bluuebunny/crossref_metadata_2025 huggingface dataset:
Maturity and Storage Quality of `Concorde' Pears
Authors: Drake S.R. , Mielke E.A. , Elfving D.C.
Published: December 2018

`Concorde' pears from three plantings were harvested at various maturities, stored in regular (RA) or controlled atmosphere (CA) storage and their quality evaluated. Starting at a firmness of 57.0 N (12.81 lbf), `Concorde' pears can be harvested over a period of 14 days with no loss in quality and be good candidates for either RA or CA storage. A 14-day delay in harvest resulted in a one box size increase. Regardless of the time of harvest, `Concorde' pears can be stored in RA for periods not to exceed 90 days. RA storage beyond 90 days resulted in reduced appearance, poor pedicel condition, and enhanced internal breakdown. Early harvest should be considered when RA storage is expected to exceed 90 days; however astringency may develop. Regardless of harvest, `Concorde' pears can be stored for 180 days in CA with no quality loss, particularly if the CA composition is 1.5% oxygen (O2) and 1.0% carbon dioxide (CO2). Internal breakdown can be a problem in CA if the CO2 exceeds 1.0%. Low O2 (<1.5%) CA is not recommended for `Concorde' pears.
Yield of Four Generations of Virus-tested Sweetpotato
Authors: La Bonte D. , Clark C. , Hoy M. , Villordon A. , Cannon J. , Sistrunk M. , Freeman E. , Roberts G.
Published: December 2018

The yield of three generations of virus-tested plants of `Beauregard' sweetpotato (Ipomoea batatas) was assessed in Louisiana over a 4-year period in 15 yield trials. Treatments included virus-infected foundation `Beauregard', virus-tested `Beauregard' mericlone, B-63 [generation 1 (G-1)], and three generations of B-63 (G-2, G-3 and G-4). Generations refer to the number of continuous years virus-tested plants are grown in the field. Use of G-2 virus-tested `Beauregard' transplants increased yields of U.S. no. 1 grade roots by 16% in comparison with virus-infected, foundation `Beauregard'. Total marketable yield was also higher (11%) using B-63 G-2 transplants in comparison to virus-infected, foundation `Beauregard'. Use of B-63 (G-1), G-3 and G-4 generation transplants did not increase yields in any grade in comparison to virus-infected, foundation `Beauregard' by planting plots amidst virus-infested sweetpotato fields. Generation one B-63 transplants were greenhouse grown and often appeared less robust after planting. Yet we were unable to show significant yield differences between greenhouse derived B-63 (G-1) and field-grown B-63 (G-1) in separate tests; other factors may be involved.
Controlling Bitter Pit in `Honeycrisp' Apples
Authors: Rosenberger D.A. , Schupp J.R. , Hoying S.A. , Cheng L. , Watkins C.B.
Published: December 2018

Control of bitter pit in `Honeycrisp' apples (Malus ×domestica) from trees treated during the growing season with foliar sprays of trifloxystrobin fungicide and calcium was evaluated in four replicated trials over 2 years. All trials were in commercial orchards of `Honeycrisp' trees that were 3 to 6 years old. The effectiveness of combining boron with foliar applications of calcium chloride (CaCl2) was evaluated in two trials, and effectiveness of harpin protein, used either alone or in alternating sprays with CaCl2 was assessed in one trial. Trifloxystrobin applied twice during the 30 days before harvest reduced bitter pit incidence at harvest in one of the four trials, but the reduction was transitory, no longer being evident when fruit were re-evaluated after 63 days of cold storage. Harpin protein did not affect disorder incidence. Calcium sprays failed to control bitter pit in treatments where the total elemental calcium applied was less than 2.7 lb/acre (3.03 kg·ha–1) per year for tree canopies that were sprayed to drip using 100 gal/acre (935.4 L·ha–1) of spray solution. In the two trials where some treatments involved application of at least 2.9 lb/acre (3.25 kg·ha–1) of elemental calcium per season, the incidence of fruit with bitter pit at harvest was reduced by 76% to 90%. Effectiveness of calcium sprays for bitter pit control was not enhanced by superimposing trifloxystrobin, boron, or harpin protein treatments. Flesh firmness at harvest was lower in calcium-treated than in non-treated fruit, and fruit maturity was more advanced on trees receiving boron sprays than on trees receiving no boron. In one trial, where the first calcium application was made approximately 2 weeks after petal fall and 4 days prior to a fruit thinning spray, crop load of trees that received calcium sprays, measured as number of fruit per cm2 trunk cross-sectional area, was 38% greater than on trees that received no calcium sprays. CaCl2 provided better control of bitter pit in `Honeycrisp' than any of the other materials tested.
Influence of Temperature Gradients on Pale and Purple Coneflower, Feverfew, and Valerian Germination
Authors: Hassell Richard L. , Dufault Robert J. , Phillips Tyron , Hale Teri A.
Published: December 2018

