@article{woodard_schultheis_jennings_woodley_suchoff_2024, title={Horizontal Planting Orientation Can Improve Yield in Organically Grown Sweetpotato}, volume={59}, ISSN={["2327-9834"]}, DOI={10.21273/HORTSCI17352-23}, abstractNote={Sweetpotato [Ipomoea batatas (L.) Lam.] is one of North Carolina’s (USA) most important organic commodity crops; however, yields tend to be less when compared with conventionally produced sweetpotato. Standard field establishment uses unrooted stem cuttings that are transplanted vertically in the soil. Producers in other countries typically use other planting orientations, including cuttings transplanted horizontally. Empirical evidence from North Carolina, USA, sweetpotato producers suggests that a horizontal orientation may improve yields. An organically managed field study using ‘Monaco’ sweetpotato was conducted in 2020 and 2021 in Bailey, NC, USA. The study evaluated stem cutting planting orientations (vertical, sleeve, horizontal), stem cutting length (25 cm and 38 cm), and harvest time (early or late) in a full-factorial randomized complete block design. In 2020, marketable yields were 16% greater for the horizontal orientation compared with the vertical orientation, with intermediate yields using the sleeve attachment. However, in 2021, there were no differences in marketable yield among planting orientations. In both years, US No. 1–grade yields were significantly greater when cuttings were planted horizontally compared with vertically, with an average increase of 18%. Delaying harvest until ∼126 days is recommended to increase yields for ‘Monaco’, regardless of planting orientation. This study provides evidence that a horizontal planting orientation could increase premium root yields and improve land-use efficiency for organically produced sweetpotatoes.}, number={1}, journal={HORTSCIENCE}, author={Woodard, Alyssa J. and Schultheis, Jonathan R. and Jennings, Katherine M. and Woodley, Alex L. and Suchoff, David H.}, year={2024}, month={Jan}, pages={36–42} }
 @article{niyakan_nagashima_singh_metrani_crosby_jifon_jayaprakasha_ravishankar_brierley_leskovar_et al._2023, title={Genetic and geographical inputs that shape Metabolomic and transcriptomic profiles of melon fruits}, volume={321}, ISSN={["1879-1018"]}, DOI={10.1016/j.scienta.2023.112337}, abstractNote={Melon (Cucumis melo) is an important crop grown worldwide. The diversity of aromatic volatiles melon fruits produce contributes to their diverse flavors. However, little is known about the chemical and molecular profiles essential for establishing the signature flavors in field conditions. Here we analyzed the metabolome and transcriptome of 10 melon varieties grown in the field in Weslaco, TX. Also, two cultivars (TTDV and F39) grown at seven locations in the US were studied further to understand how geographic conditions influence levels of metabolites and transcripts. The data obtained here were combined with sensory data, and the relationship between observed metabolites/transcripts and fruit quality QTL was evaluated. Overall, esters and lipid-derived metabolites varied significantly in different sample sets. TTDV variety was significantly enriched for esters, whereas honeydew varieties were for lipid-derived metabolites, separating their profiles from other varieties. Among transcripts associated with cultivar-specific metabolites, we identified several transcripts linked to QTLs responsible for the production of fruit metabolites, including benzyl alcohol O-benzoyltransferase (AAT2) and caffeic acid 3-O-methyltransferase 1-like. On the other hand, transcripts associated with location-specific metabolites did not produce a clear overlap with known fruit-quality QTLs, suggesting the presence of different regulatory systems for the environmental control of fruit metabolites.}, journal={SCIENTIA HORTICULTURAE}, author={Niyakan, Seyednami and Nagashima, Yukihiro and Singh, Jashbir and Metrani, Rita and Crosby, Kevin M. and Jifon, John L. and Jayaprakasha, G. K. and Ravishankar, Sadhana and Brierley, Paul and Leskovar, Daniel I. and et al.}, year={2023}, month={Nov} }
 @article{heagy_schultheis_birdsell_knuth_ward_2023, title={High-density Planting and a Smaller Row Width Increased Yield and Decreased Fruit Size of}, volume={58}, ISSN={["2327-9834"]}, DOI={10.21273/HORTSCI17246-23}, abstractNote={Pumpkins (Cucurbita sp.) grown in North Carolina are a nascent specialty crop that has only risen to a national production level in the past 10 years. There are only general cultural management guidelines for this region, resulting in variation in plant density and inefficient production. Production field studies of the cultivar Kratos were conducted to investigate the impact of plant density and row width on marketable yield and individual fruit size for large carving pumpkins. Plant densities of 2691, 3588, 5382, and 10,764 plants per hectare with row widths of 1.5 and 3.0 m were grown in 2020 and 2021 in North Carolina. Data regarding fruit size, fruit size variance, and yield per area were collected. Fruit size in terms of weight, length, and diameter increased as plant density decreased. There was no difference in fruit size variation between plant densities and row widths. The fruit number per hectare and fruit weight per hectare increased as plant density increased, with the highest production at 10,764 plants per hectare. For years combined, reducing the row width from 3.0 to 1.5 m increased the fruit weight and diameter, but not the length. Additionally, the 1.5-m row width produced more fruit weight per hectare than the 3.0-m row width for both years. Growers can optimize fruit weight per area and fruit number per area by using a density of 10,764 plants per hectare. Overall, using a row width distance that is more equidistant to the in-row spacing promotes higher fruit yield and larger fruit size.}, number={10}, journal={HORTSCIENCE}, author={Heagy, Kimberly and Schultheis, Jonathan R. and Birdsell, Travis and Knuth, Melinda and Ward, Jason K.}, year={2023}, month={Oct}, pages={1194–1200} }
 @article{heagy_knuth_schultheis_birdsell_ward_2023, title={Using Partial Budgeting Analyses to Analyze Profitability of Commercial Pumpkin Production, Standardize Bin Size Categories, and Understand Bin Sorting Accuracy}, volume={58}, ISSN={0018-5345 2327-9834}, url={http://dx.doi.org/10.21273/hortsci17499-23}, DOI={10.21273/HORTSCI17499-23}, abstractNote={Pumpkins (Cucurbita sp.) are currently sold in retail commercial bins categorized based on fruit size. There are no standards for these fruit sizes, thus creating discrepancies across the industry. Furthermore, there is not a published partial budget analysis for pumpkin fruit yield based on plant area. An observational study was conducted to quantify and standardize the fruit sizes of pumpkins packed into commercial bins. These proposed standardized fruit sizes were then correlated to the expected fruit size and quantity of different plant areas to estimate the total commercial bin yield. Additionally, a partial budget analysis was conducted to calculate the greatest profit per hectare with the varying plant areas. Pumpkins from bins labeled medium, large, extra-large, and jumbo were hand-measured to determine the diameter, length, and weight. Based on a discriminate analysis, 20% of pumpkins were incorrectly sorted based on current practices. The proposed standard fruit diameters for each bin size are as follows: medium, 23.5 to 26.8 cm; large, 26.9 to 29.9 cm; extra-large, 30.0 to 33.6 cm; and jumbo, 33.7 to 35.5 cm. The results of a partial budget analysis showed that the most profitable plant spacing area is 0.9 m2 with a 1.5-m row width, which will earn $37,163/ha. Profit for pumpkin production is contingent on both fruit quantity and fruit size because these factors dictate the quantity and category of commercial bins. Growers should consider both metrics to optimize their operation.}, number={12}, journal={HortScience}, publisher={American Society for Horticultural Science}, author={Heagy, Kimberly and Knuth, Melinda and Schultheis, Jonathan R. and Birdsell, Travis and Ward, Jason}, year={2023}, month={Dec}, pages={1587–1594} }
 @article{singh_metrani_jayaprakasha_crosby_jifon_ravishankar_brierley_leskovar_turini_schultheis_et al._2022, title={Profiling carotenoid and sugar contents in unique Cucumis melo L. cultigens harvested from different climatic regions of the United States}, volume={106}, ISSN={["1096-0481"]}, DOI={10.1016/j.jfca.2021.104306}, abstractNote={The sensory and functional quality attributes of muskmelons (Cucumis melo L.), such as flavor, sweetness, color, and texture, determine consumer preferences. Genetic makeup primarily regulates these traits, but environmental factors such as soil type, irrigation, and temperature affects yields and quality. Here, we investigated variation in quality traits of diverse melon cultigens (advanced breeding lines or cultigen) grown in multiple locations (California, Texas, Georgia, Arizona, and North Carolina) across the United States. Mesocarp sugar and carotenoid concentrations varied significantly as a function of production location and cultigen. Multivariate analyses revealed significant cultigen, location, and interactive effects on fruit quality. The highest sugar content was found in a honeydew melon cultigen (HD-150; 83.1 ± 2.36 mg/g) grown in Georgia and the Western Shipper type cantaloupe (F-39; 70.8 ± 2.85 mg/g) grown in North Carolina compared to the other cultigens. The Tuscan type (Da Vinci) grown in Texas and Georgia had the highest β-carotene contents (29.1 ± 3.37 and 33.6 ± 1.73 μg/g, respectively) compared to the other cultigens. These findings suggest that cultivar and location significantly influenced melon phytochemical composition, will help melon breeding programs improve the sensory and functional qualities of melons and identify suitable cultivars for specific environments to maximize fruit quality.}, journal={JOURNAL OF FOOD COMPOSITION AND ANALYSIS}, author={Singh, Jashbir and Metrani, Rita and Jayaprakasha, G. K. and Crosby, Kevin M. and Jifon, John L. and Ravishankar, Sadhana and Brierley, Paul and Leskovar, Daniel L. and Turini, Thomas A. and Schultheis, Jonathan and et al.}, year={2022}, month={Mar} }
 @article{trandel_johanningsmeier_schultheis_gunter_perkins-veazie_2021, title={Cell Wall Polysaccharide Composition of Grafted 'Liberty' Watermelon With Reduced Incidence of Hollow Heart Defect}, volume={12}, ISSN={["1664-462X"]}, DOI={10.3389/fpls.2021.623723}, abstractNote={Grafting watermelon scions to interspecific squash hybrids has been found to increase fruit firmness. Triploid (seedless) watermelon are prone to hollow heart (HH), an internal fruit disorder characterized by a crack in the placental tissue expanding to a cavity. Although watermelon with lower tissue firmness tend to have a higher HH incidence, associated differences in cell wall polysaccharide composition are unknown. Grafting “Liberty” watermelon to “Carnivor” (interspecific hybrid rootstock, C. moschata × C. maxima) reduced HH 39% and increased tissue firmness by 3 N. Fruit with and without severe HH from both grafted and non-grafted plants were analyzed to determine differences in cell wall polysaccharides associated with grafting and HH. Alcohol insoluble residues (AIR) were sequentially extracted from placental tissue to yield water soluble (WSF), carbonate soluble (CSF), alkali soluble (ASF), or unextractable (UNX) pectic fractions. The CSF was lower in fruit with HH (24.5%) compared to those without HH (27.1%). AIRs were also reduced, hydrolyzed, and acetylated for GC-MS analysis of monosaccharide composition, and a portion of each AIR was methylated prior to hydrolysis and acetylation to produce partially methylated alditol acetates for polysaccharide linkage assembly. No differences in degree of methylation or galacturonic and glucuronic acid concentrations were found. Glucose and galactose were in highest abundance at 75.9 and 82.4 μg⋅mg–1 AIR, respectively, followed by xylose and arabinose (29.3 and 22.0 μg⋅mg–1). Mannose was higher in fruit with HH (p < 0.05) and xylose was highest in fruit from grafted plants (p < 0.05). Mannose is primarily found in heteromannan and rhamnogalacturonan I side chains, while xylose is found in xylogalacturonan or heteroxylan. In watermelon, 34 carbohydrate linkages were identified with galactose, glucose, and arabinose linkages in highest abundance. This represents the most comprehensive polysaccharide linkage analysis to date for watermelon, including the identification of several new linkages. However, total pectin and cell wall composition data could not explain the increased tissue firmness observed in fruit from grafted plants. Nonetheless, grafting onto the interspecific hybrid rootstock decreased the incidence of HH and can be a useful method for growers using HH susceptible cultivars.}, journal={FRONTIERS IN PLANT SCIENCE}, author={Trandel, Marlee A. and Johanningsmeier, Suzanne and Schultheis, Jonathan and Gunter, Chris and Perkins-Veazie, Penelope}, year={2021}, month={Mar} }
 @article{trandel_perkins-veazie_schultheis_gunter_johannes_2021, title={Grafting watermelon onto interspecific hybrid squash reduces hollow heart disorder}, volume={1302}, ISSN={["2406-6168"]}, DOI={10.17660/ActaHortic.2021.1302.30}, journal={II INTERNATIONAL SYMPOSIUM ON VEGETABLE GRAFTING}, author={Trandel, M. A. and Perkins-Veazie, P. and Schultheis, J. R. and Gunter, C. C. and Johannes, E.}, year={2021}, pages={225–232} }
 @article{suchoff_jackson_gunter_schultheis_louws_2021, title={Non-destructive characterization of grafted tomato root systems using the mini-horhizotron}, volume={1302}, ISSN={["2406-6168"]}, url={https://publons.com/wos-op/publon/56007334/}, DOI={10.17660/ActaHortic.2021.1302.28}, journal={II INTERNATIONAL SYMPOSIUM ON VEGETABLE GRAFTING}, author={Suchoff, D. H. and Jackson, B. E. and Gunter, C. C. and Schultheis, J. R. and Louws, F. J.}, year={2021}, pages={209–214} }
 @article{smith_jennings_monks_chaudhari_schultheis_reberg-horton_2020, title={Critical timing of Palmer amaranth (Amaranthus palmeri) removal in sweetpotato}, volume={34}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2020.1}, abstractNote={Abstract Palmer amaranth is the most common and troublesome weed in North Carolina sweetpotato. Field studies were conducted in Clinton, NC, in 2016 and 2017 to determine the critical timing of Palmer amaranth removal in ‘Covington’ sweetpotato. Palmer amaranth was grown with sweetpotato from transplanting to 2, 3, 4, 5, 6, 7, 8, and 9 wk after transplanting (WAP) and maintained weed-free for the remainder of the season. Palmer amaranth height and shoot dry biomass increased as Palmer amaranth removal was delayed. Season-long competition by Palmer amaranth interference reduced marketable yields by 85% and 95% in 2016 and 2017, respectively. Sweetpotato yield loss displayed a strong inverse linear relationship with Palmer amaranth height. A 0.6% and 0.4% decrease in yield was observed for every centimeter of Palmer amaranth growth in 2016 and 2017, respectively. The critical timing for Palmer amaranth removal, based on 5% loss of marketable yield, was determined by fitting a log-logistic model to the relative yield data and was determined to be 2 WAP. These results show that Palmer amaranth is highly competitive with sweetpotato and should be managed as early as possible in the season. The requirement of an early critical timing of weed removal to prevent yield loss emphasizes the importance of early-season scouting and Palmer amaranth removal in sweetpotato fields. Any delay in removal can result in substantial yield reductions and fewer premium quality roots. Nomenclature: Palmer amaranth, Amaranthus palmeri S. Wats.; sweetpotato, Ipomoea batatas L. Lam. ‘Covington'}, number={4}, journal={WEED TECHNOLOGY}, author={Smith, Stephen C. and Jennings, Katherine M. and Monks, David W. and Chaudhari, Sushila and Schultheis, Jonathan R. and Reberg-Horton, Chris}, year={2020}, month={Aug}, pages={547–551} }
 @article{lindley_jennings_monks_chaudhari_schultheis_waldschmidt_brownie_2020, title={Effect of bicyclopyrone herbicide on sweetpotato and Palmer amaranth (Amaranthus palmeri)}, volume={34}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2020.13}, abstractNote={Abstract Management options are needed to limit sweetpotato yield loss due to weeds. Greenhouse studies were conducted in 2018 in Greensboro, NC, and in the field from 2016 to 2018 in Clinton, NC, to evaluate the effect of bicyclopyrone on sweetpotato and Palmer amaranth (field only). In greenhouse studies, Covington and NC04-531 clones were treated with bicyclopyrone (0, 25, 50, 100, or 150 g ai ha–1) either preplant (PP; i.e., immediately before transplanting) or post-transplant (PT; i.e., on the same day after transplanting). Sweetpotato plant injury and stunting increased, and vine length and shoot dry weight decreased with increasing rate of bicyclopyrone regardless of clone or application timing. In field studies, Beauregard (2016) or Covington (2017 and 2018) sweetpotato clones were treated with bicyclopyrone at 50 g ha–1 PP, flumioxazin at 107 g ai ha–1 PP, bicyclopyrone at 50 or 100 g ha–1 PP followed by (fb) S-metolachlor at 800 g ai ha–1 PT, flumioxazin at 107 g ha–1 PP fb S-metolachlor at 800 g ha–1 PT, flumioxazin at 107 g ha–1 PP fb S-metolachlor at 800 g ha–1 PT fb bicyclopyrone at 50 g ha–1 PT-directed, and clomazone at 420 g ai ha–1 PP fb S-metolachlor at 800 g ha–1 PT. Bicyclopyrone PP at 100 g ha–1 fb S-metolachlor PT caused 33% or greater crop stunting and 44% or greater marketable yield reduction compared with the weed-free check in 2016 (Beauregard) and 2017 (Covington). Bicyclopyrone PP at 50 g ha–1 alone or fb S-metolachlor PT resulted in 12% or less injury and similar no. 1 and jumbo yields as the weed-free check in 2 of 3 yr. Injury to Covington from bicyclopyrone PT-directed was 4% or less at 4 or 5 wk after transplanting and marketable yield was similar to that of the weed-free check in 2017 and 2018. Nomenclature: Bicyclopyrone; Palmer amaranth, Amaranthus palmeri S. Watson; sweetpotato, Ipomoea batatas (L.) Lam}, number={4}, journal={WEED TECHNOLOGY}, author={Lindley, Jennifer J. and Jennings, Katherine M. and Monks, David W. and Chaudhari, Sushila and Schultheis, Jonathan R. and Waldschmidt, Matthew and Brownie, Cavell}, year={2020}, month={Aug}, pages={552–559} }
 @article{trandel_perkins-veazie_schultheis_2020, title={Predicting Hollow Heart Incidence in Triploid Watermelon (Citrullus lanatus)}, volume={55}, ISSN={["2327-9834"]}, DOI={10.21273/HORTSCI15361-20}, abstractNote={In triploid (seedless) watermelon [Citrullus lanatus var. lanatus (Thunb. Matsum. and Nakai)], hollow heart (HH) is a disorder that is expressed as a crack in the center of the fruit that expands to an open cavity. Although HH incidence and severity is part of a screening process for marketable watermelon fruit during cultigen evaluations, HH incidence is highly variable with growing season, even when the best cultural practices are used. Placental tissue firmness is also measured because firmness is related to the marketability of watermelon and may be related to HH. Genetic and environmental factors can influence watermelon HH development, including plant genetics, pollen amount and viability, pollinator activity, and temperature and rainfall fluctuations. We used seedless watermelon cultigen evaluation data collected over 3 years (2012–14) to determine the relationship between germplasm HH and tissue firmness. Transplanted watermelon representing 30 to 44 cultigens per year were grown at the Central Crops Research Station, Clayton, NC, and interplanted with pollenizers ‘Ace’ and/or ‘SP-6’. Harvested fruit were cut length-wise and rated for HH incidence and severity. Flesh firmness was determined by a handheld penetrometer at five locations in the flesh (stem end, top side, ground spot, blossom end, and heart). A common cultigen subset, consisting of 13 cultigens that were grown in all three experiments, was used for analysis of HH severity and incidence, and placental firmness. The presence of HH was negatively correlated with tissue firmness in both the large multiyear cultigen set (R2 = −0.32; P = 0.0001) and the common cultigen set (R2 = −0.78; P = 0.0001). Cultigens with lower watermelon tissue firmness values had higher HH incidence and severity. By using multiyear cultigen studies and logistic regression, we were able to detect trends for cultigen susceptibility to this highly variable disorder. Using logistic regression, the probability of HH development was highest for ‘Bold Ruler’, ‘Liberty’, and ‘Affirmed’, and lowest for ‘Maxima’ and ‘Captivation’. The identification of cultigens with a tendency for higher or lower rates of HH will be useful for further research of the causes of HH. Measurements of placental flesh firmness may be useful indicators of susceptible cultigens.}, number={12}, journal={HORTSCIENCE}, author={Trandel, Marlee A. and Perkins-Veazie, Penelope and Schultheis, Jonathan}, year={2020}, month={Dec}, pages={1926-+} }
