@article{burke_thomas_allen_collins_wilcut_2008, title={A Comparison of Weed Control in Herbicide-Resistant, Herbicide-Tolerant, and Conventional Corn}, volume={22}, ISSN={["0890-037X"]}, DOI={10.1614/WT-07-184.1}, abstractNote={Experiments were conducted at three North Carolina research stations in 2003 to evaluate weed control and corn yield in glyphosate-resistant, glufosinate-resistant, imidazolinone-tolerant, and conventional corn weed management systems. Late-season control of common lambsquarters, large crabgrass, and yellow nutsedge increased with metolachlor PRE compared with no PRE herbicide treatment. Common lambsquarters, pitted morningglory, entireleaf morningglory, spurred anoda, and tropic croton control was improved by a single early POST (EPOST) application regardless of herbicide system. Control of common lambsquarters, pitted morningglory, entireleaf morningglory, and spurred anoda was similar for glyphosate and glufosinate systems for each POST over-the-top (POT) herbicide system. A single EPOST application of imazethapyr plus imazapyr to imidazolinone-tolerant corn controlled common lambsquarters, pitted morningglory, entireleaf morningglory, and spurred anoda and was better than a single EPOST application of glyphosate, glufosinate, or nicosulfuron. Tropic croton was controlled ≥ 95% with glufosinate or glyphosate, applied once or twice, or in mixture with metolachlor. A single EPOST application of imazethapyr plus imazapyr or nicosulfuron did not control tropic croton. Common lambsquarters, entireleaf morningglory, large crabgrass, Palmer amaranth, and yellow nutsedge control was greater with a late-POST–directed (LAYBY) of ametryn than no LAYBY. Systems that did not include a POT herbicide system had the lowest percentage in the weed-free yield and the lowest yield. Treatments that included a POT system with or without a PRE treatment of metolachlor yielded within 5% of the weed-free treatment, regardless of herbicide system.}, number={4}, journal={WEED TECHNOLOGY}, author={Burke, Ian C. and Thomas, Walter E. and Allen, Jayla R. and Collins, Jim and Wilcut, John W.}, year={2008}, pages={571–579} }
 @article{thomas_everman_burke_koger_wilcut_2007, title={Absorption and translocation of glyphosate and sucrose in glyphosate-resistant cotton}, volume={21}, ISSN={["0890-037X"]}, DOI={10.1614/WT-06-125.1}, abstractNote={Studies were conducted to evaluate absorption and translocation of 14C-glyphosate in glyphosate-resistant (GR) cotton. Both commercial GR cotton events [glyphosate-resistant event 1, marketed as Roundup Ready®, released 1997 (GRE1), and glyphosate-resistant event 2, marketed as Roundup Ready Flex®, released 2006 (GRE2)] were evaluated at the four-leaf and eight-leaf growth stages. Plants were harvested at 1, 3, 5, and 7 d after treatment (DAT). Glyphosate absorption, as a percentage of applied, increased over time with 29 and 36% absorption at 7 DAT in four-leaf GRE1 and GRE2 cotton, respectively. In eight-leaf cotton, glyphosate absorption (33% at 7 DAT) was not different between events. Glyphosate translocation patterns were not different between events or harvest timings and exhibited a source–sink relation. Observed translocation differences between cotton growth stages were probably due to reduced glyphosate export from the treated leaf of eight-leaf cotton. An additional study compared absorption and translocation of 14C-glyphosate and 14C-sucrose in 5- and 10-leaf GRE2 cotton. Averaged over trials, 14C compounds, and growth stages, cotton absorbed 28% of the applied dose at 14 DAT. On the basis of the percentage of 14C exported out of the treated leaf, glyphosate and sucrose translocation patterns were similar, indicating that glyphosate may be used as a photoassimilate model in GRE2 cotton.Nomenclature: Glyphosate; cotton, Gossypium hirsutum L.}, number={2}, journal={WEED TECHNOLOGY}, author={Thomas, Walter E. and Everman, Wesley J. and Burke, Ian C. and Koger, Clifford H. and Wilcut, John W.}, year={2007}, pages={459–464} }
 @article{burke_holland_burton_york_wilcut_2007, title={Johnsongrass (Sorghum halepense) pollen expresses ACCase target-site resistance}, volume={21}, ISSN={["1550-2740"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-36448953142&partnerID=MN8TOARS}, DOI={10.1614/WT-06-061.1}, abstractNote={Three studies were conducted to develop pollen tests for the screening of acetyl coenzyme-A carboxylase (ACCase) target-site resistance in a biotype of johnsongrass. The assays were based on germination of johnsongrass pollen in media supplemented with clethodim. Two different methods were used to evaluate pollen germination—a visual assessment and a spectrophotometric assay. The response of pollen to the germination media was linear for 16 h. At 6 h after treatment, absorbance at 500 nm was nearly 0.5; consequently, 6 h was chosen to conduct the pollen assays using the spectrophotometer. Both assessment methods differentiated the susceptible (S) and resistant (R) biotypes. Pollen from the susceptible biotype of johnsongrass was strongly inhibited by increasing concentrations of clethodim, with a GR50 of 25.8 ± 0.6 (SE) µM and GR50 of 16.4 ± 1.7 (SE) µM clethodim by visual assessment and spectrophotometric assessment, respectively. Minimum R/S values were > 3.9 by visual assessment and > 6.1 by spectrophotometric assessment. ACCase target-site resistance is expressed in johnsongrass pollen.Nomenclature: johnsongrass, Sorghum halepense (L.) Pers. SORHA.}, number={2}, journal={WEED TECHNOLOGY}, author={Burke, Ian C. and Holland, James B. and Burton, James D. and York, Alan C. and Wilcut, John W.}, year={2007}, pages={384–388} }
