@article{bonyak_vann_ye_lewis_gorny_2024, title={A 2-year, multi-county survey of plant-parasitic nematodes in North Carolina flue-cured tobacco}, volume={3}, ISSN={["1435-0645"]}, url={https://doi.org/10.1002/agj2.21565}, DOI={10.1002/agj2.21565}, abstractNote={AbstractNorth Carolina is the leading producer of flue‐cured tobacco (Nicotiana tabacum L.) in the United States. Production in the state is threatened by numerous plant‐parasitic nematodes, including Meloidogyne spp. (root‐knot), Globodera tabacum (tobacco cyst), Pratylenchus spp. (lesion), Rotylenchulus reniformis (reniform), and Tylenchorhynchus spp. (stunt) nematodes. The invasive Meloidogyne enterolobii is also a major threat as it can infect tobacco varieties carrying the Rk gene, which conditions resistance to other Meloidogyne species. To gain an updated understanding of which nematode taxa are present in tobacco production and investigate distribution of M. enterolobii in North Carolina, a 2‐year survey was conducted. From 2021 to 2022, 188 fields were sampled across 24 tobacco‐growing counties. Samples were assayed for identification and quantification of nematodes at the genus level; where Meloidogyne spp. was identified, molecular testing was used to determine the species. Data were also collected on the previous crop and tobacco variety grown. In both years, lesion, root‐knot, dagger, and stunt nematodes were found in the highest incidence among samples. In 2022, M. enterolobii was identified in a single sample each from Granville and Pitt counties; this is the first report of M. enterolobii from Granville County. Tobacco variety NC 196 and soybean were the most common variety and previous crop grown, respectively, in both years of the survey. Tobacco variety did not have an effect on nematode population density. The previous crop had a significant effect on root‐knot and spiral nematodes in 2021, and lesion and stubby root nematodes in 2022.}, journal={AGRONOMY JOURNAL}, author={Bonyak, Hannah C. and Vann, Matthew C. and Ye, Weimin and Lewis, Ramsey S. and Gorny, Adrienne M.}, year={2024}, month={Mar} }
 @article{schoeppner_vann_ackerman_cheek_huseth_2024, title={Evaluation of transplant drench and foliar insecticide applications for wireworm (Coleoptera: Elateridae) management in sweetpotato}, volume={10}, ISSN={["1938-291X"]}, url={https://doi.org/10.1093/jee/toae216}, DOI={10.1093/jee/toae216}, abstractNote={Abstract The revocation of chlorpyrifos tolerances in 2022 left sweetpotato growers without their most important tool to combat a complex of soil-borne root pests that includes wireworms (Coleoptera: Elateridae). Since then, growers have reported increased root damage despite a rapid pivot to pyrethroid-based management systems to replace mechanically incorporated preplant chlorpyrifos broadcast sprays. Our goal was to evaluate the efficacy of alternative insecticide chemistries and application methods to expand the portfolio of management options for wireworms, specifically Conoderus spp. and Melanotus communis (Gyllenhal). We tested (i) insecticidal transplant water drenches and (ii) a foliar spray program targeting adult elaterids. We found that incorporating insecticides into transplant water reduced wireworm damage when compared to untreated transplant water. Our treatments included a recently registered meta-diamide, broflanilide, which represents a promising path to diversify active ingredients and shift away from an overreliance on preplant and post-directed pyrethroid soil sprays. Foliar spray plots had less damage than plots that did not receive foliar sprays. One benefit of adult-focused management is the availability of effective monitoring tools such as sex pheromones and blacklight trapping. Developing a robust adult monitoring program would enable more precise applications of foliar insecticides versus season-long prophylactic soil sprays targeting larvae. Our results demonstrated a significant benefit to both alternative delivery methods. These management alternatives could expand treatment options beyond traditional preplant and post-directed pyrethroid sprays.}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Schoeppner, Emma and Vann, Matthew and Ackerman, Renee and Cheek, Joseph A. and Huseth, Anders S.}, editor={Beuzelin, JulienEditor}, year={2024}, month={Oct} }
 @article{castillo_acosta_hodge_vann_lewis_2023, title={Analysis of alkaloids and reducing sugars in processed and unprocessed tobacco leaves using a handheld near infrared spectrometer}, volume={1}, ISSN={["1751-6552"]}, DOI={10.1177/09670335221148594}, abstractNote={ Near infrared (NIR) spectroscopy calibration models were developed to predict chemical properties of flue-cured tobacco ( Nicotiana tabacum L.) leaf samples using a microPHAZIRTM handheld NIR spectrometer. The sample data set consisted of 348 leaf-bundled samples of upper-stalk flue-cured tobacco leaves collected from an array of cultivars evaluated in multiple locations. Unprocessed leaf samples were intact whole unground leaves collected from curing barns. Processed leaf samples were further dried and ground before scanning. The NIR prediction models for percent reducing sugars, percent total alkaloids, and percent nicotine were very good for processed leaves [r2 (SEP in %) values = 0.98 (0.82), 0.92 (0.17), and 0.92 (0.14), respectively]. The models for the same three variables for unprocessed leaves were also very good, with only slightly lower fit statistics [r2 (SEP) = 0.93 (1.58), 0.87 (0.22), and 0.88 (0.18), respectively). Fit statistics for anabasine NIR models were intermediate with r2 (SEP in %) values ranging from 0.73 (0.003) to 0.76 (0.003), while the lowest fit statistics were observed for anatabine and norticotine with r2 (SEP in %) ranging from 0.49 (0.005) to 0.55 (0.017), respectively, for both unprocessed and processed leaves. Hence, use of a handheld NIR spectrometer would be of more limited value for these variables. The chemical composition of flue-cured tobacco leaf samples for some chemical traits can be directly assessed at the point when the leaves exit the curing barns, thus minimizing the need to dry and grind samples for colorimetric and chromatographic analyses. }, journal={JOURNAL OF NEAR INFRARED SPECTROSCOPY}, author={Castillo, Miguel S. and Acosta, Juan J. and Hodge, Gary R. and Vann, Matthew C. and Lewis, Ramsey S.}, year={2023}, month={Jan} }
 @article{james_vann_suchoff_mcginnis_whipker_edmisten_gatiboni_2023, title={Hemp yield and cannabinoid concentrations under variable nitrogen and potassium fertilizer rates}, volume={4}, ISSN={["1435-0653"]}, url={https://doi.org/10.1002/csc2.20966}, DOI={10.1002/csc2.20966}, abstractNote={AbstractWith the passing of the 2014 US farm bill, there is more interest in industrial hemp (Cannabis sativa L. < 0.3% total tetrahydrocannabinol [THC]) grown for cannabinoid production. However, production recommendations that outline fertilizer requirements of cannabidiol (CBD) hemp do not exist. Our primary objective was to identify nitrogen (N) and potassium (K) fertilizer rates for maximizing biomass and CBD yield. A secondary objective was to identify the relationships between N and K rates and total THC and total CBD concentrations. Fertilizer rates from 0 to 224 kg N and 0 to 185 kg K ha−1 were tested separately at four general locations in North Carolina. Two locations were used in 2019 and 2020, while the other two were used only in 2020. Dry weight yield was predicted to increase linearly from 1822 to 3384 kg biomass ha−1 as N rate increased from 0 to 86.8 kg ha−1. Nitrogen rates above 86.8 kg ha−1 were not predicted to increase biomass. Likewise, as N rate increased from 0 to 84.2 kg N ha−1, CBD yield was predicted to increase linearly from 204 to 389 kg CBD ha−1. Additional N was not predicted to increase CBD yield. The CBD and THC concentrations showed a slight bell‐shaped response curve over increasing N rates, ranging from 11.33% to 12.11% and 0.473% to 0.509%, respectively. Potassium application did not affect yield nor CBD and THC concentrations. Results from this work indicate that N is a more limiting factor than K for maximizing CBD hemp biomass production.}, journal={CROP SCIENCE}, author={James, Maggie S. and Vann, Matthew C. and Suchoff, David H. and McGinnis, Michelle and Whipker, Brian E. and Edmisten, Keith L. and Gatiboni, Luciano C.}, year={2023}, month={Apr} }
 @article{henry_veazie_furman_vann_whipker_2023, title={Spectral Discrimination of Macronutrient Deficiencies in Greenhouse Grown Flue-Cured Tobacco}, volume={12}, ISSN={["2223-7747"]}, DOI={10.3390/plants12020280}, abstractNote={Remote sensing of nutrient disorders has become more common in recent years. Most research has considered one or two nutrient disorders and few studies have sought to distinguish among multiple macronutrient deficiencies. This study was conducted to provide a baseline spectral characterization of macronutrient deficiencies in flue-cured tobacco (Nicotiana tabacum L.). Reflectance measurements were obtained from greenhouse-grown nutrient-deficient plants at several stages of development. Feature selection methods including information entropy and first and second derivatives were used to identify wavelengths useful for discriminating among these deficiencies. Detected variability was primarily within wavelengths in the visible spectrum, while near-infrared and shortwave-infrared radiation contributed little to the observed variability. Principal component analysis was used to reduce data dimensionality and the selected components were used to develop linear discriminant analysis models to classify the symptoms. Classification models for young, intermediate, and mature plants had overall accuracies of 92%, 82%, and 75%, respectively, when using 10 principal components. Nitrogen, sulfur, and magnesium deficiencies exhibited greater classification accuracies, while phosphorus and potassium deficiencies demonstrated poor or inconsistent results. This study demonstrates that spectral analysis of flue-cured tobacco is a promising methodology to improve current scouting methods.}, number={2}, journal={PLANTS-BASEL}, author={Henry, Josh and Veazie, Patrick and Furman, Marschall and Vann, Matthew and Whipker, Brian}, year={2023}, month={Jan} }
 @article{oreja_inman_jordan_vann_jennings_leon_2022, title={Effect of cotton herbicide programs on weed population trajectories and frequency of glyphosate-resistant Palmer amaranth (Amaranthus palmeri)}, volume={7}, ISSN={["1550-2759"]}, url={https://doi.org/10.1017/wsc.2022.41}, DOI={10.1017/wsc.2022.41}, abstractNote={AbstractThe adoption of dicamba-resistant cotton (Gossypium hirsutum L.) cultivars allows using dicamba to reduce weed populations across growing seasons. However, the overuse of this tool risks selecting new herbicide-resistant biotypes. The objectives of this research were to determine the population trajectories of several weed species and track the frequency of glyphosate-resistant (GR) Palmer amaranth (Amaranthus palmeri S. Watson) over 8 yr in dicamba-resistant cotton. An experiment was established in North Carolina in 2011, and during the first 4 yr, different herbicide programs were applied. These programs included postemergence applications of glyphosate, alone or with dicamba, with or without residual herbicides. During the last 4 yr, all programs received glyphosate plus dicamba. Biennial rotations of postemergence applications of glyphosate only and glyphosate plus dicamba postemergence with and without preemergence herbicides were also included. Sequential applications of glyphosate plus dicamba were applied to the entire test area for the final 4 yr of the study. No herbicide program was entirely successful in controlling the weed community. Weed population trajectories were different according to species and herbicide program, creating all possible outcomes; some increased, others decreased, and others remained stable. Density of resistant A. palmeri increased during the first 4 yr with glyphosate-only programs (up to 11,739 plants m−2) and decreased a 96% during the final 4 yr, when glyphosate plus dicamba was implemented. This species had a strong influence on population levels of other weed species in the community. Goosegrass [Eleusine indica (L.) Gaertn.] was not affected by A. palmeri population levels and even increased its density in some herbicide programs, indicating that not only herbicide resistance but also reproductive rates and competitive dynamics are critical for determining weed population trajectories under intensive herbicide-based control programs. Frequency of glyphosate resistance reached a maximum of 62% after 4 yr, and those levels were maintained until the end of the experiment.}, journal={WEED SCIENCE}, publisher={Cambridge University Press (CUP)}, author={Oreja, Fernando H. and Inman, Matthew D. and Jordan, David L. and Vann, Matthew and Jennings, Katherine M. and Leon, Ramon G.}, year={2022}, month={Jul} }
