bluuebunny/crossref_metadata_2025 huggingface dataset:
Engineering and Horticultural Aspects of Robotic Fruit Harvesting: Opportunities and Constraints
Authors: Burks T. , Villegas F. , Hannan M. , Flood S. , Sivaraman B. , Subramanian V. , Sikes J.
Published: December 2018

Automated solutions for fresh market fruit and vegetable harvesting have been studied by numerous researchers around the world during the past several decades. However, very few developments have been adopted and put into practice. The reasons for this lack of success are due to technical, economic, horticultural, and producer acceptance issues. The solutions to agricultural robotic mechanization problems are multidisciplinary in nature. Although there have been significant technology advances during the past decade, many scientific challenges remain. Viable solutions will require engineers and horticultural scientists who understand crop-specific biological systems and production practices, as well as the machinery, robotics, and controls issues associated with the automated production systems. Focused multidisciplinary teams are needed to address the full range of commodity-specific technical issues involved. Although there will be common technology components, such as machine vision, robotic manipula-tion, vehicle guidance, and so on, each application will be specialized, due to the unique nature of the biological system. Collaboration and technology sharing between commodity groups offers the benefit of leveraged research and development dollars and reduced overall development time for multiple commodities. This paper presents an overview of the major horticultural and engineering aspects of robotic mechanization for horticultural crop harvesting systems.
Methods to Assess Potential Chloride Stress in Citrus: Analysis of Leaves, Fruit, Stem-xylem Sap, and Roots
Authors: Raveh Eran
Published: December 2018

Chloride stress in commercial citrus is predominantly a result of increased osmotic pressure in the plant as a result of excess chloride. The source of the chloride is usually from the soil solution, where it is absorbed by the roots. After being absorbed, chloride flows through the xylem in the transpiration stream to the shoot, where it is accumulated by transpiring tissues such as leaves and fruit. Monitoring chloride concentration along any of these steps can be used to assess potential stress in the tree. Since some of these tissues tend to accumulate chloride (fruit and leaves) while others do not (root and xylem), analyses should be interpreted within the context of these differences. Having high chloride concentration in roots or xylem-water at a specific sampling time does not necessarily mean that leaves have already accumulated chloride to a toxic level, while having high chloride concentration in fruit or leaf analysis does not necessarily mean that the trees are still being exposed to high salinity in the soil solution. The advantages of the various analyses, as well as their difficulties, are discussed. It was concluded that a combination of xylem sap chloride analysis and leaf chloride analysis are the most useful tools for assessing potential chloride stress in citrus trees.
Challenges and Benefits of Transplanting Large Trees: An Introduction to the Workshop
Authors: Arnold Michael A.
Published: December 2018

Across horticultural crops the trend is to transplant larger plants to achieve the intended landscape effects or to produce the desired yield without the long wait associated with direct seeding or small transplant technology. Consumers want immediate gratification (a landscape design that produces the desired aesthetics without the wait for plants to grow to mature sizes). This trend extends from the use of large herbaceous plants for instant landscape color, transplanting of vegetable plants already in fruit to the home garden for early yield, to transplanting larger shrubs and trees to effect the impression of an established landscape. This trend logically culminates in the transplanting of large, mature specimen trees to create the appearance of a fully mature landscape. This workshop will explore the potential benefits of this approach and the challenges associated with successful transplanting of large trees.
Influence of Tree Size on Transplant Establishment and Growth
Authors: Watson W. Todd
Published: December 2018

Studies have demonstrated that the size of transplanted trees has a measurable impact on establishment rates in the landscape. Larger trees require a longer period of time than smaller trees to produce a root system comparable in spatial distribution to similar sized non-transplanted trees. This lag in redevelopment of root system architecture results in reduced growth that increases with transplant size. Research has demonstrated that smaller transplanted trees become established more quickly and ultimately result in larger trees in the landscape in a few years. Additional studies dispute these findings. This paper provides a review of current research on the effect of tree size on transplant establishment.
Bareroot and Balled-and-burlapped Red Oak and Green Ash Can Be Summer Transplanted using the Missouri Gravel Bed System
Authors: Starbuck Chris , Struve Daniel K. , Mathers Hannah
Published: December 2018

Two experiments were conducted to determine if 5.1-cm-caliper (2 inches) `Summit' green ash (Fraxinus pensylvanica), and 7.6-cm-caliper (3 inches) northern red oak (Quercus rubra) could be successfully summer transplanted after being heeled in pea gravel or wood chips prior to planting in the landscape. Spring harvested trees of each species were either balled and burlapped (B&B) or barerooted before heeling in pea gravel or wood chips. Compared to B&B `Summit' green ash, bareroot stock had similar survival and shoot extension for three growing seasons after summer transplanting. Bareroot and B&B northern red oak trees had similar survival and central leader elongation for 3 years after summer transplanting. In the third year after transplanting, northern red oak bareroot trees heeled in pea had smaller trunk caliper than B&B trees heeled in wood chips. These two taxa can be summer transplanted B&B or bareroot if dormant stock is spring-dug and maintained in a heeling-in bed before transplanting. This method of reducing transplant shock by providing benign conditions for root regeneration can also be used to extended the planting season for field-grown nursery stock; the method is called the Missouri gravel bed system.
A Review of the Effects of Transplant Timing on Landscape Establishment of Field-grown Deciduous Trees in Temperate Climates
Authors: Richardson-Calfee Lisa E. , Harris J. Roger
Published: December 2018