Seeds of pale coneflower (Echinacea pallida), purple coneflower (Echinacea purpurea), feverfew (Tanacetum parthenium), and valerian (Valeriana officinalis), classified as “old” (1-year-old seed) or “fresh” (seed crop produced in the current year), were germinated at 62, 65, 69, 72, 75, 78, 82, 85, 89, and 92 °F, (16.7, 18.3, 20.6, 22.2, 23.9, 25.6, 27.8, 29.4, 31.6, and 33.3 °C). The optimum germination temperature, defined in this study as the temperature range within which the percent germination is greatest in the shortest period of time, was determined. Old and fresh pale coneflower seed germinated optimally after 5 days at 69 °F. Old purple coneflower seed required 5 d at 78 to 82 °F, but fresh seed germinated optimally after 3 days at 75 °F. Old feverfew germinated optimally after 5 days at 65 °F, but fresh seed germinated to its optimum after 5 days at 69 °F. Old and fresh valerian seed germinated to its optimum after 3 days at 75 °F.
Performance of 67 Native Midwestern U.S. Perennials in a Low-maintenance Landscape
Authors: Thomas Andrew L. , Schrock Denny
Published: December 2018

Hundreds of perennial plant species native to the midwestern United States have potential as ornamentals, but information on how best to use such plants in the landscape remains scarce. Many horticulturists are looking for species that perform well under low-maintenance conditions and that also attract and benefit desirable fauna, such as butterflies and birds. While many of our native plants may fit into this category, not all such species will meet aesthetic criteria for home landscapes. Some native species respond to seasonal changes in temperature and rainfall by browning or going dormant. Others have very specific site requirements for moisture, soil, and humidity that may be difficult to meet in an urban landscape, or their size, growth habit, or other characteristics may make them aesthetically undesirable in the typical home landscape. This study evaluated the performance of 67 plant taxa native to the midwestern United States selected for their promising potential in a low-maintenance landscape situation.
Rapid Estimation of Cabbage Head Volume across a Population Varying in Head Shape: A Test of Two Geometric Formulae
Authors: Radovich Theodore J.K. , Kleinhenz Matthew D.
Published: December 2018

Volume measurements are useful in crop quality management because they offer three-dimensional estimates of commodity size, which is often closely related to commodity weight and density. The objective of this study was to compare volume estimates calculated with the sphere and spherical ellipsoid volume formulae with direct measures of volume via water displacement across a population of cabbage (Brassica oleracea Capitata Group) heads varying widely in shape. A total of 157 heads with polar (P): equatorial (E) diameter ratios ranging between 0.5 (flat) to 2.1 (tall) were harvested at horticultural maturity from plants grown in 2002 and 2003 at the Ohio Agricultural Research and Development Center (OARDC) in Wooster, Ohio. The sphere formula underestimated volume in heads with P:E ratios <1 and overestimated volume in heads with P:E ratios >1. Use of the spherical ellipsoid formula reduced the shapedependency of volume estimates and was determined to be a valuable tool for the accurate, precise, and rapid measurement of head volume.
Integrating Airborne Imagery and GIS Technology to Map and Compare Citrus Blackfly Infestations Occurring in Different Years
Authors: Fletcher Reginald S. , Everitt James H. , Davis Michael R. , Escobar David E.
Published: December 2018

Major citrus blackfly (Aleurocanthus woglumi) outbreaks occur periodically in the Lower Rio Grande Valley (LRGV) of Texas, causing a reduction in citrus (Citrus sp.) tree yields. This research reports on the integration of airborne color-infrared (ACIR) imagery and geographic information system (GIS) technology for mapping citrus blackfly outbreaks appearing in this area in separate years. For this study, the 1993 and 2002 citrus blackfly infestations were mapped and compared. Outbreaks did not appear at the same sites for 1993 and 2002. In 1993, infestations occurred in the southern part of Hidalgo and Cameron counties compared with outbreaks primarily appearing in the western portion of Hidalgo County in 2002. For both years, Hidalgo County was affected more than the other citrus producing counties in the LRGV. This study demonstrated airborne remote sensing imagery integrated with GIS technology could be used to develop maps for comparing citrus blackfly infestations appearing in separate years.
Using Personal Digital Assistants and Database Forms as Tools for Field Data Collection: Practical Experiences from Research Trials
Authors: Villordon Arthur , Franklin Jason , LaBonte Don
Published: December 2018

Handheld computing devices, such as personal digital assistants (PDAs), can potentially reduce repetitive tasks that pervade data collection activities in horticultural research. PDA-collected records are electronically transferred to a desktop computer, eliminating manual reentry as well as the need of reviewing for incorrect data entries. In addition, PDAs can be enclosed in protective cases, enabling data collection in inclement weather. Visual CE-generated database forms installed on PDAs were used to electronically collect data from research trials conducted in 2003. The records were subsequently transferred to Microsoft Access desktop database tables for archiving and subsequent statistical analyses. Data for certain trials were also manually collected using paper forms to facilitate comparison between manual and PDA-assisted data collection methods under controlled conditions. Using paired samples analysis, we determined that electronic transfer of records reduced the time required to store the records into desktop computer files. Manual and PDA-based recording methods did not vary in the time required to enter numerical measurements. Our experience demonstrates that off-the-shelf software and consumer PDA devices are viable options for data collection in research. PDA-assisted data collection is potentially useful in situations where remote, site-specific records need to be merged into a central database and where standardized measurements and observations are essential for performing analysis.
Flurprimidol Foliar Sprays and Substrate Drenches Control Growth of `Pacino' Pot Sunflowers
Authors: Whipker Brian E. , McCall Ingram , Gibson James L. , Cavins Todd J.
Published: December 2018

