bluuebunny/crossref_metadata_2025 huggingface dataset:
Exogenous Application of Abscisic Acid, Putrescine, or 2,4-Epibrassinolide at Appropriate Concentrations Effectively Alleviate Damage to Tomato Seedlings from Suboptimal Temperature Stress
Authors: Jiang Weijie , Bai Jie , Yang Xueyong , Yu Hongjun , Liu Yanpeng
Published: December 2018

The application of plant growth regulators (PGRs), such as abscisic acid (ABA), putrescine (Put), and 2,4-epibrassinolide (EBR), has been shown to enhance a plant's resistance to various abiotic stresses. However, the protective effects of these PGRs on tomato (Solanum lycopersicum) seedlings under suboptimal temperature stress have not yet been evaluated. We also do not know the most effective method of application of PGRs for various tomato cultivars. We studied the effects of three rates of exogenous ABA, Put, or EBR in limiting damage from suboptimal temperature stress on two tomato cultivars, Zhongshu6 (considered sensitive to suboptimal temperatures) and SANTIAM (considered tolerant to suboptimal temperatures). Results showed that application of these PGRs at appropriate concentrations could effectively reduce the decline in the net photosynthetic rate (Pn) and the chlorophyll (Chl) content in leaves caused by suboptimal temperature stress in both ‘Zhongshu6’ and ‘SANTIAM’ and could promote an increase in organic osmolyte (proline and soluble sugar) contents and root 2,3,5-triphenyltetrazolium chloride (TTC)-reducing activity for ‘Zhongshu6’. However, these effects were inferior on ‘SANTIAM’. For both cultivars, the best treatment concentrations are 1 mm ABA, 0.1 mm Put, or 0.02 μM EBR. Results indicate that in tomato production, exogenous application of ABA, Put, or EBR at appropriate concentrations can effectively limit damage from suboptimal temperature stress.
Irrigation Method and Fertilizer Concentration Differentially Alter Growth of Vegetable Transplants
Authors: Liu Jinrong , Roland Leatherwood W. , Mattson Neil S.
Published: December 2018

In the United States, overhead irrigation is common to apply water and dissolved nutrients to vegetable transplants during greenhouse production. Overhead irrigation allows for the control of salt accumulation in the growing medium because excess water can leach salts out of the container. Alternatively, subirrigation saves labor and improves water use efficiency, but soluble salts can accumulate in the upper profile of the containers. Consequently different sets of fertilizer and electrical conductivity (EC) guidelines are required for overhead and subirrigation systems. The objective of this project was to determine the influence of fertilizer concentration and irrigation method (subirrigation vs. overhead irrigation) on the growth of several vegetable transplant crops intended for retail sale. Seedlings of collards (Brassica oleracea var. acephala ‘Vates’), kale (B. oleracea var. acephala ‘Nagoya Mix’), lettuce (Lactuca sativa ‘Buttercrunch’), pepper (Capsicum annuum ‘Sweet Banana’), and tomato (Solanum lycopersicum ‘Sweet 100’) were transplanted into 4-inch-diameter containers and grown in a greenhouse for 4 weeks. Irrigation was provided via ebb and flow benches (subirrigation) or hand-watering (overhead irrigation). Plants received a complete fertilizer solution provided at a concentration of 50, 100, 200, 350, and 500 mg·L−1 nitrogen (N). The treatments resulting in maximum shoot dry weight (DW) for overhead irrigated plants were 100 mg·L−1 N for pepper, 200 mg· L−1 N for tomato, and 350 mg·L−1 N for collards, kale, and lettuce. Irrigation method and fertilizer treatment significantly affected fresh weight (FW) and DW for kale, lettuce, and pepper. For kale and lettuce, regression analysis indicated that maximum DW was reached at a lower fertilizer concentration with overhead irrigation than subirrigation. The treatments resulting in maximum DW for subirrigated plants were 200 mg·L−1 N for kale, lettuce, pepper, and tomato and 350 mg·L−1 N for collards. Reducing fertilizer concentration was an effective method for controlling plant height for all crops we examined except for ‘Sweet Banana’ pepper. However, in many cases height control via nutritional limitation comes at substantial expense to other growth parameters. Our results suggest that, in some cases, fertilizer concentration guidelines for overhead irrigation can be reduced when growing vegetable transplants with subirrigation due to reduced leaching of nutrients and greater potential for accumulation of fertilizer salts.
Horticultural Applications of a Newly Revised USDA Plant Hardiness Zone Map
Authors: Widrlechner Mark P. , Daly Christopher , Keller Markus , Kaplan Kim
Published: December 2018

The accurate prediction of winter injury caused by low-temperature events is a key component of the effective cultivation of woody and herbaceous perennial plants. A common method employed to visualize geographic patterns in the severity of low-temperature events is to map a climatological variable that closely correlates with plant survival. The U.S. Department of Agriculture Plant Hardiness Zone Map (PHZM) is constructed for that purpose. We present a short history of PHZM development, culminating in the recent production of a new, high-resolution version of the PHZM, and discuss how such maps relate to winterhardiness per se and to other climatic factors that affect hardiness. The new PHZM is based on extreme minimum-temperature data logged annually from 1976 to 2005 at 7983 weather stations in the United States, Puerto Rico, and adjacent regions in Canada and Mexico. The PHZM is accessible via an interactive website, which facilitates a wide range of horticultural applications. For example, we highlight how the PHZM can be used as a tool for site evaluation for vineyards in the Pacific northwestern United States and as a data layer in conjunction with moisture-balance data to predict the survival of Yugoslavian woody plants in South Dakota. In addition, the new map includes a zip code finder, and we describe how it may be used by governmental agencies for risk management and development of recommended plant lists, by horticultural firms to schedule plant shipments, and by other commercial interests that market products seasonally.
Screening of Sex in Asparagus at Early Growth Stages
Authors: Ii Yusuke , Uno Yuichi , Kanechi Michio , Inagaki Noboru
Published: December 2018