 @article{machanoff_vann_woodley_suchoff_2022, title={Evaluation of conservation tillage practices in the production of organic flue-cured tobacco}, volume={5}, ISSN={["2639-6696"]}, url={https://doi.org/10.1002/agg2.20317}, DOI={10.1002/agg2.20317}, abstractNote={AbstractIntensive tillage in flue‐cured tobacco (Nicotiana tabacum L.) contributes to soil erosion and reduced water‐holding capacity of soils. Conservation tillage minimizes soil disturbance by planting a crop directly into the residue of overwintered cover crop. Reducing tillage has been shown to improve soil health (increased rainwater infiltration, improved water‐holding capacity, reduced erosion) and to reduce production costs (fuel and labor). The objective of this study was to compare the effects of conservation and conventional tillage on weed management in organically grown flue‐cured tobacco. Field studies were conducted in Kinston, NC, in 2019 and 2020 and in Rocky Mount, NC, in 2020, comparing the impacts of conventional tillage and conservation tillage on weed emergence and tobacco production. An overwintered cereal rye (Secale cereal L.) cover crop was conventionally tilled or terminated via roller‐crimper and left in place as a mulch prior to transplant of flue‐cured tobacco. Cover crop biomass, weed emergence and biomass, soil resistance, crop yield and quality, and cured leaf chemistry were evaluated. In all environments, conservation tillage with cover crop residue reduced weed density and biomass when compared with conventional tillage treatments. In 2019, cured leaf yield was higher under conservation tillage practices than under conventional tillage. In 2020, environmental conditions in both locations resulted in crop loss. These results indicate that conservation tillage practices may be an effective weed management strategy while improving yields in an organic production system. However, organic flue‐cured tobacco grown under conservation tillage is vulnerable to extreme rain events due to the exclusion of in‐season cultivation.}, number={4}, journal={AGROSYSTEMS GEOSCIENCES & ENVIRONMENT}, author={Machanoff, Cordelia H. and Vann, Matthew Christopher and Woodley, Alex L. and Suchoff, David}, year={2022} }
 @article{machanoff_vann_woodley_suchoff_2022, title={Evaluation of the use of polyethylene mulches in the production of organic flue-cured tobacco}, volume={7}, ISSN={["1435-0645"]}, url={https://doi.org/10.1002/agj2.21100}, DOI={10.1002/agj2.21100}, abstractNote={AbstractWeed and insect pest management in organic flue‐cured tobacco (Nicotiana tabacum L.) is challenging due to lack of effective and affordable approved control options. Polyethylene plastic mulches are used in vegetable and berry production to manage in‐row weed populations, buffer soil temperatures, limit rain‐induced soil loss, and maintain soil moisture. Mulch color can affect plant growth, soil temperature, and insect pest populations in vegetable crops. Field trials were conducted in Kinston, NC, in 2019 and 2020 and Whiteville, NC, in 2020. Red, white, black, and silver polyethylene mulch (with drip irrigation) and bare ground with and without drip irrigation were compared to evaluate effects on tobacco yield, quality, and pests. Tobacco yields were elevated by at least 290% in mulch treatments compared with bare ground with irrigation in 2020 (p < .05), but did not differ in 2019 due to precipitation and temperature differences that conveyed an increased benefit in 2020. Opaque mulches successfully suppressed weed emergence. Fewer aphids were present in highly reflective silver mulch than all other treatments with irrigation in both years. Black and red mulch warmed soils while silver cooled them, affecting nitrogen mineralization rates. Higher levels of plant available nitrogen were maintained in mulch treatments, but tobacco nitrate levels and overall quality were not affected. These results are consistent with plasticulture research in other crops. The factors that make plasticulture well suited to intensively managed, high value crop production may benefit organic flue‐cured tobacco production especially when grown in rotation with other intensively managed crops.}, journal={AGRONOMY JOURNAL}, author={Machanoff, Cordelia A. and Vann, Matthew Christopher and Woodley, Alex L. and Suchoff, David}, year={2022}, month={Jul} }
 @article{tiecher_pace_gatiboni_vann_hardy_fisher_2023, title={Flue-cured tobacco and Cl rates: Implications on yield, quality, and nutrient concentration}, volume={2}, ISSN={["1435-0645"]}, url={https://doi.org/10.1002/agj2.21272}, DOI={10.1002/agj2.21272}, abstractNote={AbstractThe increase in flue‐cured tobacco (Nicotiana tabacum L.) yields in recent decades due to genetic improvements of new cultivars and management technologies may increase the plant demand for Cl, and the increased dry mass may dilute Cl concentration, thereby reducing negative effects. This study evaluated the effect of increasing doses of Cl on tobacco production, quality, and chemical composition of leaves, in four growing environments located at research stations where flue‐cured tobacco is produced in North Carolina. The treatments consisted of 11 rates of Cl (0, 11, 22, 34, 45, 56, 67, 78, 90, 101, and 112 kg ha−1) in each growing environment, with four replications in a randomized complete block design. The yield and visual quality, total alkaloids, and reducing sugars concentrations of cured leaf were determined. In addition, the concentration of selected nutrients (N, P, K, Ca, Mg, S, and Cl) and nitrate (NO3−) in tobacco leaves was measured in five different periods. Rates of Cl up to 112 kg ha−1 did not reduce the productivity or quality of flue‐cured tobacco in any environment. The Cl rate required to reach the threshold of 1.0% Cl content in cured leaf was site‐specific, being surpassed even in the control treatment at one location, or with Cl rates higher than 34 and 90 kg ha−1 in two environments. In one environment, the Cl rates increased tobacco yield, probably due the direct effect of Cl as a nutrient. Although the increasing Cl rates increased the reducing sugars concentration, visual quality was not attenuated.}, journal={AGRONOMY JOURNAL}, author={Tiecher, Tales and Pace, Cara Ruth and Gatiboni, Luke and Vann, Matthew and Hardy, David and Fisher, Loren}, year={2023}, month={Feb} }
 @article{kulesza_manning_vann_suchoff_woodley_mcginnis_2022, title={Organic nitrogen fertilizer sources for field production of flue-cured tobacco (Nicotiana tabacum L.)}, volume={2}, ISSN={["1435-0645"]}, url={https://doi.org/10.1002/agj2.20989}, DOI={10.1002/agj2.20989}, abstractNote={AbstractDespite rapid expansion of organic tobacco (Nicotiana tabacum L.) production in the US, limited research has been conducted comparing the numerous organic fertilizer sources. Organic flue‐cured tobacco traditionally relies on feather meal as the organic N fertility source, as it is readily available, but there is limited information on alternative organic N fertilizers. The objective of this research was to investigate seven different organic fertilizer sources to determine their effect on the growth and development of flue‐cured tobacco. From 2018 to 2019, field sites were established at four locations in North Carolina. Fertilizer treatments included sodium nitrate, composted layer manure, feather meal, corn gluten, soy protein, blood meal, and seabird guano. Both years, these organic N treatments were banded at sidedress (10 d after transplanting) at a rate of 78 kg total N ha−1. Sodium nitrate resulted in higher foliar nitrate‐N concentration than composted layer manure at layby and higher cured leaf yield compared with feather meal and composted layer manure. However, soy protein and seabird guano were often similar to sodium nitrate in yield response and resulted in higher yields when compared with other sources of organic N, such as feather meal and composted layer manure. While feather meal and composted layer manure resulted in a 10 and 11% reduction in yield, respectively, there was no significant difference in tobacco value among treatments. Our results suggest that organic tobacco farmers have other options for N selection beyond the current feather meal standard.}, journal={AGRONOMY JOURNAL}, publisher={Wiley}, author={Kulesza, Stephanie B. and Manning, Nicholas J. and Vann, Matthew C. and Suchoff, David H. and Woodley, Alexander L. and McGinnis, Michelle M.}, year={2022}, month={Feb} }
 @article{clapp_vann_cahoon_jordan_fisher_inman_2022, title={Evaluations of S-Metolachlor in flue-cured tobacco weed management programs}, volume={2}, ISSN={["1435-0645"]}, url={https://doi.org/10.1002/agj2.20984}, DOI={10.1002/agj2.20984}, abstractNote={AbstractEffective weed control is critical to growth and development of flue‐cured tobacco; however, current herbicide options are limited in commercial production. Field experiments were conducted from 2017 to 2018 to evaluate S‐metolachlor for use in flue‐cured tobacco weed management programs. Treatments included 10 herbicide programs: pretransplanted incorporated (PTI) applications of S‐metolachlor (1.07 kg a.i. ha–1) alone or in various combinations with sulfentrazone (0.18 kg a.i. ha–1), clomazone (0.84 kg a.i. ha–1), and pendimethalin (0.79 kg a.i. ha–1). S‐metolachlor and pendimethalin were also applied posttransplanting directed to row middles (POST‐DIR) following PTI applications of sulfentrazone + clomazone. A single posttransplanting over‐the‐top (POST‐OT) application of S‐metolachlor and a non‐treated control were included for comparison. The inclusion of S‐metolachlor in PTI herbicide programs did not improve weed control beyond the combination of sulfentrazone + clomazone. However, weed control after final harvest was improved by 8%, when S‐metolachlor was applied POST‐DIR. S‐metolachlor applied POST‐OT caused injury to tobacco plants (12%), although symptoms were transient with less than 2% visual injury 6 wk after transplanting. Due to increased weed control through harvest and the low injury potential, our results suggest that POST‐DIR applications of S‐metolachlor are the best fit for flue‐cured tobacco production when used in conjunction with recommended PTI herbicide programs.}, journal={AGRONOMY JOURNAL}, author={Clapp, Andrew M. and Vann, Matthew C. and Cahoon, Charles W. and Jordan, David L. and Fisher, Loren R. and Inman, Matt D.}, year={2022}, month={Feb} }
