapidly absorbed by tall fescue, reaching 38 and 68% at 3 and 48 HAT, respectively. Translocation of 14C-AMCP was limited to the foliage, which reached maximum translocation (34%) at 96 HAT. Most of the recovered 14C-AMCP remained in the leaf wash, treated leaf, or foliage, whereas minimal radiation was detected in the crown, roots, or root exudates throughout the 192-h period. No AMCP metabolism was observed in tall fescue through the 192 HAT. These data suggest AMCP applied to tall fescue can remain bioavailable, and mishandling treated plant material could result in off-target injury. Nomenclature: Aminocyclopyrachlor; tall fescue, Lolium arundinaceum (Schreb.) S.J. Darbyshire.}, number={3}, journal={WEED SCIENCE}, author={Lewis, Dustin F. and Roten, Rory L. and Everman, Wesley J. and Gannon, Travis W. and Richardson, Robert J. and Yelverton, Fred H.}, year={2013}, pages={348–352} }
 @article{jeffries_yelverton_gannon_2013, title={Annual Bluegrass (Poa annua) Control in Creeping Bentgrass Putting Greens with Amicarbazone and Paclobutrazol}, volume={27}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-12-00144.1}, abstractNote={Abstract Amicarbazone is a photosystem II–inhibiting herbicide recently registered for annual bluegrass control in established turf systems that include creeping bentgrass. However, research to date reveals potential issues with creeping bentgrass tolerance to amicarbazone. Currently, the plant-growth regulator paclobutrazol is widely adopted by turf managers for chemical annual bluegrass suppression in creeping bentgrass putting greens. Field experiments were conducted throughout North Carolina in the spring of 2010 and 2011 to assess treatment regimens that included amicarbazone (49, 65, or 92 g ai ha−1) and paclobutrazol (70, 140, or 280 g ai ha−1) applied alone, as tank-mixtures, or used in tandem, at varying rates and sequential timings for annual bluegrass control in creeping bentgrass putting greens. In general, regimens including both compounds provided greater annual bluegrass control and acceptable turfgrass tolerance compared with stand-alone applications of amicarbazone at 8 and 12 wk after initial treatment (WAIT). When comparing regimens that included amicarbazone at 49 or 65 g ha−1, creeping bentgrass tolerance was greater for the higher application rate applied less frequently. These results indicate amicarbazone usage on creeping bentgrass greens may be beneficially affected with the incorporation of paclobutrazol to treatment regimens because annual bluegrass control with the combination was equal to or greater than stand-alone amicarbazone applications, and creeping bentgrass tolerance was superior 8 and 12 WAIT. Nomenclature: Amicarbazone; paclobutrazol; annual bluegrass; Poa annua L.; creeping bentgrass; Agrostis stolonifera L. Resumen Amicarbazone es un herbicida inhibidor del fotosistema II que fue recientemente registrado para el control de Poa annua en sistemas de céspedes establecidos incluyendo Agrostis stolonifera. Sin embargo, la investigación hasta la fecha revela problemas potenciales con la tolerancia de A. stolonifera a amicarbazone. Actualmente, el regulador de crecimiento paclobutrazol es ampliamente adoptado por especialistas en céspedes para la supresión química de P. annua en putting greens de A. stolonifera. Experimentos de campo fueron realizados en North Carolina en la primavera de 2010 y 2011 para evaluar regímenes con tratamientos que incluyeron amicarbazone (49, 65, ó 92 g ai ha−1) y paclobutrazol (70, 140, ó 280 g ai ha−1), aplicados solos o en mezcla en tanque, o usados en tándem, a dosis variables y en aplicaciones secuenciales para el control de P. annua en putting greens de A. stolonifera. En general, los regímenes que incluyeron ambos compuestos brindaron un mayor control de P. annua y una tolerancia aceptable del césped en comparación con aplicaciones solas de amicarbazone a 8 y 12 semanas después del tratamiento inicial (WAIT). Cuando se compararon regímenes que incluyeron amicarbazone a 49 ó 65 g ha−1, la tolerancia del césped fue mayor cuando las dosis más altas fueron aplicadas en menor frecuencia. Estos resultados indican que el uso de amicarbazone en greens de A. stolonifera podría ser afectado beneficiosamente con la incorporación de paclobutrazol porque el control de P. annua con la combinación fue igual o mayor que las aplicaciones solas de amicarbazone, y la tolerancia del césped fue superior a 8 y 12 WAIT.}, number={3}, journal={WEED TECHNOLOGY}, author={Jeffries, Matthew D. and Yelverton, Fred H. and Gannon, Travis W.}, year={2013}, pages={520–526} }
 @article{lewis_richardson_yelverton_wentworth_2013, title={Bioavailability of Aminocyclopyrachlor and Triclopyr plus Clopyralid from Turfgrass Clippings in Aquatic and Riparian Plants}, volume={61}, ISSN={["1550-2759"]}, DOI={10.1614/ws-d-13-00013.1}, abstractNote={Abstract Synthetic auxin herbicides are widely utilized in golf course settings for selective broadleaf weed control. Aminocyclopyrachlor (AMCP) is a newly registered pyrimidine carboxylic acid with similar chemical mode-of-action and structure to triclopyr (TRIC) and clopyralid (CLPY). Off-target injury on terrestrial plants has been documented following exposure to turfgrass clippings previously treated with TRIC and CLPY. Management practices on golf courses can distribute turfgrass clippings into water bodies; however, research has not evaluated the bioavailability of synthetic auxin residues from turfgrass clippings to aquatic and riparian plants within these environments. A bioassay study was conducted to determine the response of alligatorweed and parrotfeather to tall fescue clippings previously treated with synthetic auxin herbicides. Previously treated AMCP and TRIC + CLPY clippings were placed into growth containers mimicking a lentic system containing both alligatorweed and parrotfeather. Results indicated all herbicide treated clippings induced significant growth responses to alligatorweed and parrotfeather growth compared to a nontreated mulch and nontreated control. Alligatorweed control was greater from AMCP clippings treated 14, 7, 3, and 1 DBCC (49, 60, 90, and 80%, respectively) than comparative TRIC + CLPY clippings (33, 25, 37, and 64%, respectively) at 10 weeks after treatment (WAT). Parrotfeather control was greater from AMCP clippings (57 to 87%) than TRIC + CLPY clippings (9 to 63%) collected from all days before clipping collection (DBCC) timings when evaluated 6 WAT. At 10 WAT, greater parrotfeather control and shoot reduction was observed from AMCP than TRIC + CLPY clippings when treated 14, 7, and 3 DBCC. Based on these data, synthetic auxin residues can become bioavailable to aquatic and riparian plants within aqueous environments. Nomenclature: Aminocyclopyrachlor, clopyralid, triclopyr, alligatorweed, Alternanthera philoxeroides (Mart.) Griseb., parrotfeather, Myriophyllum aquaticum (Vell.) Verdc., tall fescue, Lolium arundinaceum (Schreb.) S.J. Darbyshire.}, number={4}, journal={WEED SCIENCE}, author={Lewis, Dustin F. and Richardson, Robert J. and Yelverton, Fred H. and Wentworth, Thomas R.}, year={2013}, pages={594–600} }
 @article{lewis_jeffries_strek_richardson_yelverton_2013, title={Effect of Ambient Moisture on Aminocyclopyrachlor Efficacy}, volume={27}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-12-00131.1}, abstractNote={Abstract Aminocyclopyrachlor (AMCP) is a newly developed synthetic auxin herbicide for broadleaf weed control in turfgrass systems. AMCP has been observed to undergo rapid photodecomposition in shallow water when exposed to sunlight. Most herbicide applications on golf courses occur during the morning when dew is still present on the turfgrass canopy. These conditions could result in efficacy loss if photolysis occurred while AMCP is suspended in dew droplets. Research was conducted to determine the effect of ambient moisture on AMCP efficacy. AMCP (79 and 105 g ae ha−1), aminopyralid (280 g ae ha −1), and two AMCP granular formulations (84 g ha−1) were applied to dew-covered (WET) and dew-excluded (DRY) ‘Tifway' bermudagrass plots. Herbicide treatments applied to WET plots had greater visually rated bermudagrass injury than respective treatments applied to DRY plots at 7 and 21 d after treatment (DAT), with the exception of aminopyralid at 21 DAT. Normalized difference vegetative index on turfgrass quality complemented visual ratings, indicating greater turfgrass quality reductions when applied to WET vs. DRY plots. These results indicate that AMCP applications made to dew-covered turfgrass can increase herbicidal efficacy, and no significant losses due to photodegradation were observed. Nomenclature: Aminocyclopyrachlor, 6-amino-5-chloro-2-cyclopropyl-4-pyrimidine-carboxylic acid; aminopyralid, 4-amino-3,6-dichloro-2-pyridinecarboxylic acid; bermudagrass, Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt-Davy ‘Tifway'. Resumen Aminocyclopyrachlor (AMCP) es un herbicida del grupo de las auxinas sintéticas recientemente desarrollado para el control de malezas de hoja ancha en sistemas de céspedes. Se ha visto que AMCP sufre una rápida fotodescomposición en aguas superficiales cuando se expone a la luz solar. La mayoría de las aplicaciones de herbicidas en campos de golf se dan durante las mañanas cuando el rocío está todavía presente sobre el dosel del césped. Estas condiciones podrían resultar en una pérdida de eficacia si ocurre fotólisis mientras AMCP se encuentra suspendido en las gotas de rocío. Se realizó una investigación para determinar el efecto de la humedad ambiental sobre la eficacia de AMCP. Se aplicó AMCP (79 y 105 g ae ha−1), aminopyralid (280 g ae ha−1), y dos formulaciones granulares de AMCP (84 g ha−1) a parcelas del césped Cynodon dactylon 'Tifway' cubiertas con rocío (WET) y sin rocío (DRY). Los herbicidas aplicados a parcelas WET tuvieron un mayor daño evaluado visualmente que los tratamientos respectivos aplicados a parcelas DRY a 7 y 21 días después del tratamiento (DAT), con la excepción de aminopyralid a 21 DAT. El índice de diferencia vegetativa normalizada de la calidad del césped complementó las evaluaciones visuales, indicando mayores reducciones en la calidad del césped cuando se aplicaron parcelas en WET vs. DRY. Estos resultados indican que las aplicaciones AMCP hechas en césped cubierto con rocío pueden incrementar la eficacia del herbicida y no se observaron pérdidas significativas debido a fotodegradación.}, number={2}, journal={WEED TECHNOLOGY}, author={Lewis, Dustin F. and Jeffries, Matthew D. and Strek, Harry J. and Richardson, Robert J. and Yelverton, Fred H.}, year={2013}, pages={317–322} }