 @article{grumet_fei_levi_mazourek_mccreight_schultheis_weng_hausbeck_kousik_ling_et al._2020, title={The CucCAP project: leveraging applied genomics to improve disease resistance in cucurbit crops}, volume={1294}, ISSN={["2406-6168"]}, DOI={10.17660/ActaHortic.2020.1294.12}, journal={VI INTERNATIONAL SYMPOSIUM ON CUCURBITS}, author={Grumet, R. and Fei, Z. and Levi, A. and Mazourek, M. and McCreight, J. D. and Schultheis, J. and Weng, Y. and Hausbeck, M. and Kousik, S. and Ling, K. S. and et al.}, year={2020}, pages={91–104} }
 @article{baselga_schultheis_boyette_quesada-ocampo_starke_monks_2020, title={Vine Removal Prior to Harvest, and Curing Duration and Temperature Affect the Incidence and Severity of Internal Necrosis in 'Covington' Sweetpotato}, volume={30}, ISSN={["1943-7714"]}, DOI={10.21273/HORTTECH04408-19}, abstractNote={Internal necrosis (IN) is a physiological disorder that affects Covington, the most commonly grown sweetpotato (Ipomoea batatas) cultivar in North Carolina. Because IN affects the quality of sweetpotato storage roots, studies have been conducted since the first report of IN in 2006. Field studies (three in 2016 and two in 2017) were conducted to evaluate preharvest and postharvest treatments on the occurrence of IN in ‘Covington’ storage roots. Four preharvest treatments consisted of combinations of high chlorine or minimal chlorine potash fertilizer and mowing vs. not mowing before harvest. For postharvest treatments, 30 storage roots were obtained at harvest from each preharvest treatment plot and immediately cured in 75 and 85 °F rooms for a duration of 0.5, 1, 2, 3, and 5 weeks in 2016, and 0.5, 1, and 2 weeks in 2017. Shorter curing durations (0.5 and 1 week) coincided with industry recommendations while longer durations mimicked the challenges that some commercial facilities face when cooling down temperatures of rooms after curing is supposed to be concluded. Once curing temperature and curing duration treatments were completed, roots were placed in a 58 °F storage room at 85% relative humidity until cut. A control comparison was included in which harvested roots were placed in a 58 °F storage room (no curing) immediately after harvest. The storage roots from all temperature treatments were then cut 49 to 80 days after harvest, and incidence and severity of IN visually rated. Preharvest potash fertilizer treatments had minimal or no effect on occurrence of IN. However, mowing vines before harvest in several studies reduced IN incidence when roots were cured for more than 0.5 week at temperatures of at least 75 °F. Lower temperature (75 vs. 85 °F) and shorter curing duration (0.5 vs. 1, 2, 3, or 5 weeks) resulted in reduced IN occurrence in ‘Covington’ sweetpotato.}, number={5}, journal={HORTTECHNOLOGY}, author={Baselga, Fernando Montero de Espinosa and Schultheis, Jonathan R. and Boyette, Michael D. and Quesada-Ocampo, Lina M. and Starke, Keith D. and Monks, David W.}, year={2020}, month={Oct}, pages={544–551} }
 @article{suchoff_schultheis_gunter_hassell_louws_2019, title={Effect of rootstock and nitrogen fertilizer on growth and yield in watermelon}, volume={94}, ISSN={["2380-4084"]}, url={http://dx.doi.org/10.1080/14620316.2019.1624629}, DOI={10.1080/14620316.2019.1624629}, abstractNote={ABSTRACT Herbaceous grafting can be used to manage numerous soilborne pathogens in cucurbits. Rootstocks have been reported to increase the growth of the scion possibly due to more efficient use of nitrogen compared with non-grafted plants. The first objective of this study was to determine if the commercial rootstocks ‘Strongtosa’, ‘Carnivor’, or ‘Macis’ improve growth and production of the watermelon ‘Melody’ scion. The second objective was to determine whether these rootstocks have different nitrogen requirements in open-field production compared with non-grafted ‘Melody’. Field studies were conducted in 2013 and 2014 on the Sandhills Research Station in Jackson Springs, North Carolina. Nitrogen fertiliser was applied via drip irrigation at 0, 84, 126, 168, and 252 kg⋅ha−1. A linear relationship between nitrogen rate and rootstock cultivar existed; however, in all cases the non-grafted plants produced more than all grafted plants. Average fruit weight from the non-grafted plants was also higher than the grafted plants. Fruit from ‘Carnivor’- and ‘Strongtosa’-grafted plants had higher flesh firmness compared with non-grafted ‘Melody’. Our findings suggest that rootstocks do not increase yield or growth in the scion nor do they require different nitrogen application rates. However, some rootstocks do improve overall fruit quality.}, number={6}, journal={JOURNAL OF HORTICULTURAL SCIENCE & BIOTECHNOLOGY}, author={Suchoff, David H. and Schultheis, Jonathan R. and Gunter, Christopher C. and Hassell, Richard L. and Louws, Frank J.}, year={2019}, month={Nov}, pages={798–804} }
 @article{suchoff_gunter_schultheis_hassell_louws_2019, title={The effect of grafting on nitrogen use in determinate field-grown tomatoes}, volume={94}, ISSN={["2380-4084"]}, url={http://dx.doi.org/10.1080/14620316.2018.1450645}, DOI={10.1080/14620316.2018.1450645}, abstractNote={ABSTRACTGrafting tomato (Solanum lycopersicum L.) onto disease resistant rootstocks has grown in use in North America over the past two decades. Rootstocks have traditionally been bred and used for...}, number={1}, journal={JOURNAL OF HORTICULTURAL SCIENCE & BIOTECHNOLOGY}, author={Suchoff, David H. and Gunter, Christopher C. and Schultheis, Jonathan R. and Hassell, Richard L. and Louws, Frank J.}, year={2019}, month={Jan}, pages={102–109} }
 @article{smith_jennings_monks_schultheis_reberg-horton_2019, title={Tolerance of Sweetpotato to Herbicides Applied in Plant Propagation Beds}, volume={33}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2018.103}, abstractNote={Abstract Field and greenhouse studies were conducted in 2016 and 2017 to determine sweetpotato tolerance to herbicides applied to plant propagation beds. Herbicide treatments included PRE application of flumioxazin (107 g ai ha-1), S-metolachlor (800 g ai ha-1), fomesafen (280 g ai ha-1), flumioxazin plus S-metolachlor (107 g ai ha-1 + 800 g ai ha-1), fomesafen plus S-metolachlor (280 g ai ha-1 + 800 g ai ha-1), fluridone (1,120 or 2,240 g ai ha-1), fluridone plus S-metolachlor (1,120 g ai ha-1 + 800 g ai ha-1), napropamide (1,120 g ai ha-1), clomazone (420 g ai ha-1), linuron (560 g ai ha-1), linuron plus S-metolachlor (560 g ai ha-1 + 800 g ai ha-1), bicyclopyrone (38 or 49.7 g ai ha-1), pyroxasulfone (149 g ai ha-1), pre-mix of flumioxazin plus pyroxasulfone (81.8 g ai ha-1 + 104.2 g ai ha-1), or metribuzin (294 g ai ha-1). Paraquat plus non-ionic surfactant (280 g ai ha-1 + 0.25% v/v) POST was also included. After plants in the propagation bed were cut and sweetpotato slip number, length, and weight had been determined, the slips were then transplanted to containers and placed either in the greenhouse or on an outdoor pad to determine any effects from the herbicide treatments on initial sweetpotato growth. Sweetpotato slip number, length, and/or weight were affected by flumioxazin with or without S-metolachlor, S-metolachlor with or without fomesafen, clomazone, and all fluridone treatments. In the greenhouse studies, initial root growth of plants after transplanting was inhibited by fluridone (1,120 g ai ha-1) and fluridone plus S-metolachlor. However, by 5 wk after transplanting few differences were observed between treatments. Fomesafen, linuron with or without S-metolachlor, bicyclopyrone (38 or 49.7 g ai ha-1), pyroxasulfone with or without flumioxazin, metribuzin, and paraquat did not cause injury to sweetpotato slips in any of the studies conducted. Nomenclature: Bicyclopyrone; clomazone; flumioxazin; fluridone; fomesafen; linuron; S-metolachlor; metribuzin; napropamide; paraquat; pyroxasulfone; sweetpotato, Ipomoea batatas L.}, number={1}, journal={WEED TECHNOLOGY}, author={Smith, Stephen C. and Jennings, Katherine M. and Monks, David W. and Schultheis, Jonathan R. and Reberg-Horton, S. Chris}, year={2019}, month={Feb}, pages={147–152} }
 @article{bertucci_suchoff_jennings_monks_gunter_schultheis_louws_2018, title={Comparison of Root System Morphology of Cucurbit Rootstocks for Use in Watermelon Grafting}, volume={28}, ISSN={["1943-7714"]}, url={https://publons.com/wos-op/publon/39930266/}, DOI={10.21273/HORTTECH04098-18}, abstractNote={Grafting of watermelon (Citrullus lanatus) is an established production practice that provides resistance to soilborne diseases or tolerance to abiotic stresses. Watermelon may be grafted on several cucurbit species (interspecific grafting); however, little research exists to describe root systems of these diverse rootstocks. A greenhouse study was conducted to compare root system morphology of nine commercially available cucurbit rootstocks, representing four species: pumpkin (Cucurbita maxima), squash (Cucurbita pepo), bottle gourd (Lagenaria siceraria), and an interspecific hybrid squash (C. maxima × C. moschata). Rootstocks were grafted with a triploid watermelon scion (‘Exclamation’), and root systems were compared with nongrafted (NG) and self-grafted (SG) ‘Exclamation’. Plants were harvested destructively at 1, 2, and 3 weeks after transplant (WAT), and data were collected on scion dry weight, total root length (TRL), average root diameter, root surface area, root:shoot dry-weight ratio, root diameter class proportions, and specific root length. For all response variables, the main effect of rootstock and rootstock species was significant (P < 0.05). The main effect of harvest was significant (P < 0.05) for all response variables, with the exception of TRL proportion in diameter class 2. ‘Ferro’ rootstock produced the largest TRL and root surface area, with observed values 122% and 120% greater than the smallest root system (‘Exclamation’ SG), respectively. Among rootstock species, pumpkin produced the largest TRL and root surface area, with observed values 100% and 82% greater than those of watermelon, respectively. These results demonstrate that substantial differences exist during the initial 3 WAT in root system morphology of rootstocks and rootstock species available for watermelon grafting and that morphologic differences of root systems can be characterized using image analysis.}, number={5}, journal={HORTTECHNOLOGY}, publisher={American Society for Horticultural Science}, author={Bertucci, Matthew B. and Suchoff, David H. and Jennings, Katherine M. and Monks, David W. and Gunter, Christopher C. and Schultheis, Jonathan R. and Louws, Frank J.}, year={2018}, month={Oct}, pages={629–636} }
 @article{mcgowen_jennings_chaudhari_monks_schultheis_reberg-horton_2018, title={Critical Period for Palmer Amaranth (Amaranthus palmeri) Control in Pickling Cucumber}, volume={32}, ISSN={0890-037X, 1550-2740}, url={https://www.cambridge.org/core/journals/weed-technology/article/critical-period-for-palmer-amaranth-amaranthus-palmeri-control-in-pickling-cucumber/4BCED15B7D9F47DAFB0DF91FC9112015}, DOI={10.1017/wet.2018.58}, abstractNote={Abstract Field studies were conducted in North Carolina to determine the critical period for Palmer amaranth control (CPPAC) in pickling cucumber. In removal treatments (REM), emerged Palmer amaranth were allowed to compete with cucumber for 14, 21, 28, or 35 d after sowing (DAS) in 2014 and 14, 21, 35, or 42 DAS in 2015, and cucumber was kept weed-free for the remainder of the season. In the establishment treatments (EST), cucumber was maintained free of Palmer amaranth by hand removal until 14, 21, 28, or 35 DAS in 2014 and until 14, 21, 35, or 42 DAS in 2015; after this, Palmer amaranth was allowed to establish and compete with the cucumber for the remainder of the season. The beginning and end of the CPPAC, based on 5% loss of marketable yield, was determined by fitting log-logistic and Gompertz equations to the relative yield data representing REM and EST, respectively. Season-long competition by Palmer amaranth reduced pickling cucumber yield by 45% to 98% and 88% to 98% during 2014 and 2015, respectively. When cucumber was planted on April 25, 2015, the CPPAC ranged from 570 to 1,002 heat units (HU), which corresponded to 32 to 49 DAS. However, when cucumber planting was delayed 2 to 4 wk (May 7 and May 21, 2014 and May 4, 2015), the CPPAC lasted from 100 to 918 HU (7 to 44 DAS). This research suggested that planting pickling cucumber as early as possible during the season may help to reduce competition by Palmer amaranth and delay the beginning of the CPPAC. Nomenclature: Palmer amaranth, Amaranthus palmeri S. Wats. AMAPA; cucumber, Cucumis sativus L.}, number={5}, journal={Weed Technology}, author={McGowen, Samuel J. and Jennings, Katherine M. and Chaudhari, Sushila and Monks, David W. and Schultheis, Jonathan R. and Reberg-Horton, Chris}, year={2018}, month={Oct}, pages={586–591} }
 @article{bertucci_jennings_monks_schultheis_louws_jordan_brownie_2018, title={Critical Period for Weed Control in Grafted and Nongrafted Watermelon Grown in Plasticulture}, volume={67}, ISSN={1550-2759}, url={http://dx.doi.org/10.1017/WSC.2018.76}, DOI={10.1017/WSC.2018.76}, abstractNote={Abstract Field experiments determined the critical period for weed control (CPWC) in grafted and nongrafted watermelon [Citrullus lanatus (Thumb.) Matsum. & Nakai] grown in plasticulture. Transplant types included ‘Exclamation’ seedless watermelon as the nongrafted control as well as Exclamation grafted onto two interspecific hybrid squash (ISH) rootstocks, ‘Carnivor’ and ‘Kazako’. To simulate weed emergence throughout the season, establishment treatments (EST) consisted of two seedlings each of common purslane (Portulaca oleracea L.), large crabgrass [Digitaria sanguinalis (L.) Scop.], and yellow nutsedge (Cyperus esculentus L.) transplanted in a 15 by 15 cm square centered on watermelon plants at 0, 2, 3, 4, and 6 wk after watermelon transplanting (WATr) and remained until the final watermelon harvest at 11 WATr. To simulate weed control at different times in the season, removal treatments (REM) consisted of two seedlings of the same weed species transplanted in a 15 by 15 cm square centered on watermelon plants on the same day of watermelon transplanting and allowed to remain until 2, 3, 4, 6, and 11 WATr, at which time they were removed. Season-long weedy and weed-free controls were included for both EST and REM studies in both years. For all transplant types, aboveground biomass of weeds decreased as weed establishment was delayed and increased as weed removal was delayed. The predicted CPWC for nongrafted Exclamation and Carnivor required only a single weed removal between 2.3 and 2.5 WATr and 1.9 and 2.6 WATr, respectively, while predicted CPWC for Kazako rootstock occurred from 0.3 to 2.6 WATr. Our study results suggest that weed control for this mixed population of weeds would be similar between nongrafted Exclamation and Exclamation grafted onto Carnivor. But the observed CPWC of Exclamation grafted onto Kazako suggests that CPWC may vary with specific rootstock–scion combinations.}, number={2}, journal={Weed Science}, publisher={Cambridge University Press (CUP)}, author={Bertucci, Matthew B. and Jennings, Katherine M. and Monks, David W. and Schultheis, Jonathan R. and Louws, Frank J. and Jordan, David L. and Brownie, Cavell}, year={2018}, month={Nov}, pages={221–228} }
 @article{bertucci_jennings_monks_schultheis_perkins-veazie_louws_jordan_2018, title={Early Season Growth, Yield, and Fruit Quality of Standard and Mini Watermelon Grafted onto Several Commercially Available Cucurbit Rootstocks}, volume={28}, ISSN={["1943-7714"]}, DOI={10.21273/HORTTECH04051-18}, abstractNote={Grafting watermelon (Citrullus lanatus) is a common practice in many parts of the world and has recently received increased interest in the United States. The present study was designed to evaluate early season growth, yield, and fruit quality of watermelon in response to grafting and in the absence of known disease pressure in a fumigated system. Field experiments were conducted using standard and mini watermelons (cv. Exclamation and Extazy, respectively) grafted onto 20 commercially available cucurbit rootstocks representing four species: giant pumpkin (Cucurbita maxima), summer squash (Cucurbita pepo), bottle gourd (Lagenaria siceraria), and interspecific hybrid squash [ISH (C. maxima × Cucurbita moschata)]. Nongrafted ‘Exclamation’ and ‘Extazy’ were included as controls. To determine early season growth, leaf area was measured at 1, 2, and 3 weeks after transplant (WAT). At 1 WAT, nongrafted ‘Exclamation’ produced the smallest leaf area; however, at 3 WAT, nongrafted ‘Exclamation’ produced the largest leaf area in 2015, and no differences were observed in 2016. Leaf area was very similar among rootstocks in the ‘Extazy’ study, with minimal differences observed. Marketable yield included fruit weighing ≥9 and ≥3 lb for ‘Exclamation’ and ‘Extazy’, respectively. In the ‘Exclamation’ study, highest marketable yields were observed in nongrafted ‘Exclamation’, and ‘Exclamation’ grafted to ‘Pelops’, ‘TZ148’, and ‘Coloso’, and lowest marketable yields were observed when using ‘Marvel’ and ‘Kazako’ rootstocks, which produced 47% and 32% of nongrafted ‘Exclamation’ yield, respectively. In the ‘Extazy’ study, the highest marketable yield was observed in nongrafted ‘Extazy’, and ‘Kazako’ produced the lowest yields (48% of nongrafted ‘Extazy’). Fruit quality was determined by measuring fruit acidity (pH), soluble solids concentration (SSC), lycopene content, and flesh firmness from a sample of two fruit from each plot from the initial two harvests of each year. Across both studies, rootstock had no effect on SSC or lycopene content. As reported in previous studies, flesh firmness was increased as a result of grafting, and nongrafted ‘Exclamation’ and ‘Extazy’ had the lowest flesh firmness among standard and mini watermelons, respectively. The present study evaluated two scions with a selection of 20 cucurbit rootstocks and observed no benefits in early season growth, yield, or phytonutrient content. Only three of 20 rootstocks in each study produced marketable yields similar to the nongrafted treatments, and no grafted treatment produced higher yields than nongrafted ‘Exclamation’ or ‘Extazy’. Because grafted seedlings have an associated increase in cost and do not produce increased yields, grafting in these optimized farming systems and using fumigated soils does not offer an advantage in the absence of soilborne pathogens or other stressors that interfere with watermelon production.}, number={4}, journal={HORTTECHNOLOGY}, publisher={American Society for Horticultural Science}, author={Bertucci, Matthew B. and Jennings, Katherine M. and Monks, David W. and Schultheis, Jonathan R. and Perkins-Veazie, Penelope and Louws, Frank J. and Jordan, David L.}, year={2018}, month={Aug}, pages={459–469} }
 @article{bertucci_jennings_monks_jordan_schultheis_louws_waldschmidt_2018, title={Effect of Bicyclopyrone on Triploid Watermelon in Plasticulture}, volume={32}, ISSN={0890-037X 1550-2740}, url={http://dx.doi.org/10.1017/WET.2018.36}, DOI={10.1017/WET.2018.36}, abstractNote={Abstract Field studies were conducted to determine watermelon tolerance and yield response when treated with bicyclopyrone preplant (PREPLANT), POST, and POST-directed (POST-DIR). Treatments consisted of two rates of bicyclopyrone (37.5 and 50 g ai ha-1), fomesafen (175 g ai ha-1), S-metolachlor (802 g ai ha-1), and a nontreated check. Preplant treatments were applied to formed beds 1 d prior to transplanting and included bicyclopyrone (37.5 and 50 g ha-1) and fomesafen (175 g ha-1), and new polyethylene mulch was subsequently laid above treated beds. POST and POST-DIR treatments were applied 14 ± 1 d after watermelon transplanting and included bicyclopyrone (37.5 and 50 g ha-1) POST and POST-DIR, and S-metolachlor (802 g ai ha-1) POST-DIR. POST-DIR treatments were applied to row middles, ensuring that no herbicide contacted watermelon vines or polyethylene mulch. At 2 wk after transplanting (WAT), 15% foliar bleaching was observed in watermelon treated with bicyclopyrone (50 g ha-1) PRE. At 3 WAT, bicyclopyrone (37.5 and 50 g ha-1) POST caused 16% and 17% foliar bleaching and 8% and 9% crop stunting, respectively. At 4 WAT, initial injury had subsided and bicyclopyrone (37.5 and 50 g ha-1) POST caused 4% and 4% foliar bleaching and 4% and 8% crop stunting, respectively. No symptoms of bleaching or stunting were observed at 6- and 8-WAT ratings. Watermelon total yield, marketable yield, total fruit number, marketable fruit number, and average fruit size were unaffected by herbicide treatments. Therefore, registration of bicyclopyrone (37.5 and 50 g ha-1) PREPLANT, POST, and POST-DIR would offer watermelon producers a safe herbicide option and a novel mode of action for weed management. Nomenclature: bicyclopyrone, fomesafen, S-metalochlor, watermelon, Citrullus lanatus (Thunb.) Matsum. & Nakai.}, number={4}, journal={Weed Technology}, publisher={Cambridge University Press (CUP)}, author={Bertucci, Matthew B. and Jennings, Katherine M. and Monks, David W. and Jordan, David L. and Schultheis, Jonathan R. and Louws, Frank J. and Waldschmidt, Matthew D.}, year={2018}, month={Jun}, pages={439–443} }
