bluuebunny/crossref_metadata_2025 huggingface dataset:
Ornamental Grower Perceptions of Wireless Irrigation Sensor Networks: Results from a National Survey
Authors: Majsztrik John , Lichtenberg Erik , Saavoss Monica
Published: December 2018

Irrigation management systems that use wireless transmission of substrate moisture data are beginning to become commercially available for ornamental growers, particularly for use in soilless substrates. These systems allow growers to precisely monitor and control irrigation in real time and are being shown to save time and other resources. On-farm evaluations indicate that these systems have potential benefits extending beyond reductions in water use and associated irrigation inputs: Some growing systems experience increases in plant growth rates, with corresponding reductions in production time, whereas some experience reductions in disease pressure and corresponding plant losses. We asked ornamental growers across the nation what they see as potential benefits and limitations of these systems as a means of assessing the likely state of acceptance of this technology at the time of its initial introduction. Grower perceptions were overwhelmingly positive, with the majority of respondents agreeing that wireless sensor systems can increase irrigation efficiency, improve product quality, reduce product losses, reduce irrigation management costs, reduce disease prevalence, increase ability to manage growth, reduce irrigation management costs, and reduce monitoring costs. System cost and reliability were major concerns. Grower perceptions of the benefits and drawbacks of irrigation sensor networks varied across size and type of operation as well as geographically and by the type of water source used. Making wireless sensor systems affordable and robust will likely be critical determinants of the speed and reach of adoption of these technologies.
IPM In-Depth: A New York Model for Hands-on Interactive Greenhouse Workshops
Authors: Mattson Neil S. , Lamb Elizabeth M. , Eshenaur Brian , Sanderson John
Published: December 2018

Growers of greenhouse ornamentals in New York State (NYS) have identified the need for improved diagnosis and management of diseases, insects, and media/fertility problems to reduce crop loss and improve crop quality. With the objective of using an interactive small-group format to encourage active learning of topics, our team developed a hands-on workshop model that we termed integrated pest management (IPM) In-depth. In addition, we wanted to deliver the workshop in several locations around NYS to reach growers who traditionally have not attended on-campus programs. Each program consisted of three modules focusing on an insect, disease, or plant culture topic. Participants were divided into small groups that rotated through the areas. From 2009 to 2013, we present 20 In-depth workshops in 14 NYS counties reaching 309 attendees. The project succeeded in its intent to reach growers who had limited access to previous IPM programming; 59% of attendees had not previously attended any type of IPM programming. The majority of attendees (66%) reported that they had learned information they intended to implement at their operations. Additional impacts and challenges of offering this hands-on program are discussed.
The Science Behind Biodynamic Preparations: A Literature Review
Authors: Chalker-Scott Linda
Published: December 2018

Biodynamics is a form of organic agriculture first described in the 1920s by Rudolph Steiner, and practitioners can become certified biodynamic farmers by following specified practices. What distinguishes biodynamic from organic certification is the required use of nine preparations thought to improve soils and increase crop yields. This literature review focuses on the published, peer-reviewed science behind the use of biodynamic preparations, with the goal of providing objective information to extension educators, including Master Gardeners.
Survey of How Hanging Baskets Influence the Light Environment at Lower Crop Level in Ornamental Greenhouses in Ontario, Canada
Authors: Llewellyn David , Zheng Youbin , Dixon Mike
Published: December 2018

Hanging basket (HB) production alters the light environment in the lower canopy of ornamental greenhouses by intercepting and altering the spectral quality of incoming light. If shading is sufficiently high, the quality of the lower crops can be reduced. This work investigated changes in light quantity and quality at the lower crop level caused by HB production in Ontario, Canada. Light sampling occurred at three commercial greenhouse facilities throughout the Spring 2012 HB season. The greenhouses represented a range of HB densities (1.8, 2.4, and 3.0 baskets/m2) and different HB canopy architectures (one, two, and three tiers of HBs). Light samples were taken at three fixed locations within each greenhouse facility: outside, HB level, and lower crop level. Photosynthetically active radiation (PAR) was logged continuously at each location within each greenhouse environment. Spectral scans were made at each sampling location, within each greenhouse facility, at various times throughout the season to assess how HB production altered the red to far red ratio (R:FR) at lower crop level. As the season progressed, outdoor daily light integrals (DLIs) more than doubled from <20 to >40 mol·m−2·d−1. Light reduction caused by polyethylene films and structural components varied among locations, but remained steady throughout the season, averaging 48.3% for the three locations. As the HB crops matured, the rate of decrease in PAR at lower crop level varied according to facility and HB density with mean reductions of 42.5%, 32.6%, and 37.7% for the one-, two-, and three-tiered facilities, respectively. Mean lower crop level DLIs were all very similar, between 9.4 and 9.9 mol·m−2·d−1. Accordingly, there may be insufficient light below HB canopies to produce high-quality crops of many varieties of bedding plants that are commonly grown in Ontario. The one- and two-tiered systems reduced the R:FR at lower crop level by 14% and 10%, respectively, whereas the three-tiered system caused no reduction. More work is required to determine if the observed far red shift is sufficient to alter crop quality. These case studies provide a backdrop against which to help determine and interpret horticultural management strategies for a variety of greenhouse crops.
Hiring Preferences of Nurseries and Greenhouses in U.S. Southern States
Authors: Posadas Benedict C. , Knight Patricia R. , Coker Christine E.H. , Coker Randal Y. , Langlois Scott A.
Published: December 2018