 @article{burke_schroeder_thomas_wilcut_2007, title={Palmer amaranth interference and seed production in peanut}, volume={21}, ISSN={["0890-037X"]}, DOI={10.1614/WT-06-058.1}, abstractNote={Studies were conducted to evaluate density-dependent effects of Palmer amaranth on weed and peanut growth and peanut yield. Palmer amaranth remained taller than peanut throughout the growing season and decreased peanut canopy diameter, although Palmer amaranth density did not affect peanut height. The rapid increase in Palmer amaranth height at Goldsboro correspondingly reduced the maximum peanut canopy diameter at that location, although the growth trends for peanut canopy diameter were similar for both locations. Palmer amaranth biomass was affected by weed density when grown with peanut. Peanut pod weight decreased linearly 2.89 kg/ha with each gram of increase in Palmer amaranth biomass per meter of crop row. Predicted peanut yield loss from season-long interference of one Palmer amaranth plant per meter of crop row was 28%. Palmer amaranth seed production was also described by the rectangular hyperbola model. At the highest density of 5.2 Palmer amaranth plants/m crop row, 1.2 billion Palmer amaranth seed/ha were produced.Nomenclature: Palmer amaranth, Amaranthus palmeri S. Wats. AMAPA; peanut, Arachis hypogaea L. ‘Perry’.}, number={2}, journal={WEED TECHNOLOGY}, author={Burke, Ian C. and Schroeder, Michelle and Thomas, Walter E. and Wilcut, John W.}, year={2007}, pages={367–371} }
 @article{burke_wilcut_allen_2007, title={Viability and in vitro germination of Johnsongrass (Sorghum halepense) pollen}, volume={21}, ISSN={["1550-2740"]}, DOI={10.1614/WT-05-171.1}, abstractNote={A high proportion of viable pollen grains must germinate to study the physiology of pollen growth to reduce the confounding effects of environmental influences on pollen germination. The objectives of this study were to evaluate the nuclear state and develop a suitable medium and culture method for in vitro germination of johnsongrass pollen. Johnsongrass pollen was trinucleate, and in vitro tests for pollen viability using Alexander's stain and a fluorochromatic reaction method (FCR) indicated johnsongrass pollen was viable (92.6 to 98.4%). A factorial treatment arrangement of four concentrations of sucrose, two concentrations of boric acid, and two concentrations of calcium nitrate were used to determine the optimum pollen-germination medium composition in suspension culture, agar culture, and cellophane membrane culture. Germination was highest in a suspension culture with a medium containing 0.3 M sucrose, 2.4 mM boric acid, and 3 mM calcium nitrate. Pollen germination using this medium was 78.9% when anthers were harvested just before anthesis.}, number={1}, journal={WEED TECHNOLOGY}, author={Burke, Ian C. and Wilcut, John W. and Allen, Nina S.}, year={2007}, pages={23–29} }
 @article{everman_burke_allen_collins_wilcut_2007, title={Weed control and yield with glufosinate-resistant cotton weed management systems}, volume={21}, DOI={10.1614/W7-06-164.1}, number={3}, journal={Weed Technology}, author={Everman, W. J. and Burke, I. C. and Allen, J. R. and Collins, J. and Wilcut, J. W.}, year={2007}, pages={695–701} }
 @article{lassiter_burke_thomas_pline-srnic_jordan_wilcut_wilkerson_2007, title={Yield and physiological response of peanut to glyphosate drift}, volume={21}, ISSN={["0890-037X"]}, DOI={10.1614/WT-07-045.1}, abstractNote={Five experiments were conducted during 2001 and 2002 in North Carolina to evaluate peanut injury and pod yield when glyphosate was applied to 10 to 15 cm diameter peanut plants at rates ranging from 9 to 1,120 g ai/ha. Shikimic acid accumulation was determined in three of the five experiments. Visual foliar injury (necrosis and chlorosis) was noted 7 d after treatment (DAT) when glyphosate was applied at 18 g/ha or higher. Glyphosate at 280 g/ha or higher significantly injured the peanut plant and reduced pod yield. Shikimic acid accumulation was negatively correlated with visual injury and pod yield. The presence of shikimic acid can be detected using a leaf tissue assay, which is an effective diagnostic tool for determining exposure of peanut to glyphosate 7 DAT.}, number={4}, journal={WEED TECHNOLOGY}, author={Lassiter, Bridget R. and Burke, Ian C. and Thomas, Walter E. and Pline-Srnic, Wendy A. and Jordan, David L. and Wilcut, John W. and Wilkerson, Gall G.}, year={2007}, pages={954–960} }
 @article{burke_thomas_burton_spears_wilcut_2006, title={A seedling assay to screen aryloxyphenoxypropionic acid and cyclohexanedione resistance in johnsongrass (Sorghum halepense)}, volume={20}, ISSN={["0890-037X"]}, DOI={10.1614/WT-05-160.1}, abstractNote={A seedling bioassay was developed for the rapid diagnosis of resistance to clethodim and fluazifop-P in johnsongrass. The assay was based on differences in the coleoptile length of susceptible (S) and resistant (R) seedlings exposed to clethodim and fluazifop-P in petri dishes for 5 d. Bioassay concentrations of 0.09 mg/L clethodim and 0.18 mg/L fluazifop-P were chosen as discriminant based on rate responses of each biotype to increasing herbicide dose. At 5 d after treatment (DAT), the amounts of clethodim required to reduce coleoptile length by 50% ( GR 50 ) for the R and S seedlings were 462.5 and 24.8 mg/L, respectively, resulting in an R:S ratio of 18.7. The fluazifop GR 50 values for the R and S seedlings were 618.7 and 17.5 mg/L, respectively, resulting in a R:S ratio of 35.4.}, number={4}, journal={WEED TECHNOLOGY}, author={Burke, Ian C. and Thomas, Walter E. and Burton, James D. and Spears, Janet F. and Wilcut, John W.}, year={2006}, pages={950–955} }