 @article{jeffries_gannon_rufty_yelverton_2013, title={Effect of Selective Amicarbazone Placement on Annual Bluegrass (Poa annua) and Creeping Bentgrass Growth}, volume={27}, ISSN={["0890-037X"]}, DOI={10.1614/wt-d-13-00015.1}, abstractNote={Abstract Growth chamber experiments were conducted to assess the effects of foliage-only, soil-only, and foliage-plus-soil placements of amicarbazone on annual bluegrass and creeping bentgrass growth. Evaluated herbicide treatments included amicarbazone at 49 or 147 g ai ha−1, as well as bispyribac-sodium at 74 g ai ha−1 for comparative purposes. Data from this research agree with previous reports of amicarbazone plant uptake. Amicarbazone is absorbed via above- and belowground pathways; however, plant growth is inhibited more by root uptake. Compared to foliage-only amicarbazone placement, soil-only placement more than doubled reductions in aboveground biomass and root mass 56 d after treatment (DAT), whereas no differences were detected between placements including soil contact. Across all evaluated parameters in this research, amicarbazone (49 g ha−1) impacted creeping bentgrass growth similarly to bispyribac-sodium, whereas annual bluegrass growth was inhibited more by amicarbazone, suggesting it provides a more efficacious chemical option for end-user applications. Nomenclature: Amicarbazone; bispyribac-sodium; annual bluegrass; Poa annua L. var. annua; creeping bentgrass; Agrostis stolonifera L. ‘Penn A1’. Resumen Se realizaron experimentos en cámaras de crecimiento para evaluar los efectos de aplicar amicarbazone solamente en el follaje, solamente en el suelo y en el follaje más el suelo, sobre el crecimiento de Poa annua y Agrostis stolonifera. Los tratamientos de herbicidas evaluados incluyeron amicarbazone a 49 ó 147 g ai ha−1, y bispyribac-sodium a 74 g ai ha−1 para fines de comparación. Los datos de esta investigación concordaron con reportes previos sobre la absorción de amicarbazone, porque este compuesto es absorbido por vías por encima y debajo del suelo. Sin embargo, el crecimiento vegetal es inhibido más cuando la absorción se da por la raíz. Al compararse con la localización foliar del amicarbazone, la localización solamente en el suelo redujo la biomasa aérea y de raíz en más del doble a 56 días después del tratamiento (DAT), mientras que no se detectaron diferencias entre tratamientos que incluyeron contacto con el suelo. A lo largo de todos los parámetros evaluados en esta investigación, amicarbazone (49 g ha−1) impactó el crecimiento de A. stolonifera en forma similar a bispyribac-sodium, mientras que el crecimiento de P. annua fue inhibido más por amicarbazone, lo que sugiere que este herbicida provee una opción química eficaz de control para los usuarios.}, number={4}, journal={WEED TECHNOLOGY}, author={Jeffries, Matthew D. and Gannon, Travis W. and Rufty, Thomas W. and Yelverton, Fred H.}, year={2013}, pages={718–724} }
 @article{hoyle_yelverton_gannon_2013, title={Evaluating Multiple Rating Methods Utilized in Turfgrass Weed Science}, volume={27}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-12-00126.1}, abstractNote={Abstract Turfgrass weed scientists commonly use visual ratings (VR) to assign a numerical value to a turfgrass or weed response. These ratings lack quantifiable numerical values and are considered subjective. Alternatives to VR, including line intersect analysis (LIA) and digital image analysis (DIA), have been used to varying extents in turfgrass research. Alternatives can be expensive, labor intensive, and can require extensive calibration and increased time for data acquisition. Minimal research has been conducted evaluating rating methods used in turfgrass weed science. Trials were conducted in 2007 and 2008 to evaluate ratings methods used to quantify large crabgrass populations as influenced by tall fescue mowing height (2.5, 5.1, 7.6, and 10.2 cm). Percent large crabgrass cover was assessed utilizing VR, LIA, and DIA to determine if differences existed among evaluation methods. Pairwise comparisons, Pearson's correlation, and linear regression were performed to compare evaluations. All rating methods were significantly correlated to one another. Differences of large crabgrass cover estimates existed between LIA and DIA data at all mowing heights and between VR and DIA data at the 7.6 and 10.2 cm mowing heights in 2007. Authors believe that shadows produced by the turf canopy at higher (≥ 7.6 cm) mowing heights increased DIA estimates of large crabgrass cover. At trial initiation in 2007, researchers did not capture calibration images because the methodology to eliminate a shadow influence using a standard digital image had not been published. Additional DIA calibration in 2008 corrected for canopy shadows, and no differences were observed in large crabgrass cover between all evaluation methods indicated by nonsignificance pairwise comparisons and estimated regression parameters. These data indicate VR are no different than LIA or DIA in estimating large crabgrass cover as affected by tall fescue mowing height. Nomenclature: Tenacity (mesotrione); large crabgrass, Digitaria sanguinalis (L.) Scop. DIGSA; tall fescue, Lolium arundinaceum (Schreb.) S. J. Darbyshire. Resumen Los científicos de malezas en céspedes usan estimaciones visuales (VR) para asignar un valor numérico a las respuestas del césped o de la maleza. Estas estimaciones carecen de valores numéricos cuantificables y son consideradas subjetivas. Las alternativas a VR incluyen el análisis de intersección de líneas y análisis digital de imágenes (DIA), que han sido usados en diferentes niveles en la investigación en céspedes. Las alternativas pueden ser costosas, intensivas en labor, y pueden requerir una calibración extensiva e incrementos en el tiempo de adquisición de datos. La investigación que se ha realizado ha sido mínima para evaluar los métodos de evaluación usados en la ciencia de malezas en céspedes. Se realizaron estudios en 2007 y 2008 para evaluar los métodos de evaluación usados para cuantificar poblaciones de Digitaria sanguinalis a su vez que la influencia de la altura de poda en Lolium arundinaceum.(2.5, 5.1, 7.6 y 10.2 cm). El porcentaje de cobertura de D. sanguinalis fue evaluado utilizando VR, LIA y DIA para determinar la existencia de diferencias entre estos métodos de evaluación. Comparaciones de pares, correlación Pearson, y regresión lineal fueron realizadas para comparar los diferentes métodos. Todos los métodos de evaluación correlacionaron entre ellos en forma significativa. Hubo diferencias en la cobertura de D. sanguinalis entre los datos de LIA y DIA en todas las alturas de poda y entre los datos de VR y DIA a alturas de 7.6 y 10.2 cm en 2007. Los autores creen que las sombras producidas por el dosel del césped a alturas de poda altas (≥7.6 cm) incrementó los estimados de DIA de la cobertura de D. sanguinalis. Al inicio del estudio en 2007, los investigadores no capturaron imágenes de calibración porque la metodología para eliminar la influencia de las sombras usando una imagen digital estándar no había sido publicada. La calibración adicional de DIA en 2008 corrigió por sombras del dosel, y no se observaron diferencias en la cobertura de D. sanguinalis entre los diferentes métodos de evaluación, lo cual fue indicado por la no-significancia de las comparaciones de pares y los parámetros de regresión estimados. Estos datos indican que VR no es diferente de LIA o DIA al estimar el porcentaje de cobertura de D. sanguinalis al ser influenciada por la altura de poda de L. arundinaceum.}, number={2}, journal={WEED TECHNOLOGY}, author={Hoyle, Jared A. and Yelverton, Fred H. and Gannon, Travis W.}, year={2013}, pages={362–368} }
 @article{gannon_hixson_weber_shi_yelverton_rufty_2013, title={Sorption of Simazine and S-Metolachlor to Soils from a Chronosequence of Turfgrass Systems}, volume={61}, ISSN={["1550-2759"]}, DOI={10.1614/ws-d-12-00173.1}, abstractNote={Abstract Pesticide sorption by soil is among the most sensitive input parameters in many pesticide-leaching models. For many pesticides, organic matter is the most important soil constituent influencing pesticide sorption. Increased fertility, irrigation, and mowing associated with highly maintained turfgrass areas result in constant deposition of organic material, creating a soil system that can change drastically with time. Changes in soil characteristics could affect the environmental fate of pesticides applied to turfgrass systems of varying ages. Sorption characteristics of simazine and S-metolachlor were determined on five soils from bermudagrass systems of increasing ages (1, 4, 10, 21, and 99 yr) and compared to adjacent native pine and bare-ground areas. Surface soil (0 to 5 cm) and subsurface soil (5 to 15 cm) from all sites were air-dried and passed through a 4-mm sieve for separation from plant material. Using a batch-equilibrium method, sorption isotherms were determined for each soil. Data were fit to the Freundlich equation, and Kd (soil sorption coefficient) and Koc (organic carbon sorption coefficient) values were determined. Sorption and soil system age were directly related to organic matter content in the soil. Sorption of both herbicides increased with age of the soil system and was greatest on the surface soil from the oldest bermudagrass soil system. Herbicide sorption decreased at greater soil depths with lower organic matter. Greater amount of 14C–simazine sorbed to subsurface soil of the oldest turfgrass system compared to 14C–S-metolachlor. Results indicate that as bermudagrass systems age and accumulate higher organic matter levels increased herbicide sorption may decrease the leaching potential and bioavailability of simazine and S-metolachlor. Nomenclature: Simazine; S-metolachlor; bermudagrass; Cynodon dactylon [(L.) Pers.].}, number={3}, journal={WEED SCIENCE}, author={Gannon, Travis W. and Hixson, Adam C. and Weber, Jerome B. and Shi, Wei and Yelverton, Fred H. and Rufty, Thomas W.}, year={2013}, pages={508–514} }
 @article{gannon_yelverton_2011, title={Application Placement Equipment for Bahiagrass (Paspalum notatum) Suppression along Roadsides}, volume={25}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-10-00074.1}, abstractNote={Abstract Experiments were initiated during 2003 and 2004 to evaluate application placement equipment for plant growth regulator (PGR) applications along bahiagrass roadsides. Recently designed equipment combine low-volume application and pesticide placement technology. Application placement equipment conceal the image of a traditional spray application. Evaluated application placement equipment included a wet-blade mower (Burch Wet Blade) and rotary-wick applicator (Weedbug™) compared with a traditional broadcast spray. Wet-blade mowers are designed to mow and simultaneously apply a pesticide solution to a cut stem or leaf in a single pass, whereas rotary-wick applicators are designed to wick a solution onto foliage. Evaluated PGRs included imazapic (9, 35, or 53 g ha−1) and sulfometuron-methyl (26 g ha−1). Bahiagrass injury varied with application placement equipment and was greater with rotary-wick applications in 2003, compared with foliar broadcast applications and the wet-blade mower. Bahiagrass seedhead suppression ranged from 31 to 60% with application placement equipment in July 2003 compared with 93% for a broadcast spray. In 2004, rotary wick- or broadcast-applied PGRs provided excellent (> 90%) seedhead suppression. Although application placement equipment may have advantages to broadcast-spray applications, evaluated equipment did not enhance bahiagrass suppression along roadsides in North Carolina compared with a foliar broadcast spray. Additional research is needed to determine if this type of application may provide consistent results with other species and compounds. Nomenclature: Imazapic; sulfometuron-methyl; bahiagrass, Paspalum notatum (Flueggé), ‘Pensacola’}, number={1}, journal={WEED TECHNOLOGY}, author={Gannon, Travis W. and Yelverton, Fred H.}, year={2011}, pages={77–83} }