This work describes workers’ socioeconomic characteristics and evaluates the determinants of workers hiring decisions among 215 randomly selected wholesale nurseries and greenhouses located in eight selected southern states in the United States. The participating nurseries and greenhouses employed on average 5.40 permanent workers per horticulture operation or 2.27 permanent workers per acre under cultivation. Participating nurseries and greenhouses hired an average 2.38 part-time workers per horticulture operation or 0.80 part-time workers per acre placed under production. Empirical models were estimated to determine the significant factors affecting hiring decisions by this industry. Hiring decision models covered age groups, racial backgrounds, formal education levels, and gender. Analysis of the decision-making process involving the employment of hired workers among the participating wholesale nurseries and greenhouses provided insights into the hiring decisions in the industry. The hiring decisions by demographic characteristics serve as benchmarks for assessing impacts of regulations affecting the industry in the near future. About 1.9% of all the establishments employed more than 50 permanent and part-time workers and 1.4% employed more than 50 permanent workers.
Optimizing Sweetpotato Production for Fresh and Processing Markets through Plant Spacing and Planting-harvest Time
Authors: Arancibia Ramón A. , Smith Cody D. , LaBonte Don R. , Main Jeffrey L. , Smith Tara P. , Villordon Arthur Q.
Published: December 2018

Consumption of sweetpotato (Ipomoea batatas) has increased in the past decade in part because of its nutritional and health attributes, and because of the availability and convenience of processed products. The sweetpotato processing industry is expanding and supplying more sweetpotato products than ever before. Unlike the medium-sized roots (U.S. no.1) preferred for fresh market, large (jumbo) roots is accepted and in certain cases desired by the processing industry, and overall yield is preferred over strict sizing requirements and aesthetic appeal. Therefore, this study investigated the yield increase and grade proportions in response to plant spacing and extension of the growing period to improve profitability of the production system. Experiments with ‘Beauregard’ and ‘Evangeline’ sweetpotato were conducted in Mississippi and Louisiana during 2010 and 2011. Treatments consisted of a combination of early and late planting date and delay in harvest, in-row plant spacing, and row width. Yield increase was inconsistent with delaying harvest and appears to depend on environmental conditions at harvest late in the season. Marketable yield was consistently greater in early plantings than late plantings. Yield of U.S. no.1 grade was unaffected by delaying harvest regardless of planting date. Delaying harvest in early plantings contributed to increase jumbo-sized roots and marketable yield. The economic assessment of delaying harvest in early plantings indicated a gain in net benefit either when hand harvested for fresh market or field run bulk harvested for processing. Row width and in-row plant spacing had only a marginal effect on yield of canner grade (small-sized roots). The economic assessment of changing plant density indicated no gain in net benefit, which indicates that choice of plant density can depend on other factors.
Weed Control in Yellow Squash Using Sequential Postdirected Applications of Pelargonic Acid
Authors: Webber Charles L. , Taylor Merritt J. , Shrefler James W.
Published: December 2018

Squash (Cucurbita pepo) producers could benefit from additional herbicide options that are safe to the crop and provide effective weed control. Research was conducted in southeastern Oklahoma (Atoka County, Lane, OK) during 2010 and 2011 to determine the impact of pelargonic acid (PA) on weed control efficacy, crop injury, and squash yields. The experiment included PA applied unshielded postdirected at 5, 10, and 15 lb/acre, plus an untreated weedy control and an untreated weed-free control. ‘Enterprise’ yellow squash was direct-seeded in single rows into raised beds. Weeds included smooth crabgrass (Digitaria ischaemum), cutleaf groundcherry (Physalis angulata), spiny amaranth (Amaranthus spinosus), and yellow nutsedge (Cyperus esculentus). Pelargonic acid was applied each year in mid-July and then reapplied 8 days later. The maximum smooth crabgrass control (98%), broadleaf weed control (94%), and yellow nutsedge control (41%) was observed with the 15-lb/acre PA treatment at 9 days after initial spray treatment (DAIT), 1 day after sequential treatment (1 DAST). Pelargonic acid at 15 lb/acre provided equal or slightly greater smooth crabgrass and broadleaf (cutleaf groundcherry and spiny amaranth) control compared with the 10-lb/acre application, and consistently greater control than the 5-lb/acre rate and the weedy control. Pelargonic acid was less effective at controlling yellow nutsedge than smooth crabgrass and broadleaf weeds. Yellow nutsedge control peaked at 9 DAIT (1 DAST) with 10-lb/acre PA (41%). As the rate of PA increased from 5 to 15 lb/acre, yellow nutsedge control also increased significantly for all observation dates, except for 28 DAIT. Increasing the PA application rate increased the crop injury rating at 1 and 3 days after each application (1 and 3 DAIT, 1 and 3 DAST). Maximum squash injury occurred for each application rate at 9 DAIT (1 DAST) with 4.4%, 8.0%, and 12.5% injury for PA rates 5, 10, and 15 lb/acre, respectively. The 10-lb/acre PA treatment produced the highest squash yields (kilograms per hectare) and fruit number (fruit per hectare) compared with either the 5- or 15-lb/acre rates, and equivalent yields and fruit number as the hand-weeded weed-free treatment. The 10-lb/acre PA rate applied in a timely sequential application has the potential of providing good weed control with minimal crop injury resulting in yields equivalent to weed-free hand-weeding conditions.
Developing a Wine Grape Site Evaluation Decision Support System for the Inland Pacific Northwestern United States
Authors: Yau Ian-Huei , Davenport Joan R. , Moyer Michelle M.
Published: December 2018