 @article{burke_wilcut_cranmer_2006, title={Cross-resistance of a johnsongrass (Sorghum halepense) biotype to aryloxyphenoxypropionate and cyclohexanedione herbicides}, volume={20}, ISSN={["0890-037X"]}, DOI={10.1614/WT-05-110R.1}, abstractNote={Dose-response experiments were conducted in a greenhouse on a biotype of johnsongrass from Washington County, Mississippi, to determine the level of resistance to the aryloxyphenoxypropionate (AOPP) herbicide fluazifop-P-butyl and the cyclohexanedione (CHD) herbicides clethodim and sethoxydim. Both seedling and rhizomatous plants were evaluated. Resistant/susceptible (R/S) ratios were calculated based on GR 50 values (the rate required to reduce shoot dry biomass, expressed as a percent of the control, 50%). The GR 50 values for the resistant and susceptible seedling plants were 110 and 10 g ai/ha for clethodim, 193 and 34 g ai/ha for fluazifop-P-butyl, and 265 and 48 g ai/ha for sethoxydim, resulting in R/S ratios of 11.0, 5.7, and 5.5, respectively. The GR 50 values for the resistant and susceptible rhizomatous plants were 609 and 39 g/ha for clethodim, 657 and 29 g/ha for fluazifop-P-butyl, and 668 and 30 g/ha for sethoxydim, resulting in R/S ratios of 15.6, 22.7, and 22.3, respectively.}, number={3}, journal={WEED TECHNOLOGY}, author={Burke, Ian C. and Wilcut, John W. and Cranmer, John}, year={2006}, pages={571–575} }
 @article{thomas_burke_spears_wilcut_2006, title={Influence of environmental factors on slender amaranth (Amaranthus viridis) germination}, volume={54}, DOI={10.1614/ws-05-54.2.316}, abstractNote={Germination response of slender amaranth to temperature, solution pH, moisture stress, and depth of emergence was evaluated under controlled environmental conditions. Results indicated that 30 C was the optimum constant temperature for germination. Germination of slender amaranth seed at 21 d was similar, with 35/25, 35/20, 30/25, and 30/20 alternating temperature regimes. As temperatures in alternating regimes increased, time to onset of germination decreased and rate of germination increased. Slender amaranth germination was greater with acidic than with basic pH conditions. Germination declined with increasing water stress and was completely inhibited at water potentials below −0.6 MPa. Slender amaranth emergence was greatest at depths of 0.5 to 2 cm, but some seeds emerged from as deep as 6 cm. Information gained in this study will contribute to an integrated control program for slender amaranth.}, number={2}, journal={Weed Science}, author={Thomas, W. E. and Burke, I. C. and Spears, J. F. and Wilcut, J. W.}, year={2006}, pages={316–320} }
 @article{burke_burton_york_cranmer_wilcut_2006, title={Mechanism of resistance to clethodim in a johnsongrass (Sorghum halepense) biotype}, volume={54}, ISSN={["1550-2759"]}, DOI={10.1614/WS-05-153R.1}, abstractNote={A biotype of johnsongrass cross resistant to clethodim, sethoxydim, quizalofop-P, and fluazifop-P was identified in several fields in Washington County, MS. Absorption, translocation, and metabolism studies using 14C-clethodim and acetyl-coenzyme A carboxylase (ACCase) activity assays were conducted to determine the resistance mechanism. Absorption of 14C-clethodim was higher in the resistant than the susceptible biotype 4 hours after treatment (HAT), but at 24, 48, and 72 HAT, similar levels of radioactivity were detected in both johnsongrass biotypes. Consequently, resistant plants had more radioactivity present in the treated leaves at 4 and 24 HAT. However, there was no difference between resistant and susceptible biotypes in the translocation of 14C out of the treated leaf at 4, 8, 24, 48, and 72 HAT as a percentage of total absorbed. Metabolism of clethodim was similar in the resistant and susceptible biotypes. There was no difference in the specific activity of ACCase from the susceptible and resistant johnsongrass biotypes (means of 0.221 and 0.223 nmol mg−1 protein min−1, respectively). ACCase from the susceptible biotype was sensitive to clethodim, with an I50 value of 0.29 μM clethodim. The ACCase enzyme from the resistant biotype was less sensitive, with an I50 value of 1.32 μM clethodim. The resultant R/S ratio for clethodim was 4.5. These results indicate that resistance to clethodim in this johnsongrass biotype resulted from an altered ACCase enzyme that confers resistance to clethodim.}, number={3}, journal={WEED SCIENCE}, author={Burke, Ian C. and Burton, James D. and York, Alan C. and Cranmer, John and Wilcut, John W.}, year={2006}, pages={401–406} }
 @article{fisher_burke_price_smith_wilcut_2006, title={Uptake, translocation, and metabolism of root absorbed sulfentrazone and sulfentrazone plus clomazone in flue-cured tobacco transplants}, volume={20}, ISSN={["0890-037X"]}, DOI={10.1614/WT-05-182.1}, abstractNote={Research was conducted to evaluate root uptake, translocation, and metabolism of 14 C-sulfentrazone alone or in a mixture with clomazone in solution in flue-cured tobacco transplants. Uptake and translocation of sulfentrazone was rapid and was not affected by the addition of clomazone. Fifty-nine and 65% of the 14 C absorbed by the plant was translocated to the leaves within 24 h with sulfentrazone alone and in the clomazone plus sulfentrazone mixture, respectively. Differences in plant metabolism were observed between sulfentrazone alone and sulfentrazone plus clomazone. After 3 h, 66% of the 14 C recovered from the leaves was metabolized when sulfentrazone was applied alone, compared to 91% when sulfentrazone was applied with clomazone. The difference could indicate that metabolism of sulfentrazone by tobacco transplants was enhanced by the presence of clomazone.}, number={4}, journal={WEED TECHNOLOGY}, author={Fisher, Loren R. and Burke, Ian C. and Price, Andrew J. and Smith, W. David and Wilcut, John W.}, year={2006}, pages={898–902} }
