@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.}, number={1}, journal={WEED TECHNOLOGY}, author={Jeffries, Matthew D. and Gannon, Travis W. and Yelverton, Fred H.}, year={2017}, pages={120–129} }
 @article{jeffries_gannon_maxwell_2017, title={Protocols for Quantifying Transferable Pesticide Residues in Turfgrass Systems}, ISSN={["1940-087X"]}, DOI={10.3791/55182}, abstractNote={Plant canopies in established turfgrass systems can intercept an appreciable amount of sprayed pesticides, which can be transferred through various routes onto humans. For this reason, transferable pesticide residue experiments are required for registration and re-registration by the United States Environmental Protection Agency (USEPA). Although such experiments are required, limited specificity is required pertaining to experimental approach. Experimental approaches used to assess pesticide transfer to humans including hand wiping with cotton gloves, modified California roller (moving a roller of known mass over cotton cloth) and soccer ball roll (ball wrapped with sorbent strip) over three treated turfgrass species (creeping bentgrass, hybrid bermudagrass and tall fescue maintained at 0.4, 5 and 9 cm, respectively) are presented. The modified California roller is the most extensively utilized approach to date, and is best suited for use at low mowing heights due to its reproducibility and large sampling area. The soccer ball roll is a less aggressive transfer approach; however, it mimics a very common occurrence in the most popular international sport, and has many implications for nondietary pesticide exposure from hand-to-mouth contact. Additionally, this approach may be adjusted for other athletic activities with limited modification. Hand wiping is the best approach to transfer pesticides at higher mowing heights, as roller-based approaches can lay blades over; however, it is more subjective due to more variable sampling pressure. Utility of these methods across turfgrass species is presented, and additional considerations to conduct transferable pesticide residue research in turfgrass systems are discussed.}, number={121}, journal={JOVE-JOURNAL OF VISUALIZED EXPERIMENTS}, author={Jeffries, Matthew D. and Gannon, Travis W. and Maxwell, Patrick J.}, year={2017}, month={Mar} }
 @article{jeffries_gannon_brosnan_breeden_2017, title={Sprayer Setup Affects Dislodgeable 2,4-D Foliar Residue in Hybrid Bermudagrass Athletic Fields}, volume={31}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2016.22}, abstractNote={2,4-dimethylamine salt (2,4-D) is a selective broadleaf herbicide commonly applied to turfgrass systems, including athletic fields, which can dislodge from treated vegetation. Building on previous research confirming 2,4-D dislodgeability is affected by management inputs, field research was initiated in 2014 and 2015 in North Carolina and Tennessee to quantify the effects of sprayer setup on dislodgeable 2,4-D foliar residue from hybrid bermudagrass, which is the most common athletic field playing surface in subtropical and tropical climates. More specifically, research evaluated dislodgeable 2,4-D foliar residue following spray applications (2.1 kg ae ha−1) at varying carrier volumes (187, 374, or 748 L ha−1) and nozzles delivering varying droplet sizes (fine=extended range [XR], coarse=drift guard, or extra coarse=air induction extended range [AIXR]). Overall, data suggest minimal 2,4-D dislodge occurs via soccer ball roll (3.6 m) outside the day of application; however, increasing carrier volume and droplet size can further decrease dislodgeable 2,4-D foliar residue. At 2 d after treatment (DAT), 3.87% of applied 2,4-D dislodged when applied at 187 L ha−1compared to 2.05% at 748 L ha−1. Pooled over data from 1 to 6 DAT, 1.59% of applied 2,4-D dislodged following XR nozzle application compared to 1.13% with AIXR nozzle. While these are small numerical differences, dislodgeable residue was measured via one soccer ball roll, which is a repeated process within the sport and the additive effect of sprayer setup treatments can be employed by turfgrass managers to reduce potential human 2,4-D human exposure.}, number={2}, journal={WEED TECHNOLOGY}, author={Jeffries, Matthew D. and Gannon, Travis W. and Brosnan, James T. and Breeden, Gregory K.}, year={2017}, pages={269–278} }
 @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.