Flurprimidol substrate drenches at 2 mg a.i. per 15.3 cm (6 inch) pot were more effective on `Pacino' pot sunflowers (Helianthus annuus) than flurprimidol foliar sprays of ≥30 mg.L–1 (ppm), but both treatments resulted in significantly smaller plant height and diameter than the control (28,350 mg = 1 oz). Flurprimidol drenches of 2 mg were comparable in controlling plant height and diameter to the commercial drench recommendations of 2 mg paclobutrazol. The commercial recommendation of daminozide foliar sprays at 4000 mg.L–1 had greater efficacy in controlling plant height than the most effective flurprimidol foliar sprays of ≥30 mg.L–1. Daminozide had no effect on plant diameter, while flurprimidol resulted in narrower plants. Flurprimidol and paclobutrazol drenches of 2 mg offer the economic advantage to producers of increased plant density on greenhouse benches, while plants treated with daminozide would require a greater amount of bench area. Producers should evaluate the trade-offs between the added costs of a drench vs. the higher cost-per-square-foot-week of production space required for a daminozide foliar spray. With these options, producers can select a plant growth regulator (PGR) that best fits their production and market requirements.
Trinexapac-ethyl, Propiconazole, Iron, and Biostimulant Effects on Shaded Creeping Bentgrass
Authors: Ervin E.H. , Zhang Xunzhong , Goatley J.M. , Askew S.D.
Published: December 2018

Creeping bentgrass (Agrostis stolonifera) is used extensively on temperate zone golf course greens, tees, and fairways, but often performs poorly in shade. Previous research has indicated that sequential applications of gibberellic acid (GA) inhibiting plant growth regulators (PGRs) such as trinexapac-ethyl (TE) increase cool-season turfgrass performance in 70-90% shade. This research was conducted to: 1) confirm appropriate TE application rates and frequencies for maintaining `Penncross' creeping bentgrass in dense shade in the mid-Atlantic region of the U.S.; 2) determine the efficacy of other PGRs, biostimulants, and iron (Fe); and 3) assess whether the addition of a biostimulant with TE would have additive, synergistic, or negative effects. The other compounds tested against TE and the control were: propiconazole (PPC), iron sulfate, CPR (a seaweed and iron containing biostimulant), and a generic seaweed extract (SWE) (Ascophyllum nodosum) plus humic acid (HA) combination. These treatments were applied to 88% shaded bentgrass every 14 days from May or June through October in 2001 and 2002, with turf quality, leaf color, root strength, photochemical efficiency, and antioxidant enzyme superoxide dismutase (SOD) activity being determined. While the quality of control plots fell below a commercially acceptable level by the second month of the trial, repeated foliar TE application provided 33% to 44% better quality throughout the experiment. Propiconazole resulted in 13% to 17% better quality through September of each year. Trinexapac-ethyl and PPC resulted in darker leaf color and increased mid-trial root strength by 27% and 29%, respectively. Canopy photochemical efficiency and leaf SOD activity were also increased due to TE in August of both years. Treatment with Fe, CPR, or SWE+HA did not have an effect on quality, root strength, SOD, or photochemical efficiency, but periodic increases in color were observed. The addition of CPR to TE in 2002 provided results that were not different from those of TE-alone. This and previous studies indicate that restricting leaf elongation with anti-GA PGRs is of primary importance for improving shade tolerance, while treatments that increase leaf color or chlorophyll levels without restricting leaf elongation are relatively ineffective.
Analysis of Effort for Plant Maintenance in Relation to Garden Composition
Authors: Stimart Dennis P. , Martin William J.
Published: December 2018

The time required to maintain plants on a standardized basis (effort) was investigated in 24 gardens of various plant composition over 5 years. Cluster analysis of data grouped gardens into five clusters based on magnitude and timing of effort. Plants grown in containers required up to 20 times more effort annually than plants grown in other gardens in ground beds. Gardens planted with annuals required about 80% less effort than container gardens but 75% more effort than other gardens evaluated. As the number of taxa in gardens decreased, effort decreased and was less variable throughout the year. Enumeration of effort in relation to garden composition should be used to project management cost for gardens.
Penetrometer and Taste Panel Perception of Pericarp Tenderness in su, se, and sh2 Sweet Corn at Three Maturities
Authors: Hale Teri A. , Hassell Richard L. , Phillips Tyron , Halpin Elizabeth
Published: December 2018