 @article{vann_inman_fisher_2021, title={Flue-cured tobacco holding-ability is affected by harvest timing}, volume={11}, ISSN={["2374-3832"]}, url={https://doi.org/10.1002/cft2.20137}, DOI={10.1002/cft2.20137}, abstractNote={AbstractThe propensity for flue‐cured tobacco (Nicotiana tabacum L.) leaves to retain or improve their visual quality and value over an extended period of time is referred to as “holding‐ability.” General holding‐ability models that are specific to popular cultivars are not available to commercial farmers. Research was conducted at five locations from 2009 to 2014 to determine the effect of flue‐cured tobacco cultivar and upper‐stalk harvest timing to cured leaf yield, visual quality, price per pound, and economic value per acre. Two commercial cultivars, ‘K326’ and ‘NC196’, were evaluated within each location, with upper‐stalk leaf harvest schedule as follows: 7 d under‐ripe (Day 0), 3 d over‐ripe (Day 10), 13 d over‐ripe (Day 20), 23 d over‐ripe (Day 30), and 33 d over‐ripe (Day 40). The measured parameters were not influenced by cultivar selection, thus indicating that K326 and NC196 are likely to have similar ripening patterns and holding‐ability when produced under the same growing conditions. Quadratic responses for harvest timing were significant for cured leaf measurements. Yield and visual quality were greatest at Days 17 and 20, respectively. Cured leaf price continued to increase until Day 25, although maximum economic value per acre was obtained at Days 20 and 21 (US$3,041 acre–1). Increases in yield, quality, and value from Day 0 through 20 suggest that a 2‐wk delay in the harvest of upper‐stalk leaves may prove to be financially advantageous to farmers.}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, publisher={Wiley}, author={Vann, Matthew C. and Inman, Matthew D. and Fisher, Loren R.}, year={2021}, month={Nov} }
 @article{vann_johnson_jordan_fisher_edmisten_2022, title={Flue-cured tobacco response to sublethal rates of glufosinate}, volume={8}, ISSN={["2374-3832"]}, url={https://doi.org/10.1002/cft2.20141}, DOI={10.1002/cft2.20141}, abstractNote={AbstractGlufosinate is a broad‐spectrum, contact herbicide that is currently applied to genetically engineered row crops that tolerate exposure to the compound. Flue‐cured tobacco (Nicotiana tabacum L.) is susceptible to glufosinate, yet it is commonly grown in close proximity to tolerant crops in North Carolina. The impact of glufosinate drift on flue‐cured tobacco is not known. Research was conducted in North Carolina to test the effects of sublethal rates of glufosinate (0.270, 0.135, 0.067, 0.034, 0.017 lb a.i. acre–1) on flue‐cured tobacco injury, yield, visual quality, financial value, and leaf chemistry. Simulated drift was imposed approximately 5 wk after transplanting. Visual injury increased with exposure rate and ranged from 15 to 83% and from 10 to 83% 1 and 2 wk after treatment, respectively. Cured leaf yield was reduced by 45% at the highest sublethal exposure rate and exhibited a linear decline of 47 lb acre–1 for every 0.01 lb glufosinate acre–1. Visual quality and per acre financial value were not affected by glufosinate, most likely due to the loss of necrotic tissue and late‐season plant growth compensation. Residues of glufosinate in green and cured leaves were likewise not detected. Producers and commercial applicators should exercise caution when applying glufosinate around flue‐cured tobacco because of the injury and yield loss that can result from physical spray drift, as well as the inability to sell tobacco that has been exposed to a pesticide that is not labeled for application.}, number={1}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, publisher={Wiley}, author={Vann, Matthew and Johnson, Virginia Alice and Jordan, David and Fisher, Loren and Edmisten, Keith}, year={2022} }
 @article{mahoney_jordan_hare_leon_roma-burgos_vann_jennings_everman_cahoon_2021, title={Palmer Amaranth (Amaranthus palmeri) Growth and Seed Production When in Competition with Peanut and Other Crops in North Carolina}, volume={11}, ISSN={["2073-4395"]}, url={https://doi.org/10.3390/agronomy11091734}, DOI={10.3390/agronomy11091734}, abstractNote={Palmer amaranth (Amaranthus palmeri S. Wats.) is a highly competitive weed that can be difficult to manage in many cropping systems. Research to date has not quantified the growth and development of A. palmeri in a manner that allows direct comparisons across cropping systems. Research was conducted to compare the growth, development, and seed production of A. palmeri when competing with corn (Zea mays L.), cotton (Gossypium hirsutum L.), peanut (Arachis hypogaea L.), and soybean [Glycine max (L.) Merr.] when emerging with crops or emerging three weeks after crops emerge. Regardless of when A. palmeri emerged, seed production was greatest and similar in cotton and peanut and exceeded that of corn and soybean; seed production in soybean exceeded that of corn. However, seed production was approximately 10-fold greater when A. palmeri emerged with crops compared with emergence three weeks later. These results illustrate the importance of controlling weeds during the first three weeks of the season relative to contributions of A. palmeri to the weed seed bank and is the first report comparing seed production in presence of these crops in a manner allowing a statistical comparison of seed production and highlighting the importance of crop sequence for seed bank management.}, number={9}, journal={AGRONOMY-BASEL}, publisher={MDPI AG}, author={Mahoney, Denis J. and Jordan, David L. and Hare, Andrew T. and Leon, Ramon G. and Roma-Burgos, Nilda and Vann, Matthew C. and Jennings, Katherine M. and Everman, Wesley J. and Cahoon, Charles W.}, year={2021}, month={Sep} }
 @article{hahn_woodley_vann_2021, title={Winter cover crop management in the production of organic flue-cured tobacco}, volume={113}, ISSN={["1435-0645"]}, url={https://doi.org/10.1002/agj2.20656}, DOI={10.1002/agj2.20656}, abstractNote={AbstractLegume cover crops are not traditionally used in tobacco (Nicotiana tabacum L.) production due to concerns related to unpredictability of N supply and extended mineralization affecting quality of cured tobacco leaf. This study was conducted to determine if cover cropping with legumes could mitigate organic N fertilizer investment in tobacco without compromising yield, value, or quality. In 2018 and 2019, three winter cover crops: hairy vetch (Vicia villosa Roth) (HV); Austrian winter pea (Pisum sativum var. arvense L.) (AWP); and crimson clover (Trifolium incarnatum L.) (CC), were compared to a no‐cover crop control with typical organic N management in Rocky Mount and Kinston, NC. This study found no significant negative effects (α = .05) from legume cover cropping on yield or value of tobacco. In addition, AWP and HV increased yields between 13 and 37% compared to the no‐cover control. Value (US$ ha−1) did not differ from the control in 2018 or 2019 at any location, except at Kinston, where HV increased value 44% in 2019. In‐season soil samples suggest that HV provided N to tobacco up to flowering, however this did not negatively impact quality, yield, or value. Our research did not support grower concerns of prolonged N availability and found evidence that legume cover crops may allow for partial reduction in applied N without compromising the value of the product.}, number={3}, journal={AGRONOMY JOURNAL}, publisher={Wiley}, author={Hahn, Samuel. L. and Woodley, Alex. L. and Vann, Matthew. C.}, year={2021}, month={May} }
 @article{inman_vann_fisher_gannon_jordan_jennings_2021, title={Evaluation of dicamba retention in spray tanks and its impact on flue-cured tobacco}, volume={35}, ISSN={["1550-2740"]}, url={http://dx.doi.org/10.1017/wet.2020.73}, DOI={10.1017/wet.2020.73}, abstractNote={AbstractIn recent years, there has been increased use of dicamba due to the introduction of dicamba-resistant cotton and soybean in the United States. Therefore, there is a potential increase in off-target movement of dicamba and injury to sensitive crops. Flue-cured tobacco is extremely sensitive to auxin herbicides, particularly dicamba. In addition to yield loss, residue from drift or equipment contamination can have severe repercussions for the marketability of the crop. Studies were conducted in 2016, 2017, and 2018 in North Carolina to evaluate spray-tank cleanout efficiency of dicamba using various cleaning procedures. No difference in dicamba recovery was observed regardless of dicamba formulation and cleaning agent. Dicamba residue decreased with the number of rinses. There was no difference in dicamba residue recovered from the third rinse compared with residue from the tank after being refilled for subsequent tank use. Recovery ranged from 2% to 19% of the original concentration rate among the three rinses. Field studies were also conducted in 2018 to evaluate flue-cured tobacco response to reduced rates of dicamba ranging, from 1/5 to 1/10,000 of a labeled rate. Injury and yield reductions varied by environment and application timing. When exposed to 1/500 of a labeled rate at 7 and 11 wk after transplanting, tobacco injury ranged from 39% to 53% and 10% to 16% 24 days after application, respectively. The maximum yield reduction was 62%, with a 55% reduction in value when exposed to 112 g ha−1 of dicamba. Correlations showed significant relationships between crop injury assessment and yield and value reductions, with Pearson values ranging from 0.24 to 0.63. These data can provide guidance to growers and stakeholders and emphasize the need for diligent stewardship when using dicamba technology.}, number={1}, journal={WEED TECHNOLOGY}, publisher={Cambridge University Press (CUP)}, author={Inman, Matthew D. and Vann, Matthew C. and Fisher, Loren R. and Gannon, Travis W. and Jordan, David L. and Jennings, Katie M.}, year={2021}, month={Feb}, pages={35–42} }
 @article{vann_cheek_machacek_whitley_moody_council_hartley_green_2020, title={First report of cigar tobacco production in western North Carolina}, volume={6}, ISSN={["2374-3832"]}, url={https://doi.org/10.1002/cft2.20063}, DOI={10.1002/cft2.20063}, abstractNote={Over the last two decades, burley tobacco (Nicotiana tabacum L.) production has declined by 5,300 acres in western North Carolina (North Carolina Department of Agriculture and Consumer Services, 2005; USDA-NASS, 2019). The loss of burley tobacco has left a void in the agricultural economy. Cigar wrapper tobacco types, such as Pennsylvania seedleaf (PA41) and Connecticut broadleaf, may be suitable replacements for burley because of their overlapping production practices. Cigar tobacco has not been produced in western North Carolina; therefore, knowledge gaps exist regarding its growth habits in the region. The objective of this study was to quantify the days to flower removal, yield, and grade distribution of six cigar tobacco varieties. In 2019, experiments were initiated at the Mountain Research Station in Waynesville, NC (35.48N, –82.96W) and the Upper Mountain Research Station in Laurel Springs, NC (36.39N, –81.30W). Treatments were arranged in a randomized complete block design replicated four times. Plots consisted of a single row measuring 4 by 33 ft with a planting density of 7,260 plants acre–1. At each location, three PA41 varieties (‘Eshbach’, ‘Grower's Choice’, and ‘Welk's Pride’) and three Connecticut broadleaf varieties (‘B2’, ‘D1’, and ‘PAB’) were compared. Tobacco was transplanted on 31 May in Waynesville and 6 June in Laurel Springs. Plants were deflowered at CORESTA growth stage 65 (CORESTA, 2019), leaving 18 to 20 leaves per plant. Twenty plants per plot were then stalk-cut 2.5 wk later and air-cured according to existing burley recommendations (Swetnam & Bailey, 