}, 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_brosnan_breeden_2016, title={Comparing Dislodgeable 2,4-D Residues across Athletic Field Turfgrass Species and Time}, volume={11}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0168086}, abstractNote={2,4-dimethylamine salt (2,4-D) is an herbicide commonly applied on athletic fields for broadleaf weed control that can dislodge from treated turfgrass. Dislodge potential is affected by numerous factors, including turfgrass canopy conditions. Building on previous research confirming herbicide-turfgrass dynamics can vary widely between species, field research was initiated in 2014 and 2015 in Raleigh, NC, USA to quantify dislodgeable 2,4-D residues from dormant hybrid bermudagrass (Cynodon dactylon L. x C. transvaalensis) and hybrid bermudagrass overseeded with perennial ryegrass (Lolium perenne L.), which are common athletic field playing surfaces in subtropical climates. Additionally, dislodgeable 2,4-D was compared at AM (7:00 eastern standard time) and PM (14:00) sample timings within a day. Samples collected from perennial ryegrass consistently resulted in greater 2,4-D dislodgment immediately after application (9.4 to 9.9% of applied) compared to dormant hybrid bermudagrass (2.3 to 2.9%), as well as at all AM compared to PM timings from 1 to 3 d after treatment (DAT; 0.4 to 6.3% compared to 0.1 to 0.8%). Dislodgeable 2,4-D did not differ across turfgrass species at PM sample collections, with ≤ 0.1% of the 2,4-D applied dislodged from 1 to 6 DAT, and 2,4-D detection did not occur at 12 and 24 DAT. In conclusion, dislodgeable 2,4-D from treated turfgrass can vary between species and over short time-scales within a day. This information should be taken into account in human exposure risk assessments, as well as by turfgrass managers and athletic field event coordinators to minimize 2,4-D exposure.}, number={12}, journal={PLOS ONE}, author={Jeffries, Matthew D. and Gannon, Travis W. and Brosnan, James T. and Breeden, Gregory K.}, year={2016}, month={Dec} }
 @article{jeffries_gannon_ou_2016, title={Effect of Indaziflam Applications on 'Tifway 419' Bermudagrass Growth}, volume={108}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2015.0352}, abstractNote={Indaziflam {N‐[(1R,S)‐2,3‐dihyrdo‐2,6‐dimethyl‐1H‐inden‐1‐yl]‐6‐(1‐fluorethyl)1,3,5‐triazine‐2,4‐diamine} is a preemergence herbicide for annual weed control in turfgrass systems. Following indaziflam U.S. registration in 2010, sporadic cases of hybrid bermudagrass (HB) injury were reported. Field research was conducted from 2012 to 2014 evaluating indaziflam application rates [16 followed by 16 (28 d), 33, 49, or 65 g a.i. ha−1] and timings (fall‐only, fall‐plus‐spring, or spring‐only) in two environments (reduced sunlight [RS] and full sunlight [FS]) to elucidate their effect on HB growth. In Year 1, differences were not detected, while in Year 2 HB cover varied between environments. In Year 2, HB cover in the RS environment treated with 49 and 65 g ha−1 had 36 and 64% less visual cover 12 wk after initial spring treatment than the FS environment, respectively. Within the RS environment, indaziflam also reduced HB visual cover compared to the nontreated (77% cover). A bioassay study conducted with soil cores collected from field plots suggested HB cover reduction was minimally affected by indaziflam‐soil bioavailability, as perennial ryegrass biomass was not reduced beyond a 2.5‐cm depth. Weather conditions varied between years, with air temperatures ≤0°C occurring more frequently and to a greater magnitude in Year 2. The weather, coupled with reduced solar radiation in the RS environment may have contributed to HB cover reduction in Year 2. Overall, indaziflam applications to established HB in areas with suitable growth conditions were safe; however, unacceptable HB cover reductions were observed in areas with poor growth conditions.