Taste panel perception and preference of pericarp tenderness in three phenotypes (su, se, and sh2) of sweet corn (Zea mays) harvested at three different maturities were compared to the readings received from a penetrometer. Pericarp tenderness perception by taste panel correlated with penetrometer measurements when phenotypes and maturities were compared. The penetrometer showed significantly lower readings for sweet corn harvested at early maturity than those harvested at late maturity. This was also noted in the panelists' perception of tenderness, with the early and mature harvest samples being preferred over those from the late harvest. The only difference between cultivars within phenotypes was noted in sh2 `Rustler' and `AXC904'. `Rustler' received the greatest overall pentrometer values and lowest panel ratings; conversely, `ACX904' had low penetrometer values and was perceived as tender and very acceptable to panelists. Correlations between penetrometer readings and panel perception of pericarp tenderness indicate that a puncture force, using a 0.118-inch (3.0 mm) probe, of greater that 0.95 g/inch2 (0.147 g·cm-2) indicated a tough pericarp and lower than 0.70 g/inch2 (0.109 g·cm-2) indicated a tender pericarp.
Effect of the Insect Growth Regulator Novaluron (Pedestal) on Silverleaf Whitefly Reproduction
Authors: Cloyd Raymond A. , Keith Stephen R. , Galle Cindy L.
Published: December 2018

Insect growth regulators, which are primarily used to kill the larval stages of certain insect groups, have indirect effects on the adult stage of whiteflies. In this study, we assessed the effect of the insect growth regulator novaluron (Pedestal) on the reproduction of silverleaf whitefly (Bemisia argentifolii). Two experiments were conducted by exposing adult female silverleaf whiteflies to the low [0.47 mL·L-1 (6 floz/100 gal)] and high [0.63 mL·L-1 (8 floz/100 gal)] label-recommended rates of novaluron. There was also an untreated control. Infested plants [mist flower (Eupatorium coelenstinum) and transvaal daisy (Gerbera jamesonii) for Expt. 1 and Expt. 2, respectively] containing adult female silverleaf whiteflies were sprayed with novaluron using a carbon dioxide (CO2) backpack sprayer. Plants were immediately placed into cages covered with antivirus insect screening. After 24 hours, six adult female silverleaf whiteflies were aspirated from the treated plants, and immobilized with CO2 before being placed onto untreated plants [transvaal daisy for Expt. 1, and rose-of-china (Hibiscus rosa-sinensis) for Expt. 2]. Three munger cells containing two adult female silverleaf whiteflies per cell were attached to leaves of each of the untreated plants. The number of live and dead eggs, and live nymphs per plant was assessed 4 and 8 days after treatment (DAT). In Expt. 1, the low rate of novaluron significantly reduced egg viability compared to the untreated control based on live nymphal counts 8 DAT. In Expt. 2, both rates of novaluron significantly reduced egg viability compared to the untreated control, based on live nymphal counts and number of dead eggs 8 DAT. The results from this study indicate that novaluron negatively affected female silverleaf whitefly reproduction by reducing egg viability, which may decrease the number of silverleaf whiteflies produced during a cropping cycle. This is an important long-term pest management strategy that may reduce the number of insecticide applications and decrease labor costs.
A Comparison of Airblast and Air Assisted Rotary Atomizer Spray Technologies in Peach Production
Authors: Reilly Charles C. , Hotchkiss Michael W. , Taylor Kathryn C.
Published: December 2018

Pesticide application in peach (Prunus persica) orchards with a commercial airblast sprayer was compared to that of an air assisted rotary atomizer (AARA), low-volume sprayer during the 2000 through 2003 seasons. The two technologies were employed during early season petal fall applications, shuck split applications and standard cover sprays using phosmet, sulfur, propiconazole, chlorothalonil, azoxystrobin and captan. Ripe fruit, picked 1 day prior to first harvest each season were rated for peach scab (Cladosporium carpophilum), brown rot (Monilinia fructicola), insect (Hemipteran) damage (cat facing), and blemishes. Differences in brown rot, insect damage, and blemish ratings were not detected between the treatments for each of the four seasons. Differences were detected during the 2000 and 2001 seasons for peach scab, with the AARA sprayer plots having a higher incidence. Spray coverage was quantitatively evaluated with Rhodamine B dye by leaf rinses that indicated there was equivalent coverage for each application method. Phosmet residue detection on trees of the treated rows was also equivalent from each method. Phosmet off-target spray movement (drift) was reduced 59% one row away from the treated row and 93% in the fifth row from the treated row by the AARA sprayer compared to airblast sprayer drift.
Consumer Preferences for Chestnuts, Eastern Black Walnuts, and Pecans
Authors: Gold Michael , Cernusca Mihaela M. , Godsey Larry
Published: December 2018