 @article{dittmar_schultheis_jennings_monks_chaudhari_meyers_jiang_2018, title={Effect of Cultivar, Ethephon, Flooding, and Storage Duration on Sweetpotato Internal Necrosis}, volume={28}, ISSN={["1943-7714"]}, DOI={10.21273/horttech03917-17}, abstractNote={The reason for internal necrosis occurrences in sweetpotato (Ipomoea batatas) storage roots is not well understood. This disorder begins internally in the storage roots as small light brown spots near the proximal end of the root that eventually can become more enlarged as brown/black regions in the cortex. The objective of this study was to determine the effect of ethephon and flooding on the development of internal necrosis in the sweetpotato cultivars Beauregard, Carolina Ruby, and Covington over storage durations from 9 to 150 days after harvest (DAH) when roots had been cured. Soil moisture treatments were no-flooding, and simulated flooding that was created by applying 10 inches of overhead irrigation during 2 weeks before harvest. Ethephon was applied at 0, 0.75, and 0.98 lb/acre 2 weeks before harvest. Overall, ‘Covington’ and ‘Carolina Ruby’ had greater internal necrosis incidence (22% to 65% and 32% to 51%, respectively) followed by ‘Beauregard’ (9% to 22%) during storage duration from 9 to 150 DAH at both soil moistures. No significant change was observed for either internal necrosis incidence or severity for ‘Beauregard’ and ‘Carolina Ruby’ over the storage duration of 9–150 DAH. However, there was an increase of internal necrosis incidence and severity 9–30 DAH in ‘Covington’, with incidence and severity remaining similar 30–150 DAH. Storage roots in treatments sprayed with 0.75 or 0.98 lb/acre ethephon had higher internal necrosis incidence and severity compared with the nontreated, regardless of cultivars at both soil moistures. This research confirms that sweetpotato cultivars differ in their susceptibility to internal necrosis (incidence and severity), ethephon applied to foliage can contribute to internal necrosis development in storage roots, and internal necrosis incidence reaches a maximum by 30 DAH in ‘Covington’ and 9 DAH in ‘Carolina Ruby’ and ‘Beauregard’.}, number={3}, journal={HORTTECHNOLOGY}, author={Dittmar, Peter J. and Schultheis, Jonathan R. and Jennings, Katherine M. and Monks, David W. and Chaudhari, Sushila and Meyers, Stephen and Jiang, Chen}, year={2018}, month={Jun}, pages={246–251} }
 @article{suchoff_perkins-veazie_sederoff_schultheis_kleinhenz_louws_gunter_2018, title={Grafting the Indeterminate Tomato Cultivar Moneymaker onto Multifort Rootstock Improves Cold Tolerance}, volume={53}, ISSN={["2327-9834"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85057832928&partnerID=MN8TOARS}, DOI={10.21273/HORTSCI13311-18}, abstractNote={Tomato (Solanum lycopersicum L.) is a warm-season, cold-sensitive crop that shows slower growth and development at temperatures below 18 °C. Improving suboptimal temperature tolerance would allow earlier planting of field-grown tomato and a reduction in energy inputs for heating greenhouses. Grafting tomato onto high-altitude Solanum habrochaites (S. Knapp and D.M. Spooner) accessions has proven effective at improving scion suboptimal temperature tolerance in limited experiments. This study was conducted to determine whether commercially available tomato rootstocks with differing parental backgrounds and root system morphologies can improve the tolerance of scion plants to suboptimal temperature. Two controlled environment growth chambers were used and maintained at either optimal (25 °C day/20 °C night) or suboptimal (15 °C day/15 °C night) temperatures. The cold-sensitive tomato cultivar Moneymaker was used as the nongrafted and self-grafted control as well as scion grafted on ‘Multifort’ (S. lycopersicum × S. habrochaites), ‘Shield’ (S. lycopersicum), and S. habrochaites LA1777 rootstocks. Plants were grown for 10 days in 3.8 L plastic containers filled with a mixture of calcined clay and sand. ‘Multifort’ rootstock significantly reduced the amount of cold-induced stress as observed by larger leaf area and higher levels of CO2 assimilation and photosystem II quantum efficiency. ‘Multifort’ had significantly longer roots, having 42% to 56% more fine root (diameter less than 0.5 mm) length compared with the other nongrafted and grafted treatments. Leaf starch concentration was significantly lower in ‘Multifort’-grafted plants at suboptimal temperatures compared with the self-grafted and nongrafted controls and the ‘Shield’-grafted plants at the same temperature. The ability for ‘Multifort’ to maintain root growth at suboptimal temperatures may improve root system sink strength, thereby promoting movement of photosynthate from leaf to root even under cold conditions. This work demonstrates that a commercially available rootstock can be used to improve suboptimal temperature tolerance in cold-sensitive ‘Moneymaker’ scions.}, number={11}, journal={HORTSCIENCE}, author={Suchoff, David H. and Perkins-Veazie, Penelope and Sederoff, Heike W. and Schultheis, Jonathan R. and Kleinhenz, Matthew D. and Louws, Frank J. and Gunter, Christopher C.}, year={2018}, month={Nov}, pages={1610–1617} }
 @article{bertucci_jennings_monks_schultheis_louws_jordan_2018, title={Interference of Palmer amaranth (Amaranthus palmeri) Density in Grafted and Nongrafted Watermelon}, volume={67}, ISSN={1550-2759}, url={http://dx.doi.org/10.1017/WSC.2018.77}, DOI={10.1017/WSC.2018.77}, abstractNote={Abstract Watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] grafting is commonly used for management of diseases caused by soilborne pathogens; however, little research exists describing the effect of grafting on the weed-competitive ability of watermelon. Field experiments determined the response in yield, fruit number, and fruit quality of grafted and nongrafted watermelon exposed to increasing densities of Palmer amaranth (Amaranthus palmeri S. Watson). Grafting treatments included ‘Exclamation’ triploid (seedless) watermelon grafted on two interspecific hybrid squash rootstocks ‘Carnivor’ and ‘Kazako’, with nongrafted Exclamation as the control. Weed treatments included A. palmeri at densities of 1, 2, 3, and 4 A. palmeri plants per watermelon planting hole (0.76-m row) and a weed-free control. Increasing A. palmeri densities caused significant reductions (P < 0.05) in marketable watermelon yield and marketable fruit number. Watermelon yield reduction was described by a rectangular hyperbola model, and 4 A. palmeri plants planting hole -1 reduced marketable yield 41%, 38%, and 65% for Exclamation, Carnivor, and Kazako, respectively. Neither grafting treatment nor A. palmeri density had a biologically meaningful effect on soluble solids content or on the incidence of hollow heart in watermelon fruit. Amaranthus palmeri seed and biomass production was similar across weed population densities, but seed number per female A. palmeri decreased according to a two-parameter exponential decay equation. Thus, increasing weed population densities resulted in increased intraspecific competition among A. palmeri plants. While grafting may offer benefits for disease resistance, no benefits regarding weed-competitive ability were observed, and a consistent yield penalty was associated with grafting, even in weed-free treatments.}, number={2}, journal={Weed Science}, publisher={Cambridge University Press (CUP)}, author={Bertucci, Matthew B. and Jennings, Katherine M. and Monks, David W. and Schultheis, Jonathan R. and Louws, Frank J. and Jordan, David L.}, year={2018}, month={Dec}, pages={229–238} }
 @article{beam_chaudhari_jennings_monks_meyers_schultheis_waldschmidt_main_2018, title={Response of Palmer Amaranth and Sweetpotato to Flumioxazin/Pyroxasulfone}, volume={33}, ISSN={0890-037X 1550-2740}, url={http://dx.doi.org/10.1017/wet.2018.80}, DOI={10.1017/wet.2018.80}, abstractNote={Abstract Studies were conducted to determine the tolerance of sweetpotato and Palmer amaranth control to a premix of flumioxazin and pyroxasulfone pretransplant (PREtr) followed by (fb) irrigation. Greenhouse studies were conducted in a factorial arrangement of four herbicide rates (flumioxazin/pyroxasulfone PREtr at 105/133 and 57/72 g ai ha–1, Smetolachlor PREtr 803 g ai ha–1, nontreated) by three irrigation timings [2, 5, and 14 d after transplanting (DAP)]. Field studies were conducted in a factorial arrangement of seven herbicide treatments (flumioxazin/pyroxasulfone PREtr at 40/51, 57/72, 63/80, and 105/133 g ha–1, 107g ha–1 flumioxazin PREtr fb 803 g ha–1 S-metolachlor 7 to 10 DAP, and season-long weedy and weed-free checks) by three 1.9-cm irrigation timings (0 to 2, 3 to 5, or 14 DAP). In greenhouse studies, flumioxazin/pyroxasulfone reduced sweetpotato vine length and shoot and storage root fresh biomass compared to the nontreated check and S-metolachlor. Irrigation timing had no influence on vine length and root fresh biomass. In field studies, Palmer amaranth control was≥91% season-long regardless of flumioxazin/pyroxasulfone rate or irrigation timing. At 38 DAP, sweetpotato injury was≤37 and≤9% at locations 1 and 2, respectively. Visual estimates of sweetpotato injury from flumioxazin/pyroxasulfone were greater when irrigation timing was delayed 3 to 5 or 14 DAP (22 and 20%, respectively) compared to 0 to 2 DAP (7%) at location 1 but similar at location 2. Irrigation timing did not influence no.1, jumbo, or marketable yields or root length-to-width ratio.With the exception of 105/133 g ha–1, all rates of flumioxazin/pyroxasulfone resulted in marketable sweetpotato yield and root length-to-width ratio similar to flumioxazin fb S-metolachlor or the weed-free checks. In conclusion, flumioxazin/pyroxasulfone PREtr at 40/51, 57/72, and 63/80 g ha–1 has potential for use in sweetpotato for Palmer amaranth control without causing significant crop injury and yield reduction. Nomenclature: Flumioxazin; pyroxasulfone; S-metolachlor; Palmer amaranth, Amaranthus palmeri (S.) Watson AMAPA; sweetpotato, Ipomoea batatas (L.) Lam}, number={1}, journal={Weed Technology}, publisher={Cambridge University Press (CUP)}, author={Beam, Shawn C. and Chaudhari, Sushila and Jennings, Katherine M. and Monks, David W. and Meyers, Stephen L. and Schultheis, Jonathan R. and Waldschmidt, Mathew and Main, Jeffrey L.}, year={2018}, month={Nov}, pages={128–134} }
 @article{beam_jennings_chaudhari_monks_schultheis_waldschmidt_2018, title={Response of Sweetpotato Cultivars to Linuron Rate and Application Time}, volume={32}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2018.68}, abstractNote={Abstract Field studies were conducted in 2015 and 2016 in North Carolina to determine the response of ‘Covington’ and ‘Murasaki-29’ sweetpotato cultivars to four rates of linuron (420, 560, 840, and 1,120 g ai ha-1) alone or with S-metolachlor (803 g ai ha-1) applied 7 or 14 d after transplanting (DAP). Injury (chlorosis/necrosis and stunting) to both cultivars was greater when linuron was applied with S-metolachlor as compared to linuron applied alone. Herbicide application at 14 DAP caused greater injury (chlorosis/necrosis and stunting) to both cultivars than when applied at 7 DAP. At 4 wk after treatment (WAT), stunting of Covington and Murasaki-29 (hereafter Murasaki) from linuron at 420 to 1,120 g ha-1 increased from 27% to 50% and 25% to 53%, respectively. At 7 or 8 WAT, crop stunting of 8% or less and 0% was observed in Covington and Murasaki, respectively, regardless of application rate and timing. Murasaki root yields were similar in the linuron alone or with S-metolachlor treatments, and were lower than the nontreated check. In 2016, no. 1 and marketable sweetpotato yields of Covington were similar for the nontreated check, linuron alone, or linuron plus S-metolachlor treatments, but not in 2015. Decreases in no. 1 and marketable root yields were observed when herbicides were applied 14 DAP compared to 7 DAP for Covington in 2015 and for Murasaki in both years. No. 1 and marketable yields of Covington were similar for 420 to 1,120 g ha-1 linuron and nontreated check except marketable root yields in 2015. No. 1 and marketable sweetpotato yields of Murasaki decreased as application rates increased. Nomenclature: Linuron; S-metolachlor; sweetpotato, Ipomoea batatas (L.) Lam. ‘Covington’, ‘Murasaki’}, number={6}, journal={WEED TECHNOLOGY}, author={Beam, Shawn C. and Jennings, Katherine M. and Chaudhari, Sushila and Monks, David W. and Schultheis, Jonathan R. and Waldschmidt, Mathew}, year={2018}, month={Dec}, pages={665–670} }
 @article{suchoff_gunter_schultheis_kleinhenz_louws_2018, title={Rootstock Effect on Grafted Tomato Transplant Shoot and Root Responses to Drying Soils}, volume={53}, ISSN={["2327-9834"]}, url={https://publons.com/wos-op/publon/45897406/}, DOI={10.21273/HORTSCI13215-18}, abstractNote={Improvement of crop water use is imperative. Plants’ responses to limited water can dictate their ability to better use available resources and avoid prolonged and severe stress. The following study was conducted to determine how tomato (Solanum lycopersicum) rootstocks with different root system morphologies respond to drying soils. Plants were grown in pots containing an inorganic substrate composed of calcined clay and sand in a greenhouse on North Carolina State University’s campus. The heirloom tomato cultivar Cherokee Purple was used as the scion for ‘Beaufort’ and ‘Shield’ rootstocks as well as the self-grafted control. These rootstocks were assigned either normal or reduced irrigation treatments. Plants grown under the normal irrigation schedule were weighed and watered daily to maintain container capacity for one week. Those receiving reduced irrigation had all water withheld for one week, at which point strong midday wilting became evident. Shoot physiological and morphological data as well as root morphological data were collected at the end of the study. A constitutive positive increase on relative water content, leaf area, stomatal conductance (gS), and net CO2 assimilation rate was observed with scions grafted on ‘Beaufort’. In addition, this rootstock had a significantly longer total root system (118.6 m) compared with ‘Shield’ (94.9 m) and the self-grafted control (104.2 m). Furthermore, 76.4% of the total root length observed in ‘Beaufort’ was composed of very thin diameter roots ( <0.5 mm), which was higher than ‘Shield’ (73.67%) and the self-grafted control (69.07%). The only significant rootstock irrigation interaction observed was for effective quantum yield of photosystem II (φPSII). At normal irrigation there were no differences among the rootstock treatments; however, at reduced irrigation ‘Beaufort’ had significantly higher φPSII than both ‘Shield’ and the self-grafted control. These results may explain some of the improved production and water use efficiency observed in field trials using ‘Beaufort’ rootstock, and data secured may allow for better screening of rootstocks for improved water use efficiency in the future.}, number={11}, journal={HORTSCIENCE}, publisher={American Society for Horticultural Science}, author={Suchoff, David H. and Gunter, Christopher C. and Schultheis, Jonathan R. and Kleinhenz, Matthew D. and Louws, Frank J.}, year={2018}, month={Nov}, pages={1586–1592} }
 @article{suchoff_schultheis_kleinhenz_louws_gunter_2018, title={Rootstock Improves High-tunnel Tomato Water Use Efficiency}, volume={28}, ISSN={["1943-7714"]}, DOI={10.21273/horttech04015-18}, abstractNote={The following study was conducted to address water use efficiency in grafted tomato (Solanum lycopersicum) in an on-farm environment. The commercial rootstock cultivars Beaufort (BE) and Shield (S) were chosen as these two have different root system morphologies that may benefit water use efficiency. The heirloom cultivar Cherokee Purple (CP) was grafted onto both rootstocks and used as the nongrafted control. The study was conducted in 2016 and 2017 on a 5-acre vegetable and cut flower farm in North Carolina’s Piedmont region. Plants were grown under protected, high-tunnel culture where they received either 100% (3 hours every other day) or 50% (1.5 hours every other day) of the grower’s normal irrigation regime. At 50% irrigation, ‘Beaufort’-grafted plants yielded significantly more than nongrafted ‘Cherokee Purple’ and ‘Shield’-grafted plants. Furthermore, ‘Beaufort’-grafted plants at 50% irrigation yielded more than nongrafted ‘Cherokee Purple’ receiving the 100% irrigation treatment. The ‘Beaufort’-grafted plants significantly improved irrigation water use efficiency (iWUE) at the 50% irrigation treatment compared with the other graft treatments. Yield and iWUE of ‘Shield’-grafted plants were comparable with the nongrafted ‘Cherokee Purple’ at both irrigation treatments. Regardless of irrigation treatment, grafting onto ‘Beaufort’ improved the quality of total fruit harvested. An economic assessment was conducted to determine the feasibility of using grafted plants in conditions lacking significant disease pressure. Purchasing grafted transplants would increase the initial investment by $5227.2 per acre. However, the increased yield obtained when using ‘Beaufort’ rootstock at 50% irrigation increased net revenue by $35,900.41 per acre compared with nongrafted ‘Cherokee Purple’ receiving 100% irrigation, amounting to a 44.6% increase in net revenue while saving ≈383,242 gal/acre of water per growing season. These results indicate that growers can select rootstocks to better manage water use in an environmentally friendly manner without limiting economic gains.}, number={3}, journal={HORTTECHNOLOGY}, publisher={American Society for Horticultural Science}, author={Suchoff, David H. and Schultheis, Jonathan R. and Kleinhenz, Matthew D. and Louws, Frank J. and Gunter, Christopher C.}, year={2018}, month={Jun}, pages={344–353} }
 @article{beam_jennings_monks_schultheis_chaudhari_2017, title={Influence of Herbicides on the Development of Internal Necrosis of Sweetpotato}, volume={31}, ISSN={0890-037X 1550-2740}, url={http://dx.doi.org/10.1017/WET.2017.60}, DOI={10.1017/WET.2017.60}, abstractNote={Field studies were conducted to determine the influence of herbicides on the development of internal necrosis (IN) in sweetpotato storage roots. In a slip propagation study, herbicide treatments included PRE application (immediately after covering seed roots with soil) of clomazone (0.42, 0.84 kg ai ha-1), flumioxazin (0.11, 0.21 kg ai ha-1), fomesafen (0.28, 0.56 kg ai ha-1), linuron (0.56, 1.12 kg ai ha-1), S-metolachlor (0.8, 1.6 kg ai ha-1), flumioxazin plus S-metolachlor (0.11 + 0.8 or 1.6 kg ha-1), and napropamide (1.12, 2.24 kg ai ha-1), and POST application (2 to 4 wk prior to cutting slips) of ethephon (0.84, 1.26 kg ai ha-1) and paraquat (0.14, 0.28 kg ai ha-1). In a field production study, flumioxazin, fomesafen, linuron, and paraquat were applied PREPLANT (one d prior to sweetpotato transplanting), clomazone, S-metolachlor, and napropamide were applied PRE [4 d after transplanting (DAP)], flumioxazin PREPLANT followed by (fb) S-metolachlor PRE, and ethephon applied POST (2 wk prior to harvest). Herbicide rates were similar to those used in the slip propagation study. Yield of sweetpotato in both studies was not affected by herbicide treatment. In both studies, IN incidence and severity increased with time and was greatest at 60 d after curing. No difference was observed between herbicide treatments for IN incidence and severity in the slip production study which indicates herbicide application at time of slip propagation does not impact the development of IN. In the field production study, the only treatment that increased IN incidence compared to the nontreated was ethephon with 53% and 2.3 incidence and severity, respectively. The presence of IN affected roots in nontreated plots indicates that some other pre- or post-curing factors other than herbicides are responsible for the development of IN. However, the ethephon application prior to sweetpotato root harvest escalates the development of IN. Nomenclature: Clomazone; ethephon; flumioxazin; fomesafen; linuron; napropamide; paraquat; S-metolachlor; sweetpotato, Ipomoea batatas (L.) Lam.}, number={6}, journal={Weed Technology}, publisher={Cambridge University Press (CUP)}, author={Beam, Shawn C. and Jennings, Katherine M. and Monks, David W. and Schultheis, Jonathan R. and Chaudhari, Sushila}, year={2017}, month={Sep}, pages={863–869} }