Site selection is critical in wine grape (Vitis vinifera) production. The wine grape industry is expanding in the inland Pacific northwestern United States (IPNW) using traditional means of site evaluation including on physical examination of topography, geomorphology, soil characteristics, and analysis of long-term observations from weather stations. Through the use of modeled spatial data, we present a geographic information system (GIS) representing environmental features important for evaluating vineyard site suitability for the production of wine grapes. Elevation, slope, insolation, heat accumulation, growing season length, extreme minimum temperature and the soil parameters of drainage, available water-holding capacity (AWC), depth to restrictive layer, and pH combine to represent composite topographic, edaphic, and overall production suitability. Comparing modeled site suitability predictions with existing vineyards, we found modeled data on site properties aligned with vineyard manager perceptions of production quality in established vineyards. Although remote spatial evaluation will never replace physical site examination for addressing specific site conditions, it allows an efficient, spatially extensive, initial assessment of sites that can direct attention to potentially problematic or distinguishing environmental characteristics.
Economic Potential of Producing Tahiti Limes in Southern Florida in the Presence of Citrus Canker and Citrus Greening
Authors: Evans Edward A. , Ballen Fredy H. , Crane Jonathan H.
Published: December 2018

This article assesses the profitability of a hypothetical 5-acre tahiti lime (Citrus latifolia) orchard in southern Florida in the presence of citrus canker (Xanthomonas axonopodis pv. citri) and citrus greening [Candidatus Liberibacter asiaticus (LAS)]. To account for the uncertainty associated with the presence of these diseases, a stochastic budgeting technique was employed in the analysis, incorporating stochastic prices and yields based on discussions with industry experts and researchers. The analysis focused on three possible types of management strategies currently practiced by citrus (Citrus sp.) growers in Florida: 1) production without any specific control activities for citrus canker and citrus greening, 2) canker and greening management without removal or replacement of infected/suspicious trees, and 3) canker and greening management with removal and replacement of infected trees. The analysis was carried out for a 20-year time horizon and average net return per acre and rate of return on investment were considered. The results suggest that despite the presence of disease, it would be profitable to produce tahiti limes in southern Florida. This is because the tahiti lime offers some resistance to both citrus greening and canker and will produce even if minimal attention is paid to controlling the diseases. Of the three management strategies investigated, strategy 2 offers the best prospect in terms of high net returns and highest probability of achieving or surpassing the desired rates of return on investment of 12% per annum. The key finding from the study is that the production of tahiti limes in southern Florida can be profitable if steps are taken to manage the diseases, but contrary to popular view, it might be better to wait until the trees become fully unproductive before disposing of them.
Germination of Nonstratified Japanese Tree Lilac Seeds as Influenced by Seed Capsule Maturity and Moisture Content
Authors: West Todd P. , DeMarais Samuel L. , Lee Chiwon W.
Published: December 2018

Temperate-zone woody plant species generally require seed stratification to overcome embryo dormancy. Embryo dormancy is variable in japanese tree lilac (Syringa reticulata) with a recommendation of 30- to 90-days stratification at 1–5 °C. Cultivar propagation generally is done by grafting onto seedling rootstocks. It would be advantageous to rootstock seedling production to be able to reduce or eliminate the need for seed stratification to increase germination numbers as well as having production moved from field beds to greenhouses for quicker production of high-quality rootstock plants suitable for grafting. Research objective of this study was to determine if “green” seed could be used without the need of stratification for japanese tree lilac seedling production. Seed capsule fresh weight and seed moisture content were evaluated to determine if these factors could be used as predictors of germination percentages. Seed was randomly collected at the North Dakota State University campus in Fargo, ND, for seven consecutive weeks starting in Sept. 2011 and 2012. Germination and seed moisture tests were performed weekly. Germination percentage was highest (89.5%) at week 2 and steadily decreased to 0% at week 7. Germination percentages were 77.5%, 89.5%, 78.5%, 67%, 24.5%, 1.5%, and 0% for consecutive collection weeks 1–7, respectively. Seed moisture content was 59.0%, 52.6%, 49.8%, 51.8%, 44.5%, 27.4%, and 8.6% for collection weeks 1–7, respectively. Germination percentage was directly correlated with seed moisture content and decreased as seed capsules matured (natural drying and splitting of capsule seem to disperse seed) during the fall season. Data suggest that timing of fall seed collection from japanese tree lilac is critical and must be done before maturation of the seed capsule to avoid the stratification requirement. Seed capsules with an average fresh weight higher than 0.2 g and seed moisture content greater than 50% produced the highest germination rates without requiring stratification.
Assessment of Subirrigation Performance in Eucalyptus Seedling Production
Authors: Ribeiro Maycon Diego , Ferrarezi Rhuanito Soranz , Testezlaf Roberto
Published: December 2018