Edible chestnuts are an ancient tree crop undergoing a global renaissance. Scattered efforts are under way throughout the U.S. to develop domestic chestnut production based on chestnut cultivars from Europe or Asia. Concurrently, it is necessary to redevelop the domestic market by reintroducing the chestnut as a food crop to a new generation of U.S. consumers. A study was conducted to gauge the familiarity of participants with chinese chestnuts (Castanea mollissima), eastern black walnuts (Juglans nigra), and northern pecans (Carya illinoensis) to determine their interest in buying, consuming, and preparing these nuts and the key attributes that influence purchase decisions. The study also determined participants' interest in obtaining more information about the production, marketing, cooking, preparation, and nutritional information of nuts. Results of the study show that consumers were not familiar with chestnuts. Most had never tasted a chestnut, but did have interest in exploring them as a new food. Quality and nutrition-diethealth were consistently listed as the most important attributes influencing purchase and consumption decisions for chestnuts and black walnuts but for pecans, locally grown was the most important attribute.
Writing Across the Curriculum: Where Does Horticultural Science Fit In?
Authors: Zambreno Karina , Hoover Emily , Anderson Neil , Gillman Jeffrey H.
Published: December 2018

In Fall 1999, the University of Minnesota implemented a writing-intensive (WI) requirement for undergraduates. As part of the requirement, students must take one upper-division WI course in their major. As of Spring 2002, the environmental horticulture major through the Department of Horticultural Science had only one WI course in its entire curriculum. Teaching faculty were interviewed and syllabi were reviewed to gather information on what types of writing are currently being assigned and to discuss where more WI courses should be placed in the environmental horticulture curriculum in the future. These surveys and interviews revealed that the majority of classes require formal writing and that the majority of the faculty review or are willing to review a draft of an assignment, two key components of the WI requirement. Informal writing assignments are less common, indicating a deficient area of the curriculum. With slight modifications, many classes in the environmental horticulture curriculum can meet the requirements to become designated as WI. Faculty agreed that WI courses should be placed in upper-level, smaller classes that place less emphasis on production techniques or plant identification.
Uses of Compost in Potting Mixes
Authors: Moore Kimberly K.
Published: December 2018

The ornamental horticulture industry uses a variety of materials as ingredients in growing substrates for many ornamental plants. There are many attributes that make growing substrates effective, including good aeration and drainage, availability at an acceptable price, and chemical attributes conducive for plant growth. In recent years there has been a trend in which more traditional organic components, such as Canadian sphagnum peat, have been partially replaced by an increasing array of waste-product compost. Plant response to increasing quantities of compost in the potting mix, and to different types of compost are variable. This paper reviews some important issues in the utilization of urban waste compost products.
Compost in the 20th Century: A Tool to Control Plant Diseases in Nursery and Vegetable Crops
Authors: Zinati Gladis M.
Published: December 2018

The discovery of disease suppression in certain bark composts increased the interest in using compost as growing substrate to control root rot diseases caused by Phytophthora cinnamomi. Disease suppression mechanisms include antibiosis, competition, hyperparasitism, and induced systemic resistance. Although abiotic factors may influence disease suppression, the latter is often based on microbial interactions—the two common mechanisms being general for pythium (Pythium spp.) and phytophthora root rot (Phytophthora spp.) and specific for rhizoctonia (Rhizoctonia solani). The discovery of disease suppression agents in compost led to the development of biocontrol agent-fortified compost during the last decade of the 20th century. The suggested recommendations for future research and extension outreach may include 1) development of methods to manage bacterial and viral diseases through the use of compost; 2) exploration of the potential effects of fortified compost on insect pests suppression; 3) improvement of inoculation methods of composts with biocontrol agents to produce consistent levels of disease suppression at the commercial scale; 4) development of effective fortified compost teas for suppressing foliar diseases; 5) education of compost producers on methods of production of fortified compost that suppress specific diseases; and 6) education of end-users on uses of fortified compost and its by-products.
Salinity Interactions with Other Abiotic and Biotic Stresses in Citrus
Authors: Syvertsen Jim , Levy Yoseph
Published: December 2018

Multiple stresses almost always have synergistic effects on plants. In citrus, there are direct and indirect interactions between salinity and other physical abiotic stresses like poor soil drainage, drought, irradiance, leaf temperature, and atmospheric evaporative demand. In addition, salinity interacts with biotic pests and diseases including root rot (Phytophthora spp.), nematodes, and mycorrhizae. Improving tree water relations through optimum irrigation/drainage management, maintaining nutrient balances, and decreasing evaporative demand can alleviate salt injury and decrease toxic ion accumulation. Irrigation with high salinity water not only can have direct effects on root pathogens, but salinity can also predispose citrus rootstocks to attack by root rot and nematodes. Rootstocks known to be tolerant to root rot and nematode pests can become more susceptible when irrigated with high salinity water. In addition, nematodes and mycorrhizae can affect the salt tolerance of citrus roots and may increase chloride (Cl-) uptake. Not all effects of salinity are negative, however, as moderate salinity stress can reduce physiological activity and growth, allowing citrus seedlings to survive cold stress, and can even enhance flowering after the salinity stress is relieved.
Effect of Cotton Gin Compost on Substrate Properties and Growth of Azalea under Differing Irrigation Regimes in a Greenhouse Setting
Authors: Cole D.M. , Sibley J.L. , Blythe E.K. , Eakes D.J. , Tilt K.M.
Published: December 2018