 @article{barkley_chaudhari_schultheis_jennings_bullen_monks_2017, title={Optimizing Sweetpotato Seed Root Density and Size for Slip Production}, volume={27}, ISSN={["1943-7714"]}, DOI={10.21273/horttech03435-16}, abstractNote={S UMMARY . There is a research gap with respect to documenting the effects of sweet- potato ( Ipomoea batatas ) seed root density and size on transplant yield and quality. Field studies were conducted in 2012 and 2014 to determine the effect of sweetpotato seed root (canner size) density [12, 24, 37, 49, 61, 73, and 85 bushels [bu (50 lb)] per 1000 ft 2 ] on ‘Covington’ and ‘Evangeline’ slip production in propagation beds. Another field study was conducted in 2012 and 2013; treatments included canner, no. 1, and jumbo-size ‘Covington’ roots at 49 bu/1000 ft 2 , to determine the effect of seed root size on slip production. As seed root density increased in the propagation bed, transplant production increased with no change in slip quality as measured by node counts and slip length except for stem diameter. In 2012, the best marketable slip yield was obtained at root densities of 73 and 85 bu/1000 ft 2 . In 2014, marketable slip production of‘Evangeline’ increased asseedroot density increased atagreater rate than ‘Covington’. In 2014, the best seed root density for marketable slip production was 49 to 85 bu/1000 ft 2 for ‘Covington’ and 85 bu/1000 ft 2 for ‘Evangeline’. In 2012, potentialsliprevenuesincreasedwithanincreaseinseedrootdensityupto73bu/1000ft 2 . In 2014, revenue trend was similar for ‘Covington’ as 2012; however, for ‘Evangeline’, revenue was greatest at 85 bu/1000 ft 2 . Seed root size had no effect on marketable slip production when using a once-over harvest system. Results suggest growers would use a seed root density from 49 to 85 bu/1000 ft 2 depending on variety, and any size roots for production of optimum marketable slips. Selection of optimum seed root density also depends on grower needs; e.g., high seed root density strategy will have a higher risk due to the upfront, higher seed costs, but potentially have higher profits at harvest time. Lower seed root density strategy would be a lower initial risk with a lower seed cost, but also potentially have lower net revenues.}, number={1}, journal={HORTTECHNOLOGY}, author={Barkley, Susan L. and Chaudhari, Sushila and Schultheis, Jonathan R. and Jennings, Katherine M. and Bullen, Stephen G. and Monks, David W.}, year={2017}, month={Feb}, pages={7–15} }
 @article{barkley_schultheis_chaudhari_johanningsmeier_jennings_truong_monks_2017, title={Yield and Consumer Acceptability of 'Evangeline' Sweetpotato for Production in North Carolina}, volume={27}, ISSN={["1943-7714"]}, DOI={10.21273/horttech03533-16}, abstractNote={Studies were conducted in 2012 and 2013 to compare Evangeline to various sweetpotato (Ipomoea batatas) varieties (Bayou Belle, Beauregard, Bonita, Covington, NC05-198, and Orleans) for commercial production in North Carolina. In another study, microwaved and oven-baked ‘Evangeline’ and ‘Covington’ sweetpotato roots were subjected to analysis of chemical and physical properties [color, dry matter (DM), texture, and sugar] and to sensory evaluation for determining consumer acceptance. ‘NC05-198’ produced the highest no. 1 grade sweetpotato 600 bushels [bu (50 lb)] per acre and total marketable storage root yield was similar to ‘Bayou Belle’ and ‘Beauregard’ (841, 775, and 759 bu/acre, respectively). No. 1 and marketable root yields were similar between ‘Orleans’ and ‘Beauregard’. However, ‘Orleans’ producedmore uniform roots than ‘Beauregard’, in which the latter had higher cull production. ‘Evangeline’ was comparable to no. 1 yield of ‘Bayou Belle’, ‘Orleans’, and ‘Covington’, which indicates the ability of this variety to produce acceptable yields in North Carolina conditions. ‘Covington’ had slightly higher DM than ‘Evangeline’, but instrumental texture analysis showed that these varieties did not differ significantly in firmness after cooking. However, microwaved roots were measurably firmer than oven-baked roots for both varieties. In this study, ‘Evangeline’ had higher levels of fructose and glucose, with similar levels of sucrose and maltose to ‘Covington’. Consumers (n = 100) indicated no difference between varieties in their ‘‘just about right’’ moisture level, texture, and flavor ratings, but showed a preference for Evangeline flesh color over Covington. Consumers in this study preferred oven-baked over microwaved sweetpotato (regardless of variety) and indicated that Evangeline is as acceptable as the standard variety Covington when grown in the North Carolina environment.}, number={2}, journal={HORTTECHNOLOGY}, author={Barkley, Susan L. and Schultheis, Jonathan R. and Chaudhari, Sushila and Johanningsmeier, Suzanne D. and Jennings, Katherine M. and Truong, Van-Den and Monks, David W.}, year={2017}, month={Apr}, pages={281–290} }
 @inproceedings{schultheis_thornton_thompson_2016, title={Evaluating pickling cucumber plant populations to maximize yield for once-over mechanical harvest in the southeastern United States}, volume={1123}, booktitle={Xxix international horticultural congress on horticulture: sustaining lives, livelihoods and landscapes (ihc2014): international symposium on high value vegetables, root and tuber crops, and edible fungi production, supply and demands}, author={Schultheis, J. R. and Thornton, A. C. and Thompson, W. B.}, year={2016}, pages={69–77} }
 @article{coleman_chaudhari_jennings_schultheis_meyers_monks_2016, title={Evaluation of Herbicide Timings for Palmer Amaranth Control in a Stale Seedbed Sweetpotato Production System}, volume={30}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-15-00133.1}, abstractNote={Studies were conducted in a stale field production system in 2012 and 2013 to determine the effect of herbicide timing on Palmer amaranth control and ‘Covington' sweetpotato yield and quality. Treatments consisted of flumioxazin at 72, 90, or 109 g ai ha−1 applied 45 d before transplanting (DBT) or 1 DBT, or sequentially the same rate at 45 DBT followed by (fb) 1 DBT; flumioxazin 109 g ha−1 applied 1 DBT fb S-metolachlor (800 g ai ha−1) at 0, 6 (± 1), or 10 d after treatment (DAT); flumioxazin at 72, 90, or 109 g ha−1 plus clomazone (630 g ai ha−1) applied 45 DBT fb S-metolachlor (800 g ha−1) applied 10 DAT; and fomesafen alone at 280 g ai ha−1 applied 45 DBT. Nontreated weed-free and weedy controls were included for comparison. Flumioxazin application time had a significant effect on Palmer amaranth control and sweetpotato yields, and the effect of flumioxazin rate was not significant. Treatments consisting of sequential application of flumioxazin 45 DBT fb 1 DBT or flumioxazin plus clomazone 45 DBT fb S-metolachlor 10 DAT provided the maximum Palmer amaranth control and sweetpotato yields (jumbo, No. 1, jumbo plus No. 1, marketable) among all treatments. Delayed flumioxazin application timings until 1 DBT allowed Palmer amaranth emergence on stale seedbeds and resulted only in 65, 62, 48, and 17% control at 14, 32, 68, and 109 DAT, respectively. POST transplant S-metolachlor applications following flumioxazin 1 DBT did not improve Palmer amaranth control, because the majority of Palmer amaranth emerged prior to S-metolachlor application. A control program consisting of flumioxazin 109 g ha−1 plus clomazone 630 g ha−1 at 45 DBT fb S-metolachlor 800 g ha−1 at 0 to 10 DAT provides an effective herbicide program for Palmer amaranth control in stale seedbed production systems in North Carolina sweetpotato. Nomenclature: Clomazone; flumioxazin; fomesafen, S-metolachlor; Palmer amaranth, Amaranthus palmeri S. Wats. AMAPA; sweetpotato, Ipomoea batatas L. Lam. ‘Covington'. En 2012 y 2013, se realizaron estudios en el sistema de producción en campo con siembra retrasada para determinar el efecto del momento de aplicación de herbicidas sobre el control de A. palmeri y el rendimiento y calidad de la batata ‘Covington'. Los tratamientos consistieron de flumioxazin a 72, 90, ó 109 g ai ha−1 aplicados 45 d antes del trasplante (DBT) o 1 DBT, o secuencialmente con la misma dosis a 45 DBT seguido por (fb) 1 DBT; flumioxazin 109 g ha−1 aplicados 1 DBT fb S-metolachlor (800 g ai ha−1) a 0, 6 (±1), ó 10 d después del tratamiento (DAT); flumioxazin a 72, 90, ó 109 g ha−1 más clomazone (630 g ai ha−1) aplicado 45 DBT fb S-metolachlor (800 g ha−1) aplicado 10 DAT; y fomesafen solo a 280 g ai ha−1 aplicado 45 DBT. Testigos sin tratamiento con y sin malezas fueron incluidos para fines de comparación. El momento de aplicación de flumioxazin tuvo un efecto significativo sobre el control de A. palmeri y los rendimientos de la batata, pero el efecto de la dosis de flumioxazin no fue significativo. Los tratamientos que consistían de aplicaciones secuenciales de flumioxazin 45 DBT fb 1 DBT o flumioxazin más clomazone 45 DBT fb S-metolachlor 10 DAT brindaron el máximo control de A. palmeri y los mayores rendimientos (jumbo, No. 1, jumbo plus No. 1, comercializable) entre todos los tratamientos. El retrasar el momento de aplicación de flumioxazin hasta 1 DBT permitió la emergencia de A. palmeri en las camas de siembra y resultó solamente en 65, 62, 48, y 17% de control a 14, 32, 68, y 109 DAT, respectivamente. Las aplicaciones POST trasplante de S-metolachlor después de flumioxazin 1 DBT no mejoraron el control de A. palmeri, porque la mayoría de las plantas de esta maleza emergieron antes de la aplicación de S-metolachlor. Un programa de control que consista de flumioxazin 109 g ha−1 más clomazone 630 g ha−1 a 45 DBT fb S-metolachlor 800 g ha−1 a 0 a 10 DAT brinda un programa efectivo de control de A. palmeri en sistemas de producción de siembra retrasada en camas de batata en North Carolina.}, number={3}, journal={WEED TECHNOLOGY}, author={Coleman, Lauren B. and Chaudhari, Sushila and Jennings, Katherine M. and Schultheis, Jonathan R. and Meyers, Stephen L. and Monks, David W.}, year={2016}, pages={725–732} }
 @article{meyers_jennings_schultheis_monks_2016, title={Evaluation of Wick-Applied Glyphosate for Palmer Amaranth (Amaranthus palmeri) Control in Sweetpotato}, volume={30}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-16-00024.1}, abstractNote={Studies were conducted in 2007 and 2008 at Clinton, NC to determine the effect of glyphosate applied POST via a Dixie wick applicator on Palmer amaranth control and sweetpotato yield and quality. In 2007, treatments consisted of glyphosate wicked sequentially 6 and 8 wk after transplanting (WAP) and glyphosate wicked sequentially 6 and 8 WAP followed by (fb) rotary mowing 9 WAP. In 2008, treatments consisted of glyphosate wicked once 4 or 7 WAP, wicked sequentially 4 and 7 WAP, mowed once 4 WAP, and mowed 4 WAP fb wicking 7 WAP. In 2008, Palmer amaranth control 6 WAP varied by location and averaged 10 and 58% for plots wicked 4 WAP. Palmer amaranth contacted by the wicking apparatus were controlled, but weeds shorter than the wicking height escaped treatment. Palmer amaranth control 9 WAP was greater than 90% for all treatments wicked 7 WAP. Competition prior to and between glyphosate treatments contributed to large sweetpotato yield losses. Treatments consisting of glyphosate 7 or 8 WAP (in 2007 and 2008, respectively) frequently had greater no. 1 and marketable yields compared to the weedy control. However, jumbo, no. 1, and marketable yields for all glyphosate and mowing treatments were generally less than half the hand-weeded check. Cracked sweetpotato roots were observed in glyphosate treatments and percent cracking (by weight) in those plots ranged from 1 to 12% for no. 1 roots, and 1 to 6% for marketable roots. Findings from this research suggest wicking might be useful in a salvage scenario, but only after currently registered preemergence herbicides and between-row cultivation have failed to control Palmer amaranth and other weed species below the sweetpotato canopy. Nomenclature: Glyphosate; Palmer amaranth, Amaranthus palmeri S. Wats.; sweetpotato, Ipomoea batatas L. Lam. ‘Beauregard', ‘Covington'.}, number={3}, journal={WEED TECHNOLOGY}, author={Meyers, Stephen L. and Jennings, Katherine M. and Schultheis, Jonathan R. and Monks, David W.}, year={2016}, pages={765–772} }
 @article{jiang_pesic-vanesbroeck_osborne_schultheis_2016, title={Factors Affecting Greenhouse Sweetpotato Slip Production}, volume={23}, ISSN={1931-5260 1931-5279}, url={http://dx.doi.org/10.1080/19315260.2016.1228729}, DOI={10.1080/19315260.2016.1228729}, abstractNote={ABSTRACT Sweetpotato certified seed producers rely on fast propagation of virus-indexed slip plants in the greenhouse to obtain transplants for the production of first generation of storage roots. Effective fertilization is important for greenhouse vegetative propagation, but relevant guidelines are rare. Greenhouse experiments were conducted in 2011 and 2012 using sweetpotato (Ipomoea batatas (L.) Lam.) var. Covington, Beauregard, and Evangeline to evaluate effects of fertilizer rate on slip production. The most commonly used commercial fertilizer mix (20N–10P–20K) was applied at the rates 50, 100, 200, 300, 400 mg·L−1 of N. Plants were harvested nine times over the season in both years. Total nodes on vines and total slip fresh weight were determined. ‘Evangeline’ produced more nodes—that is, more plants—than ‘Beauregard’ and ‘Covington’, and ‘Beauregard’ produced the highest slip fresh weight, followed by ‘Evangeline’ and ‘Covington’. Effect of fertilizer rate on vine node count was similar for early (harvests 1–3) and middle harvests (harvests 4–6) but impacted late harvests (harvests 7–9), where fertilizer rates from 100 to 300 mg·L−1 of N resulted in similar number of plant nodes, and 50 and 400 mg·L−1 of N reduced node count. Undesirable storage root formation in pots was favored by 50 mg·L−1 of N fertilizer rate, whereas fertilizer at or above 100 mg·L−1 of N inhibited them. ‘Covington’ produced the most storage roots. Fertilizer rate during slip production in the greenhouse did not affect transplant stand count in the field and subsequent field production of sweetpotato storage roots. The commercial fertilizer 20N-10P-20K should be applied from 100 to 200 mg·L−1 of N to produce the most slips and least storage roots in greenhouse pots.}, number={3}, journal={International Journal of Vegetable Science}, publisher={Informa UK Limited}, author={Jiang, Chen and Pesic-VanEsbroeck, Zvezdana and Osborne, Jason A. and Schultheis, Jonathan R.}, year={2016}, month={Oct}, pages={185–194} }
 @article{barkley_chaudhari_jennings_schultheis_meyers_monks_2016, title={Fomesafen Programs for Palmer Amaranth (Amaranthus palmeri) Control in Sweetpotato}, volume={30}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-15-00150.1}, abstractNote={Studies were conducted in 2012 and 2013 to determine the effect of fomesafen based Palmer amaranth control program in ‘Covington' and ‘Evangeline' sweetpotato cultivars. Treatments consisted of fomesafen pretransplant alone at 0.20, 0.28, 0.36, 0.42, 0.56, and 0.84 kg ai ha−1 or followed by (fb) S-metolachlor at 1.12 kg ai ha−1 0 to 7 d after transplanting (DAP), fomesafen at 0.28 kg ha−1 fb S-metolachlor at 1.12 kg ha−114 DAP, flumioxazin pretransplant at 0.105 kg ai ha−1, S-metolachlor at 1.12 kg ha−1 0 to 7 DAP, clomazone at 0.63 kg ha−1 0 to 7 DAP, napropamide at 2.24 kg ha−1 0 to7 DAP, flumioxazin fb S-metolachlor 0 to 7 DAP, and flumioxazin fb clomazone fb S-metolachlor 14 DAP. Fomesafen pretransplant at 0.28 to 0.84 kg ha−1 alone or followed by S-metolachlor at 1.12 kg ha−1 0 to 7 DAP provided 80 to 100% Palmer amaranth control without reduction of yield and significant (< 13%) injury in Covington and Evangeline sweetpotato. Flumioxazin alone or fb S-metolachlor and flumioxazin fb clomazone fb S-metolachlor provided Palmer amaranth control (≥ 95%) with little injury (≤ 5%) and similar yield to the weed-free check. Clomazone alone did not cause injury, but controlled only 24 to 32% of Palmer amaranth at 50 DAP, which resulted in reduced no. 1, marketable, and total sweetpotato yield. Napropamide provided inconsistent control of Palmer amaranth in both years; therefore jumbo and total sweetpotato yield was reduced as compared to the weed-free check in 2012. Palmer amaranth control, sweetpotato cultivar tolerance, and yield in treatments with fomesafen fb S-metolachlor were similar to flumioxazin fb S-metolachlor. In conclusion, a herbicide program consisting of pretransplant fomesafen (0.28 to 0.42 kg ha−1) fb S-metolachlor (1.12 kg ha−1) is a potential option to control Palmer amaranth without causing significant injury and yield reduction in sweetpotato. Nomenclature: Clomazone; flumioxazin; fomesafen; S-metolachlor; napropamide; Palmer amaranth, Amaranthus palmeri S. Wats.; sweetpotato, Ipomoea batatas (L.) Lam. ‘Covington', ‘Evangeline'. En 2012 y 2013, se realizaron estudios para determinar el efecto de programas de control de Amaranthus palmeri basados en el uso de fomesafen sobre los cultivares de batata ‘Covington’ y ‘Evangeline’. Los tratamientos consistieron de fomesafen solo en pre-trasplante a 0.20, 0.28, 0.36, 0.42, 0.56, y 0.84 kg ai ha−1 o seguido por (fb) S-metolachlor a 1.12 kg ai ha−1 0 a 7 d después del trasplante (DAP), fomesafen a 0.28 kg ha−1 fb S-metolachlor a 1.12 kg ha−1 14 DAP, flumioxazin en pre-trasplante a 0.105 kg ai ha−1, S-metolachlor a 1.12 kg ha−1 0 a 7 DAP, clomazone a 0.63 kg ha−1 0 a 7 DAP, napropamide a 2.24 kg ha−1 0 a 7 DAP, flumioxazin fb S-metolachlor 0 a 7 DAP, y flumioxazin fb clomazone fb S-metolachlor 14 DAP. Fomesafen solo en pre-trasplante de 0.28 a 0.84 kg ha−1 o seguido por S-metolachlor a 1.12 kg ha−1 0 a 7 DAP brindó 80 a 100% de control de A. palmeri sin reducir el rendimiento ni causar daño significativo (<13%) en batata Covington y Evangeline. Flumioxazin solo o fb S-metolachlor y flumioxazin fb clomazone fb S-metolachlor controlaron A. palmeri (≥95%), causaron poco daño (≤5%), y el rendimiento fue similar al testigo libre de malezas. Clomazone solo no causó daño, pero el control de A. palmeri fue sólo 24 a 32% a 50 DAP, lo que resultó en un rendimiento reducido de batata no. 1, comercializable, y total. Napropamide brindó un control inconsistente de A. palmeri en ambos año, por lo que el rendimiento de la batata jumbo y total fue reducido al compararse con el testigo libre de malezas en 2012. El control de A. palmeri, la tolerancia de los cultivares de batata, y el rendimiento en tratamientos con fomesafen fb S-metolachlor fueron similares a flumioxazin fb S-metolachlor. En conclusión, un programa de herbicidas que consista de fomesafen en pre-trasplante (0.28 a 0.42 kg ha−1) fb S-metolachlor (1.12 kg ha) es una opción potencial para el control de A. palmeri sin causar daño significativo ni reducciones en el rendimiento de la batata.}, number={2}, journal={WEED TECHNOLOGY}, author={Barkley, Susan L. and Chaudhari, Sushila and Jennings, Katherine M. and Schultheis, Jonathan R. and Meyers, Stephen L. and Monks, David W.}, year={2016}, pages={506–515} }
 @article{schultheis_george_pecota_thompson_yencho_2016, title={Potential yields of industrial sweetpotatoes using cut seed pieces planted at various dates}, volume={1118}, ISSN={0567-7572 2406-6168}, url={http://dx.doi.org/10.17660/ActaHortic.2016.1118.12}, DOI={10.17660/actahortic.2016.1118.12}, number={1118}, journal={Acta Horticulturae}, publisher={International Society for Horticultural Science (ISHS)}, author={Schultheis, J.R. and George, N.A. and Pecota, K.V. and Thompson, W.B. and Yencho, G.C.}, year={2016}, month={May}, pages={79–88} }