2019). Once cured, the leaves were stripped from the stalk and classified into wrapper (uniform color and structure, free of holes, >9 inches wide), binder (the same qualities as wrapper but with no more than two holes on one side of the leaf), straight strip (leaf that is not classified as wrapper or binder), or filler grades (small, inconsistent in color, moldy, rotten, or damaged). Data for days to deflowering, yield per acre, and grade distribution were subject to ANOVA via the PROC GLIMMIX procedure (SAS Institute Inc., Cary, NC). Within each analysis, replication was considered as a random factor, whereas variety and tobacco type were fixed factors. Treatment means were reported as least square means. Contrast statements were used to compare PA41 and Connecticut broadleaf types. Variety means within each type were separated by Fisher's Protected LSD at P ≤ .05. Figures were created using Sigma Plot (Systat Software, Inc., San Jose, CA). At Waynesville (P < .001) and Laurel Springs (P < .001), PA41 yielded more than Connecticut broadleaf by 684 to 1,164 lb acre–1, depending on the location (Figure 1a). Days to flower removal was also significant at both locations (P < .001), with PA41 varieties requiring 10 to 12 additional days to reach this stage of management (Figure 1b). Cured leaf grades were less consistent, as tobacco type was only significant for wrapper at Waynesville (P = .039) and binder at Laurel Springs (P = .002). The frequency of wrapper grade was extremely low, regardless of the type or location (0.5–5.3%), although PA41 produced more wrapper than Connecticut broadleaf in Waynesville (3.4% vs. 0.5%, respectively) (Figure 1c). Binder grades were more prevalent in Connecticut broadleaf at Laurel Springs (Figure 1d). Designations of straight strip and filler were not influenced by tobacco type at either of the locations (Figure 1e,f). Cured leaf yield and days to flower removal were similar within each tobacco type at Laurel Springs (Table 1). The same observations were made for wrapper, binder, and filler grades (Table 1). Eshbach produced a smaller percentage of straight strip grades relative to Grower's Choice (Table 1); however, straight strip grades were similar within Connecticut broadleaf varieties (Table 1). In contrast, cured leaf yield differed between PA41 and Connecticut broadleaf varieties at the Waynesville location. Within the PA41 varieties, Grower's Choice had a higher yield than Welk's Pride, with Eshbach being intermediate (Table 2). The yield potential of PAB was greater than that of D1 and B2 within the Connecticut broadleaf type (Table 2). Days to flower removal and grade distribution were similar among varieties within each tobacco type at this location (Table 2). Direct comparisons of these tobacco types and varieties have not been reported; therefore, this information is novel and provides useful insights to stakeholders as cigar tobacco is offered as an alternative to burley tobacco. Cigar tobacco production will not occur without substantial change and education. For example, deflowering may occur 2 wk earlier in cigar production, with fewer leaves remaining on the plant relative to burley (12–14 vs. 18–20). Farmers will also have to harvest and handle cigar tobacco much more delicately than burley to reduce physical leaf damage. The adoption of pesticide application programs that are more proactive than what is allowed by current practices will also be required. The failure to produce substantial proportions of wrapper grades in our study is a reflection of having too many leaves per plant, reactive pest control, and aggressive handling. Each of these factors will be addressed in later field studies and shared with farmers at Extension events. In addition, other research agronomists should consider that the current practices used to evaluate burley tobacco trials may not prove suitable for cigar and they should therefore be adapted accordingly. The authors declare no conflicts of interest.}, number={1}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, publisher={Wiley}, author={Vann, Matthew C. and Cheek, Joseph A. and Machacek, Jeremey L. and Whitley, D. Scott and Moody, Chad and Council, John and Hartley, Michael and Green, Benjamin}, year={2020} }
 @article{clapp_vann_cahoon_jordan_fisher_inman_2020, title={Flue-cured tobacco tolerance to S-metolachlor}, volume={6}, url={https://doi.org/10.1017/wet.2020.71}, DOI={10.1017/wet.2020.71}, abstractNote={AbstractCurrently, there are seven herbicides labeled for U.S. tobacco production; however, additional modes of action are greatly needed in order to reduce the risk of herbicide resistance. Field experiments were conducted at five locations during the 2017 and 2018 growing seasons to evaluate flue-cured tobacco tolerance to S-metolachlor applied pretransplanting incorporated (PTI) and pretransplanting (PRETR) at 1.07 (1×) and 2.14 (2×) kg ai ha−1. Severe injury was observed 6 wk after transplanting at the Whiteville environment in 2017 when S-metolachlor was applied PTI. End-of-season plant heights from PTI treatments at Whiteville were likewise reduced by 9% to 29% compared with nontreated controls, although cured leaf yield and value were reduced only when S-metolachlor was applied PTI at the 2× rate. Severe growth reduction was also observed at the Kinston location in 2018 where S-metolachlor was applied at the 2× rate. End-of-season plant heights were reduced 11% (PTI, 2×) and 20% (PRETR, 2×) compared with nontreated control plants. Cured leaf yield was reduced in Kinston when S-metolachlor was applied PRETR at the 2× rate; however, treatments did not impact cured leaf quality or value. Visual injury and reductions in stalk height, yield, quality, and value were not observed at the other three locations. Ultimately, it appears that injury potential from S-metolachlor is promoted by coarse soil texture and high early-season precipitation close to transplanting, both of which were documented at the Whiteville and Kinston locations. To reduce plant injury and the negative impacts to leaf yield and value, application rates lower than 1.07 kg ha−1 may be required in these scenarios.}, journal={Weed Technology}, publisher={Cambridge University Press (CUP)}, author={Clapp, Andrew M. and Vann, Matthew C. and Cahoon, Charles W., Jr. and Jordan, David L. and Fisher, Loren R. and Inman, Matthew D.}, year={2020}, month={Dec}, pages={1–6} }
 @article{cheek_vann_lewis_fisher_2021, title={Genetics influence postharvest measurements of flue-cured tobacco more than nitrogen application rate}, volume={113}, ISSN={["1435-0645"]}, url={https://doi.org/10.1002/agj2.20565}, DOI={10.1002/agj2.20565}, abstractNote={AbstractRegulations under consideration by the U.S. Food and Drug Administration and the World Health Organization propose that nicotine concentration in tobacco (Nicotiana tabacum L.) should be lowered to non‐addictive levels (0.3 to 0.5 mg g−1). The proposed standards are 90 to 95% lower than the nicotine concentration typically documented in commercially available cultivars. Research was conducted in six environments to evaluate two cultivars with normal alkaloid levels (K326 and NC95) and four genotypes with low alkaloid levels (DH16A, DH22A, DH32, and LAFC53). Each cultivar and genotype was paired with three N application rates: 70, 85, and 100% of the recommended rate. As N application declined, so too did cured leaf yield and nicotine, anabasine, and anatabine concentration in K326 and NC95. These factors were generally not affected by N application in the low alkaloid genotypes. In contrast, LAFC53 consistently produced the lowest cured leaf quality, value, and reducing sugar concentration when compared to all other cultivars. This observation demonstrates that K326 isolines are agronomically superior to LAFC53. Despite reductions in nicotine, the lowest documented concentration was still 10‐fold greater than the proposed minimum (LAFC53). Nitrogen did not influence the measured parameters as much as genetics; therefore, additional research that involves other agronomic practices is warranted. In addition, further genetic manipulation will be required to meet the standards proposed by regulatory groups.}, number={2}, journal={AGRONOMY JOURNAL}, publisher={Wiley}, author={Cheek, Joseph A. and Vann, Matthew C. and Lewis, Ramsey S. and Fisher, Loren R.}, year={2021}, month={Mar}, pages={1020–1028} }
 @article{finch_vann_wells_fisher_brown_2020, title={Impacts of lower-leaf removal timing, number, and nitrogen application to flue-cured tobacco}, volume={6}, ISSN={["2374-3832"]}, url={https://doi.org/10.1002/cft2.20059}, DOI={10.1002/cft2.20059}, abstractNote={AbstractThe removal and exclusion of lower‐stalk tobacco (Nicotiana tobacum L.) from harvest continues to be encouraged by industry. Very little information addresses the timing aspect of leaf removal, specifically when it occurs near floral initiation. Research was conducted in 2016 and 2017 to evaluate each possible treatment combination of two lower‐leaf removal programs (0 and 8 leaves/plant), three removal timings (2 wk before topping, at topping, and 2 wk after topping), and two N application rates (0 and 10 lb/ac). Soil plant analysis development (SPAD) measurements consistently revealed a lighter leaf color in treatments consisting of leaf removal 2 wk before topping, regardless of N application rate. Foliar cured leaf samples from upper‐stalk positions also contained less total N when eight leaves (2.25%) were removed relative to zero leaves (2.32%). These results indicate that subsequent N fertilizer application did not supply N as efficiently as remobilization from lower, older leaves. In the 8‐leaf removal program, both cured leaf yield and value declined by 27% relative to the 0‐leaf program. Despite significant losses in yield and value, the 8‐leaf program completely eliminated lug grades of tobacco. Leaf removal timing and N application rate did not affect yield, quality, value, or grade distribution. Our results suggest that there is no agronomic or cost to removing lower leaves 2 wk before or after topping; however, commercial farmers may find this information to be of use from a time management perspective, should they decide to implement this practice.}, number={1}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, publisher={Wiley}, author={Finch, Camden E. and Vann, Matthew C. and Wells, Randy and Fisher, Loren R. and Brown, A. Blake}, year={2020} }
 @article{pace_vann_fisher_hardy_2020, title={Implications of chloride application rate and nitrogen fertilizer source to flue‐cured tobacco}, volume={112}, url={https://doi.org/10.1002/agj2.20251}, DOI={10.1002/agj2.20251}, abstractNote={AbstractChloride assimilation by flue‐cured tobacco (Nicotiana tabacum L.) can negatively impact leaf development and quality when tissue concentration exceeds 1%. The influences of Cl− application rate and N fertilizer sources have not been fully described in field research utilizing reduced‐cost or custom‐blend fertility programs that are common in modern times. Research was conducted to test the interaction of four Cl− application rates (0, 34, 67, and 101 kg ha−1) and four N fertilizer sources {calcium nitrate, Ca(NO3)2; ammonium nitrate, NH4NO3; liquid urea‐ammonium nitrate [UAN], and ammonium sulfate, (NH4)2SO4} on the growth and development of flue‐cured tobacco. The impact of N source was minimal in green leaf tissue; however, (NH4)2SO4 reduced cured leaf quality relative to other N sources. Two weeks after fertilizer application, Cl− rates ≥34 kg ha−1 reduced foliar total N and NO3− measurements by 0.12−0.42% and 789−1348 mg kg−1, respectively. Leaf NO3− concentration was also reduced by Cl− application at the layby growth stage, while P, K, and Mg increased following Cl− application in late‐season measurements. After curing, total N and alkaloids were reduced by an average of 0.17 and 0.23%, respectively, while reducing sugars were increased by 1.67% where Cl− was applied. Chloride concentration exceeded 1% in application rates ≥34 kg ha−1 in early‐season and post‐curing measurements, although toxicity symptoms were not observed nor were yield, quality, or value affected. Farmers should adhere to the current recommendation of ≤34 kg Cl− ha−1 to ensure that cigarette manufacturers receive tobacco that is usable in products.}, number={4}, journal={Agronomy Journal}, publisher={Wiley}, author={Pace, C.R. and Vann, M.C. and Fisher, L.R. and Hardy, D.H.}, year={2020}, month={Jul}, pages={2916–2927} }