Indaziflam is safe on established bermudagrass grown in appropriate conditions.
Bermudagrass‐indaziflam tolerance decreased when applied in a reduced sunlight setting.
Severe winter climatic conditions exacerbated bermudagrass‐indaziflam injury.

}, number={3}, journal={AGRONOMY JOURNAL}, author={Jeffries, Matthew D. and Gannon, Travis W. and Ou, Ling}, year={2016}, pages={950–956} }
 @article{jeffries_gannon_2016, title={Effect of Soil Organic Matter Content and Volumetric Water Content on 'Tifway 419' Hybrid Bermudagrass Growth Following Indaziflam Applications}, volume={30}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-15-00192.1}, abstractNote={Indaziflam is a cellulose biosynthesis–inhibiting herbicide for PRE annual weed control in turfgrass systems. Since indaziflam's 2010 U.S. registration, sporadic cases of hybrid bermudagrass injury have been reported; however, causes are not well understood. Field research was conducted from 2013 to 2015 on sandy soil to elucidate the effects of soil organic matter content (SOMC) and soil volumetric water content (SVWC) on plant growth following indaziflam application on established or root-compromised (5 cm long) hybrid bermudagrass. The effect of SOMC was evaluated at two levels, 1.4 (low) and 5.5% (high) w/w at the soil surface (0 to 2.5 cm depth), whereas SVWC was evaluated PRE (2 wk before) and POST (6 wk after) indaziflam application at two levels (low or high). Indaziflam was applied (50 or 100 g ai ha−1) at fall-only, fall-plus-spring, and spring-only timings. Regardless of application timing or SVWC, indaziflam applied at 50 g ha−1 to high SOMC did not cause > 10% visual cover reduction on established or root-compromised hybrid bermudagrass. Indaziflam applied to hybrid bermudagrass on low SOMC exacerbated adverse growth effects, most notably when root systems were compromised before application. Overall, PRE indaziflam application SVWC did not affect hybrid bermudagrass growth. Within low SOMC, low POST indaziflam application SVWC caused less visual hybrid bermudagrass cover reduction than did high POST indaziflam application SVWC, whereas both fall-plus-spring and spring-only application timings caused similarly greater reductions than fall-only indaziflam application. Data from this research will aid turfgrass managers to effectively use indaziflam without adversely affecting hybrid bermudagrass growth.}, number={3}, journal={WEED TECHNOLOGY}, author={Jeffries, Matthew D. and Gannon, Travis W.}, year={2016}, pages={677–687} }
 @article{jeffries_gannon_brosnan_ahmed_breeden_2016, title={Factors Influencing Dislodgeable 2, 4-D Plant Residues from Hybrid Bermudagrass (Cynodon dactylon L. x C. transvaalensis) Athletic Fields}, volume={11}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0148992}, abstractNote={Research to date has confirmed 2,4-D residues may dislodge from turfgrass; however, experiments have not been conducted on hybrid bermudagrass (Cynodon dactylon L. x C. transvaalensis), the most common athletic field turfgrass in subtropical climates. More specifically, previous research has not investigated the effect of post-application irrigation on dislodgeable 2,4-D residues from hybrid bermudagrass and across turfgrass species, research has been nondescript regarding sample time within a d (TWD) or conducted in the afternoon when the turfgrass canopy is dry, possibly underestimating potential for dislodgement. The effect of irrigation and TWD on 2,4-D dislodgeability was investigated. Dislodgeable 2,4-D amine was reduced > 300% following irrigation. From 2 to 7 d after treatment (DAT), ≤ 0.5% of applied 2,4-D was dislodged from irrigated turfgrass, while ≤ 2.3% of applied 2,4-D was dislodged when not irrigated. 2,4-D dislodgeability decreased as TWD increased. Dislodgeable 2,4-D residues declined to < 0.1% of the applied at 1 DAT– 13:00, and increased to 1 to 3% of the applied 2 DAT– 5:00, suggesting 2,4-D re-suspended on treated turfgrass vegetation overnight. In conclusion, irrigating treated turfgrass reduced dislodgeable 2,4-D. 2,4-D dislodgeability increased as TWD decreased, which was attributed to non-precipitation climatic conditions favoring turfgrass canopy wetness. This research will improve turfgrass management practices and research designed to minimize human 2,4-D exposure.}, number={2}, journal={PLOS ONE}, author={Jeffries, Matthew D. and Gannon, Travis W. and Brosnan, James T. and Ahmed, Khalied A. and Breeden, Gregory K.}, year={2016}, month={Feb} }