To determine the sex of asparagus (Asparagus officinalis) at the seedling stage, an easy, economical, and reliable method was developed. We used a modified single-step DNA extraction protocol, which resulted in a crude extract containing sufficient genomic DNA for use as a template. The male-specific marker (Asp1-T7sp) is a dominant marker and may lead to false negatives caused by an incomplete reaction; therefore, a multiplex polymerase chain reaction (PCR) was developed using a ribosomal RNA gene marker. The resulting banding pattern distinguished males from females without false negatives. To determine the best tissue for extraction of template DNA, phylloclades (a specialized stem that resembles and functions like a leaf) or root tips of individual asparagus plants were collected and weighed. A 4.0-mg phylloclade sample or a 0.8-mg root sample provided sufficient DNA for PCR analysis of asparagus. Root excision at day 19 did not affect subsequent growth of asparagus seedlings after 28 days. The method can determine the sex of asparagus at day 19 after seeding. A combination of single-step DNA extraction from root tips and multiplex PCR made for a simple and reliable screening method.
Quantity and Quality of Cuttings as Influenced by Stock Plant Nutrition of Herbaceous Perennials
Authors: Twardowski Christina M. , Crocker Jaime L. , Freeborn John R. , Scoggins Holly L.
Published: December 2018

Some popular garden perennials yield low numbers of viable cuttings per stock plant or produce cuttings that are slow to root, preventing propagators from meeting demand for rooted liners. We quantified the effects of a range of nitrogen (N) rates from 0 to 300 mg·L−1 N applied to stock plants on the number of cuttings (yield), rooting percentage, and subsequent root development of cuttings. Species studied include ‘Siskiyou Pink’ gaura (Gaura lindheimeri), ‘Pixie Star’ dianthus (Dianthus alpinus), perovskia (Perovskia atriplicifolia), and ‘Mainacht’ salvia (Salvia ×sylvestris). We found 100 to 150 mg·L−1 N to be the best rates for producing quality rooted cuttings. Little benefit was obtained from the higher rates, and the 0- and 50-mg·L−1 N treatments produced the lowest number of potential cuttings across all species.
Evaluation of Experimental Bermudagrasses under Simulated Athletic Field Traffic with Perennial Ryegrass Overseeding
Authors: Haselbauer William D. , Thoms Adam W. , Sorochan John C. , Brosnan James T. , Schwartz Brian M. , Hanna Wayne W.
Published: December 2018

Hybrid bermudagrass (Cynodon dactylon × C. transvaalensis) varieties such as Tifway and TifSport commonly are used on athletic fields. Several experimental hybrid bermudagrasses have been recently developed. However, data describing the performance of these bermudagrasses under simulated athletic field traffic are limited. A 2-year study was conducted evaluating the traffic tolerance of five experimental (2004-76, 2004-83, 2004-78, Tift 11, and 2004-77) and three commercially available (‘Tifway’, ‘TifSport’, and ‘TifGrand’) hybrid bermudagrasses. These bermudagrasses were subjected to two mowing (mowing at 0.87 inches or mowing at 0.87 inches + grooming to a 0.10-inch depth) and overseeding [no overseeding or overseeding with perennial ryegrass (Lolium perenne) at 12 lb/1000 ft2 of pure live seed] regimes. Simulated traffic tolerance using the Cady traffic simulator (CTS) was quantified using measurements of turfgrass cover with digital image analysis (DIA). Experimental bermudagrasses Tift 11 and 2004-76 and the commercially available variety TifGrand yielded turfgrass cover values greater than or equal to ‘Tifway’, a commonly used variety, on all rating dates each year. Experimental bermudagrass 2004-83 yielded the lowest turfgrass cover values on each date. Findings suggest that ‘TifGrand’, 2004-76, and Tift 11 may be suitable for use on athletic fields.
Effect of Brassica Cover Crops and Hazelnut Husk Mulch on Weed Control in Hazelnut Orchards
Authors: Mennan Husrev , Ngouajio Mathieu
Published: December 2018

Weed management is critical in hazelnut (Corylus avellana) production. Weeds reduce nutrient availability, interfere with tree growth, and reduce hand-harvesting efficiency. Field experiments were conducted from Fall 2006 to 2010 to test effects of brassica (Brassica sp.) cover crops and hazelnut husk mulch as alternative weed management strategies in hazelnut. The cover crop treatments consisted of rape (Brassica napus), field mustard (Brassica rapa), oriental mustard (Brassica juncea), and fallow with no cover crop. Hazelnut husk was surface-applied at two thicknesses, 5- and 10-cm-thick layer. Dry biomass production by the cover crops was relatively consistent among years with oriental mustard producing the most biomass. Throughout the growing seasons, the cover crops reduced weed density, weed dry weight, and the number of weed species when compared with the fallow treatment. The most effective cover crop at suppressing weeds was oriental mustard. Hazelnut husk applied as a 10-cm-thick layer on the ground was highly effective at controlling weeds up to 180 days after application and reduced total weed dry weight by 83% at the end of the season. Our findings indicate that brassica cover crops or hazelnut husk may help control annual weed species in hazelnut orchards during early summer. However, these strategies should be combined with other methods like chemicals or cultivation for adequate weed management.
Economic Analysis of Food Safety Compliance Costs and Foodborne Illness Outbreaks in the United States
Authors: Ribera Luis A. , Palma Marco A. , Paggi Mechel , Knutson Ronald , Masabni Joseph G. , Anciso Juan
Published: December 2018