 @article{burke_askew_corbett_wilcut_2005, title={Glufosinate antagonizes clethodim control of goosegrass (Eleusine indica)}, volume={19}, ISSN={["1550-2740"]}, DOI={10.1614/WT-04-214R1.1}, abstractNote={Because of a previously reported antagonism of clethodim activity by other herbicides, greenhouse experiments were conducted to determine goosegrass control with clethodim and glufosinate postemergence alone, in tank mixtures, and as sequential treatments. Herbicide treatments consisted of glufosinate at 0, 290, or 410 g ai/ha and clethodim at 0, 105, or 140 g ai/ha, each applied alone, in all possible combinations of the above application rates, or sequentially. Glufosinate at either rate alone controlled goosegrass at the two- to four-leaf growth stage <44%, and control was less for goosegrass at the one- to two- and four- to six-tiller growth stages. Clethodim controlled two- to four-leaf and one- to two-tiller goosegrass 91 and 99% at application rates of 105 and 140 g/ha, respectively, and controlled four- to six-tiller goosegrass 68 and 83% at application rates of 105 and 140 g ai/ha, respectively. All tank mixtures of glufosinate with clethodim reduced goosegrass control at least 52 percentage points when compared to the control with clethodim alone. Glufosinate at 290 or 410 g/ha when applied sequentially 7 or 14 d prior to clethodim reduced goosegrass control at least 50 percentage points compared to the control obtained with clethodim applied alone. Clethodim at rates of 105 or 140 g/ha when applied 7 or 14 d prior to glufosinate controlled goosegrass equivalent to the control obtained with each respective rate of clethodim applied alone at the two- to four-leaf and one- to two-tiller growth stage. Clethodim should be applied to goosegrass no larger than at the one- to two-tiller growth stage at least 7 d prior to glufosinate application or 14 d after a glufosinate application for effective goosegrass control.}, number={3}, journal={WEED TECHNOLOGY}, author={Burke, IC and Askew, SD and Corbett, JL and Wilcut, JW}, year={2005}, pages={664–668} }
 @article{lancaster_jordan_york_burke_corbin_sheldon_wilcut_monks_2005, title={Influence of selected fungicides on efficacy of clethodim and sethoxydim}, volume={19}, ISSN={["1550-2740"]}, DOI={10.1614/WT-04-172R}, abstractNote={Field experiments were conducted to compare large crabgrass control by clethodim or sethoxydim applied alone and with selected fungicides registered for use in peanut. Fluazinam, propiconazole plus trifloxystrobin, or tebuconazole did not affect efficacy of clethodim or sethoxydim. Azoxystrobin, boscalid, chlorothalonil, and pyraclostrobin reduced efficacy of clethodim and sethoxydim in some experiments. Increasing the herbicide rate increased large crabgrass control regardless of the addition of chlorothalonil. In laboratory experiments, 14 C absorption was less when 14 C-clethodim or 14 C-sethoxydim was applied with chlorothalonil. Pyraclostrobin and tebuconazole did not affect absorption of 14 C-clethodim or 14 C-sethoxydim.}, number={2}, journal={WEED TECHNOLOGY}, author={Lancaster, SH and Jordan, DL and York, AC and Burke, IC and Corbin, FT and Sheldon, YS and Wilcut, JW and Monks, DW}, year={2005}, pages={397–403} }
 @article{burke_troxler_askew_wilcut_smith_2005, title={Weed management systems in glyphosate-resistant cotton}, volume={19}, ISSN={["1550-2740"]}, DOI={10.1614/WT-04-182R1}, abstractNote={Studies were conducted at Clayton, Lewiston-Woodville, and Rocky Mount, NC, to evaluate weed and cotton response to herbicide systems in glyphosate-resistant cotton in 1995 and 1997. Herbicide systems evaluated included various combinations of soil-applied (trifluralin and fluometuron) and postemergence (POST) (glyphosate or pyrithiobac) herbicides with or without late postemergence-directed (LAYBY) treatments of cyanazine plus MSMA. Glyphosate-resistant cotton injury was less than 5% with all herbicide treatments. Glyphosate POST systems were as efficacious in weed control as other herbicide systems. Depending on location, glyphosate and pyrithiobac POST systems usually required cyanazine plus MSMA LAYBY for season-long control of common lambsquarters, goosegrass, large crabgrass, pitted morningglory, prickly sida, and Texas panicum. Glyphosate POST applied as needed provided weed control equivalent to soil-applied plus POST herbicides, although lint yield was slightly reduced depending on location. Herbicide systems that included soil-applied herbicides required one to two treatments of glyphosate POST and post-directed for season-long weed control and high cotton lint yields, whereas the same herbicide systems without soil-applied herbicides required two to three glyphosate treatments. In all herbicide systems, a residual soil-applied or LAYBY herbicide treatment increased yield compared with glyphosate POST only systems. Location influenced weed control and cotton yield. Generally, as herbicide inputs increased, yield increased.}, number={2}, journal={WEED TECHNOLOGY}, author={Burke, IC and Troxler, SC and Askew, SD and Wilcut, JW and Smith, WD}, year={2005}, pages={422–429} }
 @article{burke_thomas_pline-srnic_fisher_smith_wilcut_2005, title={Yield and physiological response of flue-cured tobacco to simulated glyphosate drift}, volume={19}, ISSN={["0890-037X"]}, DOI={10.1614/WT-03-219R}, abstractNote={Field trials were conducted in 2001 at the Tobacco Research Station near Oxford, NC, and in 2002 at the Lower Coastal Plains Research Station near Kinston, NC, to determine tobacco yield, injury, and shikimic acid accumulation in response to simulated glyphosate drift. Glyphosate was applied to 12- to 13-cm-high tobacco ‘K326’ early postemergence at 0, 9, 18, 35, 70, 140, 280, 560, and 1,120 (1×) g ai/ha. Crop injury was rated 7 and 35 d after treatment (DAT) and shikimic acid accumulation in leaves at 7 DAT, tobacco yield, and leaf grade index (whole-plant index of harvest interval leaf value) were also assessed. Shikimic acid accumulation and injury symptoms increased similarly as glyphosate rate increased. Glyphosate rates of 140 g/ha (0.125 of recommended rate) or higher resulted in significant crop injury, reduced tobacco yield, and decreased leaf grade index. Shikimic acid accumulation at 7 DAT was inversely related to tobacco yield. Shikimic acid accumulation was found to be an effective diagnostic tool to determine glyphosate drift in tobacco; however, in-season data are needed to correlate shikimic acid accumulation with yield loss.}, number={2}, journal={WEED TECHNOLOGY}, author={Burke, IC and Thomas, WE and Pline-Srnic, WA and Fisher, LR and Smith, WD and Wilcut, JW}, year={2005}, pages={255–260} }