Prudent landscape professionals can enhance chances for successful establishment by timing tree transplant operations to coincide with ideal seasonal conditions. However, transplant timing is usually determined by economic factors, resulting in trees being transplanted at times that are unfavorable for their survival and growth. Knowledge of the effects of season of transplanting on the establishment of landscape trees can help assure the highest probability of success, especially since special post-transplant management may be required if trees are transplanted at unfavorable times. This manuscript reviews past and current research on the effects of transplant timing on landscape establishment of deciduous shade trees. Specific results are summarized from several key studies.
Challenges to Extension Programming
Authors: Cloyd Raymond A.
Published: December 2018

The way extension specialists and educators conduct programs, such as workshops, and transfer information to their designated clientele, including homeowners, professionals, and specialty groups, has changed within the last decade due to merging departments, budget cuts, reduced operating funds, and lack of refilling vacant positions. These factors have resulted in a number of driving forces that influence the way extension specialists and educators perform their duties, such as accountability, regionalization of extension, impact of technology, and expanding expertise. To be accountable under today's standards, extension specialists and educators must document the impact, relevance, and effectiveness of their programs. Required documentation must include economic, environmental, and human development factors. The effect of downsizing in many states has led to regionalization, which involves sharing extension specialists and educators across state boundaries. Although there are concerns, such as funding issues and evaluation of extension specialists and educators among states, regionalization in general has resulted in collaborative efforts to organize workshops and produce regional publications that serve a wider clientele base. Extension specialists and educators need to use computer-based and electronic technology, such as teleconferencing and distance-education, to present effective programs and address a wider audience, which will reduce the amount of required travel time. Finally, extension specialists and educators need to keep abreast of issues, such as invasive species, and develop programs to increase awareness of the economic and ecological impacts of invasive species in order to effectively serve the clientele base. Extension specialists and educators will more effectively serve their clientele, justify the importance of extension programming, demonstrate extension as a valued resource to administrators, and deal with the challenges of financial constraint existing now and in the foreseeable future by documenting impact, using multi-state programming, adopting new technology, and keeping up with current issues.
The English Garden at Stan Hywet Hall and Gardens: Interpretation, Analysis, and Documentation of a Historic Garden Restoration
Authors: Halbrooks Mary C.
Published: December 2018

Stan Hywet Hall and Gardens in Akron, Ohio, is a historical estate of national significance. Originally the home of the wealthy Seiberling family in the early 1900s, Stan Hywet Hall and Gardens was designed by renowned Boston landscape architect Warren Manning between 1911 and 1917. In 1915, the English Garden, one of several garden rooms on the estate, was designed by Manning as a walled, hidden garden. Thirteen years later, the garden's style was reconceived and its spatial dimensions restructured by Ellen Biddle Shipman, the foremost among women landscape architects of that time. Historic photographs document the implementation and maintenance of Shipman's design from 1928 to 1946. After 1946, the English Garden, lacking proper maintenance, was transformed into a shady retreat under towering evergreens on its perimeter. Few of the plantings from the Shipman period remained by 1989, whereas the architectural and structuring elements of the garden were still intact. The decision to restore the English Garden to Shipman's planting design provides a highly accurate representation of the garden during a particular period in its history (1928–46). Architectural rehabilitation of the garden's walls, walks, pathways, and pools was followed by an exacting restoration of the plantings according to Shipman's plans. In 1991, restoration of the English Garden was completed and it was opened to the public in 1992. Objectives of this paper are to 1) illustrate and illuminate contemporary historic landscape preservation practice and theory as applied to the English Garden at Stan Hywet Hall and Gardens and 2) document the horticultural methods associated with this historic garden restoration.
Influence of Winter Rye and Preemergence Herbicides on Weed Control in No-tillage Zucchini Squash Production
Authors: Walters S. Alan , Nolte Scott A. , Young Bryan G.
Published: December 2018

The influence of `Elbon', `Maton', and `Wheeler' winter rye (Secale cereale) with or without herbicide treatments on weed control in no-tillage (NT) zucchini squash (Cucurbita pepo) was determined. `Elbon' or `Maton' produced higher residue biomass, greater soil coverage, and higher weed control compared with `Wheeler'. Although winter rye alone did not provide sufficient weed control (generally <70%), it provided substantially greater redroot pigweed (Amaranthus retroflexus) and smooth crabgrass (Digitaria ischaemum) control (regardless of cultivar used) compared with no winter rye at both 28 and 56 days after transplanting (DAT). No effect (P > 0.05) of winter rye cultivar on early or total squash yield was detected. Although applying clomazone + ethalfluralin to winter rye residues improved redroot pigweed control compared with no herbicide, the level of control was generally not adequate (<85% control) by 56 DAT. Treatments that included halosulfuron provided greater control of redroot pigweed than clomazone + ethalfluralin, and redroot pigweed control from halosulfuron treatments was similar to the weed-free control. However, regardless of year or cover crop, any treatment with halosulfuron caused unacceptable injury to zucchini squash plants which lead to reduced squash yield (primarily early yields). Insignificant amounts of squash injury (<10% due to stunting) resulted from clomazone + ethalfluralin in no-tillage plots during either year. Treatments with clomazone + ethalfluralin had early and total yields that were similar to those of the weed-free control, although this herbicide combination provided less weed control compared with the weed-free control.
Colorant Effects on Dormant Buffalograss Turf Performance
Authors: Shearman R.C. , Wit L.A. , Severmutlu S. , Budak H. , Gaussoin R.E.
Published: December 2018