We evaluated the performance and determined the efficiency parameters of an automated subirrigation system in a commercial greenhouse facility for clonal eucalyptus (Eucalyptus sp.) seedling production to improve subirrigation management practices. A methodology based on the mass balance of the irrigation system was established to determine the volumes of nutrient solution (NS) applied, drained, stored, evapotranspirated, and leaked in each subirrigation bench. The application, drainage, and NS dwell time in the 55-cm3 conic containers (0.125 m height × 0.03 m diameter) and the depth of NS reached inside the bench were also assessed. The values of application efficiency, irrigation efficiency and system transport (supply and drainage), and disposal losses of NS were estimated for each bench and inferred for the entire subirrigation system. The benches had average application and irrigation efficiency values of 0.84% and 98.38%, respectively. The system showed irrigation efficiency values of 27.59% and the sum lost by transport, leakings, and disposal in the water treatment plant of 72.41%. The continuous return of NS because of the high irrigation frequency contributed to this loss, resulting in 10,070 L of NS consumed by the plants and 26,430 L lost after 15 days of cultivation. Our results demonstrated that the system presented an adequate irrigation efficiency, but a low application efficiency caused by the constant return of NS because of the high irrigation frequency and the excess of losses from leaking and disposal of NS after 15 days of cultivation. Nevertheless, the system operated like a hydroponic system, which kept the containers partially immersed in the NS and did not use the full substrate container capacity to provide adequate moisture. This reduced the overall system irrigation and the substrate storage efficiencies, which needs to be improved by proper equipment design, operation, water and nutrients use efficiency, and management to achieve all the benefits that subirrigation possess.
Grapevine Cultivars, Trellis Systems, and Mechanization of the California Raisin Industry
Authors: Fidelibus Matthew W.
Published: December 2018

Growers in California’s San Joaquin Valley produced >25% of the world’s raisins in 2012, with a farm-gate value of >$590 million, making the United States the leading global producer of raisins. California’s traditional raisin-making method is a laborious process in which clusters of grapes (Vitis vinifera) are harvested by hand onto paper trays, which are left in the vineyard to dry. The drying fruit may need to be turned or rolled, tasks requiring manual labor, and the trays of dried raisins are also picked up by hand. Most California raisins continue to be made in this way, but in recent years, the declining availability and increasing cost of labor has prompted many growers to implement one of two mechanized production systems, “continuous tray” (CT) or “dry-on-vine” (DOV). In CT systems, machines are used to pick the berries, lay them onto a tray, and pick up the dried raisins. The CT system could be considered a short-term strategy: it is compatible with existing conventional ‘Thompson Seedless’ raisin vineyards and has been widely adopted. The DOV system could be considered a medium-term strategy: it is best suited for vineyards specifically designed for DOV, with early ripening grapevine cultivars on expansive trellis systems, which ensures timely drying, and capitalizes on the fact that sunlit row middles are not needed for fruit drying. Grapevine breeding programs are currently working toward the development of raisin grape cultivars with fruitful basal nodes, with fruit that dry naturally upon ripening. This is a long-term strategy to further reduce labor needs by enabling mechanical pruning in winter and eliminating the need for cane severance in the summer.
Breeding Oil and Table Olives for Mechanical Harvesting in Spain
Authors: Rallo Luis
Published: December 2018

The olive (Olea europaea) and table olive industries worldwide are almost entirely supported by low-density rain-fed orchards planted with local cultivars empirically selected by farmers for centuries. New early and high-bearing plantation systems adapted to mechanical harvesting have been designed and developed during the past 50 years. Only certain traditional cultivars are well suited for these new olive plantations. The new orchards therefore require new cultivars. A long-term effort on the exploration, conservation, and sustainable use of olive genetic resources starting in Spain in 1970 has been followed by breeding programs developed since the early 1990s by the University of Cordoba, the University of Seville, and the Andalusia Institute for Agricultural, Food and Fisheries Research. We are trying to use crossbreeding to obtain new early bearing cultivars adapted to mechanically harvested orchards. Objectives related to shortening the juvenile period (JP) and developing early tests of selection, early bearing, high cropping, resistance to chief diseases (particularly verticillium wilt caused by Verticillium dahliae), industrial suitability, high oil content, diversity of olive oil composition for oil cultivars, and fruit size and quality for table olive are being pursued. Specific criteria for the adaptation of oil olive and table olive cultivars to mechanical harvesting, such as low-vigor trees with a compact growth habit, the force needed for fruit removal, natural fruit abscission, resistance to bruising, and extending the harvest time in cultivars showing homogeneous ripening are evaluated in the progenies. To date, more than 19,000 seedlings have been initially evaluated, 481 preselections are on intermediate field trials, and 31 advanced selections are being established in a network of field trials. A new protected cultivar Sikitita (Chiquitita in the United States), selected for very-high-density narrow hedgerows, was released in 2008. Recently, a first project on olive genomics is heralding the use of marker-assisted selection in the midterm phase of development. Cultivars adapted to the new mechanical harvest systems will be progressively released in the future.
Evaluation and Comparison of Sustainability Performance and Visual Preference of Residential Landscape Elements
Authors: Huang Xiaolin , Sherk Julieta Trevino
Published: December 2018