 @article{lewis_hoyle_fisher_yelverton_richardson_2011, title={Effect of Simulated Aminocyclopyrachlor Drift on Flue-Cured Tobacco}, volume={25}, ISSN={["0890-037X"]}, DOI={10.1614/wt-d-11-00037.1}, abstractNote={Abstract Flue-cured tobacco is sensitive to foliar and soil residues of off-target synthetic auxin drift. Aminocyclopyrachlor is a newly developed synthetic auxin herbicide that may be used in right-of-way applications for broadleaf weed and brush control. Aminocyclopyrachlor is considered a reduced-risk alternative in rights-of-way compared with similar compounds because of its low application rate and volatility risk. However, no research is available on the response of field-grown, flue-cured tobacco to aminocyclopyrachlor drift exposure. Research was conducted in 2009 and 2010 at the Border Belt Tobacco Research Station in Whiteville, NC, to determine the response of ‘NC 71’ flue-cured tobacco to five simulated drift rates of aminocyclopyrachlor (0.31, 1.6, 3.1, 15.7, and 31.4 g ae ha−1) and one aminopyralid (6.1 g ae ha−1) simulated drift rates applied pretransplant incorporated, pretransplant unincorporated, 3 wk after transplant, and 6 wk after transplant. All herbicide rates and application timings caused significant visual tobacco injury, ranging from slight to severe with increasing herbicide drift rates. Tobacco plant heights and fresh weights were reduced at all application timings receiving ≥ 15.7 g ha−1 aminocyclopyrachlor and the comparative aminopyralid rate. Nomenclature: Aminocyclopyrachlor, 6-amino-5-chloro-2-cyclopropyl-4-pyrimidine-carboxylic acid; aminopyralid 4-amino-3,6-dichloro-2-pyridinecarboxylic acid; tobacco, Nicotiana tabacum L. ‘NC-71’.}, number={4}, journal={WEED TECHNOLOGY}, author={Lewis, D. F. and Hoyle, S. T. and Fisher, L. R. and Yelverton, F. H. and Richardson, R. J.}, year={2011}, pages={609–615} }
 @article{ayers_moorman_deperno_yelverton_wang_2010, title={Effects of Mowing on Anthraquinone for Deterrence of Canada Geese}, volume={74}, ISSN={["0022-541X"]}, DOI={10.2193/2009-323}, abstractNote={Abstract Anthraquinone (AQ)-based repellents have been shown to reduce Canada goose (Branta canadensis) use of turfgrass; however, impacts of frequent mowing on efficacy of AQ have not been studied. Our objective was to determine efficacy and longevity of a rain-fast AQ-based avian repellent, FlightControl® PLUS (FCP), as a deterrent of free-ranging resident Canada geese under 2 mowing frequencies. We conducted the study at 8 sites in the Triangle region (Raleigh, Durham, and Chapel Hill) of North Carolina, USA. We arranged our experiment in a randomized complete block design, with each of 8 sites containing 4 0.1-ha treatment combinations: 1) treated with FCP and mowed every 4 days (T4), 2) treated with FCP and mowed every 8 days (T8), 3) untreated and mowed every 4 days, and 4) untreated and mowed every 8 days. We conducted 4 37-day field sessions (Jun–Jul 2007, Sep–Oct 2007, Jun–Jul 2008, and Sep–Oct 2008), representing the summer molting phase and the full-plumage phase. Resident goose use (measured by daily no. of droppings) was 41–70% lower on treated plots than on untreated plots, but use was similar between T4 and T8. Average FCP coverage on grass blades decreased in coverage from approximately 95% to 10% over the 30-day posttreatment phase. Results indicate that resident Canada goose use of FCP-treated turfgrass areas was lower than untreated areas even when chemical coverage on grass was 10%. Further, mowing frequency did not have a clear impact on the efficacy of FCP as a Canada goose repellent.}, number={8}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Ayers, Christopher R. and Moorman, Christopher E. and Deperno, Christopher S. and Yelverton, Fred H. and Wang, Huixia J.}, year={2010}, month={Nov}, pages={1863–1868} }
 @article{henry_yelverton_burton_2009, title={Asymmetric Responses of Paspalum Species to a Soil Moisture Gradient}, volume={49}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2008.08.0506}, abstractNote={Anecdotal evidence suggests that dallisgrass (Paspalum dilatatum Poir.) and bahiagrass (Paspalum notatum Flueggé), two of the most troublesome weed species in managed turfgrass, are both drought and flood tolerant. Water table depth gradient tanks were employed to identify habitat specialization and competitive differences between dallisgrass and bahiagrass. Shoot and rhizome final biomass and survival were used as metrics for plants grown in monoculture or competition with hybrid bermudagrass (Cynodon transvaalensis Burtt Davy × C. dactylon (L.) Pers. ‘Tifway 419’) in sand or sandy loam soil. Shoot and rhizome growth of dallisgrass was greatest at the levels of highest soil moisture within each gradient tank regardless of soil type or competition. Percent survival of dallisgrass decreased to a low of 50% as depth to water table increased when grown as a monoculture and 12.5% when grown in competition with hybrid bermudagrass. Percent survival of bahiagrass was 100% regardless of water table depth, soil type, or competition. Shoot and rhizome growth of bahiagrass was greatest as depth to water table increased when grown in sandy loam soil. The opposite trend was observed when grown in sandy soil. Results suggest that dallisgrass may be more competitive with hybrid bermudagrass when volumetric soil moisture is high, while bahiagrass may be more competitive when volumetric soil moisture is low.}, number={4}, journal={CROP SCIENCE}, author={Henry, Gerald M. and Yelverton, Fred H. and Burton, Michael G.}, year={2009}, pages={1473–1480} }
 @article{cummings_weber_yelverton_leidy_2009, title={Downward Mobility of C-14-Labeled Simazine in a Bermudagrass System vs. a Fallow Soil System}, volume={49}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2008.05.0297}, abstractNote={Pesticides applied to bermudagrass (Cynodon dactylon L.) can be captured by the canopy, absorbed by the roots, or bound in the thatch layer, which reduces the amount available to leach compared with a fallow soil system where pesticides may be applied directly to soil. 14C‐Simazine was applied to dormant bermudagrass and fallow soil in lysimeters in a cold growth chamber (5°C) (cold‐fallow soil) and to actively growing bermudagrass and fallow soil in lysimeters in a greenhouse (25°C) (warm‐fallow soil) in April. Following clipping collection, lysimeters were irrigated with 5 cm of water every 3–4 d, and leachate was collected. After 25 d, lysimeters were divided into 2‐cm increments from 0 to 10 cm, then 5‐cm increments from 10 to 30 cm. Because of evapotranspiration, actively growing bermudagrass and warm‐fallow soil yielded significantly less leachate than dormant bermudagrass and cold‐fallow soil indicating less moisture is available for downward movement during summer. After the addition of 31 cm of irrigation, the greatest quantities of 14C‐simazine were in the 0‐ to 2‐cm increment for all treatments and decreased with depth. Although the greatest quantities of 14C‐simazine in leachate occurred in dormant bermudagrass, the reached factor was greatest for cold‐fallow soil (0.20), followed by dormant bermudagrass (0.17), warm‐fallow soil (0.16), and actively growing bermudagrass (0.14). Therefore, simazine is least mobile in bermudagrass during summer and most mobile in fallow soil in winter.}, number={2}, journal={CROP SCIENCE}, author={Cummings, H. D. and Weber, J. B. and Yelverton, F. H. and Leidy, R. B.}, year={2009}, pages={704–713} }
 @article{henry_burton_yelverton_2009, title={Heterogeneous distribution of weedy Paspalum species and edaphic variables in turfgrass}, volume={44}, number={2}, journal={HortScience}, author={Henry, G. M. and Burton, M. G. and Yelverton, F. H.}, year={2009}, pages={447–451} }
 @article{hixson_shi_weber_yelverton_rufty_2009, title={Soil Organic Matter Changes in Turfgrass Systems Affect Binding and Biodegradation of Simazine}, volume={49}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2008.09.0541}, abstractNote={Concern about pesticide losses from maintained turfgrass areas led us to examine the fate of the triazine herbicide simazine in turfgrass systems and, specifically, interactions between simazine binding to soil organic matter and biodegradation. Soil samples were removed from turfgrass systems of different ages, placed in microcosms, conditioned as sterile or nonsterile, and exposed to 14C‐simazine. At seven sampling intervals, the soil was extracted and 14C was separated into three pools; bound, extractable, and CO2 With sterilized surface soil (0–5 cm), 52, 70, and 71% of applied 14C‐simazine was bound to soil from the 4‐, 21‐, and 99‐yr‐old turfgrass systems, respectively, after 16 wk. With nonsterile conditions, biodegradation became dominant, as 60 to 80% of the 14C was recovered in the CO2 fraction and binding was held at ∼20%. Among all soils evaluated, bound 14C and 14CO2 production was lower in subsurface soil (5–15 cm) from the 4‐ and 21‐yr‐old turfgrass systems. 14C‐simazine disappearance time (DT50) values under nonsterile conditions ranged from 0.9 to 5.8 wk. Results indicate that turfgrass systems have a relatively low amount of simazine available for leaching as the systems age due to a large capacity for biodegradation and binding to organic matter.}, number={4}, journal={CROP SCIENCE}, author={Hixson, Adam C. and Shi, Wei and Weber, Jerome B. and Yelverton, Fred H. and Rufty, Thomas W.}, year={2009}, pages={1481–1488} }
 @article{henry_burton_richardson_yelverton_2008, title={Absorption and Translocation of Foramsulfuron in Dallisgrass (Paspalum dilatatum) Following Preapplication of MSMA}, volume={56}, ISSN={["1550-2759"]}, DOI={10.1614/WS-08-035.1}, abstractNote={Abstract Several field studies have observed increased foramsulfuron efficacy for the control of dallisgrass when foramsulfuron is applied after MSMA. Therefore, laboratory studies were conducted with mature dallisgrass to study the absorption and translocation of 14C-foramsulfuron, and then examine the impact of preliminary applications (preapplications) of MSMA or foramsulfuron on herbicide absorption and movement. Herbicide absorption increased rapidly through 4 h, and by 8 h, differences in absorption between pretreated and control plants were evident. After 48 h, foramsulfuron absorption in non-pretreated plants was 55%, whereas plants that received either pretreatment absorbed 70% of the herbicide. Translocation above (younger tissue) and below (older tissue) the treated leaf was 0.65 and 0.62% for non-pretreated plants, respectively. Pretreatment with foramsulfuron resulted in the translocation of 2.12 and 1.55% of applied radioactivity above and below the treated leaf, respectively. Pretreatment with MSMA resulted in the translocation of 2.33 and 2.34% of applied radioactivity above and below the treated leaf, respectively. These data indicated that pretreatment of mature dallisgrass with either foramsulfuron or MSMA results in an increase in both uptake and translocation of foramsulfuron applied 2 wk after pretreatment. The increase in absorption and translocation of foramsulfuron in the pre–MSMA-treated plants may explain the increase in control observed in the field when comparing it to the pre–foramsulfuron-treated dallisgrass plants. Nomenclature: Foramsulfuron; MSMA; dallisgrass, Paspalum dilatatum Poir. PASDI.}, number={6}, journal={WEED SCIENCE}, author={Henry, G. and Burton, J. and Richardson, R. and Yelverton, F.}, year={2008}, pages={785–788} }
 @article{gannon_yelverton_2008, title={Effect of simulated rainfall on tall fescue (Lolium arundinaceum) control with glyphosate}, volume={22}, ISSN={["1550-2740"]}, DOI={10.1614/WT-07-158.1}, abstractNote={Field experiments were conducted to determine the effect of simulated rainfall after glyphosate application on tall fescue control. Three glyphosate formulations, three simulated rainfall amounts, two application rates, and three rain-free periods were evaluated. Glyphosate formulations evaluated included Roundup Original®, Roundup Pro®, and Roundup ProDry®. Herbicide drying periods, or rain-free intervals, included 15, 30, or 60 min. Simulated rainfall amounts were 0, 0.25, or 0.64 cm. Application rates of glyphosate were 3.4 or 6.7 kg ae/ha. Averaged across glyphosate formulation and simulated rainfall amount, excellent (≥ 90%) tall fescue control was observed when no simulated rainfall occurred within 60 min after application, whereas good (≥ 80%) tall fescue control was observed when 30 rain-free min were provided. Although current glyphosate labels are vague about rainfastness, these data indicate that critical rain-free periods may be as short as 30 min when higher application rates are used.}, number={3}, journal={WEED TECHNOLOGY}, author={Gannon, Travis W. and Yelverton, Fred H.}, year={2008}, pages={553–557} }