 @article{jeffries_gannon_brosnan_breeden_2016, title={Mitigation Practices to Effectively Overseed into Indaziflam-Treated Turfgrass Areas}, volume={30}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-15-00069.1}, abstractNote={Indaziflam is a PRE herbicide for annual broadleaf and grass control in turfgrass systems and requires a 40-wk minimum interval between application and overseeding perennial ryegrass. Currently, activated-charcoal application is recommended to reduce that interval; however, preliminary evaluations determined activated charcoal alone was not a robust mitigation practice for successful establishment during perennial ryegrass overseeding. Field research was conducted in North Carolina and Tennessee to evaluate various mitigation practices to effectively overseed perennial ryegrass into indaziflam-treated turfgrass areas. Immediately following indaziflam application (53 g ai ha−1), two scenarios were created by delivering 0 or 0.3 cm H2O before mitigation practice. Irrigated plots were air-dried before conducting mitigation practices. Evaluated mitigation practices included scalping (0.6 cm cut height; debris removed), verticutting (1.25 cm depth; debris removed), and activated-charcoal application (167 kg ha−1applied as an aqueous slurry in 3,180 L ha−1), evaluated individually and in each two-way combination in the order scalp followed by (fb) activated charcoal, scalp fb verticut, or verticut fb activated charcoal. Twenty-four hours after mitigation practice completion, perennial ryegrass was seeded (976 kg ha−1) and maintained as a golf course fairway. Overall, perennial ryegrass cover was reduced ≥ 93% at 8 and 20 wk after treatment (WAT) when no mitigation practices were performed. Stand-alone mitigation practices variably improved perennial ryegrass establishment; however, no practice provided acceptable results for end users. Combining mitigation practices improved overseeding establishment, most notably by adding activated charcoal application or verticutting to scalping before irrigation. Across experimental runs and locations, scalp fb activated-charcoal application before irrigation reduced perennial ryegrass cover 22 to 27% at 20 WAT. Results from this research suggest mitigation practices in addition to the currently recommended activated-charcoal application should be performed by turfgrass managers to improve perennial ryegrass overseeding establishment in indaziflam-treated turfgrass areas.}, number={1}, journal={WEED TECHNOLOGY}, author={Jeffries, Matthew D. and Gannon, Travis W. and Brosnan, James T. and Breeden, Gregory K.}, year={2016}, pages={154–162} }
 @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 [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt–Davy], tall fescue [Lolium arundinaceum (Schreb.) S.J. Darbyshire], and zoysiagrass (Zoysia japonica Steud.). A subsequent greenhouse experiment was conducted to measure pesticide release from clippings into water. 2,4‐D (1.6 kg a.i. ha−1) and azoxystrobin (0.6 kg a.i. ha−1) 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{jeffries_gannon_2016, title={Soil Organic Matter Content and Volumetric Water Content Affect Indaziflam-Soil Bioavailability}, volume={64}, ISSN={["1550-2759"]}, DOI={10.1614/ws-d-16-00039.1}, abstractNote={Indaziflam is a cellulose biosynthesis-inhibiting herbicide for annual weed control in various agricultural systems. Sporadic cases of unacceptable injury to desirable plants have been reported after indaziflam application, which may have been due to conditions favoring increased indaziflam–soil bioavailability. Research was conducted from 2013 to 2015 on a sandy soil to elucidate the effects of soil organic matter content (SOMC) and soil volumetric water content (SVWC) on indaziflam–soil bioavailability. Indaziflam was applied (50 or 100 g ha–1) at fall only, fall plus spring, and spring only timings to plots in a factorial arrangement of SOMC, pre–indaziflam application (PrIA) SVWC, and