 @article{inman_jordan_vann_hare_york_cahoon_2020, title={Influence of timing of Palmer amaranth control in dicamba-resistant cotton on yield and economic return}, volume={4}, url={http://dx.doi.org/10.1017/wet.2020.37}, DOI={10.1017/wet.2020.37}, abstractNote={AbstractGlyphosate-resistant (GR) Palmer amaranth continues to be challenging to control across the U.S. cotton belt. Timely application of POST herbicides and herbicides applied at planting or during the season with residual activity are utilized routinely to control this weed. Although glyphosate controls large Palmer amaranth that is not GR, herbicides such as glufosinate used in resistance management programs for GR Palmer amaranth must be applied when weeds are small. Dicamba can complement both glyphosate and glufosinate in controlling GR and glyphosate-susceptible (GS) biotypes in resistant cultivars. Two studies were conducted to determine Palmer amaranth control, weed biomass, and cotton yield, as well as to estimate economic net return when herbicides were applied 2, 3, 4, and 5 wk after planting (WAP). In one experiment POST-only applications were made. In the second experiment PRE herbicides were included. In general, Palmer amaranth was controlled at least 98% by herbicides applied at least three times regardless of timing of application or herbicide sequence. Glyphosate plus dicamba applied at 4 and 5 WAP controlled Palmer amaranth similarly compared to three applications by 8 WAP; however, yield was reduced 23% because of early-season interference. The inclusion of PRE herbicides benefited treatments that did not include herbicides applied 2 or 3 WAP. Glyphosate plus dicamba applied as the only herbicides 5 WAP provided 69% control of Palmer amaranth. PRE herbicides increased control to 96% for this POST treatment. Economic returns were similar when three or more POST applications were applied, with or without PRE herbicides.}, journal={Weed Technology}, publisher={Cambridge University Press (CUP)}, author={Inman, Matthew D. and Jordan, David L. and Vann, Matthew C. and Hare, Andrew T. and York, Alan C. and Cahoon, Charles W.}, year={2020}, month={Apr}, pages={1–7} }
 @article{montgomery_henry_vann_whipker_huseth_mitasova_2020, title={Measures of Canopy Structure from Low-Cost UAS for Monitoring Crop Nutrient Status}, volume={4}, ISSN={2504-446X}, url={http://dx.doi.org/10.3390/drones4030036}, DOI={10.3390/drones4030036}, abstractNote={Deriving crop information from remotely sensed data is an important strategy for precision agriculture. Small unmanned aerial systems (UAS) have emerged in recent years as a versatile remote sensing tool that can provide precisely-timed, fine-grained data for informing management responses to intra-field crop variability (e.g., nutrient status and pest damage). UAS sensors with high spectral resolution used to compute informative vegetation indices, however, are practically limited by high cost and data dimensionality. This research extends spectral analysis for remote crop monitoring to investigate the relationship between crop health and 3D canopy structure using low-cost UAS equipped with consumer-grade RGB cameras. We used flue-cured tobacco as a case study due to its known sensitivity to fertility variation and nutrient-specific symptomology. Fertilizer treatments were applied to induce plant health variability in a 0.5 ha field of flue-cured tobacco. Multi-view stereo images from three UAS surveys collected during crop development were processed into orthoimages used to compute a visible band spectral index and photogrammetric point clouds using Structure from Motion (SfM). Plant structural metrics were then computed from detailed high resolution canopy surface models (0.05 m resolution) interpolated from the photogrammetric point clouds. The UAS surveys were complimented by nutrient status measurements obtained from plant tissues. The relationships between foliar nitrogen (N), phosphorus (P), potassium (K), and boron (B) concentrations and the UAS-derived metrics were assessed using multiple linear regression. Symptoms of N and K deficiencies were well captured and differentiated by the structural metrics. The strongest relationship observed was between canopy shape and N foliar concentration (adj. r2 = 0.59, increasing to adj. r2 = 0.81 when combined with the spectral index). B foliar concentration was consistently better predicted by canopy structure with a maximum adj. r2 = 0.41 observed at the latest growth stage surveyed. Overall, combining information about canopy structure and spectral reflectance increased model fit for all measured nutrients compared to spectral alone. These results suggest that an important relationship exists between relative canopy shape and crop health that can be leveraged to improve the usefulness of low cost UAS for precision agriculture.}, number={3}, journal={Drones}, publisher={MDPI AG}, author={Montgomery, Kellyn and Henry, Josh and Vann, Matthew and Whipker, Brian E. and Huseth, Anders and Mitasova, Helena}, year={2020}, month={Jul}, pages={36} }
 @article{mahoney_jordan_roma-burgos_jennings_leon_vann_everman_cahoon_2020, title={Susceptibility of Palmer amaranth (Amaranthus palmeri) to herbicides in accessions collected from the North Carolina Coastal Plain}, volume={68}, ISSN={["1550-2759"]}, url={http://dx.doi.org/10.1017/wsc.2020.67}, DOI={10.1017/wsc.2020.67}, abstractNote={AbstractPalmer amaranth (Amaranthus palmeri S. Watson) populations resistant to acetolactate synthase (ALS)-inhibiting herbicides and glyphosate are fairly common throughout the state of North Carolina (NC). This has led farm managers to rely more heavily on herbicides with other sites of action (SOA) for A. palmeri control, especially protoporphyrinogen oxidase and glutamine synthetase inhibitors. In the fall of 2016, seeds from A. palmeri populations were collected from the NC Coastal Plain, the state’s most prominent agricultural region. In separate experiments, plants with 2 to 4 leaves from the 110 populations were treated with field use rates of glyphosate, glufosinate-ammonium, fomesafen, mesotrione, or thifensulfuron-methyl. Percent visible control and survival were evaluated 3 wk after treatment. Survival frequencies were highest following glyphosate (99%) or thifensulfuron-methyl (96%) treatment. Known mutations conferring resistance to ALS inhibitors were found in populations surviving thifensulfuron-methyl application (Ala-122-Ser, Pro-197-Ser, Trp-574-Leu, and/or Ser-653-Asn), in addition to a new mutation (Ala-282-Asp) that requires further investigation. Forty-two populations had survivors after mesotrione application, with one population having 17% survival. Four populations survived fomesafen treatment, while none survived glufosinate. Dose–response studies showed an increase in fomesafen needed to kill 50% of two populations (LD50); however, these rates were far below the field use rate (less than 5 g ha−1). In two populations following mesotrione dose–response studies, a 2.4- to 3.3-fold increase was noted, with LD90 values approaching the field use rate (72.8 and 89.8 g ha−1). Screening of the progeny of individuals surviving mesotrione confirmed the presence of resistance alleles, as there were a higher number of survivors at the 1X rate compared with the parent population, confirming resistance to mesotrione. These data suggest A. palmeri resistant to chemistries other than glyphosate and thifensulfuron-methyl are present in NC, which highlights the need for weed management approaches to mitigate the evolution and spread of herbicide-resistant populations.}, number={6}, journal={WEED SCIENCE}, publisher={Cambridge University Press (CUP)}, author={Mahoney, Denis J. and Jordan, David L. and Roma-Burgos, Nilda and Jennings, Katherine M. and Leon, Ramon G. and Vann, Matthew C. and Everman, Wesley J. and Cahoon, Charles W.}, year={2020}, month={Nov}, pages={582–593} }
 @article{mahoney_jordan_hare_roma-burgos_jennings_leon_vann_everman_cahoon_2021, title={The influence of soybean population and POST herbicide application timing on in-season and subsequent-season Palmer amaranth (Amaranthus palmeri) control and economic returns}, volume={35}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2020.87}, abstractNote={AbstractOverreliance on herbicides for weed control has led to the evolution of herbicide-resistant Palmer amaranth populations. Farm managers should consider the long-term consequences of their short-term management decisions, especially when considering the soil weed seedbank. The objectives of this research were to (1) determine how soybean population and POST herbicide application timing affects in-season Palmer amaranth control and soybean yield, and (2) how those variables influence Palmer amaranth densities and cotton yields the following season. Soybeans were planted (19-cm row spacing) at a low-, medium-, and high-density population (268,000, 546,000, and 778,000 plants ha–1, respectively). Fomesafen and clethodim (280 and 210 g ai ha–1, respectively) were applied at the VE, V1, or V2 to V3 soybean growth stage. Nontreated plots were also included to assess the effect of soybean population alone. The following season, cotton was planted into these plots so as to understand the effects of soybean planting population on Palmer amaranth densities in the subsequent crop. When an herbicide application occurred at the V1 or V2 to V3 soybean stage, weed control in the high-density soybean population increased 17% to 23% compared to the low-density population. Economic return was not influenced by soybean population and was increased 72% to 94% with herbicide application compared to no treatment. In the subsequent cotton crop, Palmer amaranth densities were 24% to 39% lower 3 wk after planting when following soybean sprayed with herbicides compared to soybean without herbicides. Additionally, Palmer amaranth densities in cotton were 19% lower when soybean was treated at the VE stage compared to later stages. Thus, increasing soybean population can improve Palmer amaranth control without adversely affecting economic returns and can reduce future weed densities. Reducing the weed seedbank and selection pressure from herbicides are critical in mitigating resistance evolution.}, number={1}, journal={WEED TECHNOLOGY}, author={Mahoney, Denis J. and Jordan, David L. and Hare, Andrew T. and Roma-Burgos, Nilda and Jennings, Katherine M. and Leon, Ramon G. and Vann, Matthew C. and Everman, Wesley J. and Cahoon, Charles W.}, year={2021}, month={Feb}, pages={106–112} }
 @article{vann_suchoff_machacek_cheek_whitley_2021, title={Tobacco injury and sucker control efficacy following applications of pelargonic acid}, volume={7}, ISSN={["2374-3832"]}, url={https://doi.org/10.1002/cft2.20086}, DOI={10.1002/cft2.20086}, abstractNote={Core Ideas
Low concentrations of pelargonic acid have negligible sucker control efficacy.