 @article{henry_yelverton_burton_2007, title={Dallisgrass (Paspalum dilatatum) control with foramsulfuron in bermuclagrass turf}, volume={21}, ISSN={["1550-2740"]}, DOI={10.1614/WT-06-163.1}, abstractNote={Dallisgrass response to various MSMA and foramsulfuron herbicide combinations was evaluated from 2004 through 2006 in North Carolina. Dallisgrass control declined with herbicide rates; therefore, only the highest rates (foramsulfuron, 0.15 kg ai/ha; MSMA, 2.5 kg ai/ha) are discussed. Foramsulfuron followed by (fb) foramsulfuron 1 wk after initial treatment (WAIT) provided 60% control of dallisgrass 1 mo after initial treatment (MAIT), but control declined to 40% 3 MAIT. MSMA (2.5 kg ai/ha) applied three times provided 89% dallisgrass control 1 MAIT, but control declined to 71% 3 MAIT. Among 22 MSMA and foramsulfuron sequential application programs, MSMA fb foramsulfuron 2 WAIT fb MSMA 3 WAIT provided the highest control (94%) of dallisgrass 1 MAIT, and control levels remained high (93%) 3 MAIT. This herbicide program provided 85% control 1 yr after initial treatment (YAIT), whereas no other treatment provided greater than 37% control 1 YAIT. Timing of foramsulfuron application following the initial MSMA application affected the control of dallisgrass. Waiting 2 WAIT, rather than 1 WAIT, before applying foramsulfuron increased control of dallisgrass by 20% 1 MAIT and 19% 3 MAIT. However, the increase in control 1 YAIT was only 5% regardless of herbicide rate. The addition of a second application of MSMA following the application of foramsulfuron 2 WAIT of MSMA further increased control by 10% 1 MAIT, 37% 3 MAIT, and 48% 1 YAIT. Results from this study suggest dallisgrass may be controlled with applications of MSMA fb foramsulfuron 2 WAIT fb MSMA 3 WAIT applied during early to midsummer. The use of MSMA was required to achieve dallisgrass control, however, the relatively high level of control achieved 1 YAIT with a program including sequential applications of MSMA and foramsulfuron may help reduce the total amount of arsenical herbicides used to control dallisgrass infestations over time. Nomenclature: Dallisgrass Paspalum dilatatum Poir. PASDI, hybrid bermudagrass, Cynodon transvaalensis × Cynodon dactylon ‘Tifway’}, number={3}, journal={WEED TECHNOLOGY}, author={Henry, Gerald M. and Yelverton, Fred H. and Burton, Michael G.}, year={2007}, pages={759–762} }
 @article{henry_burton_yelverton_2007, title={Effect of mowing on lateral spread and rhizome growth of troublesome Paspalum species}, volume={55}, ISSN={["1550-2759"]}, DOI={10.1614/WS-07-030.1}, abstractNote={The effect of mowing regime on lateral spread and rhizome growth of dallisgrass and bahiagrass was determined in field studies conducted in 2003 and 2004 in North Carolina over 5 mo. Treatments were selected to simulate mowing regimes common to intensively managed common bermudagrass turfgrass and include 1.3-, 5.2-, and 7.6-cm heights at frequencies of three, two, and two times per week, respectively. A nonmowed check was included for comparison. Lateral spread of dallisgrass was reduced 38 to 47% regardless of mowing regime when compared with the nonmowed check. Rhizome fresh weight of dallisgrass was reduced 49% in 2003 and 30% in 2004 when mowed at the 7.6-cm regime after 5 mo, whereas the 5.2-cm mowing regime caused a reduction of 31%. Rhizome fresh weight of dallisgrass was most negatively affected by the 1.3-cm regime, which caused reductions of 57% in 2003 and 37% in 2004. Lateral spread of bahiagrass was more strongly affected by mowing height and frequency than dallisgrass, with reductions of 21 to 27%, 40%, and 44 to 62% when mowed at 7.6, 5.2, and 1.3-cm regimes, respectively. Rhizome fresh weight of bahiagrass was reduced 24 to 33%, 55%, and 70 to 73% when mowed at 7.6, 5.2, and 1.3 cm, respectively. Based upon these results, areas mowed at a golf course rough height (≥ 5.2 cm) may be more conducive to bahiagrass spread, whereas dallisgrass may tolerate areas mowed at a fairway height (1.3 cm). Mowing at the shorter heights examined in this study clearly reduced the potential ofPaspalumspp. vegetative spread and may help to explain observed distributions ofPaspalumspp. infestations in bermudagrass turfgrass.}, number={5}, journal={WEED SCIENCE}, author={Henry, Gerald M. and Burton, Michael G. and Yelverton, Fred H.}, year={2007}, pages={486–490} }
 @article{hixson_gannon_yelverton_2007, title={Efficacy of application placement equipment for tall fescue (Lolium arundinaceum) growth and seedhead suppression}, volume={21}, ISSN={["1550-2740"]}, DOI={10.1614/WT-06-108.1}, abstractNote={Field research was conducted to evaluate plant growth-regulator efficacy for tall fescue growth and seedhead suppression applied using application placement equipment. Specially designed equipment outfitted with fluid application systems applies low-volume plant growth regulator directly on plant foliage, reducing opportunity for drift and visible application. Wet-blade mowers are equipped to apply plant growth regulators and mow in a single pass, whereas rotary-wick applicators simply wipe chemicals directly on uncut vegetation. Therefore, a wet-blade, rotary-wick, and broadcast sprayer system were chosen to apply imazapic at three rates (9, 35, and 53 g ai/ha), and a mefluidide + chlorsulfuron tank mix at 7 + 140 g ai/ha to tall fescue roadsides for vegetative growth and seedhead suppression. Experiments were conducted during the spring and summer of 2004 in central and western North Carolina. Tall fescue was slightly injured and discolored by all treatments but fully recovered by 2 mo after treatment. Imazapic suppressed new vegetative growth 3 mo after treatment compared with the nonmowed–nontreated control (16.1 cm of growth) and the mowed–nontreated control (21.1 cm) when applied with the rotary-wick applicator (8.5 cm) and broadcast sprayer (6.2 cm). However, differences in vegetative height primarily occurred when application placement equipment treatments were compared with nontreated vegetation as opposed to mowed–nontreated plants. Although mowed–nontreated and wet-blade–treated plots had more new vegetative growth, nonmowed–nontreated plots still consistently had the greatest vegetative height. Seedhead suppression ranged from 87 to 100% when compared with the nonmowed–nontreated control, with wet-blade treatments consistently providing the least-effective seedhead suppression. Overall, application placement equipment did not improve plant growth-regulator efficacy when compared with the foliar broadcast spray. Nomenclature: Chlorsulfuron; imazapic; mefluidide; tall fescue, Lolium arundinaceum (Schreb.) S.J. Darbyshire, ‘Kentucky 31’}, number={3}, journal={WEED TECHNOLOGY}, author={Hixson, Adam C. and Gannon, Travis W. and Yelverton, Fred H.}, year={2007}, pages={801–806} }
 @article{weber_warren_swain_yelverton_2007, title={Physicochemical property effects of three herbicides and three soils on herbicide mobility in field lysimeters}, volume={26}, ISSN={["1873-6904"]}, DOI={10.1016/j.cropro.2006.01.020}, abstractNote={Understanding herbicide mobility in soils is necessary to prevent ground water contamination. We studied the mass balance distribution of three 14C-labeled herbicides (atrazine, metolachlor, and primisulfuron-methyl) in three soils (Blanton, Norfolk, and Rains) 128 days after treatment (DAT) to fallow soil column field lysimeters. Analyses were made of surface soil, subsoil, and leachate samples. Volatilization losses were calculated by difference. Our objectives were to examine, measure, and correlate the leaching patterns of the chemicals and correlate their leaching characteristics with physicochemical and biological properties of the herbicides and the physicochemical properties of the soils. Metolachlor was the most mobile herbicide, as indicated by the retardation factor (Rf) (Rf=0.48 in 1992 and 0.19 in 1993), followed by primisulfuron-methyl (Rf=0.41 in 1992 and 0.12 in 1993), and atrazine (Rf=0.38 in 1992 and 0.15 in 1993), where mobility was greatly affected by water input (637 mm in 1992 and 509 mm in 1993). Herbicide mobility (Rf) was related to 14C-parent compound in leachate (0.02–6.9% of 14C applied), 14C in the subsoil (9–24%), and the pesticide leaching potential (PLP) index of each herbicide, as computed using a simple decision-aid model. The herbicides were most mobile through Blanton, followed by Norfolk and Rains soils and mobility (Rf) was inversely related to mean % organic matter (OM) content of the soil profiles and directly related to soil pH and soil leaching potential (SLP) indices of the soils. Physicochemical and biological properties of the herbicides and soils were related to many of the measured herbicide distribution parameters.}, number={3}, journal={CROP PROTECTION}, author={Weber, Jerome B. and Warren, Ralph L. and Swain, Len R. and Yelverton, Fred H.}, year={2007}, month={Mar}, pages={299–311} }
 @article{gannon_yelverton_mcelroy_2006, title={Allelopathic potential of centipedegrass (Eremochloa ophiuroides)}, volume={54}, ISSN={["0043-1745"]}, DOI={10.1614/WS-05-179R.1}, abstractNote={Abstract Laboratory and greenhouse experiments were conducted to determine the allelopathic potential of centipedegrass. Germination and growth of indicator species were evaluated in soil leachates, leaf debris, and aqueous leaf extracts of centipedegrass. Centipedegrass soil leachates did not inhibit annual bluegrass, goosegrass, henbit, large crabgrass, or perennial ryegrass germination compared with the nonfertilized control. Incorporated centipedegrass leaf debris did not reduce lettuce germination, shoot weight, or root weight compared with the control. However, shoot and root dry weights of radish were reduced with increasing rates of centipedegrass leaf debris. Six and 9 mg debris g−1 soil reduced radish shoot weight by 49 and 64%, respectively, compared with the control. Aqueous leaf extracts of centipedegrass reduced lettuce germination; however, radicle and hypocotyl length were similar to the control. These data do not conclusively suggest centipedegrass has widespread allelopathic activity; however, significant reductions in shoot and root weight of radish with increasing centipedegrass leaf debris demonstrate a pattern of inhibition of one species against another, which fulfills a requirement of allelopathic interactions. Nomenclature: Annual bluegrass, Poa annua L. POAAN; goosegrass, Eleusine indica (L.) Gaertn. ELEIN; henbit, Lamium amplexicaule L. LAMAM; large crabgrass, Digitaria sanguinalis (L.) Scop. DIGSA; centipedegrass, Eremochloa ophiuroides (Munro) Hack.; lettuce, Lactuca sativa L.; perennial ryegrass, Lolium perenne L.; radish, Raphanus sativus L.}, number={3}, journal={WEED SCIENCE}, author={Gannon, TW and Yelverton, FH and McElroy, JS}, year={2006}, pages={521–525} }