post–indaziflam application (PoIA) SVWC. After application, field soil cores were collected for a subsequent greenhouse bioassay experiment, where foliage mass reduction of perennial ryegrass seeded from 0 to 15 cm soil depth was used as an indicator of indaziflam–soil bioavailability throughout the profile. Significant edaphic effects were observed at 0 to 2.5, 2.5 to 5, and 5 to 7.5 cm depths, with increased bioavailability at low compared with high SOMC. Pre–indaziflam application SVWC did not affect bioavailability, whereas PoIA high SVWC increased indaziflam–soil bioavailability at 2.5 to 7.5 cm depth compared with PoIA low SVWC. Low SOMC–PoIA high SVWC decreased perennial ryegrass foliage mass 40 and 37% at 5 to 7.5 cm depth from cores collected 10 and 14 wk after treatment, respectively, whereas reductions from all other SOMC–PoIA SVWC combinations were < 12% and did not vary from each other. Pearson's correlation coefficients showed a moderate, positive relationship between perennial ryegrass mass reductions at 0 to 2.5, 2.5 to 5, 0 to 5, and 0 to 10 cm depths and hybrid bermudagrass cover reduction, which suggests conditions favoring increased indaziflam–soil bioavailability can adversely affect plant growth. Data from this research will aid land managers to use indaziflam effectively without adversely affecting growth of desirable species.}, number={4}, journal={WEED SCIENCE}, author={Jeffries, Matthew D. and Gannon, Travis W.}, year={2016}, pages={757–765} }
 @article{mahoney_gannon_jeffries_polizzotto_2015, title={Arsenic Distribution and Speciation in a Managed Turfgrass System Following Monosodium Methylarsenate Application}, volume={55}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2015.03.0163}, abstractNote={ABSTRACT}, number={6}, journal={CROP SCIENCE}, author={Mahoney, Denis J. and Gannon, Travis W. and Jeffries, Matthew D. and Polizzotto, Matthew L.}, year={2015}, pages={2877–2885} }
 @article{mahoney_gannon_jeffries_matteson_polizzotto_2015, title={Management considerations to minimize environmental impacts of arsenic following monosodium methylarsenate (MSMA) applications to turfgrass}, volume={150}, ISSN={["1095-8630"]}, DOI={10.1016/j.jenvman.2014.12.027}, abstractNote={Monosodium methylarsenate (MSMA) is an organic arsenical herbicide currently utilized in turfgrass and cotton systems. In recent years, concerns over adverse impacts of arsenic (As) from MSMA applications have emerged; however, little research has been conducted in controlled field experiments using typical management practices. To address this knowledge gap, a field lysimeter experiment was conducted during 2012-2013 to determine the fate of As following MSMA applications to a bareground and an established turfgrass system. Arsenic concentrations in soil, porewater, and aboveground vegetation, were measured through one yr after treatment. Aboveground vegetation As concentration was increased compared to nontreated through 120 d after initial treatment (DAIT). In both systems, increased soil As concentrations were observed at 0-4 cm at 30 and 120 DAIT and 0-8 cm at 60 and 365 DAIT, suggesting that As was bound in shallow soil depths. Porewater As concentrations in MSMA-treated lysimeters from a 30-cm depth (22.0-83.8 μg L(-1)) were greater than those at 76-cm depth (0.4-5.1 μg L(-1)). These results were combined with previous research to devise management considerations in systems where MSMA is utilized. MSMA should not be applied if rainfall is forecasted within 7 DAIT and/or in areas with shallow water tables. Further, disposing of MSMA-treated turfgrass aboveground vegetation in a confined area - a common management practice for turfgrass clippings - may be of concern due to As release to surface water or groundwater as the vegetation decomposes. Finally, long-term MSMA use may cause soil As accumulation and thus downward migration of As over time; therefore, MSMA should be used in rotation with other herbicides.}, journal={JOURNAL OF ENVIRONMENTAL MANAGEMENT}, author={Mahoney, Denis J. and Gannon, Travis W. and Jeffries, Matthew D. and Matteson, Audrey R. and Polizzotto, Matthew L.}, year={2015}, month={Mar}, pages={444–450} }