Dormant buffalograss (Buchloë dactyloides) turfs, grown under field conditions, were treated with a colorant and evaluated for turfgrass color, quality, and cover. In addition, turfgrass canopy and soil temperatures were measured. Colorant treatments improved turfgrass color and quality when compared to the untreated control, and resulted in a color response that appeared similar to cool season turfgrasses growing in areas adjacent to the studies. Colorant treatments increased canopy and soil temperatures, and enhanced spring green-up. These results support the use of colorants as a means of extending the green appearance, and enhancing dormant buffalograss turf performance.
Season and Cultivar Influence the Fruit Quality Response of Apple Cultivars to Particle Film Treatments
Authors: Glenn D. Michael , Drake Stephen , Abbott Judith A. , Puterka Gary J. , Gundrum Patricia
Published: December 2018

Experiments were performed over 3 years to examine the effect that particle film (PF) treatment had on fruit quality of several apple (Malus ×domestica) cultivars in Washington and West Virginia. In the first study, a highly reflective, white, hydrophilic particle-based kaolin mineral (Surround WP) was applied to `Empire' apple in May and June, on a season-long basis, or not at all. Red fruit color was increased by both the PF treatments compared with no treatment in all years. In a second study, the PF material was applied, starting at petal fall, every week for 6 weeks and then every 2 weeks until harvest to `Empire', `Gala', and `Fuji' trees in West Virginia and to `Cameo', `Fuji', and `Gala' trees in Washington. In the latter study, cultivar response to season-long applications varied by year and location. `Empire' consistently had improved red color with season-long applications of PF materials. `Gala' had greater fruit weight and red color with PF application in 1 of 2 years in West Virginia but not in Washington. `Fuji' had greater fruit weight and soluble solids content and `Cameo' had greater soluble solids, higher starch indices, and greater red color in Washington with the PF application. In these studies, application of a PF never reduced the surface red color in apples. A taste panel did not identify quality differences in `Empire' apples treated with PF vs. the control. Cultivar responses to PF applications were variable due to location and yearly environmental characteristics. While particle film technology has value for insect control and reducing sunburn, it has limited value to enhance fruit color due to the inconsistent response.
Effect of Carbon Dioxide Removal Systems on Volatile Profiles and Quality of `Hayward' Kiwifruit Stored in Controlled Atmosphere Rooms
Authors: Lallu N. , Burdon J. , Billing D. , Burmeister D. , Yearsley C. , Osman S. , Wang M. , Gunson A. , Young H.
Published: December 2018

There are three main systems for the removal of carbon dioxide (CO2) from controlled atmosphere (CA) stores: activated carbon (AC) scrubber, hydrated lime scrubber, and nitrogen (N2) flushing. Each system is likely to have a different effect on the accumulation of volatiles other than CO2 in the store atmosphere, and these volatiles may influence the storage performance of the produce. `Hayward' kiwifruit (Actinidia deliciosa) were stored at 0 °C (32.0 °F) under 2% oxygen (O2) and 5% CO2 in CA rooms fitted with one of the three systems. In a fourth CA room, fruit were stored at 0 °C under air conditions. All four stores had their atmosphere scrubbed for ethylene. The store atmospheres and fruit firmness were monitored at intervals up to 27 or 14 weeks of storage in the 1999 or 2000 season, respectively. At the end of CA storage, and after an additional 4 weeks of air storage at 0 °C, fruit were evaluated for rots and physiological pitting. Linear discriminant analysis (LDA) showed the three CO2 removal systems altered the volatile profiles of the store atmospheres differently. CA storage delayed fruit softening markedly, and once returned to air, softening resumed at a rate equivalent to that of fruit of equivalent firmness that had not been CA stored. There was little effect of CO2 removal system on the fruit softening during storage. Although CA storage resulted in a higher incidence of rots, there was little difference among CO2 removal systems compared to the main effect between air and CA storage. Similarly, CA storage delayed the appearance of physiological pitting, although the incidence increased rapidly during an additional 4 weeks of storage in air, and was higher than for fruit stored throughout in air. Among the CO2 removal systems, N2 flushing resulted in fruit with the lowest incidence of physiological pitting. It is concluded that different CO2 removal systems alter room volatile profiles but may not consistently affect the quality of `Hayward' kiwifruit during CA storage.
Shade Tolerance of St. Augustinegrass Cultivars
Authors: Trenholm Laurie E. , Nagata Russell T.
Published: December 2018

The objectives of this research were to rank the relative shade tolerance of some new st. augustinegrass (Stenotaphrum secundatum) cultivars and to determine what levels of shade the various cultivars can tolerate. Two consecutive studies were conducted in a glasshouse at the University of Florida Turfgrass Research Envirotron. Cultivars tested were `Bitter Blue', `Floratam', `Palmetto', `Seville', and `1997-6'. Grasses were grown in full sun or under shade structures that provided 30%, 50%, or 70% shade. In trial 1, `Seville' and `1997-6' generally provided best performance under increasing shade, with worst responses seen in `Floratam'. `Seville' and `1997-6' were predicted to maintain an acceptable quality rating of 6 at all shade levels. In trial 2, `Floratam' again had lowest visual quality scores. At 30% shade, `Seville', `Palmetto', and `Bitter Blue' ranked in the highest category, while only `Seville' and `Bitter Blue' had highest rankings at 50% shade. Reduced density was a major factor in turf decline as shade increased. Most of the cultivars performed best under some degree of shade. With the exception of `Floratam', acceptable visual scores were maintained at shade levels exceeding 60% in trial 1 and up to 61% in trial 2.
Mancozeb and Kaolin Applications Can Reduce Russet of `Comice' Pear
Authors: Sugar David , Powers Kate A. , Basile Sally R.
Published: December 2018