 @article{cummings_brandenburg_leidy_yelverton_2006, title={Impact of fipronil residues on mole cricket (Orthoptera : Gryllotalpidae) behavior and mortality in bermudagrass}, volume={89}, ISSN={["0015-4040"]}, DOI={10.1653/0015-4040(2006)89[293:IOFROM]2.0.CO;2}, abstractNote={Abstract In a greenhouse experiment, fipronil was applied at 0.014 kg ai/ha to bermudagrass, Cynodon dactylon L., in plastic 5-liter containers 120, 90, 60, 30, and 0 days before adding one tawny mole cricket nymph, Scapteriscus vicinus Scudder to the container. After the exposure period, soil in the containers was divided into depth increments of 0-4, 4-8, and 8-18 cm, and cricket status was recorded as dead, absent, or alive by thoroughly examining soil. Soil in the 0-4 cm-increment was analyzed for fipronil and four fipronil metabolite residues. Fipronil residue concentrations decreased with time (C = 0.00002x2 - 0.0053x + 0.3675, R2 = 0.9998 where C = fipronil concentration (μg/g of soil) and x = days after treatment). Concentrations of two metabolites, fipronil sulfone and fipronil sulfide, increased as fipronil residues decreased. Each treatment’s affect on late instar mole crickets was significantly different from the non-treated; however, there were no significant differences in nymph status among fipronil-treated containers. Fipronil and residues of its metabolites 120 days after application were 0.047 μg/g of soil and were high enough to kill or repel mole crickets to the same extent as the 0-day treatment, 0.368 μg/g of soil. Repellency of fipronil and its metabolites was significant as the majority of nymphs evacuated or died in the treated containers, but 35 of 37 nymphs were found alive in the non-treated containers.}, number={3}, journal={FLORIDA ENTOMOLOGIST}, author={Cummings, Hennen D. and Brandenburg, Rick L. and Leidy, Ross B. and Yelverton, Fred H.}, year={2006}, month={Sep}, pages={293–298} }
 @article{mcelroy_yelverton_warren_2005, title={Control of green and false-green kyllinga (Kyllinga brevifolia and Kyllinga gracillima) in golf course fairways and roughs}, volume={19}, ISSN={["1550-2740"]}, DOI={10.1614/WT-03-241R1.1}, abstractNote={Herbicides commonly used to control Cyperus spp. are not completely effective against Kyllinga spp. Field trials were conducted on North Carolina golf courses to evaluate green and false-green kyllinga control at fairway and rough golf course mowing heights. Treatments included single and sequential applications of bentazon (1.12 kg ai/ha), halosulfuron (0.07 kg/ha), MSMA (2.24 kg/ ha), and trifloxysulfuron (0.03 kg/ha); imazaquin (0.56 kg/ha) with and without MSMA; and two rates of sulfentrazone (0.42 and 0.56 kg/ha). Green or false-green kyllinga control was equivalent at fairway and rough mowing heights. Halosulfuron applied sequentially, imazaquin with and without MSMA, and trifloxysulfuron applied singly or sequentially, controlled green and false-green kyllinga 89 to 99% 10 wk after initial treatment (WAIT). However, Kyllinga spp. control decreased over the course of the study regardless of herbicide treatment. By one year after treatment (YAIT), bentazon or MSMA alone controlled green or false-green kyllinga 50% or less. No difference was observed in green or false-green kyllinga control between imazaquin vs. imazaquin plus MSMA, sulfentrazone 0.42 vs. 0.56 kg/ha, or trifloxysulfuron one vs. two applications at any rating date. Green kyllinga was seemingly more difficult to control than false-green kyllinga. Sequential applications of bentazon and MSMA, single applications of halosulfuron, sulfentrazone applied at 0.42 and 0.56 kg/ha, and single and sequential applications of trifloxysulfuron controlled false-green kyllinga at least 10% greater than green kyllinga at 1 YAIT. Further research is needed to assess the potential variation among Cyperus and Kyllinga spp. response to herbicides. Nomenclature: Bentazon, halosulfuron, imazaquin, monosodium methanearsonate (MSMA), sulfentrazone, trifloxysulfuron; bermudagrass, Cynodon spp.; false-green kyllinga, Kyllinga gracillima L.; green kyllinga, Kyllinga brevifolia Rottb. #3 KYLBR. Additional index words: Mowing height, turfgrass management. Abbreviations: WAIT, weeks after initial treatment; YAIT, year after initial treatment.}, number={4}, journal={WEED TECHNOLOGY}, author={McElroy, JS and Yelverton, FH and Warren, LS}, year={2005}, pages={824–829} }
 @article{mcelroy_yelverton_burton_2005, title={Habitat delineation of green and false-green kyllinga in turfgrass systems and interrelationship of elevation and edaphic factors}, volume={53}, ISSN={["0043-1745"]}, DOI={10.1614/WS-04-089R.1}, abstractNote={Knowledge of the influence of environmental factors on weed populations is important in developing sustainable turfgrass management practices. Studies were conducted to evaluate the relationship of green and false-green kyllinga population densities with elevation and edaphic factors in turfgrass systems. Studies were conducted on five different golf courses in North Carolina, three affected by green kyllinga, and two affected by false-green kyllinga. According to Spearman correlation coefficients, both green and false-green kyllinga were correlated with increasing soil volumetric water content, whereas correlation of other edaphic variables varied among sites and species. Stepwise logistic regression confirmed the correlation of volumetric water with green kyllinga presence, but model components varied among sites for false-green kyllinga. Increasing green kyllinga populations correlated with increasing soil sodium; however, sodium did not reach a level believed to be detrimental to turfgrass growth. No other variables correlated with green or false-green kyllinga across all sites. We hypothesized that the lack of significant correlations was due to the overall influence of relative elevation on edaphic variables. According to principal components analysis (PCA), relative elevation had a profound impact on the measured edaphic variables at all sites. However, results of PCA at one site differed sharply from other sites. Results from that site demonstrate the potentially strong effects of management practices to alter edaphic trends normally observed with topography.}, number={5}, journal={WEED SCIENCE}, author={McElroy, JS and Yelverton, FH and Burton, MG}, year={2005}, pages={620–630} }
 @article{mcelroy_breeden_yelverton_gannon_askew_derr_2005, title={Response of four improved seeded bermudagrass cultivars to postemergence herbicides during seeded establishment}, volume={19}, ISSN={["1550-2740"]}, DOI={10.1614/WT-04-303R2.1}, abstractNote={Herbicides and herbicide prepackaged mixtures registered for use on established bermudagrass turf may cause significant injury to recently seeded bermudagrass cultivars, delaying full establishment. Research was conducted to evaluate the use of 12 herbicide treatments applied at onset of uniform stolon development (4 to 8 wk after seeding) to recently seeded ‘Princess 77,’ ‘Riviera,’ ‘Savannah,’ and ‘Yukon’ bermudagrass cultivars. In general, Yukon was more susceptible to herbicide injury than other cultivars. Atrazine at 1.1 kg ai/ha injured all cultivars 55 to 59% 14 d after initial treatment (DAIT), which lead to reduced bermudagrass cover 21 DAIT. Triclopyr + clopyralid at 0.63 + 0.21 kg ae/ha, respectively, injured Savannah and Yukon greater than other broadleaf weed herbicides (2,4-D + mecoprop + dicamba or 2,4-D + clopyralid + dicamba). Foramsulfuron did not injure or reduce bermudagrass cover of any cultivar evaluated at any rating date. The only adverse effect of trifloxysulfuron was a reduction in Riviera and Yukon ground cover at 21 DAIT. MSMA applied sequentially and quinclorac treatments did not injure or reduce ground cover of Savannah or Princess 77. MSMA applied sequentially and/or quinclorac injured and reduced ground cover of Riviera and Yukon; however, both cultivars completely recovered from MSMA or quinclorac injury by 42 DAIT. Nomenclature: clopyralid, 2,4-D, dicamba, foramsulfuron, mecoprop, MSMA, triclopyr, trifloxysulfuron, quinclorac; common bermudagrass, Cynodon dactylon (L.) Pers. #3 CYNDA, ‘Princess 77’, ‘Riviera’, ‘Savannah’, ‘Yukon.’ Additional index words: Seeded establishment, stolon development, turfgrass tolerance. Abbreviations: DAIT, days after initial treatment; NTEP, National Turfgrass Evaluation Program.}, number={4}, journal={WEED TECHNOLOGY}, author={McElroy, JS and Breeden, GK and Yelverton, FH and Gannon, TW and Askew, SD and Derr, JF}, year={2005}, pages={979–985} }
 @article{hart_yelverton_nelson_lycan_henry_2005, title={Response of glyphosate-resistant and glyphosate-susceptible bentgrass (Agrostis spp.) to postemergence herbicides}, volume={19}, ISSN={["0890-037X"]}, DOI={10.1614/WT-03-224R2.1}, abstractNote={Studies were conducted in the summer and fall of 2001 in North Brunswick, NJ, and Marion County, Oregon, to evaluate the response of glyphosate-resistant and glyphosate-susceptible creeping bentgrass hybrids, colonial bentgrass, redtop, and dryland bentgrass grown as individual plants to postemergence (POST) herbicides. Glyphosate at 1.7 kg ae/ha, glufosinate at 1.7 kg ai/ha, fluazifop-P at 0.3 and 0.4 kg ai/ha, clethodim at 0.3 kg ai/ha, sethoxydim at 0.5 kg ai/ha, and a combination of glyphosate and fluazifop-P were applied 6 wk after planting. Glyphosate provided almost complete control of all susceptible bentgrass species at 4 weeks after treatment (WAT). Glufosinate provided 95% or greater control of all bentgrass species at 4 WAT, but regrowth was observed on all species in the summer experiment in Oregon. Fluazifop-P, clethodim, and sethoxydim provided slower control of bentgrass species, which ranged from 38 to 94% at 4 WAT, depending on species, herbicide, and experimental location. By 8 WAT, fluazifop-P at 0.4 kg/ha applied alone or in combination with glyphosate showed the highest levels of control (>90%) across all bentgrass species. Studies were also conducted in 2002 in the spring and summer in North Carolina to evaluate the response of a mature stand of glyphosate-susceptible ‘Penncross’ creeping bentgrass to POST herbicides. Two applications of glyphosate at 1.7 kg/ha were required to achieve 98% bentgrass control at 8 WAT. Fluazifop-P at 0.4 kg/ha, clethodim at 0.3 kg/ha, and sethoxydim at 0.4 kg/ha exhibited herbicidal activity, but two applications were required to reach (>82%) control of bentgrass at 8 WAT. Two sequential applications of clethodim or the combination of glyphosate and fluazifop-P provided 98% control of bentgrass at 8 WAT. Of the other herbicide treatments evaluated, only atrazine and sulfosulfuron provided (>80%) control at 8 WAT. The results of these studies demonstrate that fluazifop-P, clethodim, and sethoxydim have substantial herbicide activity on bentgrass species and may be viable alternatives to glyphosate for control of glyphosate-resistant creeping bentgrass and related bentgrass species in areas where they are not wanted. Glufosinate, atrazine, and sulfosulfuron also exhibited substantial herbicidal activity on bentgrass, and further research with these herbicides is warranted.}, number={3}, journal={WEED TECHNOLOGY}, author={Hart, SE and Yelverton, F and Nelson, EK and Lycan, DW and Henry, GM}, year={2005}, pages={549–559} }
 @article{mcelroy_yelverton_burke_wilcut_2004, title={Absorption, translocation and metabolism of halosulfuron and trifloxysulfuron in green kyllinga (Kyllinga brevifolia) and false-green kyllinga (K-gracillima)}, volume={52}, ISSN={["0043-1745"]}, DOI={10.1614/WS-03-133R}, abstractNote={Abstract Trifloxysulfuron controls green and false-green kyllinga more effectively than halosulfuron. Studies were conducted to evaluate the absorption, translocation, and metabolism of 14C-halosulfuron and 14C-trifloxysulfuron when foliar applied to green and false-green kyllinga. No differences were observed between the two kyllinga spp. with regard to absorption, translocation, or metabolism of either herbicide. The majority of 14C-halosulfuron and 14C-trifloxysulfuron was absorbed by 4 h, with an accumulation of 63 and 47% radioactivity, respectively. Accumulation of both herbicides occurred in the treated leaf and the primary shoot from whence the treated leaf was removed, with minor accumulation occurring in the roots and newly formed rhizomes. Of the total amount of 14C-halosulfuron absorbed into the plant, 77% remained in the form of the parent compound compared with 61% of 14C-trifloxysulfuron. The parent compound was distributed mainly in the treated leaf and primary shoot, whereas polar metabolites were concentrated in the roots and rhizomes. Nonpolar metabolites of 14C-trifloxysulfuron accumulated in the treated leaf and primary shoot. These data indicate that absorption, translocation, or metabolism could not explain the variation in green and false-green kyllinga control between halosulfuron and trifloxysulfuron. Nomenclature: Halosulfuron; trifloxysulfuron; false-green kyllinga, Kyllinga gracillima L.; green kyllinga, Kyllinga brevifolia Rottb. KYLBR.}, number={5}, journal={WEED SCIENCE}, author={McElroy, JS and Yelverton, FH and Burke, IC and Wilcut, JW}, year={2004}, pages={704–710} }