 @article{quesada-ocampo_withers_butler_birdsell_schultheis_2015, title={First Report of Plectosporium Blight on Pumpkin and Squash Caused by Plectosporium tabacinum in North Carolina}, volume={99}, ISSN={["1943-7692"]}, DOI={10.1094/pdis-07-14-0770-pdn}, abstractNote={HomePlant DiseaseVol. 99, No. 5First Report of Plectosporium Blight on Pumpkin and Squash Caused by Plectosporium tabacinum in North Carolina PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Plectosporium Blight on Pumpkin and Squash Caused by Plectosporium tabacinum in North CarolinaL. M. Quesada-Ocampo, S. Withers, S. Butler, T. Birdsell, and J. SchultheisL. M. Quesada-OcampoSearch for more papers by this author, S. WithersSearch for more papers by this author, S. ButlerSearch for more papers by this author, T. BirdsellSearch for more papers by this author, and J. SchultheisSearch for more papers by this authorAffiliationsAuthors and Affiliations L. M. Quesada-Ocampo S. Withers S. Butler , Department of Plant Pathology, North Carolina State University, Raleigh 27695 T. Birdsell , Cooperative Extension, North Carolina State University, Raleigh 27695 J. Schultheis , Department of Horticulture, North Carolina State University, Raleigh 27695. Published Online:29 May 2015https://doi.org/10.1094/PDIS-07-14-0770-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Cucurbits are among the most important vegetable crops in North Carolina. Plectosporium blight, caused by Plectosporium tabacinum, can significantly reduce marketable fruit in squash and pumpkin (1). Since 1988, when Plectosporium blight was first reported in the United States in Tennessee, the disease has been confirmed in New York, Alabama, Louisiana, Virginia, and Illinois (4). In July of 2013, approximately15% of zucchini squash (Cucurbita pepo ‘Zephyr’ and ‘Senator’) grown in an organic commercial field in Davidson County, NC, showed spindle-shaped, corky, sunken, tan lesions on the stems and petioles; and circular, corky, raised, tan lesions on the leaves and fruit. In September of 2013, approximately 10 to 20% of the pumpkin plants (C. pepo ‘Field Trip’) at research station fields in Ashe and Haywood Counties, NC, also showed stem, leaf, and fruit lesions characteristic of Plectosporium blight (4). After surface-sterilization with 70% ethanol, four to five lesions were excised from petioles and fruit of each cultivar, placed on potato dextrose agar, and incubated under constant fluorescent light at room temperature (21°C). Tan to light pink colonies with white aerial mycelium grew on the plates after a week, and after single-sporing, one representative isolate from each of three cultivars, Zephyr, Senator, and Field Trip, was retained for analysis. One- and two-celled, hyaline, elongate, ellipsoid, slightly curved conidia (n = 10), each with a narrow base that measured 7.4 to 10.2 × 2.1 to 3 μm were observed for the three isolates at 100× magnification. Branched, hyaline conidiophores (n = 5) with elongate, slightly sinuous, apical phialides and conidia in mucilaginous heads at the tip of each conidiophore identified the isolates as P. tabacinum (synonyms Microdochium tabacinum, Fusarium tabacinum, and Plectosphaerella cucumerina) (2). To confirm the identity of the isolates, the internal transcribed spacer (ITS) region of ribosomal DNA was amplified and sequenced with the ITS4 and ITS5 primers (3). The sequence was compared with sequences in GenBank using a BLAST alignment, which revealed that the isolates had 98% identity with ITS sequences of P. cucumerina (AB266250.1), the teleomorph of P. tabacinum. The ITS sequences of the three isolates were deposited in GenBank under accession numbers KJ130026, KJ130027, and KJ130028. No official report has been published of P. tabacinum on C. pepo in NC; however, Plectosporium blight can be misidentified as mechanical injury, e.g., from sand blasting, and it is likely that the pathogen has previously been encountered but not yet reported officially in NC. While it is uncommon for Plectosporium blight to result in devastating yield losses, the disease can cause significant reduction in marketable fruit, which may warrant applications of effective fungicides in fields where the pathogen has been found.References:(1) Mullen, J. M., and Sikora, E. J. 2003. Plant Dis. 87:749. https://doi.org/10.1094/PDIS.2003.87.6.749A Link, ISI, Google Scholar(2) Palm, M. E., et al. 1995. Mycologia 87:397. https://doi.org/10.2307/3760837 Crossref, ISI, Google Scholar(3) White, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, CA. Crossref, Google Scholar(4) Zitter, T. A. 1996. Page 28 in: Compendium of Cucurbit Diseases. T. A. Zitter, D. L. Hopkins, and C. E. Thomas, eds. The American Phytopathological Society, St. Paul, MN. Google ScholarDetailsFiguresLiterature CitedRelated Vol. 99, No. 5 May 2015SubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Issue Date: 29 May 2015Published: 29 May 2015First Look: 11 Dec 2014Accepted: 3 Dec 2014 Page: 724 Information© 2015 The American Phytopathological SocietyCited byPlectosphaerella cucumerinaCABI Compendium, Vol. CABI CompendiumDiseases of Chrysanthemum7 January 2018Diseases of Chrysanthemum24 May 2017}, number={5}, journal={PLANT DISEASE}, publisher={Scientific Societies}, author={Quesada-Ocampo, L. M. and Withers, S. and Butler, S. and Birdsell, T. and Schultheis, J.}, year={2015}, month={May}, pages={724–725} }
 @article{jiang_perkins-veazie_blankenship_boyette_pesic-vanesbroeck_jennings_schultheis_2015, title={Occurrence, severity and initiation of internal necrosis in 'Covington' sweetpotato}, volume={25}, number={3}, journal={HortTechnology}, author={Jiang, C. and Perkins-Veazie, P. and Blankenship, S. M. and Boyette, M. D. and Pesic-VanEsbroeck, Z. and Jennings, K. M. and Schultheis, J. R.}, year={2015}, pages={340–348} }
 @inproceedings{schultheis_thompson_hassell_2015, title={Specialty melon yield and quality response to grafting in trials conducted in the southeastern United States}, volume={1086}, DOI={10.17660/actahortic.2015.1086.34}, abstractNote={In 2013, the US melon industry grossed over $394 million from approximately 34 thousand hectares of cantaloupe and honeydew crops. North Carolina (NC) and South Carolina (SC) produced about 5% of the USA acreage and value, yet the melon crop in these two states are still valued at several million dollars. Most melon production involves various types of orange flesh melons commonly marketed as cantaloupes. In addition to cantaloupes, there are other types of “specialty” melons that provide new production opportunities. Several of these melon types have relatively soft flesh and limited shelf life, and are less suited for shipping or the larger grocery store retail market. Grafting was evaluated in three tests in 2011 through 2013 in NC and SC to determine if there were any advantages with respect to yield (earliness and total production) and quality (fruit size, soluble solids, and flesh firmness). The were 7 melon entries evaluated in 2011, and 16 melon entries evaluated in 2012 and 2013 studies, which were replicated 5 or 3 times, respectively. Generally, yields were reduced with the various melon cultivars and types tested when using grafted rather than self-grafted or non-grafted plants indicating that the graft itself was not a detriment to yields. Grafted plants of most melon cultivars tended to yield more fruit numbers in earlier harvests than non-grafted plants. Flesh firmness was generally found to be inferior for fruits obtained from grafted plants. Soluble solid levels differed between cultivars, with ‘Sprite’ having some of the highest readings, but did not differ between grafted and non-grafted treatments. Fruit length and width were variably affected, with little response to grafting in the SC location, and reduced fruit lengths measured in the NC location. INTRODUCTION There is increasing interest in grafting in the United States (US), especially in some vegetable crops such as tomatoes, watermelon and melon (Davis et al., 2008a, b). Grafting experiments have indicated many benefits associated with its practice, including disease resistance, especially fusarium wilt (Yetsir et al., 2003; Bletsos, 2005; Sakata et al., 2007); yield increase (Lee et al., 2010; Wu et al., 2006)); less need of fertilizer or better nutrient uptake (Lee and Oda, 2003; Ruis et al., 1997); more vigorous plants (Cohen et al., 2000; Sakata et al, 2007; Lee and Oda, 2003); and in some cases improved fruit quality such as improved nutritional value (Perkins-Veazie et al., 2007) and flesh firmness (Roberts et al., 2005; Salem et al., 2002). Grafting is a well adopted practice on cucurbits in countries such as China, Korea, Spain, and Japan (Lee et al., 2010; Davis et al., 2008a). However, adoption of grafting as a production management practice has been slow in the US. Key factors that have inhibited adoption (particularly with cucurbits) are added costs versus benefits, and the land required to rotate crops in order to avoid disease build up (Taylor et al., 2008). In jonathan_schultheis@ncsu.edu Proc. I IS on Vegetable Grafting Eds.: Zhilong Bie et al. Acta Hort. 1086, ISHS 2015 270 spite of these obstacles, there is still much interest in determining the effects of grafting on yield and production quality, as well as best management practices to mitigate the increased cost of using grafted plants, such as a reduction in planting densities (Schultheis et al., 2009). With this in mind, we used a common interspecific squash rootstock cultivar, ‘Carnivor’ and grafted a range of melon cultivars and types with the goal of determining what effects resulted with respect to yield, earliness of yield, fruit size, flesh firmness, and soluble solids when compared with non-grafted or self-grafted plants from each scion cultivar. MATERIALS AND METHODS Plant Material To better understand the potential benefits of melon grafting, we compared the effects of using grafted transplants versus self-grafted transplants. Seven melon cultivars were evaluated in 2011 in South Carolina (SC). The planting was established in early April on plastic mulch with drip irrigation. Plot length was 6.1 m and contained 10 plants. Plants were spaced 0.61 m apart and row spacing was 2.4 m. In 2012, the study was replicated 3 times with each North Carolina (NC) location serving as a replication. The trial was planted at the research stations in Clinton and Kinston, and on-farm near Wilson, NC. In 2013, the study was again replicated 3 times and planted at the research station in Clinton, NC. There were a total of 16 melon entries and each entry type or cultivar had either grafted or non-grafted plant plots at each location in 2012. Plots in each location/replication in 2012 and the three replicated plots in 2013 were established with either 15 grafted plants or 15 non-grafted plants of each cultivar. A total of 32 plots were planted at each location in late May or early June in 2012, and on 17 May in 2013. All melon transplants were grown in Charleston, South Carolina (SC) and grafted using the one cotyledon graft method (Hassell et al., 2008), then transported to NC to their respective field locations in 2012 and 2013. Plants were planted on black plastic mulch and drip irrigated. Spacing between bed centers was 1.5 m and in-row spacing was 0.61 m. Recommended cultural practices were followed for irrigation, fertilizer, and pesticide application (Kemble, 2013). Data Acquired When ripe, each fruit was harvested and weighed. Harvests occurred three times per week. In SC, the first harvest was 6 June and the last of the 12 harvests was on 1 July 2011. In NC, harvests were initiated 25 July 2012 and 11 July 2013, and completed 23 August and 7 August, respectively. There were a total of 10 harvests in 2012 and a total of 12 harvests in 2013 with early yield being defined as the first 4 harvests. Interior fruit quality was determined by taking at least 5 fruit samples at the appropriate commercial harvest stage. Flesh sweetness levels were quantified using a Atago Model PAL-1 digital refractometer (Atago USA, Inc., Bellevue, WA), and flesh firmness was determined using a fruit pressure tester (QA Supplies LLC, Norfolk, VA) by taking two readings on each side of the longitudinally cut fruit between the seed cavity and the rind. Other notes such as vine vigor and fruit appearance were observed. The most common melon types grown in the United States are muskmelon (Cucumis melo var. reticulatus) and honeydew (Cucucmis melo var. inodorus). These melon types were valued at over $394 million and produced on 34,000 ha in 2013 (United States Department of Agriculture, 2014). In addition to muskmelon and honeydew melon types, there were seven fruit cultivars evaluated in SC and 16 in NC which included specialty melon types; Athena (eastern muskmelon), Caldeo (Tuscan), Camina Europa (canary), Camposol (canary), Courier (galia), Crème de Menthe (honeydew), Duke (ananas), Hibrix (canary), Jade Delight (honeydew), NUN 7225 (honeydew), Proteo (Tuscan), Sancho (piel de sapo), Sprite (oriental crisp flesh), SXM 7057 (canary), and Visa Premium (galia). These specialty melons of each type are established as some of the best}, booktitle={I international symposium on vegetable grafting}, author={Schultheis, J. and Thompson, W. and Hassell, R.}, year={2015}, pages={269–278} }
 @article{suchoff_louws_gunter_schultheis_2014, title={2013 On-farm Grafted Tomato Trial to Manage Bacterial Wilt}, volume={1086}, ISSN={["0567-7572"]}, DOI={10.17660/actahortic.2015.1086.14}, abstractNote={Grossing over $33.7 million in annual sales, North Carolina ranks 7th in the US for the production of tomatoes (Solanum lycopersicum). A replicated on-farm trial was conducted in Rowan County, NC. On May 30th, 2013, 8.1 ha of two bacterial wilt (BW; R. solanacearum (race 1)) resistant rootstocks were planted. The objective of this trial was to evaluate disease susceptibility and production in fields with BW history. In addition, plant spacing and training systems were compared. Two experimental sites, one fumigated and one non-fumigated, were arranged in a randomized complete block design with four replications, each consisting of 91.4 m-rows in a commercial plasticulture system. Each row contained 13 10-plant treatment plots (2A—2A—3 Factorial + Control): two rootstocks (‘801’, ‘802’; Rijk Zwaan), two training systems (single-leader, double-leaders), three between-plant spacings (45.7, 61.0, and 76.2 cm) with ‘Mountain Fresh’ as the scion and a non-grafted ‘Mountain Fresh’ control spaced at 45.7 cm. Wilt incidence was collected during the two harvests. Fruit were harvested twice at 69 and 84 days after transplanting. Wilt incidence was lower in the non-fumigated field and no differences in yield between the grafted and non-grafted plants were observed. In the fumigated field, the main effect of grafting tended to increase yield. Both the main effect of training system and spacing significantly affected yield in the grafted treatments. BW incidence was significantly higher in the non-grafted treatment (29.08%) than ‘801’ and ‘802’ rootstocks (0.909 and 0.183%, respectively) (P<.0001). Single-leader grafted plants had 2.54% more BW incidence than double-leader plants (P=0.0007). Grafted tomatoes offered an alternative method to fumigation as a means to reduce BW loss and sustain marketable yield.}, number={1086}, journal={Acta Horticulturae (ISHS)}, publisher={International Society for Horticultural Science (ISHS)}, author={Suchoff, D.H. and Louws, F.J. and Gunter, C.C. and Schultheis, J.R.}, year={2014}, pages={119–127} }
 @article{biai_garzon_osborne_schultheis_gehl_gunter_2013, title={Bell Pepper Seedling Phytotoxicity Due to Abscisic Acid Drench Applications}, volume={19}, ISSN={1931-5260 1931-5279}, url={http://dx.doi.org/10.1080/19315260.2011.650297}, DOI={10.1080/19315260.2011.650297}, abstractNote={Bell pepper transplant height control is essential to produce a strong plant capable of surviving the transplant process. Transplant producers are interested in environmental, physical, and chemical methods to control plant height in the greenhouse. One emerging technology for transplant height control on bell pepper is the use abscisic acid (ABA); however, at high doses some phytotoxicity has been observed. Greenhouse experiments were conducted to determine the degree of phytotoxicity induced by an exogenous drench application of abscisic acid on ‘Aristotle’ bell pepper (Capsicum annuum L.), seedlings. Abscisic acid concentrations (1,000, 5,000, 10,000, 25,000, and 50,000 mg·L−1) were applied over a 1- to 5-week period beginning at the cotyledon stage, in addition to an untreated control. Plant survival for the control and the 1,000 mg·L−1 (baseline treatments) was significantly greater compared to a single application or multiple applications of greater concentrations. The results indicated that applying higher concentrations of ABA (5,000 mg·L−1 or more) using multiple lower concentration applications provided lower hazard ratios and increased longevity compared to a single higher concentration application. The ABA delivered as a drench at the cotyledon stage at concentrations of 5,000 mg·L−1 or below can control transplant height with no visible phytotoxicity.}, number={1}, journal={International Journal of Vegetable Science}, publisher={Informa UK Limited}, author={Biai, Christopher J. and Garzon, José G. and Osborne, Jason A. and Schultheis, Jonathan R. and Gehl, Ronald J. and Gunter, Christopher C.}, year={2013}, month={Jan}, pages={4–12} }
 @article{dittmar_monks_jennings_schultheis_2013, title={Effects of Halosulfuron POST on Sweetpotato Yield and Storage Root Quality}, volume={27}, ISSN={["1550-2740"]}, DOI={10.1614/wt-d-11-00175.1}, abstractNote={Abstract Field studies were conducted to determine the effect of halosulfuron at 0, 13, 26, 39 or 52 g ha−1 applied 10, 22, and 31 d after planting (DAP) on ‘Beauregard' and ‘Covington' sweetpotato. Storage roots were harvested, graded, cured, and stored in controlled environment for 2 mo. Where injury on storage roots was observed, external injury occurred on the surface of the storage root as a blackened area with blistering and internal injury consisted of small red-brown spots inside the sweetpotato storage root. Total yield of sweetpotato with 13 g ha−1 halosulfuron treatment (155,157 kg ha−1) was similar to the nontreated check (162,002 kg ha−1). However, halosulfuron rates above 13 g ha−1 resulted in a reduction of marketable grade roots and total yield of sweetpotato. Regardless of rate and timing of halosulfuron, external and internal injury to Beauregard storage roots was less than 6 and 9%, respectively. No external injury to Covington was observed from all rates of halosulfuron applied POST at 10 DAP. Halosulfuron at 22 DAP to Covington caused greater external injury to storage roots than was observed on the nontreated. Thus, Beauregard appears more tolerant to halosulfuron POST than Covington. To minimize internal or external injury to storage roots of Covington, halosulfuron must be applied within 10 DAP. Nomenclature: Halosulfuron; sweetpotato, Ipomoea batatas (L.) Lam. ‘Beauregard' and ‘Covington'. Resumen Se realizaron experimentos de campo para determinar el efecto de halosulfuron a 0, 13, 26, 39 ó 52 g ha−1 aplicados 10, 22 y 31 d después de la siembra (DAP) en batata 'Beauregard' y 'Covington'. Raíces de almacenamiento fueron cosechadas, evaluadas según su calidad, curadas y almacenadas en un ambiente controlado por 2 meses. Cuando se observó daño en las raíces de almacenamiento, se vio un daño externo en la superficie de la raíz con un área ennegrecida con ampollas, mientras que el daño interno consistió en puntos café-rojizo dentro de la raíz de almacenamiento de la batata. El rendimiento total de la batata del tratamiento con 13 g ha−1 de halosulfuron (155,157 kg ha−1) fue similar al testigo no tratado (162,002 kg ha−1). Sin embargo, dosis de halosulfuron por encima de 13 g ha−1 resultaron en una reducción del rendimiento total y de las raíces de batata con calidad comercializable. Sin importar la dosis o el momento de aplicación de halosulfuron, el daño externo e interno en las raíces de almacenamiento de Beauregard fue menor al 6 y 9%, respectivamente. No se observó daño externo en Covington en ninguna de las dosis aplicadas POST 10 DAP. Halosulfuron aplicado 22 DAP, causó un daño externo mayor en las raíces de almacenamiento de Covington que el daño observado en el testigo no tratado. Así, Beauregard parece ser más tolerante a halosulfuron POST que Covington. Para minimizar daños internos o externo en las raíces de almacenamiento de Covington, se debe aplicar halosulfuron dentro de los 10 DAP.}, number={1}, journal={WEED TECHNOLOGY}, author={Dittmar, Peter J. and Monks, David W. and Jennings, Katherine M. and Schultheis, Jonathan R.}, year={2013}, pages={113–116} }
 @article{clark_silva_arancibia_main_schultheis_van-esbroecle_jiang_smith_2013, title={Incidence of end rots and internal necrosis in sweetpotato is affected by cultivar, curing, and ethephon defoliation}, volume={23}, number={6}, journal={HortTechnology}, author={Clark, C. A. and Silva, W. L. and Arancibia, R. A. and Main, J. L. and Schultheis, J. R. and van-Esbroecle, Z. P. and Jiang, C. and Smith, J.}, year={2013}, pages={886–897} }
 @article{biai_garzon_osborne_schultheis_gehl_gunter_2011, title={Height control in three pepper types treated with drench-applied abscisic acid}, volume={46}, number={9}, journal={HortScience}, author={Biai, C. J. and Garzon, J. G. and Osborne, J. A. and Schultheis, J. R. and Gehl, R. J. and Gunter, C. C.}, year={2011}, pages={1265–1269} }
 @misc{george_pecota_bowen_schultheis_yencho_2011, title={Root Piece Planting in Sweetpotato-A Synthesis of Previous Research and Directions for the Future}, volume={21}, ISSN={["1063-0198"]}, DOI={10.21273/horttech.21.6.703}, abstractNote={Sweetpotato (Ipomoea batatas) is traditionally grown for fresh consumption, particularly in developed nations, but it is increasingly being used for alternative markets such as processed foods and industrial products. Sweetpotato is well suited for these end uses but its utilization is limited due to high production costs. These costs are primarily the result of high labor inputs. As a vegetatively propagated crop, sweetpotato is typically planted using unrooted plant cuttings, or ‘‘slips,’’ which requires hand labor at several stages. Consequently, planting costs can be as high as 20% of total production costs. As an alternative to slips, sweetpotato can be established using root pieces, similar to the seed piece system used for potato (Solanum tuberosum). This system can be readily mechanized and therefore has the potential to reduce labor demands. Root piece planting has been investigated several times since the 1940s but is not reported to be in large-scale commercial use anywhere in the world. In this work, we review the research literature relating to root piece planting in sweetpotato. This literature demonstrates that it is possible for sweetpotato root pieces to produce yields comparable to slips, but that in most cases yields from root pieces are usually lower than from slips. We conclude that given suitable cultural management and appropriate varieties, it may be possible to successfully produce sweetpotato using root pieces. More work is necessary to develop root piece planting as a viable alternative to slips in sweetpotato production. This work should include the selection and breeding of adapted varieties, evaluation of the economics of sweetpotato production using root pieces, development of planting equipment suited to sweetpotato root pieces, and examination of chemical treatments to improve success of root piece planting.}, number={6}, journal={HORTTECHNOLOGY}, author={George, Nicholas A. and Pecota, Kenneth V. and Bowen, Blake D. and Schultheis, Jonathan K. and Yencho, G. Craig}, year={2011}, month={Dec}, pages={703–711} }