 @article{gannon_jeffries_brosnan_breeden_tucker_henry_2015, title={Preemergence herbicide efficacy for crabgrass (Digitaria spp.) control in common bermudagrass managed under different mowing heights}, volume={50}, number={4}, journal={HortScience}, author={Gannon, T. W. and Jeffries, M. D. and Brosnan, J. T. and Breeden, G. K. and Tucker, K. A. and Henry, G. M.}, year={2015}, pages={546–550} }
 @article{matteson_gannon_jeffries_haines_lewis_polizzotto_2014, title={Arsenic Retention in Foliage and Soil after Monosodium Methyl Arsenate (MSMA) Application to Turfgrass}, volume={43}, ISSN={["1537-2537"]}, DOI={10.2134/jeq2013.07.0268}, abstractNote={Monosodium methyl arsenate (MSMA) is a commonly used herbicide for weed control in turfgrass systems. There is concern that arsenic from applied MSMA could leach to groundwater or run off into surface water, thereby threatening human and ecosystem health. The USEPA has proposed a phase-out of the herbicide but is seeking additional research about the toxicity and environmental impacts of MSMA before establishing a final ruling. Little research has systematically investigated MSMA in field-based settings; instead, risks have been inferred from isolated field measurements or model-system studies. Accordingly, the overall goal of this study was to quantify the fate of arsenic after MSMA application to a managed turfgrass system. After MSMA application to turfgrass-covered and bareground lysimeters, the majority of arsenic was retained in turfgrass foliage and soils throughout year-long experiments, with 50 to 101% of the applied arsenic recovered in turfgrass systems and 55 to 66% recovered in bareground systems. Dissolved arsenic concentrations from 76.2-cm-depth pore water in the MSMA-treated soils were consistently <2 μg L, indistinguishable from background concentrations. As measured by adsorption isotherm experiments, MSMA retention by the sandy soil from our field site was markedly less than retention by a washed sand and a clay loam. Collectively, these results suggest that under aerobic conditions, minimal arsenic leaching to groundwater would occur after a typical application of MSMA to turfgrass. However, repeated MSMA application may pose environmental risks. Additional work is needed to examine arsenic cycling near the soil surface and to define arsenic speciation changes under different soil conditions.}, number={1}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Matteson, Audrey R. and Gannon, Travis W. and Jeffries, Matthew D. and Haines, Stephanie and Lewis, Dustin F. and Polizzotto, Matthew L.}, year={2014}, pages={379–388} }
 @article{gannon_jeffries_2014, title={Dislodgeable 2,4-D from athletic field turfgrass}, volume={79}, number={3}, journal={European Journal of Horticultural Science}, author={Gannon, T. W. and Jeffries, M. D.}, year={2014}, pages={116–122} }
 @article{jeffries_mahoney_gannon_2014, title={Effect of Simulated Indaziflam Drift Rates on Various Plant Species}, volume={28}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-14-00004.1}, abstractNote={Indaziflam is a PRE herbicide for control of annual grass and broadleaf weeds in numerous settings, including managed roadsides, railroads, and noncroplands. There is a need for new and improved PRE herbicides for herbaceous vegetation management along roadsides; however, off-target crop injury via spray drift is a concern because of the close proximity of roadside applications to the wide array of crops grown throughout the southeastern United States where indaziflam is used. Greenhouse research was conducted to evaluate the effect of PRE and POST simulated indaziflam spray drift rates on the growth of cotton, bell pepper, soybean, squash, tobacco, and tomato. Simulated indaziflam spray drift rates were 100, 20, 10, 5, or 2.5% of a 73 g ai ha−1 application rate, whereas other herbicide treatments included for comparative purposes were applied at 10% of a typical North Carolina roadside vegetation management application rate. These included sulfometuron (4 g ai ha−1), aminocyclopyrachlor + metsulfuron (11 + 3.5 g ai ha−1), clopyralid + triclopyr (21 + 63 g ai ha−1), or aminopyralid (12 g ai ha−1). In general, plant growth responses varied among herbicides and application timings. Across all evaluated parameters, indaziflam