 @article{burnell_yelverton_neal_gannon_mcelroy_2004, title={Control of silvery-thread moss (Bryum argenteum Hedw.) in creeping bentgrass (Agrostis palustris Huds.) putting greens}, volume={18}, ISSN={["1550-2740"]}, DOI={10.1614/WT-03-082R1}, abstractNote={Field experiments were conducted to evaluate chemicals for silvery-thread moss control and bentgrass turfgrass quality. Treatments included iron (Fe)-containing products, nitrogen fertilizers, Ultra Dawn dishwashing detergent (UD) at 3% (v/v), and oxadiazon. In general, greater silvery-thread moss control was achieved with Fe-containing products. Ferrous sulfate at 40 kg Fe/ha plus ammonium sulfate at 30 kg N/ha, a combined product of ferrous oxide, ferrous sulfate, and iron humates (FEOSH) at 125 kg Fe/ha, and a combined product of iron disulfide and ferrous sulfate (FEDS) at 112 kg Fe/ha reduced silvery-thread moss populations 87, 81, and 69%, respectively, 6 wk after initial treatment (WAIT). UD reduced silvery-thread moss populations 57% 6 WAIT. The addition of oxadiazon to Fe-containing treatments did not improve silvery-thread moss population reduction. Other experiments evaluated two formulations of chlorothalonil, each applied at two rates, chlorothalonil with zinc at 9.5 and 17.4 kg ai/ha and chlorothalonil without zinc at 9.1 and 18.2 kg/ ha, and two spray volumes (2,038 and 4,076 L/ha). Greater silvery-thread moss population reduction was observed at Jefferson Landing in 1999 compared with Elk River in 1999 and 2000. Rainfall events at Elk River in 1999 and 2000 within 24 h after application and no rain at Jefferson Landing may account for variation in performance of products between sites. However, no difference in chlorothalonil formulation, rate, or spray volume was observed in any location or year. These data indicate that Fe-containing fertilizers or chlorothalonil can be used to reduce silvery-thread moss populations in creeping bentgrass putting greens.}, number={3}, journal={WEED TECHNOLOGY}, author={Burnell, KD and Yelverton, FH and Neal, JC and Gannon, TW and McElroy, JS}, year={2004}, pages={560–565} }
 @article{gannon_yelverton_cummings_mcelroy_2004, title={Establishment of seeded centipedegrass (Eremochloa ophiuroides) in utility turf areas}, volume={18}, ISSN={["0890-037X"]}, DOI={10.1614/WT-03-112R1}, abstractNote={Experiments were conducted to evaluate safety and effectiveness of herbicides during establishment of seeded centipedegrass. Centipedegrass tolerance to herbicides was evaluated at seeding and early postemergence. Imazapic at 105 g ai/ha, sulfometuron at 53 g ai/ha, or metsulfuron at 21 or 42 g ai/ha applied at seeding reduced centipedegrass ground cover compared with the nontreated. Imazapic at 18 or 35 g/ha or applications of atrazine or simazine at seeding did not reduce centipedegrass ground cover compared with the nontreated. Applications of chlorsulfuron plus mefluidide (7 + 140 g ai/ha) or metsulfuron at 21 or 42 g/ha applied 6 wk after seeding (WAS) centipedegrass (one-leaf to one-tiller growth stage) caused 20, 16, and 83% phytotoxicity, respectively, 56 d after treatment (DAT). Imazapic, sulfometuron, atrazine, or simazine applied 6 WAS caused <15% phytotoxicity 56 DAT. When large crabgrass and centipedegrass were seeded together, large crabgrass emergence was reduced 41% when atrazine (1,100 g ai/ha) was applied at seeding. Centipedegrass tiller production was reduced with increasing amounts of crabgrass. However, centipedegrass tiller production and ground cover were higher when atrazine was applied because of reduced interspecific interference from large crabgrass. These data indicate that centipedegrass can be established more quickly if appropriate herbicides are used at seeding or shortly after seeding.}, number={3}, journal={WEED TECHNOLOGY}, author={Gannon, TW and Yelverton, FH and Cummings, HD and McElroy, JS}, year={2004}, pages={641–647} }
 @article{mcelroy_yelverton_gannon_wilcut_2004, title={Foliar vs. soil exposure of green kyllinga (Kyllinga brevifolia) and false-green kyllinga (Kyllinga gracillima) to postemergence treatments of CGA-362622, halosulfuron, imazaquin, and MSMA}, volume={18}, ISSN={["1550-2740"]}, DOI={10.1614/WT-03-072R}, abstractNote={Greenhouse studies were conducted to evaluate shoot number, shoot weight, rhizome weight, and root weight reduction of green and false-green kyllinga at three placement levels (soil applied, foliar applied, and soil + foliar applied) and five herbicide treatments (CGA-362622, halosulfuron, imazaquin, MSMA, and imazaquin + MSMA). Averaged over herbicide and placement level, false-green kyllinga shoot number 30 d after treatment (DAT) and rhizome weight 60 DAT were reduced more than those of green kyllinga. Furthermore, imazaquin, MSMA, and imazaquin + MSMA, averaged across placement levels, as well as CGA-362622 and halosulfuron, both foliar and soil applied, reduced false-green kyllinga shoot number greater than that of green kyllinga 60 DAT. Halosulfuron reduced false-green kyllinga shoot weight greater than that of green kyllinga 60 DAT; however, MSMA reduced green kyllinga greater. In general, foliar- and soil + foliar–applied treatments reduced shoot number (30 DAT), rhizome weight, and root weight of both kyllinga species greater than soil-applied treatments, whereas soil + foliar–applied treatments were more effective in reducing shoot weight 60 DAT. CGA-362622 and halosulfuron reduced kyllinga species shoot number (30 DAT), false-green kyllinga shoot weight (60 DAT), and root weight of both species greater than all other herbicides. However, CGA-362622 reduced green kyllinga shoot weight (60 DAT) and rhizome weight of both species greater than all other herbicides. Nomenclature: CGA-362622, N-[(4,6-dimethoxy-2-pyrimidinyl)carbamoyl]-3-(2,2,2-trifluroethoxy)- pyridin-2-sulfonamide sodium salt; halosulfuron; imazaquin; MSMA; false-green kyllinga, Kyllinga gracillima L.; green kyllinga, Kyllinga brevifolia Rottb. #3 KYLBR. Additional index words: Foliar absorption, root absorption. Abbreviations: ALS, acetolactate synthase; DAP, days after planting; DAT, days after treatment; NIS, nonionic surfactant; POST, postemergence.}, number={1}, journal={WEED TECHNOLOGY}, author={McElroy, JS and Yelverton, FH and Gannon, TW and Wilcut, JW}, year={2004}, pages={145–151} }
 @article{mcelroy_yelverton_neal_rufty_2004, title={Influence of photoperiod and temperature on vegetative growth and development of Florida betony (Stachys floridana)}, volume={52}, ISSN={["1550-2759"]}, DOI={10.1614/WS-03-045R}, abstractNote={Experiments were conducted in environmental chambers to the evaluate effects of photoperiod and temperature on Florida betony growth and development. Plants were exposed to two photoperiods, short day (9 h) and long day (9 + 3 h night interruption), and three day/night temperature regimes, 18/14, 22/18, and 26/22 C. After 10 wk of growth, shoot length and weight were 3.4 and 3.5 times greater, respectively, in the long-day photoperiod and with the 26 and 22 than with the 22 and 18 C day and night temperature regime, respectively. Shoot number, however, was greatest in the short-day photoperiod and at a lower temperature of 22/18 C. Shoot number in long day 22/18 C and 26/22 C environments increased asymptotically. No difference in root weight was observed between long- and short-day environments, but root weight increased with increasing temperature. Flowering and tuber production only occurred in long-day environments, with greater production of both at higher temperatures. Results provide a general framework for understanding Florida betony growth and development characteristics in the field and provide insights that should be considered in developing control strategies.}, number={2}, journal={WEED SCIENCE}, author={McElroy, JS and Yelverton, FH and Neal, JC and Rufty, TW}, year={2004}, pages={267–270} }
 @article{fagerness_bowman_yelverton_rufty_2004, title={Nitrogen use in Tifway bermudagrass, as affected by trinexapac-ethyl}, volume={44}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2004.5950}, abstractNote={Nutrient movement from turfgrass systems into surface and ground water is a public concern. Data indicate that actively growing turf rapidly immobilizes applied N, thus restricting nutrient movement. It is possible, however, that growth suppression with plant growth regulators (PGRs) could reduce N demand and thus N uptake, resulting in greater leaching losses. An experiment was conducted with column lysimeters to investigate the effects of trinexapac‐ethyl (TE) on nitrate leaching and N‐use efficiency in Tifway bermudagrass (Cynodon dactylon × C. transvaalensis). The experiment was conducted in a growth chamber with day/night temperature set at 29/24°C and a 12‐h photoperiod. Trinexapac‐ethyl was applied twice at 4‐wk intervals at 0.11 kg a.i. ha−1 Ammonium nitrate (AN) was applied at 50 kg N ha−1 2 wk after each TE application, and again 6 wk after the second TE application. Separate sets of columns received 15N‐labeled AN for the first two applications. Irrigation was scheduled to provide a leaching fraction of ≈50%; leachate was collected after each irrigation and analyzed for nitrate and ammonium. Cumulative nitrate leaching was unaffected by TE after the first two N applications, but was reduced ≈60% by TE following the third N application. Trinexapac‐ethyl reduced 15N allocation to clippings by ≈25% and increased 15N allocation to roots and rhizomes; total recovery of applied 15N in tissues was ≈65%. Results demonstrate chemical growth suppression with TE does not reduce N uptake or increase nitrate leaching from bermudagrass.}, number={2}, journal={CROP SCIENCE}, author={Fagerness, MJ and Bowman, DC and Yelverton, FH and Rufty, TW}, year={2004}, pages={595–599} }
 @article{mcelroy_yelverton_troxler_wilcut_2003, title={Selective exposure of yellow (Cyperus esculentus) and purple nutsedge (Cyperus rotundus) to postemergence treatments of CGA-362622, imazaquin, and MSMA}, volume={17}, ISSN={["1550-2740"]}, DOI={10.1614/WT02-156}, abstractNote={Greenhouse studies were conducted to evaluate shoot number, shoot weight, and root weight reduction of yellow and purple nutsedge to three placement levels (soil, foliar, and soil + foliar applied) and four herbicide treatments (CGA-362622, imazaquin, MSMA, and imazaquin + MSMA). Soil-applied CGA-362622 reduced shoot number, shoot weight, and root weight greater than foliar-applied CGA-362622. Foliar-applied imazaquin and soil-applied MSMA achieved little reduction in measured variables compared with the nontreated control. Foliar-applied imazaquin and soil-applied MSMA reduced shoot number, shoot weight, and root weight less than imazaquin + MSMA applied in a similar manner. Averaged over placement levels, imazaquin reduced shoot weight of yellow nutsedge greater than purple nutsedge. Averaged over herbicide treatments, soil-applied treatments were more effective in reducing purple nutsedge shoot number, whereas foliar-applied treatments were more effective in reducing yellow nutsedge shoot number. Nomenclature: CGA-362622, N-[(4,6-dimethoxy-2-pyrimidinyl)carbamoyl]-3-(2,2,2-trifluroethoxy)-pyridin-2-sulfonamide sodium salt; imazaquin; MSMA; purple nutsedge, Cyperus rotundus L. #3 CYPRO; yellow nutsedge, Cyperus esculentus L. # CYPES. Additional index words: Foliar absorption, root absorption. Abbreviations: DAP, days after planting; DAT, days after treatment; NIS, nonionic surfactant; POST, postemergence.}, number={3}, journal={WEED TECHNOLOGY}, author={McElroy, JS and Yelverton, FH and Troxler, SC and Wilcut, JW}, year={2003}, pages={554–559} }