 @article{meyers_jennings_schultheis_monks_2010, title={Evaluation of Flumioxazin and S-metolachlor Rate and Timing for Palmer Amaranth (Amaranthus palmeri) Control in Sweetpotato}, volume={24}, ISSN={["0890-037X"]}, DOI={10.1614/wt-d-09-00057.1}, abstractNote={Abstract Studies were conducted in 2007 and 2008 to determine the effect of flumioxazin and S-metolachlor on Palmer amaranth control and ‘Beauregard’ and ‘Covington’ sweetpotato. Flumioxazin at 0, 91, or 109 g ai ha−1 was applied pretransplant 2 d before transplanting alone or followed by (fb) S-metolachlor at 0, 0.8, 1.1, or 1.3 kg ai ha−1 PRE applied immediately after transplanting or 2 wk after transplanting (WAP). Flumioxazin fb S-metolachlor immediately after transplanting provided greater than 90% season-long Palmer amaranth control. S-metolachlor applied alone immediately after transplanting provided 80 to 93% and 92 to 96% control in 2007 and 2008, respectively. Flumioxazin fb S-metolachlor 2 WAP provided greater than 90% control in 2007 but variable control (38 to 79%) in 2008. S-metolachlor applied alone 2 WAP did not provide acceptable Palmer amaranth control. Control was similar for all rates of S-metolachlor (0.8, 1.1, and 1.3 kg ha−1). In 2008, greater Palmer amaranth control was observed with flumioxazin at 109 g ha−1 than with 91 g ha−1. Sweetpotato crop injury due to treatment was minimal (< 3%), and sweetpotato storage root length to width ratio was similar for all treatments in 2007 (2.5 for Beauregard) and 2008 (2.4 and 1.9 for Beauregard and Covington, respectively). Sweetpotato yield was directly related to Palmer amaranth control. Results indicate that flumioxazin pretransplant fb S-metolachlor after transplanting provides an effective herbicide program for control of Palmer amaranth in sweetpotato. Nomenclature: Flumioxazin; S-metolachlor; Palmer amaranth, Amaranthus palmeri S. Wats. AMAPA; sweetpotato, Ipomoea batatas L. Lam. ‘Covington’, ‘Beauregard’.}, number={4}, journal={WEED TECHNOLOGY}, author={Meyers, Stephen L. and Jennings, Katherine M. and Schultheis, Jonathan R. and Monks, David W.}, year={2010}, pages={495–503} }
 @article{willis_abney_holmes_schultheis_kennedy_2010, title={Influence of Preceding Crop on Wireworm (Coleoptera: Elateridae) Abundance in the Coastal Plain of North Carolina}, volume={103}, ISSN={["1938-291X"]}, DOI={10.1603/ec10184}, abstractNote={ABSTRACT Three studies were conducted to determine the effect of preceding crop on wireworm (Coleoptera: Elateridae) abundance in the coastal plain of North Carolina. In all three studies, samples of wireworm populations were taken from the soil by using oat, Avena sativa L., baits. Treatments were defined by the previous year's crop and were chosen to reflect common crop rotations in the region. Across all three studies, eight wireworm species were recovered from the baits: Conoderus amplicollis (Gyllenhal), Conoderus bellus (Say), Conoderus falli (Lane), Conoderus lividus (Degeer), Conoderus scissus (Schaeffer), Conoderus vespertinus (F.), Glyphonyx bimarginatus (Schaeffer), and Melanotus communis (Gyllenhal). The effect of corn, Zea mays L.; cotton, Gossypium hirsutum L.; fallow; soybean, Glycine max (L.) Merr.; sweet potato, Ipomoea batatas (L.) Lam.; and tobacco (Nicotiana spp.) was evaluated in a small-plot replicated study. M. communis was the most frequently collected species in the small-plot study and was found in significantly higher numbers following soybean and corn. The mean total number of wireworms per bait (all species) was highest following soybean. A second study conducted in late fall and early spring assessed the abundance of overwintering wireworm populations in commercial fields planted to corn, cotton, peanut (Arachis hypogaea L.), soybean, sweet potato, and tobacco in the most recent previous growing season. C. lividus was the most abundant species, and the mean total number of wireworms was highest following corn and soybean. A survey was conducted in commercial sweet potato in late spring and early summer in fields that had been planted to corn, cotton, cucurbit (Cucurbita pepo L.), peanut, soybean, sweet potato, or tobacco in the most recent previous growing season. C. vespertinus was the most abundant species, and the mean total number of wireworms per bait was highest following corn.}, number={6}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Willis, Rebecca B. and Abney, Mark R. and Holmes, Gerald J. and Schultheis, Jonathan R. and Kennedy, George G.}, year={2010}, month={Dec}, pages={2087–2093} }
 @article{meyers_jennings_schultheis_monks_2010, title={Interference of Palmer Amaranth (Amaranthus palmeri) in Sweetpotato}, volume={58}, ISSN={["0043-1745"]}, DOI={10.1614/ws-d-09-00048.1}, abstractNote={Abstract Field studies were conducted in 2007 and 2008 at Clinton and Faison, NC, to evaluate the influence of Palmer amaranth density on ‘Beauregard’ and ‘Covington’ sweetpotato yield and quality and to quantify the influence of Palmer amaranth on light interception. Palmer amaranth was established at 0, 0.5, 1.1, 1.6, 3.3, and 6.5 plants m−1 within the sweetpotato row and densities were maintained season-long. Jumbo, number (no.) 1, and marketable sweetpotato yield losses were fit to a rectangular hyperbola model, and predicted yield loss ranged from 56 to 94%, 30 to 85%, and 36 to 81%, respectively for Palmer amaranth densities of 0.5 to 6.5 plants m−1. Percentage of jumbo, no. 1, and marketable sweetpotato yield loss displayed a positive linear relationship with Palmer amaranth light interception as early as 6 to 7 wk after planting (R2  =  0.99, 0.86, and 0.93, respectively). Predicted Palmer amaranth light interception 6 to 7, 10, and 13 to 14 wk after planting ranged from 47 to 68%, 46 to 82%, and 42 to 71%, respectively for Palmer amaranth densities of 0.5 to 6.5 plants m−1. Palmer amaranth height increased from 177 to 197 cm at densities of 0.5 to 4.1 plants m−1 and decreased from 197 to 188 cm at densities of 4.1 to 6.5 plants m−1; plant width (69 to 145 cm) and shoot dry biomass plant−1 (0.2 to 1.1 kg) decreased linearly as density increased. Nomenclature: Palmer amaranth, Amaranthus palmeri S. Wats. AMAPA; sweetpotato, Ipomoea batatas L. Lam. ‘Beauregard’ and ‘Covington’ IPOBA}, number={3}, journal={WEED SCIENCE}, author={Meyers, Stephen L. and Jennings, Katherine M. and Schultheis, Jonathan R. and Monks, David W.}, year={2010}, pages={199–203} }
 @article{osmond_cahill_schultheis_holmes_jester_2010, title={Tillage Practices and Nitrogen Rates on Pickling Cucumber Production}, volume={17}, ISSN={1931-5260 1931-5279}, url={http://dx.doi.org/10.1080/19315260.2010.499892}, DOI={10.1080/19315260.2010.499892}, abstractNote={Cucumbers require adequate nitrogen (N) for growth and development. This study was undertaken to determine the most effective tillage system and N rate for hand-picked, processing, cucumber (Cucumis sativus L.) production. Three tillage systems and five N fertilizer rates were compared for effects on yield, fertilizer N use efficiency (NUE), and effects on belly rot disease caused by Rhizoctonia solani. In both years conventional tillage had greater yields than no till and was greater than strip tillage one year. Cucumber NUE was not different between tillage systems or N rates; NUE averaged 35%. In one of two years, incidence of belly rot disease was greater under no till and increased with increasing N rate; in the other year, there was no affect of tillage on belly rot. In most years, conventional tillage for cucumbers will outperform strip tillage and no till.}, number={1}, journal={International Journal of Vegetable Science}, publisher={Informa UK Limited}, author={Osmond, Deanna L. and Cahill, Sheri L. and Schultheis, Jonathan R. and Holmes, Gerald J. and Jester, Wilfred R.}, year={2010}, month={Dec}, pages={13–25} }
 @article{dittmar_monks_schultheis_2010, title={Use of Commercially Available Pollenizers for Optimizing Triploid Watermelon Production}, volume={45}, ISSN={["0018-5345"]}, DOI={10.21273/hortsci.45.4.541}, abstractNote={An experiment was conducted during 2005 and 2006 in Kinston, NC, with the objective of maximizing triploid watermelon [Citrullus lanatus (Thunb.) Matsum. and Nak.] fruit yield and quality by optimizing the choice and use of pollenizers. Treatments were pollenizer cultivars planted singly ['Companion', 'Super Pollenizer 1' ('SP1'), 'Summer Flavor 800' ('SF800'), and 'Mickylee'] or in pairs ('Companion' + 'SP1', 'Companion' + 'SF800', and 'SP1' + 'SF800'). All pollenizers from these seven treatments were interplanted with the triploid cultivar Tri-X-313. Planting arrangement was compared by establishing 'SF800' in a hill versus an interplanted field arrangement. Effect of pollenizer establishment timing on triploid fruit yields and quality was evaluated by establishing 'SP1' 3 weeks after planting and comparing it with the establishment of 'SP1' at the time of triploid plant establishment. Finally, a triploid planting with no pollenizer (control) was included to determine pollen movement. Fruit yield from the control was 22% or less of yield of the other treatments containing a pollenizer and less than 10% in the initial or early harvests. Pollen movement was minimal among plots and differences in yield and fruit quality could be attributed to pollenizer treatment. In 2005, the use of 'Companion', 'SP1', or 'Mickylee' as pollenizers produced similar total yields, whereas 'SF800' produced the lowest yield. In 2005, 'Companion' produced more large fruit than the other individual pollenizer treatments. Combining the pollenizers generally did not enhance triploid yields or quality. Interplanting of pollenizers consistently resulted in greater yield compared with the hill system. Late planting of 'SP1' increased the incidence of hollow heart in the marketable fruit and decreased yield compared with simultaneously planting 'SP1' and triploid plants. Thus, selection of pollenizer, planting arrangement, and time of pollenizer establishment are all important considerations to optimizing triploid yield and quality.}, number={4}, journal={HORTSCIENCE}, author={Dittmar, Peter J. and Monks, David W. and Schultheis, Jonathan R.}, year={2010}, month={Apr}, pages={541–545} }
 @article{walters_schultheis_2009, title={Directionality of pollinator movements in watermelon plantings}, volume={44}, number={1}, journal={HortScience}, author={Walters, S. A. and Schultheis, J. R.}, year={2009}, pages={49–52} }
 @article{hasse_schultheis_jester_olson_miller_2009, title={In-row Distance in Triploid Miniwatermelon Cultivars Affects Yield and Quality in Diverse Environments in the Southeastern United States}, volume={19}, ISSN={["1063-0198"]}, DOI={10.21273/hortsci.19.3.538}, abstractNote={The goals of these studies were to determine how miniwatermelon (Citrullus lanatus) cultivars differed and responded to plant in-row spacing in terms of percentage of marketable fruit and yields, and if plant spacing impacted internal fruit quality. Three genetically diverse triploid miniwatermelon cultivars (Mohican, Petite Perfection, and Xite) were selected. These cultivars were evaluated in field locations at northern Florida (Quincy), central South Carolina (Blackville), coastal South Carolina (Charleston), and eastern North Carolina (Kinston) at five within-row distances. Within-row distance included 9, 12, 15, 18, and 21 inches. All plots were15 ft long with row middles 9 ft apart. Fruit were categorized as marketable if they weighed between 3.1 and 9.0 lb per fruit. Within this range further categories were divided as follows: ≤3.0 lb (cull), 3.1 to 5.0 lb (small), 5.1 to 7.0 lb (average), 7.1 to 9.0 lb (large), and ≥9.1 lb (cull). There was a cultivar by location interaction, suggesting that the three cultivars responded differently at each of the four locations. ‘Petite Perfection’ was among the highest yielding at all locations except Quincy, where it was the lowest yielding cultivar. As with total yields, the percentage of marketable fruit was similar for some cultivars across locations. Cultivar Petite Perfection produced the highest percentage of marketable fruit at three of the four locations. The exception was the Quincy site where ‘Xite’ had the highest percentage of marketable fruit. Within-row plant distances and populations affected total marketable yield, both for fruit weight and number per plant, regardless of cultivar and location. As the plant population increased from eight plants per plot (21-inch in-row spacing) to 12 plants per plot (15-inch in-row spacing), total marketable miniwatermelon fruit yields increased in total fruit number as well as total weight. There was a cultivar by location interaction for the percentage of soluble solids and the rind thickness measurements, suggesting that some cultivars responded differently at each of the four locations. Quality effects were more apparent with ‘Mohican’ and ‘Xite’, as they were more responsive to location than ‘Petite Perfection’.}, number={3}, journal={HORTTECHNOLOGY}, author={Hasse, Richard L. and Schultheis, Jonathan R. and Jester, Wilfred R. and Olson, Stephen M. and Miller, Gilbert A.}, year={2009}, pages={538–545} }
 @article{dittmar_monks_schultheis_2009, title={Maximum Potential Vegetative and Floral Production and Fruit Characteristics of Watermelon Pollenizers}, volume={44}, ISSN={["2327-9834"]}, DOI={10.21273/hortsci.44.1.59}, abstractNote={Triploid (seedless) watermelon [Citrullus lanatus (Thunb.) Matsum. and Nak.] pollen is nonviable; thus, diploid (pollenizer) watermelon cultigens are required to supply viable pollen for triploid watermelon fruit set. The objective of this research was to characterize maximum potential vegetative growth, staminate and pistillate flower production over time, and measure exterior and interior fruit characteristics of pollenizer cultigens. Sixteen commercially available and numbered line (hereafter collectively referred to as cultigens) pollenizer and two triploid cultigens were evaluated in 2005 and 2006 at Clayton, NC. Vegetative growth was measured using vine and internode length, and staminate and pistillate flower development was counted weekly. Fruit quality and quantity were determined by measuring individual fruit weights, soluble solids, and rind thickness. Based on vegetative growth, pollenizer cultigens were placed into two distinct groups. Pollenizers, which produced a compact or dwarf plant were ‘Companion’, ‘Sidekick’, ‘TP91’, ‘TPS92’, and ‘WC5108-1216’. Pollenizers having a standard vine length were ‘Jenny’, ‘High Set 11’, ‘Mickylee’, ‘Minipol’, ‘Pinnacle’, ‘Summer Flavor 800’ (‘SF800’), ‘Super Pollenizer 1’ (‘SP1’), and ‘WH6818’. Cultigens with compact growth habit had shorter internodes and vine lengths compared with the cultigens with standard growth habit. Cultigens with the greatest quantity of staminate flower production through the entire season were ‘Sidekick’ and ‘SP1’. The lowest number of staminate flowers was produced by ‘TP91’ and ‘TPS92’. Based on fruit quality characteristics and production, pollenizers currently or possibly marketed for consumption include ‘Mickylee’, ‘SF800’, ‘Minipol’, ‘Jenny’, and ‘Pinnacle’. The remaining cultigens evaluated in this study should be used strictly as pollenizers based on fruit quality. Arrangement of diploid pollenizers in a commercial planting of triploid watermelons is an important consideration depending on plant vegetative development. Based on staminate flower production, cultigens with higher staminate flower production are potentially superior pollenizers and may lead to improved triploid quality and production. Furthermore, pollenizer selection by fruit characteristics should include a rind pattern easily distinguished from triploid fruit in the field. Watermelon production in the United States was 38 million pounds in 2005 [U.S. Department of Agriculture (USDA), National Agricultural Statistics Service, 2006]. Triploid (seedless) watermelons were introduced to the United States in 1951 (Kihara, 1951); and in 2005, three-fourths of the United States’ watermelon production was devoted to triploid cultivars (USDA, Economic Research Service, 2005). In triploid watermelon production, diploids are included as a viable pollen source for pollination and fruit set (Kihara, 1951; Rubatzky and Yamaguchi, 1997). To provide sufficient pollen for maximum triploid fruit yield, plants should be planted in a ratio of one pollenizer plant for every two to four triploid plants (Fiacchino and Walters, 2003; Maynard and Elmstrom, 1992; NeSmith and Duval, 2001). The pollenizer cultivar has an effect on the yield of triploid fruit (Fiacchino and Walters, 2003; Freeman et al., 2007b). Triploid plants and pollenizers can be planted in separate rows or interplanted in the same row (Maynard and Elmstrom, 1992). The separate row planting method establishes one row of pollenizers and then two to four rows of triploids (Maynard and Elmstrom, 1992; Rubatzky and Yamaguchi, 1997). NeSmith and Duval (2001) reported a decrease in yield when the pollenizer ‘Ferarri’ was planted more than 6 m from the triploid ‘Genesis’ indicating that field arrangement of the pollenizer is an important consideration. Planting a pollenizer in the same row to reduce the distance between pollenizer and triploid plant can be done by planting the pollenizer in between two to three triploid plants (interplanted) or by planting a pollenizer in every third or fourth hill that would normally be occupied by a triploid plant. Planting in the same row adds complexity to the planting and harvesting of the crop (Maynard and Elmstrom, 1992). Pollenizer fruit should have a different rind pattern from the triploid so it can be separated and marketed properly (Kihara, 1951; Maynard and Elmstrom, 1992). The objective of this research was to characterize and quantify the growth and development of diploid watermelon pollenizers, especially recently bred pollenizers developed exclusively for triploid watermelon production (dedicated pollenizers). The vine and internode length were measured because plant competition and suitability of different planting arrangement for pollenizers need to be considered when planted with triploid plants. Determining number of flowers gives an understanding of potential pollen produced from the various pollenizers for fruit set on triploid watermelons. Counting fruit, quantifying harvestable fruit and size, measuring fruit qualities, and observing rind pattern provides information as to which pollenizers could be sold as seeded fruit as well as these that are more suitable for production with specific triploid cultivars. Materials and Methods Treatments. Thirteen pollenizer cultigens were evaluated: ‘Companion’, ‘Jenny’, ‘High Set 11’, ‘Mickylee’, ‘Minipol’, ‘Pinnacle’, ‘Summer Flavor 800’ (‘SF800’), ‘Super Pollenizer 1’ (‘SP1’), ‘Sidekick’, ‘TP91’, ‘TPS92’, ‘WC5108-1216’, and ‘WH6818’. Triploid watermelon cultigens, ‘Petite Perfection’ and ‘Tri-X-313’, were included for comparison of vegetative and floral habit. Cultural practices. Seeds were sown into 3.8 cm · 3.8-cm cell trays on 20 Apr. each year. Plants were grown in the greenhouse for 2 weeks and moved to a coldframe for 2 weeks of conditioning for field establishment. Seedlings were hand planted into beds covered with black polyethylene mulch at the Central Crops Research Station, Clayton, NC, into a Norfolk loamy sand (fine-loamy, kaolinitic, thermic typic Kandiudults) soil on 24 May 2005 and 17 May 2006. As beds were formed and just before mulch was laid, the soil was fumigated with 1,3-dichloropropene and chloropicrin (Telone C-35: Dow AgroSciences, Calgary, Alberta, Canada) and broadcast-fertilized (0N–0P–50K at 149.1 kg ha and 16N–0P–0K at 213.0 kg ha) according to soil test recommendations. Inrow spacing was 1.3 m and between-row spacing was 3.1 m. Plant spacing around plants was maximized to facilitate individual plant measurements. Four watermelon plants of each cultigen were included in each plot. Cultigens were arranged in a randomized complete block design with five replications. Pesticides and fertigation were applied based on North Carolina cultural recommendations (Sanders, 2004, 2005). Received for publication 8 July 2008. Accepted for publication 1 Nov. 2008. Technical assistance by W. Bradfred Thompson and statistical assistance from Joy Smith are greatly appreciated. Graduate research assistant. Professor. To whom reprint requests should be addressed; e-mail jonathan_schultheis@ncsu.edu. HORTSCIENCE VOL. 44(1) FEBRUARY 2009 59 JOBNAME: horts 44#1 2009 PAGE: 1 OUTPUT: December 29 22:41:23 2008 tsp/horts/180127/03114}, number={1}, journal={HORTSCIENCE}, author={Dittmar, Peter J. and Monks, David W. and Schultheis, Jonathan R.}, year={2009}, month={Feb}, pages={59–63} }