Mancozeb (Manzate 200) and kaolin (Surround WP) were applied individually and in combination in a commercial pear (Pyrus communis) orchard by air-blast sprayer in two growing seasons and in a research orchard by handgun sprayer in four growing seasons. Mancozeb was applied at 50% bloom, petal fall (PF), PF + 2 weeks and PF + 4 weeks, while kaolin and mancozeb + kaolin were applied at PF, PF + 2 weeks and PF + 4 weeks. Both materials reduced russet in both years of the commercial orchard trial and in 2 years of the research orchard trial. In one trial, kaolin treatment reduced russet to a greater extent than did mancozeb, and in one trial the combination of mancozeb plus kaolin reduced russet to a greater extent than either material alone. The year with the greatest amount of russet was the year with the most rainfall, and the year with the least russet was the year with the least rainfall. Considering that mancozeb may be used in pear orchards for suppression of pear scab (Venturia pirina) and pear psylla (Cacopsylla pyricola), and kaolin may be used for suppression of pear psylla, russet reduction by each of these materials adds to their multipurpose utility.
The Effect of Ethanol Dip and Modified Atmosphere on Prevention of Botrytis Rot of Table Grapes
Authors: Lichter Amnon , Zutahy Yohanan , Kaplunov Tatiana , Aharoni Nehemia , Lurie Susan
Published: December 2018

Grape (Vitis vinifera) storage requires stringent control of gray mold caused by Botrytis cinerea. The commercial practice is dependent on sulfur dioxide (SO2) as a fumigant, which is applied by various means with well-known advantages and disadvantages. Many alternative technologies were developed over the years, most of them with limited efficacy or applicability. Modified atmosphere of table grapes suffers from a narrow threshold between control of gray mold and damage to the berries and stems due to high level of carbon dioxide (CO2) within the film-enclosed package. We demonstrated in the past that dipping table grapes in ethanol after harvest has a very pronounced effect on prevention of decay. However, ethanol does not leave a protective residue within the grapes, so it is not expected to prevent latent infections from developing decay nests during prolonged storage. However, if grapes of cultivar Superior were treated with ethanol and then subjected to a modified atmosphere using plastic films (Xtend), we achieved an additive effect and observed persistent control of gray mold without injury to the grapes. The advantage of this plastic film was mainly in its water conductance, which prevented accumulation of free water that is often the limiting factor in modified atmosphere packaging. This combination results in greater decay control, which is a prerequisite for commercial applicability. If undesired aftertaste did develop within the fruit due to the modified atmosphere, 1 day of exposure to ambient air was sufficient to dissipate it.
Evaluating the Storage of Elephant Ears Acclimatized from Tissue Culture
Authors: Faust James E. , Adelberg Jeffrey W. , Lewis Kelly P. , Niu Genhua
Published: December 2018

The effects of storage temperature and shoot preparation of elephant ears (Colocasia antiquorum `Illustris') were examined to determine how to successfully store plants prior to greenhouse forcing. A series of experiments were conducted that provided storage temperatures of 4, 7, 10, 13, or 16 °C (39.2, 44.6, 50.0, 55.4, or 60.8 °F), and plants were placed into storage with the shoots uncut or cut to 3.0 cm (1.18 inches) above the surface of the growing medium. The storage duration ranged from 40 to 49 days. All plants stored at 4 or 7 °C died. Plant survival was 89% to 100% at 10 °C, while plant survival was 100% at 13 or 16 °C. Shoot emergence and plant growth was faster following storage at 13 and 16 °C, than storage at 10 °C. Storage at 16 °C resulted in leaf growth occurring during storage, which was undesirable. Removing shoots prior to storage had no effect on plant survival and performance during forcing. A fungicide drench with iprodione immediately prior to storage did not improve plant survival. This study suggests that 13 °C is near the base temperature for leaf development of elephant ears, thus the plants survive at this temperature with no growth occurring. Shoot removal prior to storage is recommended in order to optimize storage room space.
Effects of Garden Visits on Long-term Care Residents as Related to Depression
Authors: Rappe Erja , Kivelä Sirkka-Liisa
Published: December 2018