A study was conducted to compare sustainability performance (SP) and visual preference of landscape elements in six professionally designed landscapes. The sites chosen for study provided a range of low to high emphasis on sustainable landscape design. Landscape elements in each site were evaluated for two attributes: SP and visual preference. Sustainability performance was evaluated using the Sustainable Sites Initiative (SSI) scoring system. Visual preferences for landscape elements were assembled by surveying three populations of volunteers: landscape design professionals, landscape design students, and nondesigners (potential residential clients). Few significant differences were observed among the visual preference responses of participant groups. In the few differences noted, we found that the more knowledgeable participants were about landscape element’s ability to improve the environment, the more likely they were to rate them as visually preferred. Average values for SP and visual preference were negatively correlated. However, many individual landscape elements were rated highly in both SP and visual preference. These results suggest it is possible to design landscapes with both highly sustainable elements that are also highly visually preferred.
Quantifying the Effects of Hanging Baskets on the Greenhouse Light Environment
Authors: Faust James E. , Korczynski Pamela C. , Samarakoon Uttara C.
Published: December 2018

During the production of ornamentals in commercial greenhouses, hanging baskets are often grown above the bench or floor space to maximize production. These hanging baskets impact the light environment delivered to the crop underneath. An experiment was conducted to quantify the effect of hanging basket density (determined by number of lines of containers per greenhouse bay and container spacing per line), container content (with plants vs. no plants), and container color (white vs. green) on photosynthetic photon flux (PPF) transmission and red (R) and far-red (FR) light measurements at the greenhouse floor under the hanging basket treatments. Interception of PPF was calculated as a proportion of the treatment with no hanging baskets. Interception of PPF increased as hanging basket density increased, from 5.3% interception at 0.21 containers/yard2 to 25.5% interception at 2.57 containers/yard2. Green containers intercepted 36.1% more radiation than the white containers. Presence of plants in the containers resulted in 62.3% greater PPF interception than containers without plants. R:FR was reduced from 1.15 measured under hanging basket treatments without plants to 1.07 under hanging basket treatments containing plants.
Veggie Compass: A Spreadsheet-based Tool to Calculate Cost of Production for Diversified Organic Vegetable Farmers
Authors: Silva Erin M. , Claypool Rebecca , Munsch Jim , Hendrickson John , Mitchell Paul , Mills Jean
Published: December 2018

Organic sales continue to increase in the United States, particularly in the category of fruits and vegetables. Many organic vegetable producers are highly diversified in both crop production and marketing strategies, selling many different crops through several different market channels. With this level of operational complexity, determination of cost of production and calculation of breakeven prices for each crop in each market channels is extremely challenging. A spreadsheet-based tool called Veggie Compass was created to assist growers in tracking their operational costs and determining crop-specific and market-specific costs of production, breakeven prices, and gross profits. The spreadsheet uses farm-specific data regarding expenses, sales, and labor inputs in its calculations. A farmer can define the crops grown and markets sold to tailor the information specifically for their operations. Continued development in collaboration with farmers will improve the program and allow growers to perform analyses that enable them to set prices that more accurately reflect their respective operational costs.
Improving Fruit Quality of Apricot by Means of Preharvest Benzyladenine and Benzyladenine Plus Gibberellin Applications
Authors: Canli Fatih Ali , Sahin Murat , Temurtas Nurettin , Pektas Mustafa
Published: December 2018

Applications that could improve apricot (Prunus armeniaca) fruit size and quality would enhance their marketability. In this study, the effects of preharvest benzyladenine (BA) and BA plus gibberellin (GA) applications on fruit quality of ‘Alyanak’ apricot were investigated. BA (50, 100, and 150 ppm) and BA + GA4+7 (12.5, 25, and 50 ppm) were applied at the beginning of pit hardening stage. When fruit reached their maturity, samples were harvested and evaluated in terms of: weight, size, firmness, soluble solids content (SSC), acidity, and pH. Fruit treated with BA were significantly heavier and larger than fruit not treated, and there were significant differences in fruit size within the BA-treated fruit. The heaviest and the largest fruit were obtained from 100 to 150 ppm BA concentrations. BA + GA4+7 treatments did not affect fruit size. Application of 100 ppm BA and 25 ppm BA + GA4+7 increased fruit firmness at harvest. SSC, pH, and acidity were unaffected by the applications. The results obtained in this study showed a practical benefit of a single application of BA at the end of pit hardening for improving apricot quality. Fruit treated with the optimum dose of BA (100 ppm) were larger and firmer than untreated fruit.
Efficacy of Binary Pesticide Mixtures Against Western Flower Thrips
Authors: Cloyd Raymond A. , Raudenbush Amy L.
Published: December 2018