`Formosa' azalea (Rhododendron indicum) was grown for 4 months in 7.6-L (2 gal) containers in four substrate blends: 100% pine bark (PB) (by volume), 1 PB: 1 cotton gin compost (CGC), 3 PB: 1 CGC, and 3 PB: 1 peat (PT) at three irrigation levels [600, 1200, and 1800 mL·d-1 (20.3, 40.6, and 60.9 floz/d)] in a polyethylene-covered greenhouse. Plants were evaluated for growth on a biweekly basis using a growth index. Roots were evaluated visually at the end of the study using a 0 (no root growth) to 5 (root bound) scale. Initial physical properties were determined and leachates were collected every 30 days. There was no difference in percent increase in growth across irrigation and substrate treatments. Visual root rating was greatest (4.5) for azaleas grown in 3 PB: 1 PT and least (3.5) in 1 PB: 1 CGC. The two PB/CGC blends improved water-holding capacity (WHC) in comparison to 100% PB, with 1 PB: 1 CGC exhibiting the greatest WHC among all four substrates. Bulk density was greatest with the CGC-amended substrates. Leachate pH tended to increase and electrical conductivity (EC) tended to decrease with increasing irrigation volume. Leachates from the CGC-amended substrates were less acidic and EC tended to be similar or greater than leachates from the 100% PB and 3 PB: 1 PT substrates.
Maximizing Performance of Plant Growth Regulators by Improving Spray Application
Authors: Bukovac Martin J.
Published: December 2018

The importance of spray application and the role of spray additives are reviewed in reference to increasing the effectiveness of plant growth regulators (PGR). The spray application process is composed of a number of interrelated components, from formulation of the active ingredient into a sprayable, bioactive solution (emulsion/suspension), to atomization, delivery, retention, and penetration into the plant tissue. Each of these events is critical to performance of the PGR. Also, each can be affected by spray additives, particularly adjuvants, which may be incorporated in the formulation of the active ingredient or added to the spray mixture. The role of the individual components and effects of spray adjuvants, particularly surfactants and fertilizer adjuvants, on the component processes are discussed.
Turf and Ornamental Plant Tolerances to Endothall in Irrigation Water I. Ornamental Species
Authors: Koschnick Tyler J. , Haller William T. , MacDonald Greg E.
Published: December 2018

Restrictions on the endothall aquatic herbicide label include the use of endothall treated water for irrigating plants from 7 to 25 days after application. This interval was established to allow sufficient time for endothall to dissipate to levels that were considered safe for irrigation to prevent phytotoxicity to desirable plants. The affects of endothall on begonias (Begonia semperflorens `Vodka Cocktail'), pansies (Viola × wittrockiana `Atlas Purple'), petunias (Petunia hybrida), and impatiens (Impatiens wallerana `Lipstick') were determined by comparing aboveground dry weight to control plants after exposure to endothall in irrigation water. The objective was to determine if endothall concentrations used for aquatic weed control were phytotoxic to ornamental plants. Plants were irrigated every other day for 6 days in Expt. 1 with constant concentrations of endothall, and for 8 days in Expt. 2 with decreasing concentrations of endothall. Concentrations causing a 10% reduction in dry weight (effective concentration: EC10) compared to control plants showed there was a wide range of tolerance among plants exposed to endothall in irrigation water in the two experiments. Begonias, pansies, and impatiens had the lowest tolerance to two formulations of endothall in irrigation water with EC10 values ranging from 2 to 4 mg·L–1 (ppm) a.i. (a.i. based on acid equivalence) in both experiments. Petunias, which were more tolerant to endothall, had EC10 values of 15 and 34 mg·L–1 a.i. in Expt. 1 and 11 and 20 mg·L–1 a.i. in Expt. 2 for the amine and dipotassium formulations of endothall, respectively. Endothall did abscise flowers on impatiens after irrigation with endothall at concentrations of 10 mg·L–1 a.i. and higher. Effects of endothall on begonias at concentrations close to the EC10 values (2 to 3 mg·L–1 a.i.) were limited to growth inhibition with no apparent desiccation or necrosis of plant tissue.
Creating a School Gardens Program in the Challenging Environment of Las Vegas, Nevada
Authors: O'Callaghan Angela M.
Published: December 2018