Depression is a major health problem among the elderly. Its prevalence is high among those in long-term care. Exposure to the garden environment may alleviate depressive symptoms, but there is little research evidence to confirm this hypothesis. In this study we investigated the perceived effects and meanings related to garden visits among older individuals living in long-term care and assessed whether there are associations between experiences from garden visits and self-rated depression. Data were gathered by surveying 30 elderly people living in Kustaankartano, a nursing home and service center for elderly people in Helsinki, Finland. Prevalence of self-rated depression was high; 46% of the participants were depressed. Both being in the garden and seeing it from the balcony and observing nature were of great significance for most of the participants. For more than half of the participants, visiting the garden improved mood, quality of sleep, and ability to concentrate; it generated feelings of recovery and promoted peace of mind. Affective effects of visiting the garden tended to be more pronounced among the depressed than among those not depressed. The depressed did not consider social interaction and participation in social activities very important for their well-being. Depression tended to be related to perception of the residents that they experienced hindrances and distresses associated with visiting the garden. Although there were indicative differences between the depressed and nondepressed participants in garden experiences, the results suggest that visiting the garden may affect the subjective well-being of both groups positively.
Performance and Transition Date of a Turf-type Annual Ryegrass in Comparison to Perennial Ryegrass and Fine Fescues
Authors: Nelson L.R. , Crowder J. , Pemberton H.B.
Published: December 2018

Perennial ryegrass (Lolium perenne) has traditionally been used to overseed warm-season grasses in the southern U.S. when warm-season sods are dormant due to chilling temperatures. In this study we investigated overseeding turf-type annual ryegrass (two cultivars of L. multiflorum and one cultivar of L. rigidum) and chewing fescue (Festuca rubra var. commutata) as well as perennial ryegrass onto a warm-season common bermudagrass (Cynodon dactylon) sod. The objective was to compare turf quality, turf color, and transition date of turf-type annuals with perennials and other cool-season grasses. Results for turf quality indicated that the annual ryegrass cultivars `Axcella' and `Panterra' (L. multiflorum) compared very well with perennials through March; however, in April and May, perennials were superior for quality. `Hardtop' fine fescue is a hard fescue (F. ovina var. duriuscula). It was inferior to the annuals for turf quality from December to April when the annuals began to die. For turf color, annuals had a lower rating compared to dark green perennials such as `Premier II', `Derby Supreme', or `Allstar'. `Panterra' was darker compared to `Axcella' in March and April. Chewing fescue was intermediate in color compared to annuals and perennials. For turf height, `Axcella' was taller than `Panterra', which were both taller than the perennials, and the fine fescues were shorter than the perennials. For transition in the spring, the annuals had a shorter transition and died about 1 month earlier than the perennials. `Transtar' (L. rigidum) had an earlier transition than the other annuals. The perennials tended to have a longer transition period. The fescues had a very long transition period and were similar to the perennials.
Taste Panel Perception of Sweetness and Sweetness Acceptability Compared to High Pressure Liquid Chromatography Analysis of Sucrose and Total Sugars Among Three Phenotypes (su, se, and sh2) at Varying Maturities of Fresh Sweet Corn
Authors: Hale Teri A. , Hassell Richard L. , Phillips Tyron , Halpin Elizabeth
Published: December 2018

Increased value of fresh sweet corn (Zea mays) during the last decade has lead to increased interest into the characteristics that increase marketability. Sweetness was examined over three phenotypes (su, se, and sh2) to determine if there was an optimum phenotype or cultivar within a phenotype. Each phenotype was isolated to prevent cross-pollinization. Cultivars were grown on sandy loam soil located at the Clemson University Coastal Research and Education Center (Charleston, S.C.). Early, mature, and late harvest dates were also evaluated to determine the optimal harvest date(s) for maximum flavor. High performance liquid chromatography was used to determine sucrose, fructose, glucose, and total sugars. Panelists' evaluation of sweetness and its acceptability significantly correlated with the high performance liquid chromatography analysis for sucrose and total sugars (sweetness, R = 0.70 and 0.61; acceptability, R = 0.64 and 0.55). Sucrose correlated with the total sugars (R = 0.95). As maturity increased, the ability of the taste panel to identify differences in phenotypes also increased. Although sucrose and total sugar levels were different between se, sh2, and su, taste panelists indicated no difference between se and sh2. Sh2 cultivars were considered sweet and acceptable on all harvest dates, but su was only acceptable to panelists at early maturity.
Turf and Ornamental Plant Tolerances to Endothall in Irrigation Water II. Turf Species
Authors: Koschnick Tyler J. , Haller William T. , Fox Alison M.
Published: December 2018

Two formulations of the contact herbicide endothall are used to control submersed aquatic weeds. Waters treated with the amine or dipotassium salt formulations have irrigation restrictions varying from 7 to 25 days depending on the concentration of endothall applied. These water-use restrictions may be reduced for turfgrass if studies conclude there is no phytotoxicity to turf species irrigated with concentrations of endothall that may exist after an aquatic application. Two separate experiments were conducted to determine turfgrass tolerance to endothall in irrigation water on five species of grass: annual ryegrass (Lolium multiflorum), annual bluegrass (Poa annua), centipedegrass (Eremochloa ophiuroides), `Floratam' st. augustinegrass (Stenotaphrum secundatum), and `Tifton 419' bermudagrass (Cynodon dactylon). Expt. 1 used constant concentrations of endothall; Expt. 2 used decreasing concentrations of endothall over time. Annual turf species (bluegrass and ryegrass) were generally more susceptible than perennial turfgrasses. Concentrations resulting in a 10% reduction in total dry weight harvested compared to control plants [effective concentration (EC10)] for the amine and dipotassium salt formulations were 10 and 14 mg·L–1 (ppm) a.i. on annual ryegrass, 10 and 16 mg·L–1 a.i. on annual bluegrass, 50 and 54 mg·L–1 a.i. on centipedegrass, 47 and 72 mg·L–1 a.i. for st. augustinegrass, and for bermudagrass 1301 and 908 mg·L–1 a.i. in Expt. 1. Expt. 2 resulted in EC10 values of 31 and 35 mg·L–1 a.i. on annual ryegrass, 7 and 12 mg·L–1 a.i. on annual bluegrass, 32 and 99 mg·L–1 a.i. on centipedegrass, 27 and 20 mg·L–1 a.i. on st. augustinegrass for the amine and dipotassium formulations of endothall respectively, and 958 mg·L–1 a.i. for the dipotassium formulation on bermudagrass. There was no effect on bermudagrass dry weights when exposed to the amine formulation of endothall in Expt. 2 at concentrations up to 1600 mg·L–1 a.i. There is a low risk of inhibiting growth of turf species at endothall concentrations used for aquatic weed control considering the maximum use concentrations, typical uses of the products, and decomposition rates.
Chemical Height Control of Containerized Seashore Mallow
Authors: Hilgers Kimberly R. , Haynes Cynthia , Graves William R.
Published: December 2018