This study was designed to determine the efficacy of binary pesticide mixtures against one of the most important insect pests of greenhouse-grown horticultural crops, western flower thrips (Frankliniella occidentalis). Two separate experiments were conducted under greenhouse conditions to simulate a greenhouse production cycle using yellow transvaal daisy (Gerbera jamesonii) cut flowers, which were artificially infested with a known number of western flower thrips. The pesticides used in the two experiments were spinosad, pymetrozine, abamectin, pyridalyl, fluvalinate, chlorfenapyr, bifenazate, azadirachtin, petroleum oil, tolfenpyrad, fenhexamid, azoxystrobin, and spirotetramat. Pesticide mixtures were evaluated at the recommended labeled rates (Expt. 1) and assessments were made to determine if adding didecyl dimethyl ammonium chloride enhanced the efficacy of the pesticide mixtures (Expt. 2). Results from Expt. 1 indicated that many of the binary pesticide mixtures provided ≥80% mortality of western flower thrips although this was a baseline population without previous exposure to pesticides. In Expt. 2, the addition of didecyl dimethyl ammonium chloride failed to increase the efficacy of most of the designated pesticide mixtures compared with the pesticides applied separately. Furthermore, none of the binary pesticide mixtures were phytotoxic to the transvaal daisy flowers. Although there are issues associated with using pesticide mixtures such as the potential for resistance developing to different pesticides in mixtures, greenhouse producers combine pesticides together to reduce labor costs and expand the spectrum of activity against insect and mite (Tetranychidae) pests. Therefore, the relevance of this information is that greenhouse producers now understand which pesticide mixtures may be used and those that should be avoided when suppressing populations of western flower thrips thus minimizing feeding damage to greenhouse-grown horticultural crops.
Red and Far-red Light Treatments to Modify Thermoinhibition, Photoblasticity, and Longevity in Lettuce Seeds
Authors: Pimentel Isabel , Contreras Samuel
Published: December 2018

Germination in lettuce (Lactuca sativa) seeds can be inhibited by high temperatures (thermoinhibition) or darkness (positive photoblasticity). Priming is commonly used as a seed treatment to avoid these problems. However, this treatment is complicated, expensive and has detrimental effect on seed longevity. The objectives of this study were to 1) develop a simple alternative treatment to priming, based on red light irradiations and 2) to develop a treatment to extend seed longevity. Lettuce seeds from cultivars Tango, Milanesa, Ideal Cos, and Gallega de Invierno were partially hydrated in containers with 98% relative humidity (RH) and irradiated with red (R) light for 24 hours, or far-red (FR) light for 216 hours. Throughout the treatment, seeds reached 16% water content and, once finished, they were dried with air at 30 °C. Untreated (control) and primed seeds were also evaluated. Germination was evaluated in light and darkness at temperatures between 12 and 36 °C in a thermogradient table. Effects in longevity were estimated by evaluating germination after various aging periods at 45 °C and 75% RH. The R-light treatment improved germination in the dark at temperatures up to 25 °C, but did not have a significant effect on seed germination under light. Germination after accelerated aging showed that R- and FR- light treatments extended seed longevity when compared with control seeds. Therefore, this effect would not be associated to photoblasticity alleviation or imposition. Primed seeds deteriorated faster than the control. Compared with priming, the R-light treatment was simpler and improved seed longevity. However, priming effects on alleviation of seed photoblasticity and thermoinhibition at temperatures over 25 °C were greater.
Effects of Seed Aging on Seed Germination and Seed Reserve Utilization in Mumian
Authors: Zheng Yan-Ling , Ma Huan-Cheng
Published: December 2018

Mumian (Bombax ceiba) is a deciduous tree that can grow in the dry-hot valley of southwestern China. However, natural regeneration of mumian is significantly inhibited by some factors such as high temperature that can accelerate seed deterioration. The objective of this study was to identify the change of seedling growth component(s) in response to seed aging at 45 °C either at low relative humidity (15%) or at high relative humidity (100%) for 0, 1, 2, 3, and 4 days. Germination assay results at 30 °C in darkness showed an interaction between relative humidity and aging duration. At high temperature and low relative humidity seedling growth, weight of used seed reserve and fraction of seed reserve depletion significantly decreased with increasing of aging duration. But the conversion efficiency of mobilized reserve to seedling tissues did not change significantly. In contrast, at high temperature and high relative humidity, seedling growth and conversion efficiency of seed reserve utilization decreased significantly, but weight of used seed reserve and fraction of seed reserve depletion did not change significantly until seeds were dead. It was concluded that there existed a different pattern of seed reserve utilization for seeds aged at low and high relative humidity, and humidification of seeds at 45 °C for 1 day is a possible way to increase germination of mumian.
Screening Ornamental Sunflowers in the Seedling Stage for Flowering Reaction to Photoperiod
Authors: Wien Hans C.
Published: December 2018