This study investigates the potential impact of food safety outbreaks on domestic shipments, imports, and prices of the produce industry. Moreover, the compliance costs associated with new food safety standards were also estimated. Three case studies were analyzed to assess these potential impacts: the muskmelon (Cucumis melo) outbreak of Mar.–Apr. 2008, the spinach (Spinacea oleracea) outbreak of Sept. 2006, and the tomato (Solanum lycopersicum) outbreak of June–July 2008. The results demonstrate that the costs incurred by producers because of food safety outbreaks in produce are far greater than preventing such incidents.
Foliar Fertilization by Tank-mixing with Organic Amendment on Creeping Bentgrass
Authors: Gao Yang , Li Deying
Published: December 2018

Foliar application of fertilizers on turfgrass via overhead fertigation or spray can improve nutrient absorption efficiency and uniformity. Foliar fertilizers can also be combined with other chemical applications to save labor and energy. However, foliar application of nitrogen may result in root growth reduction. The objective of this study was to evaluate if a liquid organic amendment can be tank-mixed with liquid fertilizer to improve creeping bentgrass (Agrostis stolonifera) performance. This greenhouse study was conducted on ‘Penncross’ creeping bentgrass grown in sand or 90 sand:10 peat (v/v) root zones. Three fertilizer packages (4N–0P–0.8K, 29N–0.9P–2.5K, and 20N–8.8P–16.6K) with or without the organic amendment, a liquid suspension derived from naturally mined humic materials, were tested in the study. Tank-mixing organic amendment resulted in better or same turfgrass visual quality and lower clipping yield compared with foliar fertilization alone. Tank-mixing organic amendment in liquid fertilizers resulted in an average increase of root/shoot biomass ratio from 0.62 to 0.65 grown in the sand-based root zones. The effect of organic amendment was shown in all liquid fertilizers tested except 20N–8.8P–16.6K. The results showed tank-mixing organic amendment with the right liquid fertilizer can reduce mowing frequency without reducing the turf quality. Field work is needed to test if the increased root/shoot biomass ratio by tank-mixing organic amendment with liquid fertilizer can contribute to drought tolerance in creeping bentgrass maintained at fairway height in sand-based root zones.
Substrate Drenches Containing Flurprimidol Suppress Height of ‘Nellie White’ Easter Lilies
Authors: Currey Christopher J. , Lopez Roberto G. , Krug Brian A. , McCall Ingram , Whipker Brian E.
Published: December 2018

The objective of this research was to quantify how flurprimidol substrate drenches applied to ‘Nellie White’ easter lilies (Lilium longiflorum) affected height at flowering, time to flower, and flower number. In Expt. 1, size 9/10 ‘Nellie White’ easter lilies were treated with a 4-fl oz drench applied to the surface of the substrate when shoots were ≈3 inches tall providing 0.0, 0.02, 0.04, 0.08, 0.16, or 0.24 mg flurprimidol per pot or 0.03 or 0.06 mg uniconazole per pot. In Expt. 2, size 10/12 ‘Nellie White’ easter lilies were treated with 4-fl oz drenches applied to the surface of the substrate when shoots were ≈3 inches tall providing 0.0, 0.01, 0.02, 0.04, 0.06, or 0.08 mg flurprimidol per pot. In Expt. 1, plants treated with flurprimidol or uniconazole were up to 38.9 cm (59%) shorter than untreated plants, while time to flower and flower number remained unaffected by plant growth retardant (PGR) treatments. In Expt. 2, as the amount of flurprimidol increased from 0.01 to 0.08 mg/pot, plant height was suppressed linearly (r2 = 0.63), by up to 23.2 cm (28%), while time to flower and flower number remained unaffected. Additionally, the chemical cost for drenches containing flurprimidol is less than the cost of uniconazole required to achieve comparable height control. Flurprimidol substrate drenches appear to be an effective and economical alternative to control easter lily height.
Survey of Ornamental Nurseries in Florida Participating in the U.S.-Canadian Greenhouse Certification Program
Authors: Merritt Joyce L. , Dickstein Ellen , Johnson Robert S. , Ward Michael , Balaam Robert J. , Harmon Carrie L. , Harmon Philip F. , Ali G. Shad , Palmateer Aaron J. , Schubert Timothy , van Bruggen Ariena H.C.
Published: December 2018

The purpose of this study was to evaluate the U.S.-Canadian Greenhouse Certification Program (USGCP) that was initiated in 1998. A survey consisting of 34 questions was designed and 43 out of ≈48 nurseries in Florida participating in the USGCP were visited. Based on the answers to the questionnaire, most of the nurseries were in compliance with the majority of USGCP requirements, growers were satisfied with the program, and there was an economic benefit to participating in the program. The main problems identified were the ambiguous wording of some of the requirements and the impracticality of keeping imported and domestic plants completely segregated. Moreover, many of the respondents did not have a written description of a pest management plan. Chi square statistical analysis showed that there was almost no difference between nursery groups in their responses to the majority of the survey questions, indicating that the USGCP is a successful program for both large and small nurseries. This quantitative assessment of the USGCP is the first assessment conducted for this program and discussed in a peer-reviewed publication.
Cover Crops Can Improve Potato Tuber Yield and Quality
Authors: Essah Samuel Y.C. , Delgado Jorge A. , Dillon Merlin , Sparks Richard
Published: December 2018