Higher concentrations of pelargonic acid are extremely injurious to tobacco.
Pelargonic acid is not a suitable candidate for tobacco sucker control.
}, number={1}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, publisher={Wiley}, author={Vann, Matthew C. and Suchoff, David H. and Machacek, Jeremy L. and Cheek, Joseph A. and Whitley, D. Scott}, year={2021} }
 @article{agronomic practices affecting nicotine concentration in flue-cured tobacco: a review_2019, DOI={doi:10.2134/agronj2019.04.0268}, abstractNote={Proposed regulations mandating lower nicotine concentrations in tobacco (Nicotiana tabacum L.) products will likely require changes in tobacco production to reduce nicotine while maintaining yield and quality. The agronomic practices used for tobacco production have a significant impact on the synthesis and accumulation of nicotine in flue‐cured tobacco. Nicotine is the primary alkaloid in flue‐cured tobacco and is one of the main reasons for its commercial production. Most agronomic practices that improve plant health and yield have a positive effect on nicotine production and accumulation. Some of the most important factors that affect nicotine concentrations are N fertilization, planting density, topping practices, sucker control, and harvesting practices. The amount of N available to the plant has a substantial effect on nicotine, as N is a primary component of the nicotine molecule. Factors leading to higher N uptake lead to higher nicotine concentrations. Plant and leaf densities within the field also have a significant effect on nicotine, where increasing densities leads to lower nicotine concentrations. Flowering and sucker production are both significant sinks of energy and other resources. Eliminating the inflorescence via topping and controlling suckers lead to higher nicotine concentrations. In fact, substantial nicotine synthesis and accumulation occurs in the days and weeks following topping. This comprehensive review discusses the agronomic factors affecting alkaloid production in flue‐cured tobacco, and how these factors can be adjusted to manipulate the ultimate nicotine concentration.Core Ideas

Proposed regulations may require lower tobacco nicotine concentrations.
Production practices and timing significantly influence nicotine and leaf quality.
Nitrogen fertility, crop density, growth regulation, and harvesting are paramount.
Low density, high N, and increased maturity enhance nicotine accumulation.
Flowers and axillary shoots are sinks that limit foliar nicotine concentrations.
}, journal={Agronomy Journal}, year={2019}, month={Sep} }
 @misc{henry_vann_lewis_2019, title={Agronomic Practices Affecting Nicotine Concentration in Flue-Cured Tobacco: A Review}, volume={111}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2019.04.0268}, abstractNote={Proposed regulations mandating lower nicotine concentrations in tobacco (Nicotiana tabacum L.) products will likely require changes in tobacco production to reduce nicotine while maintaining yield and quality. The agronomic practices used for tobacco production have a significant impact on the synthesis and accumulation of nicotine in flue‐cured tobacco. Nicotine is the primary alkaloid in flue‐cured tobacco and is one of the main reasons for its commercial production. Most agronomic practices that improve plant health and yield have a positive effect on nicotine production and accumulation. Some of the most important factors that affect nicotine concentrations are N fertilization, planting density, topping practices, sucker control, and harvesting practices. The amount of N available to the plant has a substantial effect on nicotine, as N is a primary component of the nicotine molecule. Factors leading to higher N uptake lead to higher nicotine concentrations. Plant and leaf densities within the field also have a significant effect on nicotine, where increasing densities leads to lower nicotine concentrations. Flowering and sucker production are both significant sinks of energy and other resources. Eliminating the inflorescence via topping and controlling suckers lead to higher nicotine concentrations. In fact, substantial nicotine synthesis and accumulation occurs in the days and weeks following topping. This comprehensive review discusses the agronomic factors affecting alkaloid production in flue‐cured tobacco, and how these factors can be adjusted to manipulate the ultimate nicotine concentration.Core Ideas

Proposed regulations may require lower tobacco nicotine concentrations.
Production practices and timing significantly influence nicotine and leaf quality.
Nitrogen fertility, crop density, growth regulation, and harvesting are paramount.
Low density, high N, and increased maturity enhance nicotine accumulation.
Flowers and axillary shoots are sinks that limit foliar nicotine concentrations.
}, number={6}, journal={AGRONOMY JOURNAL}, author={Henry, Josh B. and Vann, Matthew C. and Lewis, Ramsey S.}, year={2019}, pages={3067–3075} }
 @article{finch_vann_fisher_wells_brown_2019, title={Lower-Leaf Removal and Nitrogen Application Programs for Flue-Cured Tobacco Production}, volume={111}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2018.10.0637}, abstractNote={Core Ideas
Lower‐leaf removal will reduce cured leaf yield but can reduce the portion of lower‐demand stalk positionsNitrogen application after leaf removal is of limited value and is currently discouragedIf these programs are to find commercial success, a higher selling price should be offered by leaf purchasers
With a current global over‐supply of flue‐cured tobacco (Nicotiana tabacum L.), tobacco producers in North Carolina have been encouraged to remove the lowermost leaves prior to harvest due to their low value in manufactured products. The objective of this research was to compare lower‐leaf removal programs. Research was conducted in 2016 and 2017 to quantify the agronomic effects of three lower‐leaf removal programs (0, 4, and 8 leaves plant−1) and the subsequent delivery of four N application rates (0, 5.6, 11.2, and 16.9 kg N ha−1 above base recommendation). All treatments combinations were applied during the early flowering stage of growth (8–10 wk after transplanting), when plants were approximately 120 cm tall. Programs absent of leaf removal generally produced the highest cured leaf yield. The addition of 16.9 kg N ha−1 increased yield when compared to lower N application rates within the 4‐leaf removal program. Nitrogen application did not affect yield in the 8‐leaf removal program. Cured leaf value was greatest in the 0‐leaf removal program (USD $10,131 ha−1) and was reduced in the 4‐ and 8‐leaf programs by $1611 and $2645 ha−1, respectively. Lower‐stalk positions were nearly eliminated in the 8‐leaf removal program, while the 4‐leaf removal program reduced their presence by more than 50%. Ultimately, if these programs are to be encouraged or required by industry, the removal of four leaves per plant proved to be more practical when paired with additional N, due to moderate yield reduction and lower‐stalk leaf production.}, number={4}, journal={AGRONOMY JOURNAL}, author={Finch, Camden E. and Vann, Matthew C. and Fisher, Loren R. and Wells, Randy and Brown, A. Blake}, year={2019}, pages={1933–1939} }
 @article{perceptions of undergraduate students regarding global hunger_2019, journal={NACTA}, year={2019}, month={Mar} }
 @article{mahoney_jordan_hare_leon_vann_burgos_jennings_2019, title={The Effect of Nozzle Selection and Carrier Volume on Weed Control in Soybean in North Carolina}, volume={5}, ISSN={["2374-3832"]}, DOI={10.2134/cftm2019.05.0037}, abstractNote={Core Ideas Nozzle selection did not affect PRE or POST herbicide efficacy. Carrier volumes from 7.5 to 60 gal/acre generally provided similar weed control. Soybean yield was not affected by nozzle selection or carrier volume. Lower carrier volumes may provide increased farm efficiency.}, number={1}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, author={Mahoney, Denis J. and Jordan, David L. and Hare, Andrew T. and Leon, Ramon G. and Vann, Matthew C. and Burgos, Nilda R. and Jennings, Katherine M.}, year={2019}, month={Oct} }
 @article{mahoney_jordan_hare_leon_vann_burgos_jennings_2019, title={The Influence of Postemergence Herbicide Timing and Frequency on Weed Control and Soybean Yield}, volume={5}, ISSN={["2374-3832"]}, DOI={10.2134/cftm2019.05.0036}, abstractNote={Core Ideas Optimizing herbicide timing and frequency for weed control in soybean is critical. Two or more postemergence herbicide applications were required in twin- and narrow-row soybean. Herbicide programs generally provided similar soybean yield. More intensive herbicide programs did not reduce economic returns. Understanding optimal herbicide timing and frequency is critical for mitigating weed seed return to the soil seedbank and maximizing crop yields. Research was conducted over 2016–2018 in North Carolina to determine postemergence-only herbicide application timing and the frequency necessary for adequate weed control, soybean [Glycine max (L.) Merr.] yield, and economic return in twin- and narrow-row soybean. Predominant weeds included common ragweed (Ambrosia artemisiifolia L.), large crabgrass [Digitaria sanguinalis (L.) Scop.], Palmer amaranth (Amaranthus palmeri S.Watson), and Texas millet [Urochloa texana (Buckley) R.D.Webster]. Four postemergence timings included early (EPOST), mid-postemergence, late, and very late postemergence (VLPOST) applications in various combinations. An untreated control was included for comparison. Regardless of planting pattern, broadleaf weed control was 9 to 48% higher when herbicides were applied two or more times than with single EPOST or VLPOST-only applications. Generally, two to three applications were needed to provide 100% annual grass control, whereas single applications only provided 71 to 92% control. Applying herbicides increased yield by 21 to 46% when compared with untreated soybean. In treated soybean, yield following the VLPOST treatment was generally lower than under other regimes. Trends for economic return were similar to those of yield. The data illustrate that multiple postemergence applications are needed for adequate weed control and do not adversely affect net returns. Although yields were protected with the EPOST-only treatment, caution must be taken to mitigate returning weed seed to the soil seedbank, as control for this treatment was lower than when herbicides were applied multiple times.}, number={1}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, author={Mahoney, Denis J. and Jordan, David L. and Hare, Andrew T. and Leon, Ramon G. and Vann, Matthew C. and Burgos, Nilda R. and Jennings, Katherine M.}, year={2019}, month={Nov} }
 @article{bennett_vann_fisher_2018, title={Application Methods of Organic Poultry Feather Meal to Flue-Cured Tobacco}, volume={110}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2017.11.0678}, abstractNote={Core Ideas
There is flexibility with poultry feather meal application methods.
Broadcast application before planting initiates N release earlier.
Sidedress application is more efficient in high rainfall growing seasons.