Ornamental sunflower (Helianthus annuus) cultivars grown as cut flowers range in sensitivity to photoperiod with regard to flowering from facultative short day (SD) to facultative long day (LD), with others insensitive to daylength. SD sensitivity is a problem for production in tropical areas, or in early spring sowings when the daylength triggers early flowering, and leads to small flowers and production of unsightly axillary buds. In the current work, 59 cultivars of sunflower were exposed to either 12- or 16-hour photoperiod in seedling trays in a greenhouse for 3 weeks, and transplanted outside. At flowering, plant height, leaf number, and flower diameter were measured. The studies were conducted in 2006, 2007, 2009, 2011, and 2012 with two cultivars (Procut Lemon and Sunrich Orange) serving as controls in each trial. Of the 59 cultivars screened, 52% were found to be day-neutral, 44% were SD, and two (3%) had a LD reaction. Two standard cultivars grown in each season showed consistent reactions to the photoperiod treatments in each year. The seedling screen is useful to identify cultivars suited for production in early spring in a temperate environment.
Self-reported Willingness to Pay for Texas Persimmon Fruit as a Food Source
Authors: Glover Benjamin J. , Waliczek Tina M. , Gandonou Jean-Marc
Published: December 2018

The purpose of this study was to test the consumer-stated willingness to pay (WTP) of a native Texas plant fruit product, texas persimmon (Diospyros texana), for the restaurant industry, as well as for the consumer market. Farmers’ markets and restaurants specializing in either local foods, organic foods, or both were the focus of the market samples. Responses were gathered from five cities located in the geographic area of central Texas where the fruit is native including: San Marcos, Austin, New Braunfels, Wimberley, and Bastrop. About 400 quantitative survey responses were collected from farmers’ markets consumers during market days. Seven interviews collecting qualitative responses from restaurateurs provided more in-depth data on the value of the product to specialty restaurants. Restaurateurs responded positively to the texas persimmon and stated they would be willing to pay between $3.59 and $3.69/lb of texas persimmon. Results indicated the prime audience for the texas persimmon to be those who attend farmers’ markets in the age group of 25–34 years who value locally produced foods and are concerned about the environment. Farmers’ market consumers were willing to pay prices similar to specialty fruit prices.
Effects of Nitrogen Fertilization Rate on Aesthetic Quality of Landscape-grown Annuals and Perennials
Authors: Moore Kimberly A. , Shober Amy L. , Hasing Gitta S. , Wiese Christine L. , Denny Geoffrey C. , Knox Gary W.
Published: December 2018

Recent research suggested that the nitrogen (N) fertilizer rates needed to maintain high-quality landscape plants was lower than rates needed to grow the largest size plants. Our objective was to evaluate the effect of N fertilizer rate on the aesthetic quality of various landscape-grown annual and perennials species. Nineteen cool-season annuals, 20 warm-season annuals, and 4 perennials were planted into raised beds containing subsoil fill material in a completely randomized design in west-central Florida (U.S. Department of Agriculture hardiness zone 9b). Plants were fertilized every 12 weeks with polymer coated, slow-release N (42N–0P–0K) fertilizer at annual N rate of 3, 5, or 7 lb/1000 ft2 (annuals) or 1, 3, or 5 lb/1000 ft2 (perennials). Plants were rated for aesthetic quality every 6 weeks for a period of 18 weeks (annuals) or 54 weeks (perennials). For most species, quality ratings of plants fertilized with 3 lb/1000 ft2 of N per year (annuals) or 1 lb/1000 ft2 of N per year (perennials) were not significantly lower than plants receiving higher rates of N annually. Previously reported N fertilizer recommendations for central Florida of 2 to 4 lb/1000 ft2 per year should be adequate for maintaining acceptable quality landscape-grown annual and herbaceous perennial plant species.
Assessing Student Learning From an Experiential Module in a Greenhouse Management Course Using Hydroponics and Recirculating Solution Culture
Authors: Craver Joshua K. , Williams Kimberly A.
Published: December 2018

Student learning from producing crops in recirculating culture for a 6-week module in the Fall 2013 course HORT 570 Greenhouse Operations Management at Kansas State University was assessed. The module design followed Kolb’s experiential learning model, with teams of students responsible for production of lettuce (Lactuca sativa ‘Green Oak Leaf’) or basil (Ocimum basilicum ‘Italian Large Leaf’) and chives (Allium schoenoprasum ‘Purly’) crops in either a nutrient film technique (NFT) or in-pot recirculating culture system. Goals were to discern if this class experience would 1) improve student confidence and understanding of not only recirculating solution culture systems, but also general crop nutrient management; and 2) improve higher-order learning (HOL) skills of applying, analyzing, and evaluating information. Student learning was evaluated by administering the same survey, which included questions to evaluate student perception, lower-order learning (LOL), and HOL, at four separate times during the semester: 1) before mentioning plant nutrition, hydroponics, or recirculating solution culture; 2) after plant nutrition lectures but before the experiential module; 3) immediately upon completion of the experiential module; and 4) at the end of the semester. An increase in student confidence related to managing crop production in recirculating solution culture and nutrient management was perceived by students upon completion of the module. A significant increase in LOL occurred after the material was presented during the course lectures with an increase also occurring upon completion of the experiential module. In contrast, HOL did not significantly increase after the lecture material was presented, but significantly increased upon completion of the module. Both LOL and HOL was retained at the end of the semester. This evidence supports the role of experiential learning in improving student understanding and fostering HOL.
Evaluation of Peach Cultivars in Cool, Mesic Ullensvang, Norway
Authors: Meland Mekjell , Frøynes Oddmund , Kaiser Clive
Published: December 2018