There is the need to develop potato (Solanum tuberosum) cropping systems with higher yields and crop quality. Field studies were conducted with cover crops grown under limited irrigation (<8 inches) to assess the effects of certain types of cover crops on potato tuber yield and quality. On a commercial farm operation before the 2006 and 2007 potato season, mustard (Brassica sp.), canola (Brassica napus), and two cultivars of sorghum-sudangrass (Sorghum bicolor × S. sudanense) were planted. A wet fallow ground treatment where no cover crop was planted was used as a control. Before the 2008 season, barley (Hordeum vulgare), barley plus applied compost, sunflower (Helianthus annus), pea (Pisum sativum), and annual ryegrass (Lolium multiflorum) cover crops were added. The results of these 2006–08 studies showed that cover crops have the potential to increase potato tuber yield and quality, as measured by tuber size (larger tubers) and appearance (e.g., tubers with reduced defects such as cracks, knobs, and misshapes). In 2 of the 3 years, most of the cover crops, especially sorghum-sudangrass, increased yields and tuber quality. Positive results from sorghum-sudangrass suggest there is potential to harvest hay from cover crops and still obtain tuber benefits.
Requirement for Pollenizer in New Monoecious Hybrid Cucumber ‘NC-Sunshine’
Authors: Wehner Todd C. , Kumar Rakesh
Published: December 2018

Monoecious cucumber (Cucumis sativus) plants generally produce enough pollen for fruit set. The amount of pollen required for fruit set depends on the number of pistillate flowers produced by the cultivar. ‘NC-Sunshine’ is a new monoecious slicing hybrid cucumber with a high percentage of pistillate nodes. Because of the high percentage of pistillate nodes, a pollenizer might be required to maximize pollination to get high total and early yield. Hence, an experiment was conducted at three locations to evaluate the effect of the pollenizer ‘Poinsett 76’ on yield of ‘NC-Sunshine’ compared with no pollenizer ‘Gray Zucchini’ squash (Cucurbita pepo). Differences (P ≥ 0.05) due to pollenizer, location, and the interaction of pollenizer and location on ‘NC-Sunshine’ yield traits were detected. Pollenizer influenced cucumber yield at two of three locations. Results indicated that the pollenizer ‘Poinsett 76’ significantly increased total, marketable, and early yield of ‘NC-Sunshine’. The percentage of early and marketable yield was also higher with the pollenizer ‘Poinsett 76’. In addition, the use of a pollenizer decreased cull yield. Therefore, a pollenizer is needed for monoecious hybrids having a high percentage of pistillate nodes.
Herbicide Application Timings on Weed Control and Jack-O-Lantern Pumpkin Yield
Authors: Walters S. Alan , Young Bryan G.
Published: December 2018

A study was conducted in a no-tillage (NT) jack-o-lantern pumpkin (Cucurbita pepo) field following winter wheat (Triticum aestivum) harvest to determine the effects of using registered herbicides at various timings on weed control and pumpkin yield. All application timings used in this study were important to maximize weed control over the pumpkin growing season. For an initial stale seedbed burndown treatment, paraquat provided better broadleaf weed control than glyphosate, which lead to greater pumpkin yields. The use of s-metolachlor + halosulfuron-methyl preemergence (PRE) and clethodim postemergence (POST) gave the best results for the second series of herbicide applications which related to higher pumpkin yields compared with none or only a PRE application. The last application timing (midseason POST-directed paraquat application between rows) also improved weed control and provided higher pumpkin yields compared with no treatment. Growers who use a stale seedbed burndown treatment in NT pumpkin production, before seedling emergence or transplanting, will generally use glyphosate although this study indicated that paraquat may prove to be a better choice depending on the weed species that are present at this application timing. Most weed control in NT pumpkin production is achieved by a PRE application of various tank-mixed herbicides for both grass and broadleaf weed control, with a POST grass herbicide, a POST application of halosulfuron-methyl, or both [for control of nutsedge (Cyperus sp.), specific broadleaf weed species, or both] applied 3 to 4 weeks later, and this study indicated that the use of labeled PRE and POST herbicides are essential to optimize weed control and pumpkin yields in NT. Most pumpkin growers do not use a POST-directed application of a nonselective herbicide (such as paraquat) before vines cover the soil surface although it appears that this application may be warranted to control weeds that have emerged later in the growing season to maximize pumpkin yield, especially if POST midseason over-the-top herbicide applications are not used. This study indicated that in addition to applying the limited PRE and POST herbicides available for weed control in pumpkin, the use of other chemical weed management practices (e.g., stale seedbed herbicide treatments or POST-directed nonselective herbicide applications) can provide valuable weed control in NT production systems and should be considered by growers to maximize pumpkin yield.
Strategies for Weed Suppression and Improving Soil Fertility during Transition to Organic Vegetable Production
Authors: Wedryk Stephanie , Felix Joel , Doohan Doug , Cardina John
Published: December 2018