 @article{finney_creamer_schultheis_wagger_brownie_2009, title={Sorghum sudangrass as a summer cover and hay crop for organic fall cabbage production}, volume={24}, ISSN={["1742-1713"]}, DOI={10.1017/S174217050999007X}, abstractNote={Abstract No-tillage (NT) organic vegetable production presents several economic opportunities for growers in the southeastern United States while promoting natural resource conservation. This study was conducted to determine if removal of sorghum sudangrass (SS) cover crop biomass as hay, frequency at which the cover crop is mowed, and tillage affect weed suppression and head weight of transplanted organic cabbage. Sorghum sudangrass [Sorghum bicolor (L.) Moench×Sorgum sudanense (Piper) Staph.] was planted in May 2004 at Reidsville and Goldsboro, NC, preceding the planting of organic ‘Bravo’ cabbage (Brassica oleracea L. Capitata group) in August and September 2004, respectively. SS management systems included: low-frequency mowing with hay removed following the first mowing operation (LFM-H), low-frequency mowing with hay not removed (LFM), high-frequency mowing with hay not removed (HFM) and a no cover crop control. Two tillage treatments were applied within each management system: conventional tillage (CT) and NT. Under NT conditions, SS mulch generated by LFM offered broadleaf weed control in cabbage similar to that achieved under CT, regardless of whether cover crop biomass was removed as hay. Mowing with higher frequency reduced SS cover crop biomass by 18–33% and reduced weed suppression in NT cabbage. Mowing frequency did not influence the quantity of SS that re-grew in the cabbage crop. SS re-growth contributed to lower head weight in NT compared to CT cabbage in Goldsboro, and crop failure of NT cabbage in Reidsville. Cabbage head weight was highest when the crop was not preceded by SS in both CT and NT systems (1.6 as opposed to 1.3–1.4 kg head−1). Our findings suggest that the potential for growers to manage a cover crop also as a hay crop does exist; however, SS may not be a compatible cover crop species for organic fall cabbage production due to high amounts of re-growth.}, number={3}, journal={RENEWABLE AGRICULTURE AND FOOD SYSTEMS}, author={Finney, Denise M. and Creamer, Nancy G. and Schultheis, Jonathan R. and Wagger, Michael G. and Brownie, Cavell}, year={2009}, month={Sep}, pages={225–233} }
 @article{yencho_pecota_schultheis_vanesbroeck_holmes_little_thornton_truong_2008, title={'Covington' sweetpotato}, volume={43}, ISSN={["0018-5345"]}, DOI={10.21273/hortsci.43.6.1911}, abstractNote={‘Covington’ is an orange-fleshed, smooth-skinned, rose-colored, table-stock sweetpotato [ Ipomoea batatas (L.) Lam.] developed by North Carolina State University (NCSU). ‘Covington’, named after the late Henry M. Covington, an esteemed sweetpotato scientist at North Carolina State, was evaluated as NC98-608 in multiple state and regional yield trials during 2001 to 2006. ‘Covington’ produces yields equal to ‘Beauregard’, a dominant sweetpotato variety produced in the United States, but it is typically 5 to 10 days later in maturity. ‘Covington’ typically sizes its storage roots more evenly than ‘Beauregard’ resulting in fewer jumbo class roots and a higher percentage of number one roots. Total yields are similar for the two clones with the dry matter content of ‘Covington’ storage roots typically being 1 to 2 points higher than that of ‘Beauregard’. ‘Covington’ is resistant to fusarium wilt [ Fusarium oxysporum Schlect. f.sp. batatas (Wollenw.) Snyd. & Hans.], southern root-knot nematode [ Meloidogyne incognita (Kofoid & White 1919) Chitwood 1949 race 3], and moderately resistant to streptomyces soil rot [ Streptomyces ipomoeae (Person & W.J. Martin) Wakswan & Henrici]. Symptoms of the russet crack strain of Sweet Potato Feathery Mottle Virus have not been observed in ‘Covington’. The flavor of the baked storage roots of ‘Covington’ has been rated as very good by standardized and informal taste panels and typically scores as well or better in this regard when compared with ‘Beauregard’.}, number={6}, journal={HORTSCIENCE}, author={Yencho, G. Craig and Pecota, Kenneth V. and Schultheis, Jonathan R. and VanEsbroeck, Zvezdana-Pesic and Holmes, Gerald J. and Little, Billy E. and Thornton, Allan C. and Truong, Van-Den}, year={2008}, month={Oct}, pages={1911–1914} }
 @article{dittmar_monks_schultheis_jennings_2008, title={Effects of Postemergence and Postemergence-Directed Halosulfuron on Triploid Watermelon (Citrullus Lanatus)}, volume={22}, ISSN={0890-037X 1550-2740}, url={http://dx.doi.org/10.1614/wt-07-056.1}, DOI={10.1614/WT-07-056.1}, abstractNote={Studies were conducted in 2006 at Clinton and Kinston, NC, to determine the influence of halosulfuron POST (over the crop plant) or POST-directed (to the crop) on growth and yield of transplanted ‘Precious Petite’ and ‘Tri-X-313’ triploid watermelon. Treatments included a nontreated control, 39 g/ha halosulfuron applied POST-directed to 25% of the plant (distal or proximal region), POST-directed to 50% of the plant (distal or proximal; Precious Petite only), and POST. Watermelon treated with halosulfuron displayed chlorotic leaves, shortened internodes, and increased stem splitting. Vines were longest in the nontreated control (Tri-X-313  =  146 cm, Precious Petite  =  206 cm) but were shortest in the POST treatment (Tri-X-313  =  88 cm, Precious Petite  =  77 cm). Halosulfuron POST to watermelon caused the greatest injury (Tri-X-313  =  64%, Precious Petite  =  67%). Halosulfuron directed to 25 or 50% (distal or proximal) of the plant caused less injury than halosulfuron applied POST. Stem splitting was greatest when halosulfuron was applied to the proximal area of the stem compared with POST-directed distal or POST. Internode shortening was greatest in treatments where halosulfuron was applied to the distal region of the stem. However, Tri-X-313 in the POST-directed 25% distal treatment produced similar total and marketable fruit weight as the nontreated control at Clinton. Fruit number did not differ among treatments for either cultivar. At Kinston, Precious Petite nontreated control and POST-directed 25% distal end treatment had greater marketable fruit weight than the POST-directed 50% proximal and POST treatments. The current halosulfuron registration allows POST application between rows or PRE. Limiting halosulfuron contact to no more than 25% of the watermelon plant will likely improve crop tolerance. Nomenclature: Halosulfuron; watermelon, Citrullus lanatus (Thunb.) Matsum. & Nakai ‘Tri-X-313’ and ‘Precious Petite’}, number={3}, journal={Weed Technology}, publisher={Cambridge University Press (CUP)}, author={Dittmar, Peter J. and Monks, David W. and Schultheis, Jonathan R. and Jennings, Katherine M.}, year={2008}, month={Sep}, pages={467–471} }
 @article{treadwell_creamer_hoyt_schultheis_2008, title={Nutrient management with cover crops and compost affects development and yield in organically managed sweetpotato systems}, volume={43}, number={5}, journal={HortScience}, author={Treadwell, D. D. and Creamer, N. G. and Hoyt, G. D. and Schultheis, J. R.}, year={2008}, pages={1423–1433} }
 @article{treadwell_creamer_schultheis_hoyt_2007, title={Cover crop management affects weeds and yield in organically managed sweetpotato systems}, volume={21}, ISSN={["1550-2740"]}, DOI={10.1614/WT-07-005.1}, abstractNote={A 3-yr field experiment was initiated in 2001 to evaluate weed suppression and sweetpotato productivity in three organic sweetpotato production systems. Organic systems were (1) compost and no cover crop with tillage (Org-NC), (2) compost and a cover crop mixture of hairy vetch and rye incorporated before transplanting (Org-CI), and (3) compost and the same cover crop mixture with reduced tillage (Org-RT). A conventional system with tillage and chemical controls (Conv) was included for comparison. Suppression of monocot and dicot weed density and biomass was similar between Org-NC and Org-CI each year, and were frequently similar to Conv. Org-RT was as effective as Org-NC in controlling dicot weed density and biomass each year, but did not suppress monocot weeds. At sweetpotato harvest, an increase in cover crop surface residue biomass in Org-RT was associated with a decrease in cumulative total weed density (R2= 0.43, P = 0.0001); however, the amount of that residue was insufficient to suppress late-emerging monocot weeds. Total sweetpotato yield in Org-RT was at least 45% lower than other systems in 2002 and was most likely due to an increase in monocot weed density and biomass concurrent with a decrease in sweetpotato vine biomass. Total sweetpotato yield was similar among all systems in 2001 and 2004; the exception was lowest yields obtained in the Org-RT system in 2002. Organically managed sweetpotato with or without an incorporated cover crop produced sweetpotato yields equal to conventionally managed systems despite difficulties controlling weeds that emerged later in the season.}, number={4}, journal={WEED TECHNOLOGY}, author={Treadwell, Danielle D. and Creamer, Nancy G. and Schultheis, Jonathan R. and Hoyt, Greg D.}, year={2007}, pages={1039–1048} }
 @article{macrae_monks_batts_thorton_schultheis_2007, title={Sweetpotato tolerance to halosulfuron applied postemergence}, volume={21}, ISSN={["1550-2740"]}, DOI={10.1614/WT-060178.1}, abstractNote={Studies were conducted in 2003 and 2004 to determine the effect of application timing and halosulfuron rate on sweetpotato yield and quality. Halosulfuron was applied 1, 2, and 4 wks after transplanting (WAP) sweetpotato in 2003, and 2, 3, and 4 WAP in 2004. Treatments within each timing included halosulfuron at 13, 26, 39, 52, and 65 g ai/ha plus a weed-free control. Combined over year, site, cultivar and rate, halosulfuron applied at 1, 2, 3, and 4 WAP stunted sweetpotato 32, 15, 11, and 14%, respectively, rated 2 wks after treatment. The stunting observed with the 1 and 2 WAP timings caused a 17 and 10% reduction in yield of No. 1 roots, respectively, compared with the weed-free control. The 3 and 4 WAP timings of halosulfuron did not reduce yield of No. 1 roots. Total yield was reduced approximately 11% at the 1, 2, and 3 WAP application timings. Halosulfuron at 4 WAP did not reduce total yield. Combined over year, site, and cultivar, halosulfuron applied at 39 g/ha did not reduce the weight of No. 1 roots or total crop yield and thus could be an effective POST option for weed control in sweetpotato.}, number={4}, journal={WEED TECHNOLOGY}, author={MacRae, Andrew W. and Monks, David W. and Batts, Roger B. and Thorton, Allan C. and Schultheis, Jonathan R.}, year={2007}, pages={993–996} }
 @article{hassell_schultheis_jester_olson_maynard_miller_2007, title={Yield and quality of triploid miniwatermelon cultivars and experimental hybrids in diverse environments in the Southeastern United States}, volume={17}, DOI={10.21273/horttech.17.4.608}, abstractNote={The goal of this study was to evaluate miniwatermelon (Citrullus lanatus) cultivars/experimental hybrids (cultigens) for yield, quality, and adaptability in various growing environments. Eighteen cultigens were evaluated in field locations at southern Florida (Bradenton), northern Florida (Quincy), central South Carolina (Blackville), coastal South Carolina (Charleston), and eastern North Carolina (Kinston). Fruit at each site were harvested when watermelons in several plots were at market maturity. Fruit were categorized as marketable if they weighed between 3.0 and 9.0 lb. Fruit were categorized by size as follows: ≤3.0 lb (cull), 3.1–5.0 lb, 5.1–7.0 lb, 7.1–9.0 lb, and ≥9.1 lb (cull). Fruit were graded according to U.S. Department of Agriculture (USDA) grading standards for all watermelon fruit. We found that eight cultigens (Meilhart, Petite Perfection, Precious Petite, Little Deuce Coupe, RWT 8162, Master, Bibo, and Vanessa) were consistently among the top yielding and four cultigens (HA 5138, HA 5117, Petite Treat, and Valdoria) were consistently among the lowest yielding. These had a consistent yield response regardless of location. Within the small marketable melon category (3.1–5.0 lb), ‘Bibo’, ‘Precious Petite’, and RWT 8162 produced a uniform fruit over the five locations. Within the medium marketable melon category (5.1–7.0 lb) ‘Meilhart’, ‘Little Deuce Coupe’, HA 5109, ‘Xite’, ‘Mohican’, SR 8101, and ‘Vanessa’ produced uniform fruit size over the five locations. HA 5117, HA 5109, ‘Extazy’, ‘Mohican’, ‘Petite Treat’, and ‘Valdoria’ produced more fruit in the larger category. Those cultigens that produced melons that were consistently >9.0 lb were HA 5138, HA 5117, Bobbie, and Valdoria. The larger USDA marketable class (7.1–9.0 lb) was considered too large to be in the miniwatermelon market. We found five cultigens that provided consistently high soluble solids readings at each location: Master, RWT 8162, Betsy, Bobbie, and Bibo. We sampled only five fruit at each location for internal quality, and found dark seeds in all of the cultigens in at least one of the locations. Rind thickness and fruit shape did not appear to be influenced by test site location.}, number={4}, journal={HortTechnology}, author={Hassell, R. L. and Schultheis, J. R. and Jester, W. B. R. and Olson, S. M. and Maynard, D. N. and Miller, G. A.}, year={2007}, pages={608–617} }
 @article{stanghellini_schultheis_2005, title={Genotypic variability in staminate flower and pollen grain production of diploid watermelons}, volume={40}, number={3}, journal={HortScience}, author={Stanghellini, M. S. and Schultheis, J. R.}, year={2005}, pages={752–755} }
 @article{gusmini_schultheis_wehner_2004, title={Rind thickness of watermelon cultivars for use in pickle production}, volume={14}, number={4}, journal={HortTechnology}, author={Gusmini, G. and Schultheis, J. R. and Wehner, T. C.}, year={2004}, pages={540–545} }
 @article{gusmini_schultheis_wehner_2004, title={Some considerations on speed of weighing watermelon fruit in yield trials}, ISBN={1064-5594}, number={27}, journal={Report (Cucurbit Genetics Cooperative)}, author={Gusmini, G. and Schultheis, J. R. and Wehner, T. C.}, year={2004}, pages={49} }
 @article{stanghellini_schultheis_holmes_2003, title={Adaptation and market potential of Jack o' Lantern and miniature pumpkin cultivars in eastern North Carolina}, volume={13}, ISSN={["1063-0198"]}, DOI={10.21273/horttech.13.3.0532}, abstractNote={In 1998 and 1999, a total of 27 large-fruited and 15 miniature-fruited pumpkin (Cucurbita pepo) cultivars were evaluated for adaptation to eastern North Carolina grow- ing conditions. Test categories were yield (fruit number and weight); fruit characteristics (shape, rind and stem attributes); and susceptibility to edema (wart-like growths on fruit exterior), foliar diseases, preharvest and postharvest fruit decay, and viruses. Yields of large pumpkins ranged from over 3,200 fruit/acre (7,907 fruit/ha) for `SVT 4613367', `Autumn Gold', and `Gold Standard' to less than 1,000 fruit/acre (2,471 fruit/ha) for `Gold Rush' and `Progold 200'. For miniature pumpkins, over 33,000 fruit/acre (81,542 fruit/ha) were produced by `Touch of Autumn', `Lil' Pump- ke-mon', and `HMX 5682', whereas `Mystic' and `Progold 100' produced less than 7,000 fruit/acre (17,297 fruit/ha). `Gold Rush', `Howden', and `Progold 510' (large), and `EXT 4612297', `Lil' Goblin', and `Lil' Ironsides' (miniature) appeared the most susceptible to foliar diseases. Preharvest fruit decay ranged from 0% for `Howden' and `EXT 4612297' to over 20% for `Lil' Goblin', `Jumping Jack', `Peek-A-Boo', and `Tom Fox'. Virus incidence on fruit and foliage was low on virus-resistant cultivars ('SVT 4613367' and `EXT 4612297'), and ranged from 4% to 74% for nontransgenic cultivars. Virus incidence and/or severity on foliage and fruit were not related. `Early Autumn' (large) and `Touch of Autumn' (miniature) were the most prone to edema. `Aspen' and `Magic Lantern' (large) and `Baby Pam', `Lil' Goblin', and `Spooktacular' (miniature) were the most susceptible to postharvest fruit decay. Fruit characteristics are discussed in relation to marketability and possible consumer appeal to pumpkins.}, number={3}, journal={HORTTECHNOLOGY}, author={Stanghellini, MS and Schultheis, JR and Holmes, GJ}, year={2003}, pages={532–539} }
 @article{bryan_pesic-vanesbroeck_schultheis_pecota_swallow_yencho_2003, title={Cultivar decline in sweetpotato: I. Impact of micropropagation on yield, storage root quality, and virus incidence in 'Beauregard'}, volume={128}, number={6}, journal={Journal of the American Society for Horticultural Science}, author={Bryan, A. D. and Pesic-Vanesbroeck, Z. and Schultheis, J. R. and Pecota, K. V. and Swallow, W. H. and Yencho, G. C.}, year={2003}, pages={846–855} }
 @article{bryan_schultheis_pesic-vanesbroeck_yencho_2003, title={Cultivar decline in sweetpotato: II. Impact of virus infection on yield and storage root quality in 'Beauregard' and 'Hernandez'}, volume={128}, number={6}, journal={Journal of the American Society for Horticultural Science}, author={Bryan, A. D. and Schultheis, J. R. and Pesic-Vanesbroeck, Z. and Yencho, G. C.}, year={2003}, pages={856–863} }
 @article{neppl_wehner_schultheis_2003, title={Interaction of border and center rows of multiple row plots in watermelon yield trials}, volume={131}, ISSN={["1573-5060"]}, DOI={10.1023/A:1023958321626}, number={2}, journal={EUPHYTICA}, author={Neppl, GP and Wehner, TC and Schultheis, JR}, year={2003}, pages={225–234} }
 @article{holmes_schultheis_2003, title={Sensitivity of watermelon cultigens to ambient ozone in North Carolina}, volume={87}, ISSN={["0191-2917"]}, DOI={10.1094/PDIS.2003.87.4.428}, abstractNote={Foliar ozone (O3) injury is common on watermelon grown in eastern North Carolina. During the 2000 and 2001 growing seasons, 93 cultivars and breeding lines (i.e., cultigens) were evaluated for foliar injury caused by ambient levels of O3. One tetraploid, 42 diploid, and 50 triploid cultigens were evaluated. Injury developed on all cultigens in both years, but severity of injury varied among cultigens and between years. Visible foliar injury (percent surface area necrotic or chlorotic) was rated 1 week after the first harvest in both years. Mean injury for all cultigens was 39% in 2000 (range = 16 to 66%) and 20% in 2001 (range = 2.5 to 60%). This corresponded to greater mean seasonal O3levels (12-h [0900 to 2100 h EST] mean daily O3concentration between early May and mid-June) in 2000 (58 ppb) than in 2001 (52 ppb). Triploid cultigens were less sensitive to injury than diploid cultigens. Mean injury for all triploids was 31% in 2000 and 16% in 2001, whereas injury for diploids was 47% in 2000 and 25% in 2001. Injury level was consistently negatively correlated with average number of days between transplanting and harvest. Correlations between injury level and yield, fruit size, fruit shape, and fruit sweetness were inconsistent between years and/or insignificant. O3tolerance in watermelon cultivars should receive increased attention in watermelon breeding programs and in cultivar selection in areas of high O3pollution.}, number={4}, journal={PLANT DISEASE}, author={Holmes, GJ and Schultheis, JR}, year={2003}, month={Apr}, pages={428–434} }
 @article{stanghellini_ambrose_schultheis_2002, title={Diurnal activity, floral visitation and pollen deposition by honey bees and bumble bees on field-grown cucumber and watermelon}, volume={41}, ISSN={["2078-6913"]}, DOI={10.1080/00218839.2002.11101065}, abstractNote={SUMMARY Honey bees (Apis mellifera) and bumble bees (Bombus impatiens) were compared for three aspects of pollinating behaviour on field-grown cucumber (Cucumis sativus) and watermelon (Citrullus lanatus). We measured: (1), diurnal foraging activity periods (as related to anthesis); (2), floral visitation rates (number of flowers visited per min by individual foragers); and (3), stigmatic pollen deposition (number of pollen grains deposited on stigmas after single bee visits to female flowers). B. impatiens was more effective than A. mellifera for all three parameters on both crops. B. impatiens initiated foraging activity 15–40 min before A. mellifera; both species continued foraging until flowers closed in early afternoon. B. impatiens consistently visited more flowers per min (P < 0.001) and deposited equal or greater amounts of pollen (P < 0.001) than A. mellifera, particularly during the initial hours of floral anthesis which is when these crops are most receptive to pollination. The data additionally suggest that researchers evaluating different pollinator candidates should consider time-of-day effects when comparing pollen deposition rates between pollinators, as time-of-day had a marked influence on pollen deposition in these studies.}, number={1-2}, journal={JOURNAL OF APICULTURAL RESEARCH}, author={Stanghellini, MS and Ambrose, JT and Schultheis, JR}, year={2002}, pages={27–34} }