 @article{thomas_burke_robinson_pline-srnic_edmisten_wells_wilcut_2005, title={Yield and physiological response of nontransgenic cotton to simulated glyphosate drift}, volume={19}, ISSN={["1550-2740"]}, DOI={10.1614/WT-03-194R}, abstractNote={Field studies were conducted in 2001 in Lewiston, NC, and in 2002 at Clayton and Lewiston, NC, to investigate the response of nontransgenic cotton to simulated glyphosate drift in a weed-free environment. Nontransgenic cotton variety ‘Fibermax 989’ was planted in a conventional seedbed at all locations. Glyphosate treatments were applied early postemergence (EPOST) at the four-leaf growth stage of cotton at 0, 8.7, 17.5, 35, 70, 140, 280, 560, and 1,120 g ai/ha and represent 0, 0.78, 1.55, 3.13, 6.25, 12.5, 25, 50, and 100% of the commercial use rate, respectively. Rates as low as 140 g/ha caused lint yield reductions depending on year and location. When averaged over all locations, lint yield reductions of 4, 49, 72, and 87% compared with nontreated cotton were observed with glyphosate rates of 140, 280, 560, and 1,120 g/ha, respectively. Visual injury and shikimic acid accumulation were evident at glyphosate rates greater or equal to 70 g/ha. Collectively, visual injury and shikimic acid accumulation at...}, number={1}, journal={WEED TECHNOLOGY}, author={Thomas, WE and Burke, IC and Robinson, BL and Pline-Srnic, WA and Edmisten, KL and Wells, R and Wilcut, JW}, year={2005}, pages={35–42} }
 @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={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.}, number={5}, journal={WEED SCIENCE}, author={McElroy, JS and Yelverton, FH and Burke, IC and Wilcut, JW}, year={2004}, pages={704–710} }
 @article{burke_price_wilcut_jordan_culpepper_tredaway-ducar_2004, title={Annual grass control in peanut (Arachis hypogaea) with clethodim and imazapic}, volume={18}, ISSN={["1550-2740"]}, DOI={10.1614/WT-03-026R}, abstractNote={Field experiments were conducted to evaluate possible interactions of clethodim with imazapic applied as mixtures or sequentially for control of broadleaf signalgrass, fall panicum, goosegrass, and large crabgrass. Imazapic at 70 g ai/ha alone controlled grass weeds inconsistently, whereas clethodim at 140 g ai/ha alone controlled the same weeds at least 99%. Imazapic did not affect broadleaf signalgrass control by clethodim. Reduced control of fall panicum, goosegrass, and large crabgrass was observed when clethodim and imazapic were applied in mixture. Antagonism of clethodim occurred when clethodim was applied 1 d before or up to 3 d after application of imazapic (fall panicum and large crabgrass). Antagonism of goosegrass control was noted when imazapic was applied 3 d before or up to 7 d after application of clethodim. In other experiments, large crabgrass and Texas panicum control by clethodim (70 and 140 g/ha) applied alone or with imazapic (70 g/ ha) or bentazon (1.1 kg ai/ha) plus 2,4-DB (0.28 kg ai/ha) either with or without ammonium sulfate (2.8 kg/ha) was evaluated. Texas panicum control by clethodim was reduced by imazapic regardless of the ammonium sulfate rate. However, large crabgrass control by imazapic was not affected in these experiments. Control of both grasses by clethodim was reduced substantially by bentazon plus 2,4-DB, although in some instances ammonium sulfate improved control when in mixture. Ammonium sulfate improved control by clethodim in some instances irrespective of the broadleaf–sedge herbicide treatments.Nomenclature: Bentazon; clethodim; 2,4-DB; imazapic; broadleaf signalgrass, Brachiaria platyphylla (Griseb) Nash #3 BRAPP; fall panicum, Panicum dichotomiflorum L. # PANDI; goosegrass, Eleusine indica L. Gaertn. # ELEIN; large crabgrass, Digitaria sanguinalis L. Scop. # DIGSA; Texas panicum, Panicum texanum Buckl. # PANTE.Additional index words: Ammonium sulfate, antagonism, herbicide compatibility, herbicide interaction, sequential application.}, number={1}, journal={WEED TECHNOLOGY}, author={Burke, IC and Price, AJ and Wilcut, JW and Jordan, DL and Culpepper, AS and Tredaway-Ducar, J}, year={2004}, pages={88–92} }
 @article{burke_wilcut_2004, title={Weed management in cotton with CGA-362622, fluometuron, and pyrithiobac}, volume={18}, ISSN={["1550-2740"]}, DOI={10.1614/WT-03-035R}, abstractNote={An experiment was conducted at five locations in North Carolina during 2000 and 2001 to evaluate weed control, crop injury, and cotton yield. Weed management systems included different combinations of pyrithiobac preemergence (PRE), fluometuron PRE, CGA-362622 postemergence (POST), pyrithiobac POST, and monosodium salt of methylarsonic acid (MSMA) plus prometryn applied late POST-directed (LAYBY). At Goldsboro in 2000, cotton was injured 74 to 78% by CGA-362622 POST when evaluated 4 to 7 d after treatment (DAT). Injury at Clayton, Goldsboro, and Lewiston in 2001 and Rocky Mount in 2000 was less than 16% 4 to 7 DAT with the same treatment and was not apparent by 62 DAT. CGA-362622 controlled common lambsquarters, common ragweed, Palmer amaranth, sicklepod, smooth pigweed, and Ipomoea species including entireleaf, ivyleaf, and pitted morningglory, and the addition of pyrithiobac to the herbicide system, either PRE or POST, increased control of Amaranthus species, jimsonweed, and prickly sida. CGA-362622 did not control jimsonweed or prickly sida. Fluometuron PRE, pyrithiobac PRE, and MSMA plus prometryn LAYBY were beneficial for increasing weed control and cotton lint yields. Prometryn plus MSMA LAYBY increased control of common ragweed, entireleaf morningglory, jimsonweed, pitted morningglory, and smooth pigweed and provided higher cotton yields than similar systems without a LAYBY. The greatest weed control and greatest cotton lint yields required complete weed management systems that included a combination of PRE, POST, and LAYBY treatments.}, number={2}, journal={WEED TECHNOLOGY}, author={Burke, IC and Wilcut, JW}, year={2004}, pages={268–276} }