Optimal application methods of organic poultry feather meal for flue‐cured tobacco (Nicotiana tabacum L.) production are unknown. Research was conducted in 2012 and 2013 to quantify the effects of two poultry feather meal sources, 13–0–0 Nature Safe and 12–1–0 Nutrimax, applied using three different methods: 100% broadcast before transplanting, 50% broadcast before transplanting + 50% sidedress, 10 d after transplanting, and 100% sidedress 10 d after transplanting. A conventional N treatment comprised of 28% liquid urea–ammonium nitrate (UAN) was split‐applied 10 d after transplanting and at layby. Leaf yield was similar between each individual organic N treatment and UAN. Nature Safe applied 100% sidedress resulted in leaf N concentration and cured leaf quality similar to UAN. In the absence of the UAN treatment, application method typically had a greater impact on measurements than feather meal source. Leaf N concentration was generally increased with the 100% sidedress application, most likely due to closer nutrient proximity relative to roots. Increased N assimilation from 100% sidedress treatments also produced a slightly darker leaf color as quantified by Soil Plant Analysis Development (SPAD) measurements and a higher total alkaloid concentration in cured leaves. Leaf yield was similar among application methods in 2012, but was highest in the 100% sidedress treatment in 2013 due to high early season rainfall. Results from this study demonstrate the effectiveness of both feather meal sources and that 100% sidedress applications may prove ideal under a range of environmental conditions commonly encountered in North Carolina.}, number={5}, journal={AGRONOMY JOURNAL}, publisher={American Society of Agronomy}, author={Bennett, Nathan and Vann, Matthew and Fisher, Loren}, year={2018}, pages={1874–1882} }
 @article{mason_vann_fisher_mcginnis_2018, title={Late-Season Nitrogen Application to Tobacco Produced in Fine-Textured Soils}, volume={4}, ISSN={["2374-3832"]}, DOI={10.2134/cftm2018.02.0007}, abstractNote={Core Ideas
Nitrogen is key to maximum leaf yield and quality.
Nitrogen management is currently based upon expected conditions.
Alternative strategies could improve N management.
Alternative strategies are not suitable for fine‐textured soil types.
Late‐season nitrogen (N) assimilation can greatly impact the yield and quality of flue‐cured tobacco, particularly in the fine‐textured Piedmont soils of North Carolina. Research was conducted in 2015 to 2016 to evaluate the effects of N application rate and number of N applications to the yield, quality, value, and leaf chemistry of flue‐cured tobacco. Liquid N (28% urea ammonium nitrate) was applied at 50, 70, and 90 lb N/acre. Each rate was either applied in two splits (0.5 rate 7–10 days after transplanting and 0.5 rate at layby) or three (0.5 rate 7–10 days after transplanting, a 0.25 rate at layby, and a 0.25 rate 2 weeks after layby) after transplanting. Cured leaf N concentration was similar at 50 and 70 lb N/acre (2.58 and 2.61%, respectively) but was increased in treatments receiving 90 lb N/acre (2.77%). Additionally, three N applications (2.73%) increased cured leaf N relative to two N applications (2.58%). The same treatment parameters did not impact yield or value but reduced cured leaf quality in one growing environment due to prolonged N assimilation. Results indicate that current recommendations for N application rates (50 lb/acre) and timings (split‐applied twice in equal portions) are adequate to obtain maximum yield, quality, and value on fine‐textured soils similar to those evaluated in this study.}, number={1}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, publisher={American Society of Agronomy}, author={Mason, J. Hunter and Vann, Matthew C. and Fisher, Loren R. and McGinnis, Michelle S.}, year={2018}, month={Jul} }
 @article{henry_vann_mccall_cockson_whipker_2018, title={Nutrient Disorders o Burley and Flue-Cured Tobacco: Part 1-Macronutrient Deficiencies}, volume={4}, ISSN={["2374-3832"]}, DOI={10.2134/cftm2017.11.0076}, abstractNote={Core Ideas
Recognizing macronutrient disorders is important for commercial production.
Foliar nutrient concentrations were identified for burley and flue‐cured tobacco.
Symptoms and critical values were compared with published results.
Nutrient deficiency disorders often manifest unique symptoms and vary in critical nutrient ranges depending on species and type. Understanding and recognizing nutrient disorders for different types of tobacco (Nicotiana tabacum L.) is important for maintaining quality and yield. Burley and flue‐cured tobacco account for over 90% of all tobacco produced in the United States, and thus, were grown in this study to investigate the effects of macronutrient deficiencies. Tobacco plants were grown in silica sand culture, and control plants received a complete modified Hoagland's all‐nitrate solution, whereas nutrient‐deficient treatments were induced with a complete nutrient formula withholding a single nutrient. Plants were automatically irrigated, and the leached solution was captured for reuse. A complete replacement of nutrient solutions was done weekly. Plants were monitored daily to document and photograph symptoms as they developed. A description of nutrient disorder symptomology and critical tissue concentrations are presented.}, number={1}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, publisher={American Society of Agronomy}, author={Henry, Josh B. and Vann, Matthew and McCall, Ingram and Cockson, Paul and Whipker, Brian E.}, year={2018}, month={Mar} }
 @article{henry_vann_mccall_cockson_whipker_2018, title={Nutrient Disorders of Burley and Flue-Cured Tobacco: Part 2-Micronutrient Disorders}, volume={4}, ISSN={["2374-3832"]}, DOI={10.2134/cftm2017.11.0077}, abstractNote={Core Ideas
Recognizing micronutrient disorders is important for commercial production.
Unique, previously unobserved nutrient disorder symptoms were observed.
Foliar nutrient concentrations were identified for burley and flue‐cured tobacco.
Symptoms and critical values were compared with published results.
Nutrient disorders often manifest unique symptoms and vary in critical nutrient ranges where visual symptoms appear depending on plant species and type. Understanding and recognizing nutrient disorders for different types of tobacco is important for maintaining yield and quality. Burley and flue‐cured tobacco (Nicotiana tabacum L.) account for over 90% of all tobacco produced in the United States, and thus, were grown in this study to investigate the effects of micronutrient disorders. Tobacco plants were grown in silica sand culture, and control plants received a complete modified Hoagland's all‐nitrate solution, whereas nutrient‐deficient treatments were induced with a complete nutrient formula withholding a single nutrient. Boron toxicity was also induced by increasing the element tenfold higher than the complete nutrient formula. Plants were automatically irrigated, and the leached solution was captured for reuse. A complete replacement of nutrient solutions was done weekly. Plants were monitored daily to document and photograph symptoms as they developed. A description of nutrient disorder symptomology and critical tissue concentrations associated with symptomology are presented.}, number={1}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, publisher={American Society of Agronomy}, author={Henry, Josh B. and Vann, Matthew and McCall, Ingram and Cockson, Paul and Whipker, Brian E.}, year={2018}, month={Mar} }
 @inbook{vann_fisher_inman_2018, place={Boca Raton, FL}, title={Sustainable Weed Control in Tobacco}, booktitle={Weed Control: Sustainability, Hazards, and Risks in Cropping Systems Worldwide}, publisher={CRC Press-Taylor and Francis Group}, author={Vann, M.C. and Fisher, L.R. and Inman, M.D.}, editor={Korres, N.E. and Burgos, N.R. and Duke, S.O.Editors}, year={2018}, pages={367–382} }
 @article{vann_fisher_wells_jordan_heitman_2017, title={Alternative Ridging Practices for Flue-Cured Tobacco Production in North Carolina}, volume={3}, ISSN={2374-3832}, url={http://dx.doi.org/10.2134/cftm2017.02.0016}, DOI={10.2134/cftm2017.02.0016}, abstractNote={Core Ideas
Alternative ridging methods could prove beneficial for tobacco producers.
Conservation tillage efforts have demonstrated little success.
Fine‐textured soils will require special management considerations.
Soil resistance is considered to be a limiting production factor.
Coarse‐textured soils appear to be better suited than fine‐textured soils.
With increasing farm size and the necessity for timely field preparation, flue‐cured tobacco (Nicotiana tabacum L.) producers in North Carolina would benefit from alternatives to current ridging practices. Research was conducted in 2012 and 2013 to evaluate the effects of differing ridging methods on soil physical properties and the growth and development of flue‐cured tobacco. In each environment, two alternative ridging methods were compared with the grower standard of spring ridging (SR): fall ridging (FR) and rotary ridging (RR) in the Piedmont, and FR and no ridging (NR) in the Coastal Plain. In the Piedmont, FR reduced leaf yield and value when compared with RR and SR systems. Reduced yield and value were a result of high soil resistance that inhibited plant growth. In the Coastal Plain, treatments imposed did not affect the soil physical properties or tobacco yield and quality. Results indicate that FR and NR systems are acceptable alternative ridging methods for the production of flue‐cured tobacco in the sandy Coastal Plain growing region. Alternatively, FR should not be used in the Piedmont growing region due to the fine soil texture that is prone to high resistance.}, number={1}, journal={Crop, Forage & Turfgrass Management}, publisher={Wiley}, author={Vann, Matthew C. and Fisher, Loren R. and Wells, Randy and Jordan, David L. and Heitman, Joshua L.}, year={2017}, month={Jun}, pages={cftm2017.02.0016} }
 @article{vann_fisher_whitley_2017, title={Cyantraniliprole and Spinosad Residues in Flue-Cured Tobacco}, volume={54}, url={http://www.tobaccoscienceonline.org/doi/full/10.3381/17-059}, DOI={10.3381/17-059}, number={1}, journal={Tobacco Science}, author={Vann, M.C. and Fisher, L.R. and Whitley, D.S.}, year={2017}, month={Jan}, pages={1–3} }
 @article{vann_bennett_fisher_reberg-horton_burrack_2017, title={Poultry Feather Meal Application in Organic Flue-Cured Tobacco Production}, volume={109}, ISSN={["1435-0645"]}, url={https://dl.sciencesocieties.org/publications/aj/articles/109/6/2800?highlight=&search-result=1}, DOI={10.2134/agronj2017.05.0287}, abstractNote={Core Ideas
Poultry feather meal is acceptable in organic flue‐cured tobacco production.
Application rates of organic N should reflect those in conventional production.
Soil moisture is critical for N mineralization and assimilation.
Information on N management in organic flue‐cured tobacco production is limited. Research was conducted from 2012–2013 to determine the effects of two certified organic N sources applied at three rates on the yield, quality, and chemical constituents of flue‐cured tobacco. These organic N sources included Nature Safe 13–0–0 (NS) and Nutrimax 12–1–0 (NM), both of which consisted of hydrolyzed poultry feather meal. Application rates for both fertilizer sources were 17 kg N ha−1 above recommendation (B+), at recommendation (B), and 17 kg N ha−1 below recommendation (B–). A conventional control containing urea‐ammonium‐nitrate (UAN) was applied at the B application rate. Tobacco yield and quality were similar among conventional and organic N programs. Leaf N concentration, SPAD measurements at flowering, and total alkaloid concentration of cured leaves responded positively to increased N application rates, regardless of organic fertilizer source. The largest increases in nitrogenous‐based leaf constituents were observed in this study where B+ treatments were applied; however, those increases did not translate into increased leaf yield or quality and could delay the initiation of leaf senescence in growing seasons with low soil moisture. Results from this study demonstrate the acceptability of poultry feather meal sources for organic tobacco production, and confirm that application rates of organic N sources should follow conventional recommendations.}, number={6}, journal={AGRONOMY JOURNAL}, publisher={American Society of Agronomy}, author={Vann, Matthew and Bennett, Nathan and Fisher, Loren and Reberg-Horton, S. C. and Burrack, Hannah}, year={2017}, pages={2800–2807} }
 @article{vann_2017, title={Soil Applied Malefic Hydrazide Does Not Suppress Tobacco Axillary Bud Growth}, volume={3}, ISSN={["2374-3832"]}, url={https://dl.sciencesocieties.org/publications/cftm/articles/3/1/cftm2017.07.0043?highlight=&search-result=1}, DOI={10.2134/cftm2017.07.0043}, abstractNote={Core Ideas
Maleic hydrazide residues are a threat to the US tobacco industry.