at the 10% simulated drift rate adversely effected plant growth similarly or less than all other herbicides when applied PRE (squash and tomato), POST (bell pepper and soybean), and PRE or POST (cotton and tobacco). No clear trends were observed regarding indaziflam application timing, as PRE squash and tomato, and POST bell pepper and soybean applications were safer than their respective alternative timing, and no significant differences were detected between timings on cotton or tobacco. Across application timings, plant susceptibility to indaziflam-simulated spray drift rates ranked cotton < tobacco < tomato < squash < pepper < soybean. Finally, it should be noted that the lowest simulated indaziflam drift rate (2.5%) caused greater than 20% root mass reduction on cotton (POST), bell pepper (PRE and POST), soybean (PRE and POST), squash (PRE), and tomato (POST). Although this research supports indaziflam use along roadsides, it still poses an off-target plant injury risk. Future research should evaluate techniques to minimize spray drift from roadside pesticide applications.}, number={4}, journal={WEED TECHNOLOGY}, author={Jeffries, Matthew D. and Mahoney, Denis J. and Gannon, Travis W.}, year={2014}, pages={608–616} }
 @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={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.}, 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{mahoney_jeffries_gannon_2014, title={Weed Control with Liquid Carbon Dioxide in Established Turfgrass}, volume={28}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-14-00003.1}, abstractNote={In recent years, increasing implementation of biological, cultural, and mechanical weed-control methods is desired; however, many of these techniques are not viable in established turfgrass systems. The use of freezing or frost for weed control has previously been researched; however, is not well elucidated. Field and greenhouse experiments were conducted to evaluate liquid carbon dioxide (LCD) for weed control in established turfgrass systems. LCD was applied with handheld prototypes that were modified to reduce the amount of LCD required for weed control. Common annual and perennial turfgrass weeds included common chickweed, corn speedwell, goosegrass, large crabgrass, smooth crabgrass, Virginia buttonweed, and white clover. Turfgrass tolerance was evaluated on the following species: hybrid bermudagrass, Kentucky bluegrass, tall fescue, and zoysiagrass. The final modification allowed for lower output (0.5 kg LCD min−1) when compared with the initial prototype (3 kg LCD min−1). In general, weed control increased as LCD increased. When comparing weed species life cycles, annuals were controlled more than perennials (P < 0.0001) at 14 and 28 d after treatment (DAT). Further, exposure time affected control as white clover, Virginia buttonweed, and large crabgrass control was greater (18, 14, 15%, respectively) from the longer exposure time (30 vs. 15 s), although equivalent amounts of LCD (30 kg m−2) were applied. These data also suggest that plant maturity affects control, as large crabgrass control in one- to two- and three- to four-leaf stages (> 90%) was greater than in the one- to two-tiller stage (< 70%). Turfgrass injury at 7 DAT was unacceptable (> 30%) on all species, but declined to 0% by 28 DAT. These data suggest that LCD has the potential to provide an alternative for weed control of select species where synthetic herbicides are not allowed or desired.}, number={3}, journal={WEED TECHNOLOGY}, author={Mahoney, Denis J. and Jeffries, Matthew D. and Gannon, Travis W.}, year={2014}, pages={560–568} }
 @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={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.}, number={3}, journal={WEED TECHNOLOGY}, author={Jeffries, Matthew D. and Yelverton, Fred H. and Gannon, Travis W.}, year={2013}, pages={520–526} }
 @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={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.}, 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={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−1for 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.}, 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} }