An important element of the social horticulture program at the University of Nevada Cooperative Extension has been the creation of school gardens to enhance educational efforts for children in Las Vegas. Since 2002, a variety of methods has been employed to train teachers and administrators in using gardens, and this has resulted in establishment of successful gardening programs. Southern Nevada has experienced a 400% population increase in 25 years. Results of surveys of area stakeholders between 2000 and 2002, Clark County elementary school staff in 2001, and Clark County school principals in 2004, indicate a desire to incorporate gardens in schools, but concerns about establishing and maintaining them persist. Furthermore, apprehension about trying to garden under challenging climatic conditions characteristic of the Mojave Desert is expressed frequently, as is hesitation about using gardens to enhance the school curriculum in at-risk schools. When offered training in use of gardens, however, a majority of principals surveyed responded positively. They also expressed interest in tracking the educational and social impacts of gardens on students and faculty. This article reports on results of community stakeholder meetings and surveys of Clark County schools, as well as the methods that are being used to create a school gardens program in the most rapidly growing metropolis in the United States.
Development of a Science Achievement Evaluation Instrument for a School Garden Program
Authors: Klemmer C.D. , Waliczek T.M. , Zajicek J.M.
Published: December 2018

School gardens show promise as a tool for developing science process skills through real-world investigations. However, little research data exist attesting to their actual effectiveness in enhancing students' science achievement. The purpose of this study was to develop three cognitive test instruments for assessing science achievement gain of third, fourth, and fifth grade students using a garden curriculum. The development of the test instruments occurred in three phases: 1) an initial set of test instruments which served as a prototype for length, scope, and format; 2) an adapted set of test instruments which were piloted; and 3) a final set of test instruments which were used for the assessment of the school gardening curriculum. The final Cronbach's alpha reliability for the final set of test questions was 0.82, indicating an acceptable level of internal consistency. Content validity of the test instruments developed for this study was established based on the science content standards specified in the Texas Essential Knowledge and Skills (TEKS) for each grade level along with the gardening curriculum, as well as the Science Scope and Sequence documents for Temple, Texas Independent School District (ISD). Construct validity was established for the testing instruments by soliciting help from various curriculum experts from the Temple ISD.
An Evaluation of the Junior Master Gardener Program in Third Grade Classrooms
Authors: Dirks Amy E. , Orvis Kathryn
Published: December 2018

Studies have shown gardening to have the potential to influence students in several positive ways. The hands-on and informal learning that occurs in these outdoor areas can be incorporated into all areas of the curriculum, fostering environmental awareness and increased interest in science. Junior Master Gardener (JMG) was chosen to be evaluated in 14 Indiana third grade classrooms as little formal classroom usage data exists for the program. It was hypothesized that the use of the program could help improve agriculture awareness and knowledge in youth. Quantitative and qualitative instruments and observations were utilized in a effort to evaluate knowledge gain and change of attitude towards the topics covered by the JMG curriculum; science, horticulture, and the environment. Student pre- and posttest results indicated overall significant gains in knowledge and attitudes. Performance was not attributed to student age, gender, race, or location of the school, although those schools with a garden achieved more positive gains in attitude and specific performance varied according to classroom. Qualitative data also indicated that the students enjoyed the program, shared what they learned with others, and wanted to participate in more JMG and gardening type activities. Teachers indicated that they were satisfied with the program in their classrooms and planned to reuse their JMG materials for future classes.
Can an Educational Program on the Nutritional Benefits of Citrus Fruit Positively Influence the Nutritional Attitudes of Children?
Authors: Koch Shari , Lineberger Sarah , Zajicek J.M.
Published: December 2018

The Citrus Guide, Teaching Healthy Living Through Horticulture (Citrus Guide) is an activity guide designed to help teachers integrate nutrition education into their classrooms. The objectives of this research project were to: 1) help teachers integrate nutrition education, specifically as it relates to citrus fruit, into their curricula by using the Citrus Guide; and 2) evaluate whether students developed more positive attitudes towards citrus fruit by participating in activities from the Citrus Guide. The nutritional attitudes of 157 second through fifth grade students were measured with a citrus fruit preference questionnaire divided into two sections: one targeting citrus fruit and the other targeting citrus snacks. After participating in the activities, no differences were detected in attitudes towards citrus fruit. However, students did have more positive attitudes towards citrus snacks after participating in the activities, with female students and younger students having the greatest improvement in citrus snack attitude scores. Also, there was a direct positive correlation between more grapefruit and oranges consumed daily and students' attitudes towards citrus fruit.
Children's Active and Passive Interactions with Plants Influence Their Attitudes and Actions toward Trees and Gardening as Adults
Authors: Lohr Virginia I. , Pearson-Mims Caroline H.
Published: December 2018

A nationwide phone survey of attitudes toward urban trees, participation in civic or educational activities, and memories of childhood experiences with gardening and nature was conducted with 2004 adults in large urban areas. We analyzed the influence of 11 childhood experiences and five adult demographic characteristics on three items: “Trees in cities help people feel calmer,” “Do trees have a particular personal, symbolic, or spiritual meaning to you?” and “During the past year, have you participated in a class or program about gardening?” Growing up next to natural elements such as flower beds, visiting parks, taking environmental classes, and gardening during childhood were associated with stronger adult attitudes and more actions. Growing up next to urban elements, such as large buildings, had a small, but opposite, influence. Demographics played a role in adult attitudes and actions. While both passive and active interactions with plants during childhood were associated with positive adult values about trees, the strongest influence came from active gardening, such as picking flowers or planting trees. These results indicate that horticultural programs for children raised in urban surroundings with few or no plants can be effective in fostering an appreciation for gardening in adults.
Trends in Stone Fruit Cultivar Development
Authors: Byrne David H.
Published: December 2018