 @inproceedings{yencho_pecota_schultheis_sosinski_2002, title={Grower-participatory sweetpotato breeding efforts in North Carolina}, volume={583}, DOI={10.17660/actahortic.2002.583.6}, abstractNote={Sweetpotato, based on area and value, is the most important vegetable crop produced in North Carolina, and NC is the leading supplier of sweetpotatoes in the US producing ca. 218 thousand metric tons per year (ca. 35-40% of the national supply) worth an estimated $55.7 million. In 1997, we initiated a grower-participatory breeding effort to develop improved sweetpotato varieties for NC growers. This highly collaborative project involves researchers and extension specialists from NC State University, county extension agents, growers and industry representatives. Our variety development efforts are supported by the NC Sweetpotato Commission. To date, the project has been highly successful. This manuscript will describe our overall breeding efforts and it will focus on how this project has resulted in: 1) improved two-way learning between the breeding program and our clientele - growers; and 2) increased support and awareness of our conventional and genomics-based sweetpotato breeding and research efforts.}, number={583}, booktitle={Proceedings of the first international conference on sweetpotato food and health: Lima, Peru 26-29 July, 2001}, publisher={Leuven, Belgium: International Society for Horticultural Science}, author={Yencho, G. C. and Pecota, K. V. and Schultheis, J. R. and Sosinski, B. R.}, year={2002}, pages={69–76} }
 @article{stanghellini_schultheis_ambrose_2002, title={Pollen mobilization in selected cucurbitaceae and the putative effects of pollinator abundance on pollen depletion rates}, volume={127}, ISSN={["2327-9788"]}, DOI={10.21273/jashs.127.5.729}, abstractNote={Very little is known about the rate at which pollen grains are mobilized within insect-pollinated crop systems, and this is especially true the for commercial production of field-grown cucumber (Cucumis sativus L.), monoecious muskmelon (Cucumis melo L.), and triploid watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai]. The rates of pollen depletion for these crops were therefore investigated on plots simulating commercial crop production using a mixed honey bee (Apis mellifera L.) and bumble bee (Bombus impatiens Cresson) pollinator complex. At anthesis, staminate cucumber, muskmelon, and watermelon flowers contained on average 10539, 11176, and 30739 pollen grains/flower, respectively. At the time flowers closed in the early afternoon (1300 to 1400 hr), only 61% of the total pollen produced had been removed from staminate cucumber flowers, 44% to 62% from muskmelon, and 81% from watermelon flowers. The results suggest that total pollen production in these crops may not necessarily reflect total pollen availability to floral visitors (bees). However, of the total amount of pollen actually removed per flower, >57% occurred during the 2 h following flower anthesis of cucumber and muskmelon, and >77% occurred during the 2 h following flower anthesis of watermelon. Thus, most of the accessible pollen was removed shortly after anthesis, which is when these crops are most receptive to pollination. Nonviable triploid and viable diploid watermelon pollen were removed at similar rates (P = 0.4604). While correlation analyses were not possible for the influence of variable bee abundance on pollen depletion rates, higher bee populations in one year appeared to increase the rate at which pollen grains were removed from staminate flowers.}, number={5}, journal={JOURNAL OF THE AMERICAN SOCIETY FOR HORTICULTURAL SCIENCE}, author={Stanghellini, MS and Schultheis, JR and Ambrose, JT}, year={2002}, month={Sep}, pages={729–736} }
 @article{bonte_villordon_schultheis_monks_2000, title={Black polyethylene tunnel covers affect plant production and quality of sweetpotato transplants}, volume={35}, ISSN={["0018-5345"]}, DOI={10.21273/hortsci.35.2.202}, abstractNote={The influence of a black polyethylene tunnel cover (BTC) was evaluated for its effect on quantity and quality of sweetpotato [Ipomoea batatas (L.) Lam.] transplants in plant beds in Louisiana and North Carolina. Use of BTC increased production of `Beauregard' transplants from 63% to 553% in comparison with the bare ground control. `Jewel' was less responsive; BTC treatments increased transplant production by at least 48% in Louisiana over the bare ground control, but no increase was observed in North Carolina. Individual transplant weight was at least 34% less in BTC treatments than in the control. The first harvest of cuttings in BTC beds was at least 14 days prior to that in control beds. Transplant quality was assessed as yield of storage roots in repeated trials that extended throughout the normal growing season. Yield of storage roots was not affected by BTC in early season plantings, but was frequently lower for BTC treatment transplants in middle and late season plantings. We therefore do not recommend this method as a means of increasing sweetpotato plant production from bedded roots.}, number={2}, journal={HORTSCIENCE}, author={Bonte, La and Villordon, AQ and Schultheis, JR and Monks, DW}, year={2000}, month={Apr}, pages={202–204} }
 @article{galloway_monks_schultheis_2000, title={Effect of herbicides on pepper (Capsicum annuum) stand establishment and yield from transplants produced using various irrigation systems}, volume={14}, ISSN={["0890-037X"]}, DOI={10.1614/0890-037x(2000)014[0241:eohopc]2.0.co;2}, abstractNote={Abstract: Studies were conducted in 1996 and 1997 to determine the effect of irrigation systems used to produce transplants on subsequent tolerance of banana and bell pepper (Capsicum annuum) transplants to field-applied herbicides. The irrigation systems were overhead (OH), ebb and flood (EF), and float (F). At 2 and 4 wk, banana and bell pepper injury was greatest from clomazone (1.1 kg/ha) treatments. Banana and bell pepper yield were not influenced by herbicide treatment. Although crop injury was greater in 1997, there was no herbicide or irrigation system interaction with year. OH and EF irrigated banana pepper and OH irrigated bell pepper produced the greatest total yield over two harvests, whereas F irrigated pepper yielded the least. F irrigated bell pepper plants had reduced early total yield and fancy fruits relative to other irrigation treatments. F irrigated plants yielded 32 and 22% less than OH irrigated plants in banana and bell pepper, respectively. Stand counts at 3 wk after planting (WAP) show that, unlike OH and EF treatments, F treatments lost 240 to 330 plants/ha. Differences in stand among treatments were greater in 1997 than 1996. Based on our study, the OH irrigated system appears to be the best system for producing bell pepper transplants with the greatest total yield. With banana pepper, both OH and EF irrigated systems appear to produce banana pepper transplants with the greatest total yield. Also, pepper transplant tolerance to herbicides is not affected by the irrigation system used to produce transplants. Nomenclature: Clomazone, 2-[(2-chlorophenyl)methyl]-4,4-dimethyl-3-isoxazolidinone; napropamide, N,N-diethyl-2-(1-napthalenyloxy)propanamide; trifluralin, 2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine; pepper, Capsicum annuum L. Additional index words: Overhead irrigation, float irrigation, ebb and flow irrigation, bell pepper, banana pepper, herbicide tolerance. Abbreviations: DAP, days after planting; EC, emulsifiable concentrate; EF, ebb and flood; F, float; ME, microencapsulated; OH, overhead; PPI, preplant incorporated; PRE, premergence; WAP, weeks after planting.}, number={2}, journal={WEED TECHNOLOGY}, author={Galloway, BA and Monks, DW and Schultheis, JR}, year={2000}, pages={241–245} }
 @article{schultheis_walters_adams_1999, title={In-row plant spacing and date of harvest of 'Beauregard' sweetpotato affect yield and return on investment}, volume={34}, number={7}, journal={HortScience}, author={Schultheis, J. R. and Walters, S. A. and Adams, D. E.}, year={1999}, pages={1229–1233} }
 @article{sanders_cure_schultheis_1999, title={Yield response of watermelon to planting density, planting pattern, and polyethylene mulch}, volume={34}, ISSN={["2327-9834"]}, DOI={10.21273/hortsci.34.7.1221}, abstractNote={One or two plants per hill of `Prince Charles' and `Royal Jubilee' watermelon were grown with drip fertigation at five in-row spacings, with or without polyethylene mulch, in four location × year combinations (environments). Rows were 1.5 m apart and in-row spacings were 45, 60, 90, 120, and 150 cm. `Royal Jubilee' yielded more than `Prince Charles' in all environments, and the highest yields were associated with low percent culls and high fruit numbers per hectare. Highest yields of marketable fruits (≥4.5 kg/melon) were obtained using polyethylene mulch and areas per plant between 0.4 and 0.9 m2. Average weight per melon, however, was ≥9 kg only at areas per plant >0.9 to 1.0 m2. Unless there is a market for small fruits (≥4.5–9 kg), optimum area per plant was ≈1.0 m2. Results for one plant per hill at one in-row spacing were similar to those for the alternative planting pattern of two plants per hill at half the in-row spacing, thus supporting the feasibility of using the more economical alternative planting pattern.}, number={7}, journal={HORTSCIENCE}, author={Sanders, DC and Cure, JD and Schultheis, JR}, year={1999}, month={Dec}, pages={1221–1223} }
 @article{monks_schultheis_1998, title={Critical weed-free period for large crabgrass (Digitaria sanguinalis) in transplanted watermelon (Citrullus lanatus)}, volume={46}, number={5}, journal={Weed Science}, author={Monks, D. W. and Schultheis, J. R.}, year={1998}, pages={530–532} }
 @article{ferko_poore_schultheis_rogers_1998, title={Feeding potato and sweetpotato byproducts to beef cattle}, volume={93}, number={1}, journal={Veterinary Medicine}, author={Ferko, B. L. and Poore, M. H. and Schultheis, J. R. and Rogers, G. M.}, year={1998}, pages={82-} }
 @article{schultheis_wehner_walters_1998, title={Optimum planting density and harvest stage for little-leaf and normal-leaf cucumbers for once-over harvest}, volume={78}, ISSN={["0008-4220"]}, DOI={10.4141/P97-065}, abstractNote={ Optimum planting density and harvest stage were determined for once-over harvest of little-leaf and normal-leaf cucumbers. Three harvest stages (10, 25, and 50% oversize fruit) and four plant densities (37,000, 75,000, 150,000, and 300,000 plants/ha) were evaluated on little-leaf cucumber (H-19) and normal-leaf cucumber (Sumter and Regal). Plant density did not affect skin color, seedcell size, and seed size in the cultivars evaluated. However, lighter skin color, larger seedcell, and larger seed size were detected at the later harvest stages in H-19. Harvest stage did not influence fruit skin color in Regal and Sumter, but seedcell size and seed size increased quadratically with harvest stage. H-19 produced the highest yield (tonne/ha) and dollar value ($/ha) followed by Regal and Sumter. Considering fruit quality and dollar value, the 10% harvest stage at 330 000 plants ha−1 was the optimum stage and density for once-over harvest of H-19 under North Carolina growing conditions. Higher yield occurred at the later harvest stages, but poorer fruit quality (increased seed and seedcell size, and a lighter skin color) was associated with those stages. Fruit quality and dollar value of Regal was best at the 10% harvest stage at approximately 240 000 plants ha−1, while 200 000 plants ha−1 was best for Sumter. Key words: Cucumis sativus, cucumber, plant type, spacing, crop ideotype, vegetable production }, number={2}, journal={CANADIAN JOURNAL OF PLANT SCIENCE}, author={Schultheis, JR and Wehner, TC and Walters, SA}, year={1998}, month={Apr}, pages={333–340} }
 @article{stanghellini_ambrose_schultheis_1998, title={Seed production in watermelon: A comparison between two commercially available pollinators}, volume={33}, ISSN={["2327-9834"]}, DOI={10.21273/hortsci.33.1.28}, abstractNote={The number of honey bees (Apis mellifera L.) continues to decline due to parasitic mite pests and other factors. Honey bees and bumble bees (Bombus impatiens Cresson) were therefore compared for their effects on the seed set of watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] in a 2-year field experiment. The experiment was a 2 x 4 + 2 factorial, comparing bee type (honey bee or bumble bee) at four visitation levels (1, 6, 12, and 18 bee visits) to pistillate flowers, with two controls: a no-visit treatment and an open-pollinated treatment. Bee visitation level had a strong positive influence on seed set (P ≤ 0.0001). All flowers bagged to prevent insect visitation aborted, demonstrating the need for active pollen transfer between staminate and pistillate watermelon flowers. Flowers visited by B. impatiens consistently contained more seed than those visited by A. mellifera, when compared at equal bee visitation levels (P ≤ 0.0001). We conclude that bumble bees have great potential to serve as a supplemental pollinator for watermelon when honey bees available for rental are in limited supply.}, number={1}, journal={HORTSCIENCE}, author={Stanghellini, MS and Ambrose, JT and Schultheis, JR}, year={1998}, month={Feb}, pages={28–30} }
 @article{stanghellini_ambrose_schultheis_1998, title={Using commercial bumble bee colonies as backup pollinators for honey bees to produce cucumbers and watermelons}, volume={8}, DOI={10.21273/horttech.8.4.590}, abstractNote={The effectiveness of bumble bees, Bombus impatiens Cresson, and honey bees, Apis mellifera L., on the pollination of cucumber, Cucumis sativus L., and watermelon, Citrullus lanatus (Thunb.) Matsum. & Nakai, was compared under field conditions. Comparisons were based on fruit abortion rates and seed set as influenced by bee type (honey bee or bumble bee) and the number of bee visits to treatment flowers (1, 6, 12, and 18 bee visits), plus two controls: a no-visit treatment and an open-pollinated (unrestricted visitation) treatment. For both crops, an increased number of bee visits had a strong positive effect on fruit and seed set. All cucumber and watermelon flowers bagged to prevent insect visitation aborted, demonstrating the need for active transfer of pollen between staminate and pistillate flowers. Bumble bee-visited flowers consistently had lower abortion rates and higher seed sets in the cucumber and watermelon studies than did honey bee-visited flowers when compared at the same bee visitation level. Only slight differences in fruit abortion rates were detected between bee types in the watermelon study. However, abortion rates for bumble bee-visited flowers were consistently less than those for honey bee-visited flowers when compared at equal bee visitation levels, with one exception at the 12 bee visit level. As the number of honey bee colonies continues to decline due to parasitic mite pests and based on the data obtained, we conclude that bumble bees have a great potential to serve as a supplemental pollinator for cucumbers, watermelons, and possibly other vine crops, when honey bees available for rental are in limited supply.}, number={4}, journal={HortTechnology}, author={Stanghellini, M. S. and Ambrose, J. T. and Schultheis, J. R.}, year={1998}, pages={590–594} }
 @article{schultheis_walters_1998, title={Yield and virus resistance of summer squash cultivars and breeding lines in North Carolina}, volume={8}, DOI={10.21273/horttech.8.1.31}, abstractNote={Yellow and zucchini squash ( Cucurbita pepo L.) cultigens (breeding lines and cultivars) were evaluated over a 2-year (1995 and 1996) period in North Carolina. Yellow squash cultigens that performed well (based on total marketable yields) were `Destiny III', `Freedom III', `Multipik', XPHT 1815, and `Liberator III' in Fall 1995 and HMX 4716, `Superpik', PSX 391, `Monet', `Dixie', XPH 1780, and `Picasso' in Spring 1996. Some of the yellow squash cultigens evaluated had superior viral resistance: XPHT 1815, XPHT 1817, `Freedom III', `Destiny III', `Freedom II', TW 941121, `Prelude II', and `Liberator III' in Fall 1995 and XPHT 1815, `Liberator III', `Prelude II', and `Destiny III' in Fall 1996; all these cultigens were transgenic. The yellow squash cultigens that performed well (based on total marketable yields) in the Fall 1995 test had transgenic virus resistance (`Destiny III', `Freedom III', XPHT 1815, and `Liberator III') or had the Py gene present in its genetic background (`Multipik'). Based on total marketable yields, the best zucchini cultigens were XPHT 1800, `Tigress', XPHT 1814, `Dividend' (ZS 19), `Elite', and `Noblesse' in Fall 1995; and `Leonardo', `Tigress', `Hurricane', `Elite', and `Noblesse' in Spring 1996. The zucchini cultigens with virus resistance were TW 940966, XPHT 1814, and XPHT 1800 in Fall 1995 and XPHT 1800, XPHT 1776, XPHT 1777, XPHT 1814, and XPHT 1784 in Fall 1996. Even though TW 940966 had a high level of resistance in the Fall 1995 test, it was not as high yielding as some of the more susceptible lines. Viruses detected in the field were papaya ringspot virus (PRSV) and watermelon mosaic virus (WMV) for Fall 1995; while PRSV, zucchini yellow mosaic virus (ZYMV), and WMV were detected for Fall 1996. Summer squash cultigens transgenic for WMV and ZYMV have potential to improve yield, especially during the fall when viruses are more prevalent. Most transgenic cultigens do not possess resistance to PRSV, except XPHT 1815 and XPHT 1817. Papaya ringspot virus was present in the squash tests during the fall of both years. Thus, PRSV resistance must be transferred to the transgenic cultigens before summer squash can be grown during the fall season without the risk of yield loss due to viruses.}, number={1}, journal={HortTechnology}, author={Schultheis, J. R. and Walters, S. A.}, year={1998}, pages={31} }
 @article{schultheis_wehner_walters_1997, title={Mixtures of cucumber cultigens affect yield in a multiple-harvest system}, volume={32}, number={6}, journal={HortScience}, author={Schultheis, J. R. and Wehner, T. C. and Walters, S. A.}, year={1997}, pages={1024–1027} }
 @article{stanghellini_ambrose_schultheis_1997, title={The effects of honey bee and bumble bee pollination on fruit set and abortion of cucumber and watermelon}, volume={137}, number={5}, journal={American Bee Journal}, author={Stanghellini, M. S. and Ambrose, J. T. and Schultheis, J. R.}, year={1997}, pages={386–391} }
 @article{schultheis_ambrose_bambara_mangum_1994, title={SELECTIVE BEE ATTRACTANTS DID NOT IMPROVE CUCUMBER AND WATERMELON YIELD}, volume={29}, ISSN={["0018-5345"]}, DOI={10.21273/hortsci.29.3.155}, abstractNote={The effectiveness of two commercial bee attractants, Bee-Scent and Beeline, for enhancing pollination of cucumber (Cucumis sativus L.) and watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) was evaluated by counting the number of bee visitations to blossoms of cucumber and watermelon and their effect(s) on fruit quality, yield, and crop profitability. In 1989, Bee-Scent was tested in a commercial pickling cucumber field. In 1990, watermelon plots were sprayed with Bee-Scent and Beeline and compared with a nontreated control. The compounds did not improve bee visitations for either pickling cucumbers or watermelons. There was no significant improvement in cucumber or watermelon yield or monetary returns.}, number={3}, journal={HORTSCIENCE}, author={SCHULTHEIS, JR and AMBROSE, JT and BAMBARA, SB and MANGUM, WA}, year={1994}, month={Mar}, pages={155–158} }
 @article{schultheis_dufault_1994, title={WATERMELON SEEDLING GROWTH, FRUIT YIELD, AND QUALITY FOLLOWING PRETRANSPLANT NUTRITIONAL CONDITIONING}, volume={29}, ISSN={["0018-5345"]}, DOI={10.21273/hortsci.29.11.1264}, abstractNote={Pretransplant nutritional conditioning (PNC) oftransplants during greenhouse production may improve recovery from transplanting stress and enhance earliness and yield of watermelon [Citrullus lanatus (Thumb.) Matsum. & Nakai]. Two greenhouse experiments (Expts. 1 and 2) and field experiments in South Carolina and North Carolina (Expt. 3) were conducted to evaluate N and P PNC effects on watermelon seedling growth and their effects on fruit yield and quality. «Queen of Hearts» triploid and «Crimson Sweet» diploid watermelon seedlings were fertilized with N from calcium nitrate at 25, 75, or 225 mg.liter -1 and P from calcium phosphate at 5, 15, or 45 mg.liter -1}, number={11}, journal={HORTSCIENCE}, author={SCHULTHEIS, JR and DUFAULT, RJ}, year={1994}, month={Nov}, pages={1264–1268} }
 @article{schultheis_1992, title={Survey of cucumber cultivars grown in North Carolina}, number={15}, journal={Report (Cucurbit Genetics Cooperative)}, author={Schultheis, J. R.}, year={1992}, pages={9} }