 @article{thomas_burke_wilcut_2004, title={Weed management in glyphosate-resistant corn with glyphosate and halosulfuron}, volume={18}, ISSN={["1550-2740"]}, DOI={10.1614/WT-03-222R}, abstractNote={Three field studies were conducted at Lewiston Woodville, NC, in 2001 and 2002 to evaluate crop tolerance, weed control, grain yield, and net returns in glyphosate-resistant corn with various herbicide systems. Crop injury, weed control, and grain yield were not influenced by glyphosate formulation. Atrazine preemergence (PRE) and atrazine plus metolachlor PRE, averaged over postemergence (POST) systems, controlled Texas panicum at least 80 and 87%, respectively. Sequential glyphosate applications (early postemergence [EPOST] followed by [fb] POST) provided at least 99% control of Texas panicum compared with at least 86 and 88% control with glyphosate EPOST and glyphosate plus halosulfuron EPOST, respectively. Atrazine plus metolachlor PRE fb any glyphosate system controlled large crabgrass and goosegrass 89 to 100% and 94 to 100%, respectively. Sequential glyphosate treatments controlled large crabgrass and goosegrass at least 99 and 95%, respectively. Regardless of PRE system, glyphosate plus halosulfuron EPOST and sequential applications of glyphosate controlled common ragweed and common lambsquarters at least 99%, whereas glyphosate EPOST alone provided at least 88 and 96% control, respectively. Glyphosate plus halosulfuron EPOST and glyphosate sequentially controlled yellow nutsedge similarly and more consistently than glyphosate EPOST. Regardless of PRE treatment, sequential glyphosate applications provided at least 98% control of entireleaf and pitted morningglory, whereas glyphosate EPOST controlled at least 64 and 62%, respectively. Glyphosate EPOST and the sequential glyphosate EPOST fb POST systems yielded similarly at all three locations. Net returns were highest at all three locations with the glyphosate sequential system, with similar net returns obtained with glyphosate EPOST and glyphosate plus halosulfuron EPOST at two and one locations, respectively.}, number={4}, journal={WEED TECHNOLOGY}, author={Thomas, WE and Burke, IC and Wilcut, JW}, year={2004}, pages={1049–1057} }
 @article{thomas_burke_wilcut_2004, title={Weed management in glyphosate-resistant corn with glyphosate, halosulfuron, and mesotrione}, volume={18}, ISSN={["1550-2740"]}, DOI={10.1614/WT-03-221R}, abstractNote={Four field studies were conducted at the Peanut Belt Research Station near Lewiston Woodville, NC, in 2000, 2001, and 2002 to evaluate crop tolerance, weed control, grain yield, and net returns in glyphosate-resistant corn with various herbicide systems. Preemergence (PRE) treatment options included no herbicide, atrazine at 1.12 kg ai/ha, or atrazine plus metolachlor at 1.68 kg ai/ha. Postemergence (POST) treatment options included glyphosate at 1.12 kg ai/ha as either the isopropylamine salt or the diammonium salt, either alone or in mixtures with mesotrione at 105 g ai/ha plus crop oil concentrate at 1% (v/v) or halosulfuron at 53 g ai/ha plus 0.25% (v/v) nonionic surfactant. All response variables were independent of glyphosate formulation. Addition of metolachlor to atrazine PRE improved large crabgrass and goosegrass control but did not always improve Texas panicum control. POST control of these annual grasses was similar with glyphosate alone or in mixture with halosulfuron or mesotrione. Glyphosate POST controlled common lambsquarters and common ragweed 89 and 93%, respectively. Glyphosate plus halosulfuron POST provided more effective yellow nutsedge control than glyphosate POST. Atrazine PRE or atrazine plus metolachlor PRE followed by any glyphosate POST treatment controlled Ipomoea spp. at least 93%. Glyphosate plus mesotrione in total POST systems always provided greater control of Ipomoea spp. than glyphosate alone. The highest yielding treatments always included glyphosate POST, either with or without a PRE herbicide treatment. Similarly, systems that included any glyphosate POST treatment had the highest net returns.}, number={3}, journal={WEED TECHNOLOGY}, author={Thomas, WE and Burke, IC and Wilcut, JW}, year={2004}, pages={826–834} }
 @article{ducar_wilcut_richburg_2004, title={Weed management in imidazolinone-resistant corn with imazapic}, volume={18}, ISSN={["1550-2740"]}, DOI={10.1614/WT-03-204R}, abstractNote={Field studies were conducted in 1992 and 1993 to evaluate imazapic alone and in postemergence (POST) mixtures with atrazine or bentazon for weed control in imidazolinone-resistant corn treated with carbofuran. Nicosulfuron and nicosulfuron plus atrazine also were evaluated. Imazapic at 36 and 72 g ai/ha controlled large crabgrass 85 and 92%, respectively, which was equivalent to control obtained with nicosulfuron plus atrazine. Imazapic at the higher rate controlled large crabgrass better than nicosulfuron alone. Imazapic at 36 and 72 g/ha controlled Texas panicum 88 and 99%, respectively, and at the higher rate control was equivalent to that obtained with nicosulfuron alone or in mixture with atrazine. Imazapic plus bentazon POST controlled Texas panicum less than imazapic at the lower rate applied alone. Redroot pigweed was controlled 100% with all herbicide treatments. Imazapic at either rate alone or in tank mixture with bentazon or atrazine controlled prickly sida >99%, which was superior to control obtained with nicosulfuron or nicosulfuron plus atrazine. Smallflower, entireleaf, ivyleaf, pitted, and tall morningglories were controlled 96% or greater with all herbicide treatments except nicosulfuron alone. Sicklepod control was >88% with all imazapic treatments, whereas control from nicosulfuron alone was 72%. Corn yields were improved by the addition of POST herbicides with no differences among POST herbicide treatments.}, number={4}, journal={WEED TECHNOLOGY}, author={Ducar, JT and Wilcut, JW and Richburg, JS}, year={2004}, pages={1018–1022} }