The objective of this study was to determine the efficacy of plant growth regulators applied as foliar sprays on height and branching of seashore mallow (Kosteletzkya virginica). Five chemical plant growth regulators were applied: ancymidol [15, 25, and 50 mg·L–1 (ppm)] (A-Rest; Elanco Products Co., Indianapolis), dikegulac sodium (500, 1000, and 1500 mg.L–1) (Atrimmec; PBI/Gordon Corp., Kansas City, Mo.), paclobutrazol (10, 20, and 60 mg·L–1) (Bonzi; Uniroyal Chemical Co., Middlebury, Conn.), chlormequat chloride (CCC) (750, 1000, and 1500 mg·L–1) (Cycocel; Olympic Horticultural Products, Mainland, Pa.), and CCC/daminozide mixes (1000/2500, 1000/5000, and 1500/5000 mg·L–1) (Cycocel and B-Nine; Uniroyal Chemical Co.). Ten replicate plants of each concentration were evaluated weekly for plant height and number of branches for 8 weeks. Plants that received CCC and CCC/daminozide treatments at all concentrations and paclobutrazol at 60 mg·L–1 were 60%, 60%, and 48% shorter than control plants and had 113%, 100%, and 75% more branches than control plants, respectively. All concentrations of ancymidol and dikegulac sodium-treated plants were similar to control plants. Paclobutrazol was applied twice, and only the highest concentration was effective for height control. Chlormequat chloride at the lowest concentration was as effective as all other concentrations of CCC and CCC/daminozide.
Rates of Ammonium-nitrogen, Nitrate-nitrogen, Phosphorus, and Potassium from Two Controlled-release Fertilizers under Different Substrate Environments
Authors: Broschat Timothy K.
Published: December 2018

Five-gram (0.18 oz) samples of two controlled-release fertilizers (CRFs), Osmocote 15N–3.9P–10K (8–9 month) (OSM) and Nutricote 18N–2.6P–6.7K (type 180) (NUTR), were sealed into polypropylene mesh packets that were placed on the surface of a 5 pine bark: 4 sedge peat: 1 sand (by volume) potting substrate (PS), buried 10 cm (3.9 inches) deep below the surface of PS, buried 10 cm below the surface of saturated silica sand (SS), or in a container of deionized water only. Containers with PS received 120 mL (4.1 floz) of deionized water three times per week, but the containers with SS or water only had no drainage and were sealed to prevent evaporation. Samples were removed after 2, 5, or 7 months of incubation at 23 °C (73.4 °F) and fertilizer prills were crushed, extracted with water, and analyzed for ammonium-nitrogen (NH4-N), nitrate-nitrogen (NO3-N), phosphorus (P), and potassium (K). Release rates of NO3-N were slightly faster than those of NH4-N and both N ions were released from both products much more rapidly than P or K. After 7 months, OSM prills retained only 8% of their NO3-N, 11% of their NH4-N, 25% of their K, and 46% of their P when averaged across all treatments. Nutricote prills retained 21% of their NO3-N, 28% of their NH4-N, 51% of their K, and 65% of their P. Release of all nutrients from both fertilizers was slowest when applied to the surface of PS, while both products released most rapidly in water only. Release rates in water only exceeded those in SS, presumably due to lower rates of mass flow in SS.
Topping and Manual Pruning Effects on the Production of Commercially Valuable Fruit in a Midseason Navel Orange Variety
Authors: Kallsen Craig E.
Published: December 2018

The objective of this experiment was to determine how yield, size, and quality of fruit would respond to mechanical topping and manual pruning of mature `Frost nucellar' navel orange (Citrus sinensis) trees. Mechanically topping trees at 4.3 m (14 ft) or 4.9 m (16 ft) produced annual fruit yields and quality similar to that of untopped trees. Over the 4 years of this experiment, trees that were not manually pruned produced as much or more of the most valuable fruit sizes than either the severe or moderate manual pruning treatments without the associated pruning costs. Manual pruning did not improve fruit grade compared to unpruned trees. A highly significant positive and linear relationship was found between numbers of commercially valuable fruit and the total number of fruit produced annually within the range of 50,000 to 325,000 fruit/ha (20,235 to 131,528 fruit/acre). Manual pruning, which reduced total fruit numbers, reduced the number of commercially valuable fruit predictively according to this relationship.
Current Developments in Seeders and Transplanters for Vegetable Crops
Authors: Parish Richard L.
Published: December 2018