 @article{fagerness_yelverton_cooper_2002, title={Bermudagrass [Cynodon dactylon (L.) Pers.] and zoysiagrass (Zoysia japonica) establishment after preemergence herbicide applications}, volume={16}, ISSN={["0890-037X"]}, DOI={10.1614/0890-037X(2002)016[0597:BCDLPA]2.0.CO;2}, abstractNote={Preemergence (PRE) herbicides may affect the ability to reestablish warm-season turfgrasses in winter-injured areas. Experiments were conducted in 1996 and 1997 to evaluate the effects of fall or spring applications of six PRE herbicides on the vegetative establishment of Tifway bermudagrass, and Meyer and El Toro zoysiagrass. PRE herbicides were applied at the recommended rates during the fall of 1995 and 1996 and at recommended or reduced rates during the spring of 1996 and 1997. Oxadiazon, benefin plus trifluralin, or oryzalin did not inhibit Tifway bermudagrass or zoysiagrass sprig establishment. Fall applications of prodiamine and dithiopyr at full rates suppressed Tifway bermudagrass establishment as much as 25%, but recovery was evident by the end of the growing season. Reduced spring rates of prodiamine diminished its suppressive effects on Tifway establishment. Zoysiagrass establishment was suppressed as much as 20% by full or reduced rates of prodiamine but was less affected by dithiopyr. Pendimethalin had lesser and briefer suppressive effects than prodiamine and dithiopyr had on either species. Results suggested that avoidance of or reduced rates of prodiamine or dithiopyr may be warranted in areas prone to winter injury. Nomenclature: Benefin; dithiopyr; oryzalin; oxadiazon; pendimethalin; prodiamine; trifluralin; bermudagrass, Cynodon transvaalensis Burtt-Davey × C. dactylon (L.) Pers. ‘Tifway’; zoysiagrass, Zoysia japonica L. ‘Meyer’, ‘El Toro’. Additional index words: Application timing, vegetative turfgrass establishment. Abbreviations: POST, postemergence; PRE, preemergence; WAE, weeks after establishment.}, number={3}, journal={WEED TECHNOLOGY}, author={Fagerness, MJ and Yelverton, FH and Cooper, RJ}, year={2002}, pages={597–602} }
 @article{isgrigg_yelverton_brownie_warren_2002, title={Dinitroaniline resistant annual bluegrass in North Carolina}, volume={50}, ISSN={["1550-2759"]}, DOI={10.1614/0043-1745(2002)050[0086:DRABIN]2.0.CO;2}, abstractNote={Abstract Annual bluegrass control was reduced following 7 yr of continuous fall application of dinitroaniline (DNA) herbicides. Annual bluegrass control was < 40% on two fairways in year eight following prodiamine applied at 1.1 kg ai ha−1. In dose–response studies conducted in growth chambers, this annual bluegrass population exhibited 105-fold resistance in shoot growth to prodiamine compared with a known susceptible population. A 6.4-fold resistance to prodiamine was found when comparing annual bluegrass root growth to the known susceptible biotype. Spring-applied oxadiazon did not affect shoot or root growth between annual bluegrass biotypes. Equivalent levels of control were attained with pronamide. The presence of DNA-resistant annual bluegrass, in addition to previously confirmed triazine-resistant biotypes on North Carolina golf courses, indicates a need for resistance management strategies to be integrated into golf turf management practices. Nomenclature: Oxadiazon; prodiamine; pronamide; annual bluegrass, Poa annua L. POANN.}, number={1}, journal={WEED SCIENCE}, author={Isgrigg, J and Yelverton, FH and Brownie, C and Warren, LS}, year={2002}, pages={86–90} }
 @article{fagerness_yelverton_livingston_rufty_2002, title={Temperature and trinexapac-ethyl effects on bermudagrass growth, dormancy, and freezing tolerance}, volume={42}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2002.0853}, abstractNote={Applications of the plant growth regulator (PGR) trinexapac-ethyl [4-(cyclopropyl-α-hydroxymethylene)-3,5-dioxocyclohexane carboxylic acid ethylester] (TE) can delay winter dormancy in ‘Tifway’ bermudagrass (Cynodon dactylon var. dactylon), which suggests a response to TE when temperatures are suboptimum for bermudagrass growth. The purpose of this study was to investigate the interactive role of temperature and TE in bermudagrass growth responses, dormancy, and freezing tolerance. Trinexapac-ethyl (0.11 kg a.i. ha−1) was applied in two growth chamber experiments, and across a 2-yr period in the field. Results indicated that TE reduced vertical shoot growth and increased stolon production, turf density, and quality when applied at high temperatures (35–36°C). While TE effectively reduced vertical shoot growth at low (20–22°C) temperatures, little impact on stolon development was observed under these conditions. Autumn applications of TE when temperatures were cool (≈25°C) at the time of application led to decreased turfgrass density and quality. These responses may explain the effectiveness of using TE to aid in bermudagrass transition to overseeded cool-season grasses and were probably due to the limited ability of bermudagrass to recover from initial post-application growth reduction and observed leaf chlorosis. Observed delayed autumn dormancy due to summer applications of TE and accelerated dormancy due to late-season applications did not conclusively relate to the freezing tolerance of bermudagrass.}, number={3}, journal={CROP SCIENCE}, author={Fagerness, MJ and Yelverton, FH and Livingston, DP and Rufty, TW}, year={2002}, pages={853–858} }
 @article{reicher_hardebeck_yelverton_christians_bingaman_turner_2002, title={Tolerance to quinclorac by seedling creeping bentgrass}, volume={37}, number={1}, journal={HortScience}, author={Reicher, Z. J. and Hardebeck, G. A. and Yelverton, F. F. and Christians, N. E. and Bingaman, B. and Turner, J.}, year={2002}, pages={210–213} }
 @article{fagerness_yelverton_2001, title={Plant growth regulator and mowing height effects on seasonal root growth of penncross creeping bentgrass}, volume={41}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2001.1901}, abstractNote={Summer decline of creeping bentgrass [Agrostis palustris Huds. (=Agrostis stolonifera var. palustris (Huds.) Farw.] root growth is an annual concern in many regions of the USA. A 2‐yr field study was conducted to investigate the effects of mowing height and plant growth regulator (PGR) treatments on root biomass (RB) patterns in ‘Penncross’ creeping bentgrass, grown on a Wakulla sand (sandy, siliceous, Thermic Psammentic Hapludults) with 94% sand, 4% silt, 2% clay, 24 mg g−1 organic matter, and a pH of 6.1. Plots were maintained at 3.2, 4.0, or 4.8 mm throughout the experiment. Plant growth regulator treatments were trinexapac‐ethyl, [4‐(cyclopropyl‐α‐hydroxymethylene)‐3,5‐dioxo‐cyclohexane carboxylic acid ethyl ester] applied at 0.05 kg a.i. ha−1 and paclobutrazol, {(±)‐(R*,R*)‐β‐[(4‐chloro‐phenyl)methyl]‐α‐(1,1‐dimethylethyl)‐1H‐1,2,4‐triazole‐1‐ethanol} applied at 0.14, 0.28, or 0.56 kg a.i. ha−1 Plant growth regulator treatments initially were applied in April 1997 and were reapplied monthly for 24 mo. Annual variation in air and soil temperature accounted for variable RB across years. Root biomass declined 76% from a May maximum to a minimum in September; however, RB increased between September and January. Turf mowed to a height of 3.2 mm consistently had lower RB than turf maintained at 4.0 or 4.8 mm, and had slower early autumn RB recovery. When averaged across mowing heights, only paclobutrazol (0.56 kg a.i. ha−1) reduced RB and no PGR increased rooting when compared with nontreated turf. From September to January of each year, a PGR by mowing height interaction showed that paclobutrazol applied at 0.56 kg a.i. ha−1 delayed RB recovery in turf mowed to a height of 4.8 mm, while no PGR delayed RB recovery in turf maintained at the 3.2 mm mowing height. Slower RB recovery in turf mowed to 3.2 mm following the September minimum RB was attributed to reductions in turf quality and density, rather than the effects of PGRs. Paclobutrazol only reduced Penncross RB when applied at twice the labeled rate and with greater application frequency than is typical for most PGR use patterns. These results showed that labeled rates of paclobutrazol and trinexapac‐ethyl did not adversely affect root growth under putting green conditions.}, number={6}, journal={CROP SCIENCE}, author={Fagerness, MJ and Yelverton, FH}, year={2001}, pages={1901–1905} }
 @article{horgan_yelverton_2001, title={Removal of perennial ryegrass from overseeded bermudagrass using cultural methods}, volume={41}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2001.411118x}, abstractNote={Turfgrass managers in the southeastern United States often overseed ‘Tifway’ bermudagrass [Cynodon transvaalensis Burtt‐Davey × C. dactylon (L.) Pers.] with perennial ryegrass (Lolium perenne L.) to provide a dense green turf during winter months. Although overseeding provides benefits, the spring transition from perennial ryegrass to bermudagrass can be troublesome and inconsistent. Perennial ryegrass may survive longer into the spring than is desired due to cool, wet conditions. The following experiment evaluated cultural methods for removal of perennial ryegrass from overseeded bermudagrass in the spring and early summer. The experiment was conducted at the North Carolina State University Turfgrass Field Center in Raleigh in the 1995 to 1996 and 1996 to 1997 growing seasons. Monocultures of ‘Gator’ and ‘Derby Supreme’ perennial ryegrass were overseeded into an established Tifway bermudagrass turf managed at golf course fairway conditions. It was hypothesized that various cultural treatments in the spring and summer could promote bermudagrass and/or discourage perennial ryegrass, and that the perennial ryegrass transition would differ depending on heat tolerance of the selected overseeding monocultures. The cultural treatments were biweekly vertical mowing, scalping, core cultivation, and vertical mowing/scalping, or two application timings of NH4NO3 Chemical removal of perennial ryegrass using pronamide [3,5‐dichloro‐N‐(1,1‐dimethyl‐2‐propynyl)benzamide] was included as a check treatment because it is commonly used to promote transition. Bermudagrass shoot density was consistently higher in nonoverseeded plots, illustrating perennial ryegrass competition. Cultural treatments affected perennial ryegrass cover during the spring and early summer but did not hasten its ultimate disappearance. Early or late applied NH4NO3 enhanced bermudagrass shoot density in both years. In contrast, plots receiving core cultivation had lower bermudagrass shoot density at the end of the transition period than the nontreated plots. Pronamide did hasten transition through 7 and 13 wk after initial treatment for 1996 and 1997, respectively. Regression analysis between natural perennial ryegrass disappearance over both years and air temperature or relative humidity indicates a significant association. This implies that cultural treatments alone may not consistently enhance natural transition of perennial ryegrass to bermudagrass.}, number={1}, journal={CROP SCIENCE}, author={Horgan, BP and Yelverton, FH}, year={2001}, pages={118–126} }
 @article{yelverton_mccarty_2001, title={Tolerance of perennial ryegrass and Poa annua control with herbicides in overseeded bermudagrass}, volume={9}, journal={International Turfgrass Society Research Journal}, author={Yelverton, F. H. and McCarty, L. B.}, year={2001}, pages={1050} }