 @article{troxler_burke_wilcut_smith_burton_2003, title={Absorption, translocation, and metabolism of foliar-applied CGA-362622 in purple and yellow nutsedge (Cyperus rotundus and C-esculentus)}, volume={51}, ISSN={["0043-1745"]}, DOI={10.1614/0043-1745(2003)051[0013:ATAMOF]2.0.CO;2}, abstractNote={Studies were conducted to evaluate the absorption, translocation, and metabolism of 14C–CGA-362622 when foliar-applied to purple and yellow nutsedge. Less than 53% of the herbicide was absorbed after 96 h. Both nutsedge species translocated appreciable amounts of herbicide (30%) out of treated leaves. Translocation was both acropetal and basipetal, with at least 25% transported basipetally. Neither nutsedge species translocated more than 4% of applied radioactivity to the tubers and roots. Most of the metabolites formed by the nutsedge species were more polar than 14C–CGA-362622 and averaged 69 and 61% of the radioactivity in purple and yellow nutsedge, respectively. The half-life of CGA-362622 was estimated at 4 h in both purple and yellow nutsedge.}, number={1}, journal={WEED SCIENCE}, author={Troxler, SC and Burke, IC and Wilcut, JW and Smith, WD and Burton, J}, year={2003}, pages={13–18} }
 @article{burke_thomas_spears_wilcut_2003, title={Influence of environmental factors on after-ripened crowfootgrass (Dactyloctenium aegyptium) seed germination}, volume={51}, ISSN={["0043-1745"]}, DOI={10.1614/0043-1745(2003)051[0342:IOEFOA]2.0.CO;2}, abstractNote={Laboratory and greenhouse studies were conducted to determine the effect of temperature, pH, water stress, and planting depth on crowfootgrass germination. When treated with constant temperature, crowfootgrass germinated over a range of 15 to 40 C, with the optimum germination occurring at 30 C (42%). Onset, rate, and total germination (94%) were greatest in an alternating 20 and 35 C temperature regime. Germination decreased as pH increased, with greatest germination occurring at pH 4 and 5. Germination was reduced when seed was subjected to water stress, and no germination occurred below −0.8 mPa. Emergence was similar when seed were placed on the soil surface or buried at depths of 0.5 or 1 cm. Germination decreased with burial depth, and no seed emerged from 10 cm. These data suggest that crowfootgrass may emerge later in the season with warmer temperatures and after a precipitation event, and may emerge rapidly. These attributes could contribute to poor control later in the season by soil-applied herbicides or allow crowfootgrass to emerge after final postemergence treatments are made.}, number={3}, journal={WEED SCIENCE}, author={Burke, IC and Thomas, WE and Spears, JF and Wilcut, JW}, year={2003}, pages={342–347} }
 @article{burke_thomas_spears_wilcut_2003, title={Influence of environmental factors on broadleaf signalgrass (Brachiaria platyphylla) germination}, volume={51}, ISSN={["1550-2759"]}, DOI={10.1614/0043-1745(2003)051[0683:IOEFOB]2.0.CO;2}, abstractNote={Laboratory and greenhouse studies were conducted to determine the effect of temperature, solution pH, water stress, and planting depth on broadleaf signalgrass germination. Broadleaf signalgrass seed required removal of the husk for germination. When treated with constant temperature, broadleaf signalgrass germinated over a range of 20 to 35 C, with optimum germination occurring at 30 and 35 C. Onset, rate, and total germination (87%) was greatest in an alternating 20/30 C temperature regime. Germination decreased as solution pH increased, with greatest germination occurring at pH values of 4 and 5. Germination decreased with increasing water potential, and no germination occurred below −0.8 mPa. Emergence was above 42% when seed were placed on the soil surface or buried 0.5 cm deep. Germination decreased with burial depth, but 10% of broadleaf signalgrass seed emerged from 6.0-cm depth. No seed emerged from 10-cm depth. These data suggest that broadleaf signalgrass may emerge later in the season, after rains, and could germinate rapidly and in high numbers. These attributes could contribute to poor control later in the season by soil-applied herbicides or allow broadleaf signalgrass to emerge after final postemergence treatments were made.}, number={5}, journal={WEED SCIENCE}, author={Burke, IC and Thomas, WE and Spears, JF and Wilcut, JW}, year={2003}, pages={683–689} }
 @article{burke_wilcut_2003, title={Physiological basis for antagonism of clethodim by CGA 362622}, volume={51}, ISSN={["1550-2759"]}, DOI={10.1614/P2002-072}, abstractNote={Abstract Greenhouse and laboratory experiments were conducted to determine the effect of CGA 362622 on the herbicidal activity of clethodim on goosegrass. CGA 362622 did not affect absorption and translocation of 14C-clethodim by goosegrass. Averaged across the two treatments of clethodim alone and clethodim plus CGA 362622, absorption was 27 and 85% of the applied 14C-clethodim at 0.5 and 96 h, respectively. By 96 HAT, only 0.8% of applied 14C had translocated to the shoot below the treated leaf. Metabolism of clethodim was not affected by the presence of CGA 362622. Three metabolites of clethodim were detected in treated tissue at all harvest intervals. By 96 HAT, 56% of absorbed 14C converted to a relatively polar form when clethodim was applied alone or in the presence of CGA 362622. One day after treatment, the photosynthetic rate in plants treated with CGA 362622 had decreased below the rate in the nontreated check and remained lower until 6 d after treatment. These data suggest that the antagonism ...}, number={5}, journal={WEED SCIENCE}, author={Burke, IC and Wilcut, JW}, year={2003}, pages={671–677} }