This article is a review of the current status in planting and transplanting equipment and practices for vegetable crops. A review of horticultural and agricultural engineering literature is supplemented by information from an informal survey of members of American Society of Agricultural Engineers (ASAE) committee PM-48, Fruit and Vegetable Production Engineering, and other engineers and horticulturists working in this field. Areas covered include precision seed metering, seed placement, and high-speed transplanting with automated plant handling.
Greenhouse-grown Colored Peppers: A Profitable Alternative for Vegetable Production in Florida?
Authors: Jovicich Elio , VanSickle John J. , Cantliffe Daniel J. , Stoffella Peter J.
Published: December 2018

The increase in U.S. demand for colored bell peppers (Capsicum annuum) has been satisfied with increased supplies from imports and increased domestic production. Greenhouse-grown peppers of red, orange, and yellow colors were imported during the period 1993–2002 at wholesale fruit market prices that were three to five times greater than field-grown fruits. With high market prices and a suitable environment for growing colored peppers under inexpensive greenhouse structures [<$40/m2 ($3.7/ft2)], up to 14 ha (34.6 acres) of greenhouses produced bell peppers in Florida in the year 2002. To estimate the profitability of a bell pepper greenhouse enterprise, a budget analysis was used to calculate the returns to capital and management. Production costs of greenhouse-grown peppers were estimated assuming the use of current technology applied in commercial greenhouse crops in Florida and in experimental crops at the University of Florida. Production assumptions included a crop of nonpruned plants grown in soilless media in a highroof polyethylene-covered greenhouse [0.78 ha (1.927 acres)] located in north-central Florida. For a fruit yield of 13 kg·m–2 (2.7 lb/ft2), the total cost of production was $41.09/m2 ($3.82/ft2), the estimated return was $17.89/m2 ($1.66/ft2), and the return over investment was 17.1%. A sensitivity analysis indicated that fruit yields should be greater than 7.8 kg·m–2 (1.60 lb/ft2) in order to generate positive returns based on a season average wholesale fruit price of $5.29/kg ($2.40/lb). For this price, a range of possible fruit yields [5–17 kg·m–2 (1.0–3.5 lb/ft2)] led to returns ranging from –$9.52 to 30.84/m2 (–$0.88 to 2.87/ft2), respectively. The estimates indicate that production of greenhouse-grown peppers could represent a viable vegetable production alternative for Florida growers.
Flurprimidol Is Effective at Controlling Height of `Star Gazer' Oriental Lily
Authors: Krug Brian A. , Whipker Brian E. , McCall Ingram
Published: December 2018

Flurprimidol preplant soaks, foliar sprays, and substrate drenches were compared to commercially recommended concentrations of uniconazole as a preplant bulb soak and a foliar spray for height control of `Star Gazer' oriental lily (Lilium hybrids). Foliar sprays of uniconazole at 10 mg·L–1 (ppm) did not control plant height and foliar sprays of flurprimidol concentrations ≥80 mg·L–1 provided only minimal height control. Substrate drenches of flurprimidol at 0.5 mg/pot a.i. (28,350 mg = 1 oz) controlled plant height, resulting in plants 45.3 cm (17.83 inches) tall, which were 24% shorter than the untreated control. Uniconazole preplant bulb soaks of 5 and 10 mg·L–1 controlled plant height, resulting in plants 41.8 cm (16.46 inches) and 37.8 cm (14.88 inches), respectively. Preplant bulb soaks of flurprimidol (25 to 400 mg·L–1) were applied and a concentration of 25 mg·L–1 resulted in plants 47.7 cm (18.78 inches) tall, which were 23% shorter than the untreated control. Flurprimidol substrate drenches and preplant bulb soaks at concentrations of 0.5 mg/pot a.i. and 25 mg·L–1, respectively, were effective in controlling height in `Star Gazer' lily. In Expt. 2, flurprimidol substrate drenches were applied as either a single or two split applications. A one-time flurprimidol substrate drench of 0.5 mg/pot a.i. provided similar control as two split applications of 0.25 mg/pot a.i.
Defoliation of Woody Cut Stems with Preharvest, Less Toxic Chemical and Postharvest Environmental Methods
Authors: Greer Lane , Dole John M.
Published: December 2018

Six defoliants were applied in fall and tested for their efficacy in preharvest defoliation of fieldgrown curly willow (Salix matsudana `Tortuosa'), american bittersweet (Celastrus scandens), and american beautyberry (Callicarpa americana). Defoliants included acetic acid, chelated copper, crop oil concentrate surfactant (COC), ethephon, dimethipin plus COC, pelargonic acid, and a tap water control. For chelated copper, a concentration of 800 mg·L–1 (ppm) was most effective at promoting defoliation, providing 100% defoliation of american bittersweet and 76% defoliation of american beautyberry. For curly willow and american beautyberry, all concentrations of dimethipin produced good or excellent defoliation. Increasing concentrations of ethephon from 200 to 2500 mg·L–1 increased defoliation from 0% to 67%. Pelargonic acid was not effective at promoting defoliation of woody plants at the concentrations used. In an experiment conducted during spring using containerized curly willow, irrigation was stopped for 0, 3, or 6 days before defoliants were applied, but none of the irrigation treatments promoted defoliation. In a postharvest study using cut curly willow, stems were held in distilled water at 5, 20, or 35 °C (41.0, 68.0, or 95.0 °F) for 1, 3, 5, or 7 days. Holding cut stems of curly willow at 20 °C promoted 68% defoliation, compared to 53% or 28% for 5 or 35 °C, respectively.
Photoperiodic Response and Vase Life of Ornamental Sunflower Cultivars
Authors: Yañez Paola , Ohno Hajime , Ohkawa Kiyoshi
Published: December 2018