 @article{summerlin_coble_yelverton_2000, title={Effect of mowing on perennial sedges}, volume={48}, ISSN={["0043-1745"]}, DOI={10.1614/0043-1745(2000)048[0501:EOMOPS]2.0.CO;2}, abstractNote={Abstract Field studies were conducted in 1996 and 1997 to determine the response of Cyperus rotundus and Cyperus esculentus, Kyllinga brevifolia, and Kyllinga gracillima to mowing regimens common to recreational turfgrass. Treatments were selected to simulate Cynodon dactylon golf course management and included mowing at 1.3 and 3.8 cm with mowing frequencies of three times per week and once a week, respectively. A nonmowed check was included for comparison. Reductions in C. rotundus shoot number were observed beginning 6 wk after initial treatment (WAIT) in 1996 and 9 WAIT in 1997 for the 1.3-cm mowing regime. The 3.8-cm mowing regime did not reduce C. rotundus shoot number until the final evaluation of each year. Reductions in C. rotundus rhizome length, tuber number, and tuber size were observed for both mowing regimes in both years. Cyperus esculentus shoot number was reduced by the 1.3-cm treatment at each evaluation date in 1996 and 1997. Cyperus esculentus shoot number reductions in the 3.8-cm regime were first observed 4 and 6 WAIT in the 2 yr and continued until termination. The 1.3-cm regime reduced C. esculentus spread beginning 6 WAIT in 1996 and 3 WAIT in 1997. Cyperus esculentus spread was also reduced by the 3.8-cm treatment, but reduction began at later evaluations (8 and 9 WAIT). Tuber production by C. esculentus was completely inhibited by the two mowing regimes in both years. The only treatment effect observed in K. brevifolia and K. gracillima in 1996 was a reduction in internode length of K. gracillima by the 1.3-cm mowing regime. In 1997, the 1.3-cm regime reduced K. brevifolia shoot number at 15 and 18 WAIT and plant spread beginning 6 WAIT and continuing until termination. The 3.8-cm treatment did not affect K. brevifolia shoot number and reductions in spread were only observed at the final evaluation. Kyllinga gracillima shoot number and plant spread were reduced by the 1.3-cm mowing regime at each 1997 evaluation. Reductions in K. gracillima shoot number occurred at the final evaluation, and reductions in spread began 12 WAIT when subjected to the 3.8-cm treatment. Both mowing regimes reduced K. brevifolia and K. gracillima internode length. Kyllinga brevifolia total rhizome length and total node number were reduced by the 1.3-cm regime only. Kyllinga gracillima rhizome length, internode length, and node number were reduced by both regimes in 1997. Nomenclature:Cynodon dactylon (L.) Pers., bermudagrass; Cyperus rotundus L. CYPRO, purple nutsedge; Cyperus esculentus L. CYPES, yellow nutsedge; Kyllinga brevifolia Rottb. KYLBR, green kyllinga; Kyllinga gracillima Miq. KYLGR, false green kyllinga.}, number={4}, journal={WEED SCIENCE}, author={Summerlin, JR and Coble, HD and Yelverton, FH}, year={2000}, pages={501–507} }
 @article{fagerness_yelverton_isgrigg_cooper_2000, title={Plant growth regulators and mowing height affect ball roll and quality of creeping bentgrass putting greens}, volume={35}, number={4}, journal={HortScience}, author={Fagerness, M. J. and Yelverton, F. H. and Isgrigg, J. and Cooper, R. J.}, year={2000}, pages={755–759} }
 @article{blum_isgrigg_yelverton_2000, title={Purple (Cyperus rotundus) and yellow nutsedge (C-esculentus) control in bermudagrass (Cynodon dactylon) turf}, volume={14}, ISSN={["0890-037X"]}, DOI={10.1614/0890-037x(2000)014[0357:pcrayn]2.0.co;2}, abstractNote={Abstract: Field studies were conducted in 1996 and 1997 to determine postemergence control of purple (Cyperus rotundus) and yellow nutsedge (Cyperus esculentus) by single and sequential applications of bentazon, halosulfuron, and sulfentrazone; sequential applications of MSMA; and single applications of imazaquin and imazaquin plus MSMA. Sequential applications of halosulfuron at 70 g ai/ha controlled purple nutsedge more effectively at 10 wk after initial application (WAI) than all other herbicides. Single applications of imazaquin (0.56 kg ai/ha) or imazaquin plus monosodium salt of methylarsonic acid (MSMA, 2.24 kg ai/ha) controlled purple nutsedge adequately 6 WAI (78 and 90%, respectively) but not 18 WAI. Single applications of either halosulfuron (70 g/ha) or imazaquin plus MSMA or sequential applications of either bentazon (1.12 kg ai/ha), MSMA (2.8 kg/ha), or halosulfuron controlled yellow nutsedge greater than 80% by the end of the season in 1996 when nutsedge was in bermudagrass (Cynodon dactylon L.). However, in absence of bermudagrass in 1997, only sulfentrazone or the halosulfuron sequential treatments controlled yellow nutsedge 13 WAI. In 1996, single and sequential applications of halosulfuron reduced viability of purple nutsedge tubers to 33 and 30%, respectively, compared to 84% in the nontreated control. However, herbicide treatments did not reduce tuber viability in 1997. Sulfentrazone (0.28 kg ai/ha) plus MSMA (2.24 kg/ha) and sequential MSMA applications reduced viability of yellow nutsedge tubers to 6 and 31%, respectively, in 1997. Nomenclature: Bentazon, 3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide; halosulfuron, methyl 5-[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonylami-nosulfonyl]-3-chloro-1-methyl-1-H-pyrazole-4-carboxylate; imazaquin, 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid; MSMA, monosodium salt of methylarsonic acid; sulfentrazone, N-[2,4-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl] phenyl] methanesulfonamide; purple nutsedge, Cyperus rotundus L. #3 CYPRO; yellow nutsedge, Cyperus esculentus L. # CYPES; bermudagrass, Cynodon dactylon (L.) Pers. #CYNDA. Additional index words: Tuber viability, weed management, CYNDA, CYPES, CYPRO. Abbreviations: fb, followed by; MSMA, monosodium salt of methylarsonic acid; NIS, nonionic surfactant; POST, postemergence; WAI, weeks after initial treatment; WP, wettable powder.}, number={2}, journal={WEED TECHNOLOGY}, author={Blum, RR and Isgrigg, J and Yelverton, FH}, year={2000}, pages={357–365} }
 @article{fagerness_yelverton_2000, title={Tissue production and quality of 'Tifway' bermudagrass as affected by seasonal application patterns of trinexapac-ethyl}, volume={40}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2000.402493x}, abstractNote={Research on the gibberellic acid (GA)–inhibiting plant‐growth regulator (PGR) trinexapac‐ethyl (TE) regarding seasonal effects of single vs. multiple applications of this product on turfgrass quality and tissue production has not been reported. Research was conducted at North Carolina State University on ‘Tifway’ bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon transvaalensis (Burtt‐Davy)] to compare effects of different seasonal application patterns of TE. Applications of TE were made to fully established Tifway bermudagrass at either 0.107 or 0.071 kg a.i. ha−1 Seasonal application patterns included an initial application, followed by zero, one, or two sequential applications at 4‐wk intervals. Plots were rated weekly for turfgrass quality and clippings were collected weekly for evaluation of tissue production. Results demonstrated that one application of TE provided temporary growth inhibition of Tifway bermudagrass. This effect, as expected, disappeared 4 wk after initial treatment (WAIT). Post‐inhibition growth enhancement (PIGE) was observed from 6 to 10 WAIT in areas treated with a single application of TE at 0.071 kg a.i. ha−1 However, total seasonal tissue production following a single application of TE was equal to untreated areas, suggesting limited overall effects of PIGE. Conversely, one or two sequential applications of TE provided prolonged growth inhibition; total seasonal tissue production was reduced by up to 40%. Overall quality of Tifway bermudagrass was enhanced by multiple TE applications and perceived fall dormancy was delayed. Results support the use of sequential applications of TE in Tifway bermudagrass for consistent growth management throughout the growing season, avoidance of PIGE, and improvement in visual turfgrass quality.}, number={2}, journal={CROP SCIENCE}, author={Fagerness, MJ and Yelverton, FH}, year={2000}, pages={493–497} }
 @article{kay_yelverton_1998, title={Dormant season herbicide treatments for kudzu control}, volume={51}, number={1998}, journal={Proceedings, Southern Weed Science Society}, author={Kay, S.H. and Yelverton, F.H.}, year={1998}, pages={190–191} }
 @article{wickliffe_yelverton_worsham_nagabhushana_1998, title={Effect of manipulation of seeding rate on diboa-glucoside, diboa, and boa levels in rye}, volume={51}, number={1998}, journal={Proceedings, Southern Weed Science Society}, author={Wickliffe, W. B. and Yelverton, F. H. and Worsham, A. D. and Nagabhushana, G. G.}, year={1998}, pages={199} }
 @article{yelverton_1998, title={Effects of trinexapac-ethyl and paclobutrazol on ball roll and summer stress of creeping bentgrass}, volume={51}, number={1998}, journal={Proceedings, Southern Weed Science Society}, author={Yelverton, F. H.}, year={1998}, pages={68} }
 @article{fagerness_yelverton_1998, title={Effects of turfgrass growth regulators on lateral development of hybrid and common bermudagrass}, volume={51}, number={1998}, journal={Proceedings, Southern Weed Science Society}, author={Fagerness, M. J. and Yelverton, F. H.}, year={1998}, pages={65–66} }
 @article{impact of mowing on growth and spread of green kyllinga (kyllinga brevifolia) and yellow nutsedge (cyperus esculentus)_1998, volume={51}, number={1998}, journal={Proceedings, Southern Weed Science Society}, year={1998}, pages={70–71} }
 @article{yelverton_1998, title={Influence of bulb packing systems on forcing of Dutch-grown Hippeastrum (Amaryllis) as flowering potted plants in North America}, volume={33}, number={9}, journal={Grounds Maintenance}, author={Yelverton, F. H.}, year={1998}, pages={20,-2224} }
 @article{moss control in bentgrass putting greens_1998, volume={51}, number={1998}, journal={Proceedings, Southern Weed Science Society}, year={1998}, pages={75} }
 @article{batts_york_yelverton_bradley_1998, title={Potential for cotoran carryover to flue-cured tobacco}, volume={1}, number={1998}, journal={Beltwide Cotton Conferences. Proceedings}, author={Batts, R. B. and York, A. C. and Yelverton, F. H. and Bradley, A. L.}, year={1998}, pages={873} }
 @article{the effect of paclobutrazol on the relative growth of annual bluegrass and creeping bentgrass_1998, volume={51}, number={1998}, journal={Proceedings, Southern Weed Science Society}, year={1998}, pages={248} }
 @article{yelverton_mccarty_murphy_1997, title={Effects of imazameth on the growth of Paspalum notatum Fluegge}, volume={8}, journal={International Turfgrass Society Research Journal}, author={Yelverton, F. H. and McCarty, L. B. and Murphy, T. R.}, year={1997}, pages={1085} }
 @article{bryson_carter_mccarty_yelverton_1997, title={Kyllinga, a genus of neglected weeds in the continental United States}, volume={11}, ISSN={["0890-037X"]}, DOI={10.1017/s0890037x00043530}, abstractNote={The sedge genus Kyllinga consists of 40 to 45 species distributed in tropical, subtropical, and warm temperate regions around the world (KUkenthal 1936; Tucker 1987). This genus of low rhizomatous perennials or cespitose annuals is classified in the large cosmopolitan family Cyperaceae. Many Kyllinga species are considered weedy (Holm et al. 1979; Tucker 1987), while Kyllinga nervosa Steudel is considered an important forage plant in Africa (McNaughton 1985).}, number={4}, journal={WEED TECHNOLOGY}, author={Bryson, CT and Carter, R and McCarty, LB and Yelverton, FH}, year={1997}, pages={838–842} }