 @article{burke_wilcut_2003, title={Physiological basis for antagonism of clethodim by imazapic on goosegrass (Eleusine indica (L.) Gaertn.)}, volume={76}, ISSN={["0048-3575"]}, DOI={10.1016/S0048-3575(03)00062-2}, abstractNote={Greenhouse and laboratory experiments were conducted to determine the effect of imazapic on the herbicidal activity of clethodim on goosegrass. Imazapic did not affect absorption of [14C]clethodim by goosegrass. Averaged across the two treatments of clethodim alone and clethodim plus imazapic, absorption was 36 and 89% of applied [14C]clethodim at 0.5 and 96 h, respectively. The majority of [14C]clethodim (79% of applied) was absorbed by 24 h. Translocation of 14C was not affected by imazapic, and 3.6% of applied 14C had translocated into the portion of the shoot below the treated leaf at 96 h after treatment. Metabolism of clethodim was not affected by the presence of imazapic. Three major metabolites of clethodim were detected in treated tissue at all harvest intervals. The majority (58%) of [14C]clethodim was converted to a relative polar metabolite form 96 h after treatment, whether clethodim was applied alone or in the presence of imazapic. One day after treatment, the photosynthetic rate in plants treated with imazapic decreased below the rate in the non-treated check, and was less for 8 days, the duration of the study. These data suggest that the antagonism of clethodim by imazapic may be caused by imazapic reducing the photosynthetic rate of goosegrass and therefore the sensitivity of ACCase to clethodim.}, number={2}, journal={PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY}, author={Burke, IC and Wilcut, JW}, year={2003}, month={Jun}, pages={37–45} }
 @article{burke_wilcut_porterfield_2002, title={CGA-362622 antagonizes annual grass control with clethodim}, volume={16}, ISSN={["0890-037X"]}, DOI={10.1614/0890-037X(2002)016[0749:CAAGCW]2.0.CO;2}, abstractNote={Field and greenhouse experiments were conducted to evaluate clethodim, CGA-362622, mixtures thereof, and sequential treatments for control of broadleaf signalgrass, fall panicum, goosegrass, and large crabgrass. In greenhouse experiments, clethodim alone provided 93 and 100% control of three- to four-leaf goosegrass at the low (105 g ai/ha) and high (140 g/ha) rates, respectively, whereas CGA-362622 did not control grasses in greenhouse or field experiments. Control of six- to eight-leaf goosegrass in the greenhouse with clethodim was 75% for the low rate and 89% for the high rate. Control of goosegrass in greenhouse studies was reduced at least 43 percentage points with CGA-362622 and clethodim at the high rate in mixture compared with control provided by clethodim at the high rate alone. When CGA-362622 and clethodim were applied in mixture in field studies, the effectiveness of the graminicide was decreased from > 97 to < 57% control for all annual grasses. Antagonism of clethodim activity was greater than that of the tank mixture when clethodim was applied 1 d after CGA-362622 on large crabgrass, goosegrass, and fall panicum. Clethodim applied 7 d before or after CGA-362622 controlled the four grass species as well as did clethodim applied alone. When CGA-362622 was applied to goosegrass alone, fresh weight accumulation stopped for a period of 4 d compared with untreated plants. Normal growth resumed after 4 d.Nomenclature: CGA-362622, N-[(4,6-dimethoxy-2-pyrimidinyl)carbamoyl]-3-(2,2,2-trifluoroethoxy)-pyridin-2-sulfonamide sodium salt; clethodim; broadleaf signalgrass, Brachiaria platyphylla (Griseb.) Nash #3 BRAPP; fall panicum, Panicum dichotomiflorum (L.) # PANDI; goosegrass, Eleusine indica (L.) Gaertn. # ELEIN; large crabgrass, Digitaria sanguinalis (L.) Scop. # DIGSA.Additional index words: Antagonism, growth analysis, orthogonal contrasts.Abbreviations: ALS, acetolactase synthase (EC 4.1.3.18); DAT, days after treatment; POST, postemergence.}, number={4}, journal={WEED TECHNOLOGY}, author={Burke, IC and Wilcut, JW and Porterfield, D}, year={2002}, pages={749–754} }
 @article{burke_askew_wilcut_2002, title={Flumioxazin systems for weed management in North Carolina peanut (Arachis hypogaea)}, volume={16}, ISSN={["0890-037X"]}, DOI={10.1614/0890-037X(2002)016[0743:FSFWMI]2.0.CO;2}, abstractNote={A study was conducted to evaluate flumioxazin preemergence (PRE) at 71 and 105 g ai/ha, when used with dimethenamid PRE, dimethenamid preplant incorporated (PPI), or ethalfluralin PPI, for crop injury, weed control, and yield. Peanut injury from treatments including flumioxazin 2 wk after soil-applied treatment (WAST) was less than 2% at two locations and 50 to 67% at a third location. Peanut injury increased with flumioxazin rate. Soil-applied treatments that included flumioxazin at either rate controlled common lambsquarters and prickly sida at least 96 and 89%, respectively. Addition of postemergence (POST) herbicides to any soil-applied program controlled prickly sida and ivyleaf morningglory at least 94 and 98%, respectively. Treatments that included ethafluralin or dimethenamid controlled goosegrass at least 82%. With a few exceptions, peanut yields were not improved by use of POST herbicides. Where peanut injury occurred, increased flumioxazin rate resulted in lower peanut yield when averaged over PPI and POST herbicide treatments.Nomenclature: Dimethenamid; ethalfluralin; flumioxazin; common lambsquarters, Chenopodium album L. #3 CHEAL; goosegrass, Eleusine indica (L.) Gaertn. # ELEIN; ivyleaf morningglory, Ipomoea hederacea (L.) Jacq. # IPOHE; prickly sida, Sida spinosa L. # SIDSP; peanut, Arachis hypogaea L. ‘NC 7’, ‘NC 10C’.Additional index words: Acifluorfen, bentazon, 2,4-DB, imazapic.Abbreviations: fb, followed by; POST, postemergence; PPI, preplant incorporated; PRE, preemergence; WAPT, weeks after POST treatment; WAST, weeks after soil-applied treatment.}, number={4}, journal={WEED TECHNOLOGY}, author={Burke, IC and Askew, SD and Wilcut, JW}, year={2002}, pages={743–748} }