Alternative application methods could prove beneficial.
Root absorption of maleic hydrazide appears to be limited.
With an increasing focus on maleic hydrazide (MH) residues and the need to sufficiently control axillary bud (sucker) growth, flue‐cured tobacco (Nicotiana tabacum L.) producers would benefit from an alternative to the conventional foliar application method of the plant growth regulator. Research was conducted in four North Carolina environments from 2014 to 2015 to quantify the efficacy of soil applications of MH. Two rates of MH were selected (2.25 and 4.50 lb a.i./acre) and were applied in combination with one of three sucker control programs: foliar MH preceded by foliar flumetralin (F treatment), soil MH preceded by foliar flumetralin (SF treatment), or soil MH preceded by foliar fatty alcohol (SFA treatment). Ranging from 95 to 100%, sucker suppression was greatest in F treatments. In two Coastal Plain environments, the control in SF treatments was similar to that of F treatments; however, in the two Piedmont environments, the control was reduced by 30 to 50%. Sucker suppression was lowest in SFA treatments, particularly in the Piedmont environments, thus indicating that flumetralin was the likely source of suppression in SF treatments. No differences were observed between the two MH application rates evaluated. Given the observations of this study, it is unlikely that a soil application of MH will serve as an effective sucker control alternative to the standard foliar application used at present by commercial growers.}, number={1}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, publisher={American Society of Agronomy}, author={Vann, Matthew C.}, year={2017}, month={Dec} }
 @article{verification of nitrogen and phosphorus application rates to flue-cured tobacco_2017, journal={Tobacco Science}, year={2017} }
 @article{vann_fisher_2017, title={Verification of nitrogen and phosphorus application rates to flue-cured tobacco}, volume={54}, journal={Tobacco Science}, author={Vann, M. and Fisher, L.}, year={2017}, pages={4–5} }
 @article{wells_eickholt_lewis_vann_fisher_2016, title={Heat Unit Accumulation and Days to Anthesis Relationship in Tobacco Genotypes with an Introgressed QTL Affecting Leaf Number}, volume={56}, ISSN={["1435-0653"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84990194504&partnerID=MN8TOARS}, DOI={10.2135/cropsci2016.04.0278}, abstractNote={Plant breeders and crop managers would benefit from an increased ability to predict the requirements for onset of anthesis in tobacco (Nicotiana tabacum L.). This study was performed to determine the relationship in the field between heat unit (HU) accumulation and the onset of anthesis in tobacco genotypes varying for the zygosity of an introgressed quantitative trait loci (QTL) designated as Many Leaves (Ml) affecting flowering team and leaf number. Three commercially important cultivars or breeding lines (Speight 168, K326, and NCTG‐61), their nearly isogenic homozygous (MlMl) and heterozygous (Mlml) counterparts, and three BC6F3 null‐segregant (mlml) lines, were evaluated at three locations and over 2 yr. Days to anthesis (DTA) and HU accumulation were determined. In each environment, the MlMl, Mlml, and mlml genotypes were found to be grouped according to the zygosity of the Ml trait, with the mlml genotypes flowering first followed by Mlml and MlMl genotypes, respectively. An exception to this trend was Speight 168 MlMl, which consistently fell within the Mlml grouping for DTA. No consistent relationships were observed between HU and DTA, which was highly variable among environments. Integrated HU (area under the HU curve) during the 28 d after transplanting (DAT) was positively associated (R2 = 0.98; P = 0.0001) with the range of DTA among all genotypes. Integrated HU was a better indicator of the pattern of HU attainment than merely the amount. Early HU exposure seemed important in determining the range in DTA amongst the genotypes examined.}, number={6}, journal={CROP SCIENCE}, author={Wells, Randy and Eickholt, David P. J. and Lewis, Ramsey and Vann, Matthew C. and Fisher, Loren R.}, year={2016}, pages={3228–3236} }
 @article{drake_vann_fisher_2015, title={INFLUENCE OF NITROGEN APPLICATION RATE ON THE YIELD, QUALITY, AND CHEMICAL COMPONENTS OF FLUE-CURED TOBACCO, PART II: APPLICATION METHOD}, volume={52}, DOI={10.3381/14-043}, abstractNote={Research was conducted in 2012 and 2013 to determine the effect of nitrogen application timing and method on the yield, quality, and leaf chemistry of flue-cured tobacco. Liquid urea–ammonium–nitrate supplied 100% of the total nitrogen and was applied in differing combinations of rates, timings, and methods. Nitrogen rates above, at, and below recommendation for specific locations were split into two, three, or four application timings depending on treatment. Nitrogen application was initiated at transplanting and concluded before or at topping. Applications of nitrogen were either soil applied at each interval or were soil applied until topping where application occurred over top to promote stalk rundown. Leaf tissue samples were collected at layby and topping to evaluate total nitrogen content throughout the growing season. Composite cured leaf tissue samples from all four stalk positions were analyzed for total alkaloid and reducing-sugar content. Yield data were collected and leaf quality was determin...}, journal={Tobacco Science}, publisher={Tobacco Science}, author={Drake, M.P and Vann, M.C and Fisher, L.R}, year={2015}, month={Jan}, pages={26–34} }
 @article{drake_vann_fisher_2015, title={NITROGEN APPLICATION RATE INFLUENCE ON YIELD, QUALITY, AND CHEMICAL CONSTITUENTS OF FLUE-CURED TOBACCO, PART I: APPLICATION TIMING}, volume={52}, DOI={10.3381/14-041r.1}, abstractNote={Research was conducted at 5 locations between 2012 and 2013 to determine the effect of nitrogen application rate and timing on yield, quality, and leaf chemistry of flue-cured tobacco. Urea–ammoniu...}, journal={Tobacco Science}, publisher={Tobacco Science}, author={Drake, M.P. and Vann, M.C. and Fisher, L.R.}, year={2015}, month={Jan}, pages={11–17} }
 @article{azoxystrobin, butralin, and flumetralin residues in flue-cured tobacco_2014, url={http://www.tobaccoscienceonline.org/doi/pdf/10.3381/14-034R.1}, DOI={10.3381/14-034R.1}, journal={Tobacco Science}, year={2014} }
 @article{vann_fisher_2014, title={Azoxystrobin, butralin, and flumetralin residues in flue-cured tobacco}, volume={51}, journal={Tobacco Science}, author={Vann, M.C and Fisher, L.R.}, year={2014}, pages={23–28} }
 @article{bifenthrin, clothianidin, and flubendiamide residues in flue-cured tobacco_2013, url={http://www.tobaccoscienceonline.org/doi/pdf/10.3381/13-029R.1}, DOI={10.3381/13-029R.1}, journal={Tobacco Science}, year={2013}, month={Jan} }
 @article{vann_fisher_stewart_2013, title={Bifenthrin, clothianidin, and flubendiamide residues in flue-cured tobacco}, volume={50}, journal={Tobacco Science}, author={Vann, M.C. and Fisher, L.R. and Stewart, A.M.}, year={2013}, pages={25–30} }
 @article{vann_fisher_jordan_smith_hardy_stewart_2013, title={Potassium Rate and Application Effect on Flue-Cured Tobacco}, volume={105}, ISSN={["0002-1962"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84875203584&partnerID=MN8TOARS}, DOI={10.2134/agronj2012.0259}, abstractNote={Research was conducted at two locations in 2009 and 2010 to evaluate the effect of various K rates and application methods on the yield and quality of flue‐cured tobacco (Nicotiana tabacum L.). Treatments included five rates of K from sulfate of potash magnesia (0–0–22): 0, 84, 140, 196, and 252 kg K2O ha−1 that were applied: broadcast 1 mo before transplanting, broadcast 1 wk before transplanting, banded at transplanting, and a split application with one‐half rate banded at transplanting followed by one‐half rate banded at layby. Tissue samples were collected throughout the season at three separate growth stages: layby, topping, and after curing. Tissue samples were analyzed for total alkaloid and reducing sugars, N, P, K, and Mg content. Soil samples were collected the same day as K fertilizer application from plots not receiving supplemental K. Data were subjected to ANOVA using the PROC GLM procedure in SAS. Treatment means were separated using Fisher’s Protected LSD test at p ≤ 0.05. Application method and timing had no effect on any measured parameters; furthermore, crop yield and quality was not affected by K rates >0 kg K2O ha−1 at three of four locations. It is likely that early broadcast applications of K2O with current rate recommendations would only be of concern with combinations of conditions that included coarse soil textures, low K indices, and/or excessive leaching rainfall.}, number={2}, journal={AGRONOMY JOURNAL}, author={Vann, Matthew C. and Fisher, Loren R. and Jordan, David L. and Smith, W. David and Hardy, David H. and Stewart, Alexander M.}, year={2013}, pages={304–310} }
 @article{vann_fisher_jordan_hardy_smith_stewart_2012, title={THE EFFECT OF POTASSIUM RATE ON THE YIELD AND QUALITY OF FLUE-CURED TOBACCO (NICOTIANA TABACUM L.)}, volume={49}, DOI={10.3381/12-019r.1}, abstractNote={Research was conducted at 2 locations in 2009 and 2010 to determine the effect of potassium rate on the yield and quality of flue-cured tobacco. Treatments included 8 rates of potassium from sulfate of potash magnesia (K-Mag, 0–0–22): 0, 84, 112, 140, 168, 196, 224, and 252 kg K2O ha−1. A complete (N–P–K) fertilizer that supplied 134 kg K2O ha−1 was also included as a control treatment. All fertilizer was applied in a single band application within 10 days after transplanting. Yield was measured and samples were assigned an official U.S. Department of Agriculture (USDA) grade. Crop value was determined based on yield and grade. Tissue samples were collected throughout the season at 3 separate times: at layby, at topping, and after curing. Tissue samples were analyzed for total alkaloid and reducing sugar content as well as N, P, K, and Mg content at North Carolina State University. Soil samples were also collected at transplanting, which corresponded with potassium fertilizer application, and were analyze...}, journal={Tobacco Science}, publisher={Tobacco Science}, author={Vann, M. C. and Fisher, L. R. and Jordan, D. L. and Hardy, D. H. and Smith, W. D. and Stewart, A. M.}, year={2012}, month={Jan}, pages={14–20} }