Photoperiodic response and vase life of 28 cultivars of ornamental sunflower (Helianthus annuus) were evaluated. Plants were grown in a glasshouse under 16-hour long-day (LD) or 11.5-hour shortday (SD) conditions. Most cultivars (82%) reached visible flower bud stage earlier under SD than LD. All cultivars flowered under both SD and LD conditions, but in 26 cultivars (92.9%) flowering was significantly delayed under LD, demonstrating them to be quantitative SD plants. The delay was variable among the cultivars. A 14-day or greater hastening of flowering was found under SD in 18 cultivars. Photoperiod had no effect on flowering of `Lemon Eclair' and `Moonshadow'; these cultivars are day-neutral (DN) plants. For some cultivars the LD photoperiod increased plant height and the number of nodes and leaves. Vase life varied from 6.8 to 11.2 days depending on the cultivar, but no photoperiodic effect was found.
Single-centered and Super Colossal Bulbs from Yellow Onion Cultivars
Authors: Shock Clinton C. , Feibert Erik , Saunders Lamont D.
Published: December 2018

Onion (Allium cepa) cultivars for commercial production in eastern Oregon and southwestern Idaho are evaluated annually in replicated yield trials conducted at the Malheur Experiment Station, Oregon State University, Ontario. Market demand has progressively called for larger bulb size and bulbs with single centers. At harvest onions were evaluated for maturity, number of bolters, and single centeredness. Cultivars showed a wide range of bulbs with only one growing point or “bullet” single centers, ranging from 1% to 57% in 2000, from 7% to 70% in 2001, and from 1% to 74% in 2002. The percentages of bulbs functionally single-centered for processing uses ranged from 18% to 88% in 2000, from 24.7% to 91.3% in 2001, and from 14.4% to 92% in 2002. Bulb yield and market grade were evaluated out of storage. Marketable yield after 4 months of storage varied significantly by cultivar from 643 to 1196 cwt/acre (72.1 to 134.1 Mg·ha–1) in 2000, from 538 to 980 cwt/acre (60.3 to 109.8 Mg·ha–1) in 2001, and from 583 to 1119 cwt/acre (65.3 to125.4 Mg·ha–1) in 2002. Averaging over cultivars, super colossal bulb size averaged 26%, 14%, and 10% in 2000, 2001, and 2002, respectively.
Improving Research on Youth Gardening
Authors: Phibbs Elizabeth J. , Relf Diane
Published: December 2018

Results of research on youth gardening programs indicate a variety of benefits; however, most studies to date have encountered difficulties in separating treatment effect from confounding variables. A survey of those recently involved in this type of research was conducted to identify common problems and generate suggestions for improving future research efforts. Problems reported as most frequently encountered include difficulty with timing and logistics, lack of funding, and finding and keeping sufficient numbers of participants. Suggestions for obtaining stronger results include: allowing plenty of time for planning, establishing good communication with collaborators, choosing topics relevant to funding agencies and policy makers, and creating interdisciplinary studies that are longitudinal or large-scale collaborative efforts.
Impact of Hands-on Science through School Gardening in Louisiana Public Elementary Schools
Authors: Smith Leanna L. , Motsenbocker Carl E.
Published: December 2018

The first four chapters of a hands-on gardening curriculum (Junior Master Gardener Handbook Level One) were introduced into three East Baton Rouge Parish (Louisiana) elementary schools in the fall semester of 2002 as an informal education program conducted by East Baton Rouge Parish Master Gardener volunteers and Louisiana State University students. The curriculum took place once per week for 2 hours during regular school hours. Science achievement tests, developed at Texas A&M University specifically for the Junior Master Gardener program, were given before and after the students participated in the gardening activities to determine whether or not the activities helped improve achievement scores. Science achievement was significantly different (P ≤ 0.0167) between the experimental classes' pretest and posttest scores, while no significant difference was found between the pretest and posttest scores of the control classes. No significant difference was found between the experimental and control classes due to treatment. Several variables may have affected the outcome of the study, but the results show once weekly use of gardening activities and hands-on classroom activities help improve science achievement test scores.
Growing Minds: The Effect of a School Gardening Program on the Science Achievement of Elementary Students
Authors: Klemmer C.D. , Waliczek T.M. , Zajicek J.M.
Published: December 2018

Science achievement of third, fourth, and fifth grade elementary students was studied using a sample of 647 students from seven elementary schools in Temple, Texas. Students in the experimental group participated in school gardening activities as part of their science curriculum in addition to using traditional classroom-based methods. In contrast, students in the control group were taught science using traditional classroom-based methods only. Students in the experimental group scored significantly higher on the science achievement test compared to the students in the control group. No statistical significance was found between girls and boys in the experimental group, indicating that gardening was equally effective at teaching science for both genders. After separating the data into the grade levels, the garden curriculum was more effective as a teaching method in raising science achievement scores for boys in third and fifth grades, and for girls in the fifth grade compared to traditional classroom-based methods alone.