Farmers view weed management and the risk of lower yields as barriers to transition from conventional to organic agriculture. The 3 years of transition before organic certification can be used to implement strategies to suppress weeds and improve soil fertility. The objective of this research was to evaluate the effects of five organic transition strategies on soil quality, weed suppression, and yield of tomato (Solanum lycopersicum) and potato (Solanum tuberosum) in the first year of organic production. The transition strategies included a tilled fallow, nontreated weedy, high diversity prairie mixture, smother crops, and vegetable rotation. Subplots with and without compost application were also included. Transition strategies affected weed density and biomass in the first organic year with the prairie strategy being the most suppressive of monocotyledonous weeds before potato. Compost application increased plant available nutrients and soil organic matter (OM). The quantity of plant available phosphorus was greatest in the fallow transition strategy (55 mg·kg−1) when compost was applied, while percent soil OM was highest in the prairie (3.2%) and nontreated (3.1%) strategies in comparison with the other strategies. Compost application increased yields of potato and tomato with transition strategy affecting the number and weight of cull potato tubers. The selection of transition strategies before conversion to organic agriculture affected weed pressure, soil quality, and crop production in the first certified organic year.
Reducing Sprinkler Irrigation Volumes for Strawberry Transplant Establishment in Florida
Authors: Santos Bielinski M. , Salame-Donoso Teresa P. , Whidden Alicia J.
Published: December 2018

Two field studies were conducted to determine whether foliar kaolin clay applications would reduce water volumes during the establishment of bare-root strawberry (Fragaria ×ananassa) transplants. Transplant establishment treatments resulted from combinations of duration of sprinkler irrigation and foliar application of kaolin clay were: a) 4 days of sprinkler irrigation, b) 4 days of sprinkler irrigation plus kaolin clay on day 5, c) 6 days of sprinkler irrigation, d) 6 days of sprinkler irrigation plus kaolin clay on day 7, e) 8 days of sprinkler irrigation, f) 8 days of sprinkler irrigation plus kaolin clay on day 9, and g) 10 days of sprinkler irrigation (control). One day of sprinkler irrigation was defined as the application of 8 hours per day of irrigation to ensure plant establishment, using ≈6000 gal/acre per hour of water. Kaolin clay treatments were applied using a rate of 25 lb/acre and on the early morning of the following day after sprinkler irrigation was suspended. Treatments influenced the number of established plants and diameter at 4 and 8 weeks after transplanting (WAT), leaf greenness at 8 WAT, and early and total fruit weight. There were no differences in the number of established plants among treatments that received 10 days of sprinkler irrigation (control), 8 days of sprinkler irrigation followed by kaolin clay on day 9, and 6 days of sprinkler irrigation followed by kaolin clay on day 7, ranged between 97% and 98% plant survival. The highest strawberry early and total fruit weights (3.6 and 15.7 tons/acre, respectively) occurred in plots transplanted with either 6 days of sprinkler irrigation plus kaolin clay on day 7, 8 days of sprinkler irrigation plus kaolin clay on day 9, or 10 days of sprinkler irrigation. These data indicated that the addition to kaolin clay after 6 or 8 days of sprinkler irrigation improved strawberry establishment, growth, and yields to the same levels as the control treatment, while saving at least 20% of the water volume needed for establishment.
Active and Passive Zonal Heating Creates Distinct Microclimates and Influences Spring- and Fall-time Lettuce Growth in Ohio
Authors: Bumgarner Natalie R. , Bennett Mark A. , Ling Peter P. , Mullen Robert W. , Kleinhenz Matthew D.
Published: December 2018

Low and high tunnels and root-zone heating systems are proven tools in horticultural production. However, impacts of their individual and combined application on crop yield, composition, and microclimates are under-reported. We set out to enhance the record of management strategy effects on abiotic environmental conditions and cropping variables in open field and high-tunnel settings. In each setting, raised bed plots were subsurface heated (underlain by electric heating cables), aerial covered (0.8-mil, clear, vented, low tunnels), subsurface heated and aerial covered, or unheated and uncovered (control). The study was repeated four times in spring and fall seasons across 3 years in Wooster, OH. Red-leaved romaine lettuce (Lactuca sativa ‘Outredgeous’ and ‘Flagship’) was direct seeded in all plots in early October and late March and harvested after ≈4 weeks. Subsurface and aerial temperatures were monitored throughout the experiments. Here, we report primarily on treatment effects on crop microclimate conditions, including temperature and light, and related cropping variables. Subsurface and aerial temperatures varied consistently with plot microenvironment management. Relative to control plots, variability in shoot- and root-zone temperatures generally increased and decreased, respectively, with the addition of low tunnels and electric heating cables, regardless of setting. Still, the relative influence of aerial and soil temperature on crop biomass appeared to differ by setting; aerial temperature correlated most strongly with yield in the high tunnel, while the combination of aerial and root-zone temperature correlated most strongly with yield in the field. Growing degree day accumulation was least in control plots. And, the highest thermal energy to plant biomass conversion efficiency was recorded in the high tunnel. Comparing study-wide and historical climatic data collected in Wooster and other locations in the region suggests that results reported here may hold over a larger area and longer time frame in Wooster, OH.
Economic Analysis of Investing in Open-field or High Tunnel Primocane-fruiting Blackberry Production in Northwestern Arkansas
Authors: Rodríguez Héctor Germán , Popp Jennie , Thomsen Michael , Friedrich Heather , Rom Curt R.
Published: December 2018