In a cool, maritime Nordic climate, where fruit have been grown for many centuries, 13 early maturing peach (Prunus persica) cultivars from northern European climates were evaluated over a 6-year period. Peach leaf curl (Taphrina deformans) was the main disease affecting production. The most consistent yielding cultivar was Riga with 5.74 kg/tree in 2009, 2.06 kg/tree in 2010, and 4.71 kg/tree in 2011. Harnas yielded 6.93 kg/tree in 2010, but had very low yields in 2009 and no yield at all in 2011. ‘Harnas’ fruit quality was excellent when compared with all other cultivars, but trees were extremely susceptible to peach leaf curl. ‘Riga’ was somewhat tolerant of peach leaf curl but flowered early. We conclude that none of the cultivars tested are suitable for commercial production. However, looking forward, both ‘Riga’ and ‘Harnas’ may be suitable for commercial tunnel production and home gardens. Furthermore, ‘Harnas’ and ‘Riga’ could be considered for use in future breeding programs for this cool, mesic Nordic climate.
Improving Sea Oats Seedling Production from Seed with Fungicides
Authors: Barrios Kaitlin , Knott Carrie , Geaghan James
Published: December 2018

In Louisiana, sea oats (Uniola paniculata) are incorporated into beach restoration projects to build and stabilize sand dunes. Unfortunately, sea oats seed yield, germination, and seedling survival are poor. The objectives of this study were to assess the impact of commercial fungicide(s) on sea oats germination, seedling survival, and seedling quality. Sea oats seed were planted into soilless media and grown in greenhouse conditions in Baton Rouge, LA. Four fungicide treatments at two rates were applied to seeded trays: mefenoxam, thiophanate-methyl, azoxystrobin, and iprodione. Two control treatments were included: a 15-minute seed soak in water before seeding and dry seed. Percentage germination, percentage survival, shoot height, and fresh weight were measured. Sea oats seed treated with thiophanate-methyl at twice the fungicide label’s recommended rate [2× (23.0 oz/1000 ft2 a.i.)] had the greatest mean germination and survival and were the tallest seedlings 8 weeks after seeding. These results strongly suggest that treating seed with thiophanate-methyl 2× increased sea oats germination, survival, seedling quality, and profitability of sea oats production. The cost to apply thiophanate-methyl 2× to 1000 sea oats seed was $1.74. The additional revenue generated from greater germination, survival, and seedling quality when growing media was treated with thiophanate-methyl 2× was $37.72 per 1000 sea oats seeds. Therefore, the fungicide thiophanate-methyl was identified to be a practical and economical method to rapidly produce a large number of genetically diverse sea oats plants.
Seed Ratios for Optimum Turf Quality of Mixtures of Kentucky Bluegrass, Creeping Red Fescue, and Alkaligrass Subjected to Deicing Salts
Authors: Yuan Longyi , Li Deying , Gao Yang , Xiao Wenjing
Published: December 2018

Deicing salts often are applied to sidewalks and roadways to enhance pedestrian and driving safety during freezing weather. For example, in eastern North Dakota, average annual snow days and amount are 29 days and 40 inches, respectively. This study was conducted in Fargo, ND, to investigate the population dynamics of turfgrass mixtures composed of kentucky bluegrass [KB (Poa pratensis)], creeping red fescue [RF (Festuca rubra)], and alkaligrass [ALK (Puccinellia sp.)] with the goal of optimizing turf quality by selecting seed ratios containing these species in home lawn mixtures and subject to frequent applications of deicing salts. A total of 21 mixtures were generated based on simplex-lattice design with KB, ALK, and RF contributing to 0%, 20%, 40%, 60%, 80%, and 100% of their respective full-seeding rate of 150, 150, and 300 lb/acre, respectively, after pure live seed (PLS) adjustment. The mixtures were tested at annual deicing salt rates of 0, 160, 320 lb/acre, which represent typical application. The results showed that the botanical component of the stands of grasses shifted over a 2-year period for all salt levels. Despite the good salinity tolerance of ALK reported elsewhere, it did not contribute to the improvement of turf quality in mixtures receiving deicing salts at 320 lb/acre per year. Therefore, ALK is not recommended for lawn, but mixing KB and RF in 48% and 52% of their respective full-seeding rates was recommended for areas adjacent to deicing salt applications.