Extending the production season of blackberry (Rubus subgenus Rubus) cultivars allows producers the opportunity to potentially receive better prices. Producers could benefit from out-of-season production by sustaining cash flow during more of the year and thereby expanding their market. The objective of this study was to compare the present value (PV) probabilities of being able to cover the total cost (TC) of production (break-even) for open-field and high tunnel production systems for the primocane-fruiting blackberry cultivar Prime-Jan® in northwestern Arkansas. (PVs) of gross revenues (GRs) of each production system were simulated 500 times. Total yields were higher in the open-field system in the first 2 years of production and consistently higher in weeks 33 to 34 and 36 to 37 than high tunnel production. It seems that there are no yield benefits from the high tunnel system early in the harvest season, except in the first year of primocane-fruiting production. The break-even probability was sensitive to the different percentage of yield sold, the percentage of the retail price received by the producer, and the production system analyzed. Even though the potential gross returns obtained with the high tunnel system are high (when compared with open-field production), the PV distributions of the gross returns do not offset the high tunnel TC in half of the simulations. Conversely, open-field production proves to be more profitable both in magnitude and in terms of the likelihood of exceeding the break-even threshold over the productive life of the enterprise.
Cost Benefit Analysis of Using Grafted Transplants for Root-knot Nematode Management in Organic Heirloom Tomato Production
Authors: Barrett Charles E. , Zhao Xin , Hodges Alan W.
Published: December 2018

Growers are looking for sustainable alternatives to methyl bromide as a soil fumigant that are effective and economical. Increased demand for organically produced fruits and vegetables has also contributed to the need for environmentally friendly soil-borne disease control methods. Grafting may be a valuable tool for vegetable growers to cope with pest management challenges in production of cucurbits and solanaceous crops; however, there are concerns regarding the higher costs associated with the use of grafted plants in the United States. The main objective of this 2-year study was to determine if grafting with a resistant rootstock could be cost-effective to overcome root-knot nematodes (RKN) (Meloidogyne sp.) and maintain fruit yield in organic heirloom tomato (Solanum lycopersicum) production in Florida's sandy soils. The heirloom tomato cultivar Brandywine was grafted onto the rootstock ‘Multifort’. Nongrafted and grafted ‘Brandywine’ plants were grown organically in two fields that exhibited different levels of RKN infestations. Grafted and nongrafted transplants were estimated to cost $0.78 and $0.17 per plant, respectively. The cost of rootstock seeds accounted for 36% ($0.28/plant) of the total cost of the grafted transplants and 46% of the cost difference between grafted and nongrafted plants. Sensitivity analyses were conducted using these estimated transplant production costs and crop yield data from the field trials as well as price information for heirloom tomato. Results showed that under severe RKN pressure, grafting may be an economically feasible pest control measure to help maintain a profitable production given that the risk of economic crop losses due to RKN outweighed the higher cost of grafted transplants.
Gardening Increases Vegetable Consumption in School-aged Children: A Meta-analytical Synthesis
Authors: Langellotto Gail A. , Gupta Abha
Published: December 2018

Although a handful of published reports suggest that garden-based nutrition education programs are effective in increasing fruit and vegetable consumption, many of these studies have low statistical power because of small sample sizes and lack of long-term data. In this study, we used meta-analytical techniques to examine the efficacy of garden-based nutrition education programs for increasing children’s nutrition knowledge, preference for fruit and vegetables, and/or consumption of fruit and vegetables. We confined our analysis to peer-reviewed studies that examined programs that were delivered to children in the United States. We looked at the relative impacts of garden-based nutrition education programs, compared with experimental controls (i.e., no nutrition education) and nutrition education programs without a gardening component. We compared the results of our meta-analysis with those of a vote counting analysis to illustrate the importance of repeated studies and quantitative analysis. In our vote counting analysis, the majority of the outcomes were nonsignificant in the control and nutrition education groups, but positive and significant for the gardening group. Our quantitative analysis of the impacts of gardening education programs on children’s nutrition knowledge, preference for fruit and vegetables, and/or consumption of fruit and vegetables was limited by the small number of studies that reported the full suite of descriptive statistics needed to conduct a meta-analysis. Nonetheless, one striking and robust result emerged: gardening increased vegetable consumption in children, whereas the impacts of nutrition education programs were marginal or nonsignificant. We suggest two nonmutually exclusive hypotheses to explain our results: gardening increases access to vegetables and gardening decreases children’s reluctance to try new foods. Our results suggest that gardening should be an integral component of wellness programs and policies. A historical lack of funding has impeded both the broader adoption of school gardens and rigorous research on the social, behavioral, and academic impacts of gardening on children. Recently, however, there has been an increase in federal support for gardening and garden-based research projects—a trend that we hope will continue and grow.
Master Gardener Perceptions and Preferences of a Novel Horticultural Product—Do-It-Yourself Living Structures Kits
Authors: Pagliughi Erica , Kuzovkina Yulia A. , Ricard Robert M.
Published: December 2018

An online survey was developed to investigate Master Gardener perceptions of and preferences for a novel horticultural product, “Do-It-Yourself (DIY) Living Structures Kits,” which include live willow (Salix sp.) stems, instructions on how to build various forms, ties, and cultural guidelines. The survey consisted of 37 items to assess the interest level in this product, to examine the likelihood of consumers’ interest in purchasing this product, and to evaluate preferred designs and potential price points. A total of 249 Connecticut Master Gardeners completed the survey. The respondents provided valuable insights on product popularity and potential. The majority of them were between the ages of 56 and 65 years, female, Caucasian, married, without children in the household, and own a house with a yard in suburban areas. Most of the respondents represented plant purchasers and experienced gardeners. The two most popular structures were the decorative fence and the arbor, and Master Gardeners indicated specific preferred price ranges for the products. Aesthetic appeal was perceived as the main attractive aspect of the product. Among the major factors affecting their decision to purchase DIY Living Structures Kits, most respondents indicated design/type and price as “very important.” Forty-four percent of people were interested in buying one of these kits as a gift for someone. Results revealed that there is potential for a niche market as this group of consumers was enthusiastic about the new product: 74.1% of Master Gardeners responded positively that DIY Living Structures Kits have potential to become new horticultural products. More in-depth product evaluation studies using trial kits and marketing research targeting additional segments of consumers should be conducted in future.
Influence of High Tunnel Production and Planting Date on Yield, Growth, and Early Blight Development on Organically Grown Heirloom and Hybrid Tomato
Authors: Rogers Mary A. , Wszelaki Annette L.
Published: December 2018

High tunnels are rapidly gaining favor from growers in many regions of the United States because these structures extend the growing season and increase quality of high-value horticultural crops. Small to midsized organic growers who sell tomatoes (Solanum lycopersicum) for the fresh market can benefit from lower disease pressure and higher marketable yields that can be achieved in high tunnels. High tunnels also protect crops from environmental damage and benefit production of heirloom tomatoes as these varieties often have softer fruit and are more susceptible to diseases and cracking and splitting than hybrid varieties. The objective of this study was to determine the impacts of high tunnel production and planting date on heirloom and hybrid tomato varieties by observing differences in plant growth, yield, marketability, and early blight (Alternaria solani) development within an organic production system. This study showed no increase in total yields in high tunnels as compared with the open field, but increased marketability and size of tomatoes, and lowered incidence of defoliation resulting from early blight. Tomato planted earlier in both high tunnels and the open field yielded more marketable fruit during the production season than plants established on later planting dates. Hybrid varieties yielded more marketable fruit than heirloom varieties; however, heirloom tomatoes can have equivalent market value because of greater consumer demand and premium prices attained in the local market.
Fungicide Efficacy in Prevention of Root Rot Incited by Phytophthora cactorum and Phytophthora drechsleri in Fraser Fir Seedlings
Authors: Hoover Benjamin K. , Bates R.M.
Published: December 2018

The most serious disease problem in fraser fir (Abies fraseri) Christmas tree production is phytophthora root rot (PRR). The efficacies of six fungicide treatments in preventing PRR incited by Phytophthora cactorum and P. drechsleri in 2-year-old fraser fir seedlings were evaluated in 2010 and 2011 in central Pennsylvania. The study examined five fungicide drench treatments [dimethomorph, fosetyl-aluminum (fosetyl-Al), hydrogen dioxide, mefenoxam, propamocarb hydrochloride] and one soil spray treatment (mefenoxam) in raised planting boxes. Dimethomorph applied on 14-day intervals prevented foliar disease symptoms and mortality in fraser fir seedlings exposed to either P. cactorum or P. drechsleri. One-time application of fosetyl-Al or mefenoxam were effective at times in preventing foliar disease symptoms and mortality in fraser fir seedlings exposed to P. drechsleri but were not as effective against P. cactorum.
Trinexapac-ethyl Effects on Stolon Activity and Node Vitality of ‘Tifway’ Hybrid Bermudagrass
Authors: Volterrani Marco , Magni Simone , Gaetani Monica , Lulli Filippo
Published: December 2018

The stoloniferous-rhizomatous growth habit of bermudagrass [Cynodon dactylon (L.) Pers.] is a key feature for fast turf establishment and effective recovery from wear and divots. Trinexapac-ethyl (TE) is a plant growth regulator used extensively to reduce the need for mowing. However, vertical growth suppression of vertical growth has the potential to reduce horizontal growth. Furthermore, side effects reported on several physiological functions could affect node ability to generate new plants. In a greenhouse trial, ‘Tifway’ hybrid bermudagrass (C. dactylon × C. transvaalensis Burtt Davy) grown in pots was treated with increasing rates of TE (untreated control, 0.015, 0.075, 0.150, and 0.300 g·m−2). The treatment effects on the number of stolons produced and their linear growth rate, node production, node vitality, and daughter plant characteristics were investigated. The effects of growth inhibition because of TE application on nodes and daughter plants and the relative duration were also assessed. Starting from 2 weeks after treatment (2 WAT), TE application resulted in reductions of stolon length of 24.6% and 52.9% compared with the untreated control, while at 3 and 4 WAT only 0.150 and 0.300 g·m−2 application rates produced significant reductions in stolon length with values of 37.1% and 52.9% at 3 WAT and of 34.1% and 48.3% at 4 WAT, respectively. The number of nodes per stolon was unaffected by treatments. No effect was observed in node vitality but daughter plants showed a postinhibition growth enhancement when nodes were excised at 4 WAT. TE application at the labeled rate did not affect the number of stolons produced by ‘Tifway’ hybrid bermudagrass compared with untreated control, while a reduction in stolon growth rate was recorded only at 2 WAT. Application at higher rates reduced stolon growth rate longer than labeled rate but not stolon production. None of the treatments reduced the number of vital nodes. Application rates higher than labeled rate produced a postinhibition growth enhancement in plants that originated from nodes excised at 4 WAT.
Transitional Effects of Double-lateral Drip Irrigation and Straw Mulch on Irrigation Water Consumption, Mineral Nutrition, Yield, and Storability of Sweet Cherry
Authors: Yin Xinhua , Long Lynn E. , Huang Xiao-Lan , Jaja Ngowari , Bai Jinhe , Seavert Clark F. , le Roux Jac
Published: December 2018

A field trial was conducted on a Cherryhill silt loam soil at The Dalles, OR, from 2006 to 2008. The impacts of switching from the traditional micro sprinkler irrigation (MS) to double-lateral drip irrigation (DD) and from no groundcover with herbicide control of weeds (NC) to in-row wheat (Triticum aestivum) straw mulching (ST) were evaluated in a split-plot design with four replicates. Irrigation water use, mineral nutrition, and productivity of ‘Lapins’ sweet cherry (Prunus avium) on ‘Mazzard’ rootstock (P. avium) and soil quality were measured on a plot basis. DD reduced irrigation water consumption by 47.6% to 58.2% compared with MS. Straw mulch lowered irrigation water use by 9.7% relative to NC. Total fruit yield and fruit quality of firmness, size, and sugar at harvest were similar for the irrigation treatments. Straw mulch increased fruit size by 0.6 mm on average relative to NC, which could result in increased grower profitability. The DD system enhanced percentage of marketable fruit by 8.6% relative to MS. Leaf phosphorus (P), boron (B), zinc (Zn), and iron (Fe) concentrations were reduced with DD over MS; consequently, more P, B, Zn, and Fe fertilizers might be needed under DD. Straw mulch markedly decreased the populations of flagellates and amoebae but slightly increased the population of ciliates. Straw mulch resulted in a soil microbial community with remarkably less protozoa. Overall, DD is a viable alternate irrigation system for producing sweet cherry orchards with limited water resources for irrigation. Switching from NC to ST could lower irrigation water use, reduce herbicide runoff, and protect soil from erosion.
Comparison of Pallet Cover Systems to Maintain Strawberry Fruit Quality During Transport
Authors: Macnish Andrew J. , Padda Malkeet S. , Pupin Francine , Tsouvaltzis Pavlos I. , Deltsidis Angelos I. , Sims Charles A. , Brecht Jeffrey K. , Mitcham Elizabeth J.
Published: December 2018

The efficacy of several proprietary plastic pallet cover systems to maintain strawberry (Fragaria ×ananassa) fruit quality during commercial shipment was determined. ‘Albion’ fruit were harvested from farms near Watsonville, CA. Fruit in vented plastic clamshells were palletized and forced-air cooled to 33–35 °F. Different cover systems (CO2 West, PEAKfresh, PrimePro, Tectrol) were placed over the pallets. Pads that released carbon dioxide (CO2) gas were placed inside the CO2 West cover. The Tectrol cover was sealed to the pallet base, a partial vacuum was applied, and pressurized CO2 gas was injected inside. The systems other than Tectrol remained open at the base. Six separate shipments of palletized fruit were transported in refrigerated (32–39 °F) truck trailers to distribution centers in either Florida or Georgia in 2.3–4.7 days. CO2 concentrations within pallets at the beginning and end of transport were highest (11% to 16%) in the sealed Tectrol system and relatively low (0.06% to 0.30%) in the open CO2 West, PEAKfresh, and PrimePro cover systems. Relative to noncovered control fruit, which lost 0.8% fresh weight during shipment, the pallet covers reduced the transport-related weight loss by 38% to 52%. The incidence of fruit decay was low (1.0% to 1.4%) after transport but increased substantially following a 2-day shelf life at 68 °F. However, fruit from the Tectrol pallets exhibited significantly less decay (36%) after shelf life than the CO2 West (39%), noncovered control (41%), PrimePro (42%), and PEAKfresh (43%) pallets. Fruit sensory quality was unaffected by the different pallet cover systems. Our findings show that transporting strawberries in the sealed Tectrol pallet cover system, in which CO2 concentrations were elevated to 11% to 16%, was most effective in complementing current low temperature management practices to maintain fruit quality.
Mechanical Canopy Management Reduces Labor Costs and Maintains Fruit Composition in ‘Cabernet Sauvignon’ Grape Production
Authors: Kurtural S. Kaan , Dervishian Geoffrey , Wample Robert L.
Published: December 2018

Three canopy management methods, hand pruning (HP), mechanical prepruning with hand shoot thinning (MP+HT), and mechanical box-pruning with mechanical shoot thinning (MP+MT), were applied with the objective of achieving similar and commercially marketable ‘Cabernet sauvignon’ grape (Vitis vinifera) yields while maintaining vine balance and comparing labor operations costs. Canopy management system labor operation cost estimates indicated a 62% and 80% labor savings with the MP+HT and MP+MT treatments, respectively when compared with HP. The total shoot density of the vines was unaffected by the treatments applied. However, the contribution of count shoots increased with the concomitant addition of mechanization to canopy management. All treatments achieved similar canopy architecture and microclimate. The treatments did not affect photosynthetically active radiation (PAR) intercepted in the fruiting zone of canopy at veraison. All treatments had similar yield, total soluble solids (TSS), juice pH, and titratable acidity (TA) at harvest. Berry skin total phenolics, anthocyanins, and tannins when measured at harvest were also similar among the treatments applied. All treatments tested were within acceptable Ravaz index limits of 5 to 10 lb/lb. However, only MP+MT treatment reached a near optimum leaf area to fruit ratio of 1.2 m2·kg−1 and pruning weight of 1.0 kg·m−1 for warm climate viticulture. The results of this study provide commercially acceptable mechanical canopy management options that may provide labor cost savings for winegrape growers in the San Joaquin Valley (SJV) of California.