Despite the hundreds of existing stone fruit (Prunus spp.) cultivars used for fresh market, there is a continuing need to develop new stone fruit cultivars as the requirements of the industry change. Over the last 20 years there has been a shift toward private breeding as the public sector decreases its support of these long-range programs. As a result there are fewer public breeding programs and many of those still operating protect their releases and partially fund their programs with royalty payments. Other trends that are shaping the development of new stone fruit cultivars are a need for smaller or more easily managed tree architecture, a trend toward the use of fewer agricultural chemicals, the expansion of production zones into the milder winter zones to allow year-round availability of stone fruit, a general diversification of fruit types being marketed, the increased awareness of the health benefits of fruit consumption, the need for better and more consistent quality, and given the global marketing of these fruit the increased need for enhanced postharvest qualities. The breeding programs of the world are responding to these trends and working toward developing the cultivars for the world markets of the future.
The Effect of Irrigation on Terbacil Tolerance in Field-grown Strawberry
Authors: Polter Steven B. , Doohan Douglas , Scheerens Joseph C.
Published: December 2018

Field experiments were conducted in newly planted strawberry (Fragaria ×ananassa) with terbacil applied at rates of 0 to 6.4 oz/acre a.i. either 4 days after planting but before appearance of new growth, or at the three-leaf stage. Irrigation of 0.4 inch was applied to half of the plots immediately after application of terbacil. Injury was greater when terbacil was applied before new growth than when applied at the three-leaf stage. Injury symptoms increased linearly with terbacil rate. Irrigation immediately following terbacil application reduced injury relative to non-irrigated plots. Weed control was reduced when terbacil was applied at the three-leaf stage than when applied before new growth. Irrigation did not reduce weed control. Herbicide injury symptoms were not detected the spring following terbacil application. Fruit yield was not affected by herbicide and irrigation treatments applied the previous year. The combination of low rates of terbacil, 0.8–1.6 oz/acre a.i., followed by irrigation to remove the herbicide from foliage is a safe option that growers can use to improve weed control and reduce hand weeding costs in the planting year.
Screening for Resistance to Pythium Root Rot among Twenty-three Caladium Cultivars
Authors: Deng Zhanao , Harbaugh Brent K. , Kelly Rick O. , Seijo Teresa , McGovern Robert J.
Published: December 2018

Caladiums (Caladium ×hortulanum) are widely grown as pot or landscape plants for their attractive leaves. Pythium root rot (Pythium myriotylum) is one of the most damaging diseases in caladium, severely reducing plant growth, aesthetic value, and tuber yield. Twenty-three commercial cultivars were inoculated with three aggressive isolates of P. myriotylum and evaluated for their resistance to root rot. Three cultivars, `Apple Blossom', `Blizzard', and `Etta Moore', were found to have a moderate level of resistance (partial resistance) to pythium root rot. The rest of these cultivars were susceptible or highly susceptible to Pythium infection, losing up to 94% of their root tissue to rotting within 10 days after inoculation. Data indicated a linear relationship between root rot severity and leaf loss severity on Pythium-inoculated plants and highlight the importance of controlling pythium root rot in caladium pot plant and tuber production. Comparison of some recent releases with their parents for pythium root rot resistance suggests the potential of developing new resistant caladium cultivars using the identified sources of resistance.
Application of a Biosolid Soil Amendment, Calcium Hydroxide, and Streptomyces for Management of Root-knot Nematode on Cantaloupe
Authors: Meyer Susan L.F. , Zasada Inga A. , Tenuta Mario , Roberts Daniel P.
Published: December 2018

The biosolid soil amendment N-Viro Soil (NVS) and a Streptomyces isolate (S 99-60) were tested for effects on root-knot nematode [RKN (Meloidogyne incognita)] egg populations on cantaloupe (Cucumis melo). Application of 3% NVS (dry weight amendment/dry weight soil) in the soil mixture resulted in significant (P ≤ 0.01) suppression of RKN egg numbers on cantaloupe roots compared to all other treatments, including 1% NVS and untreated controls. Ammonia accumulation was higher with the 3% NVS amendment than with any other treatment. Adjustment of soil pH with calcium hydroxide [Ca(OH)2] to the same levels that resulted from NVS amendment did not suppress nematode populations. When cultured in yeast-malt extract broth and particularly in nutrient broth, S 99-60 was capable of producing a compound(s) that reduced RKN egg hatch and activity of second-stage juveniles. However, when this isolate was applied to soil and to seedling roots, no suppression of RKN egg populations was observed on cantaloupe roots. Combining S 99-60 with NVS or Ca(OH)2 did not result in enhanced nematode suppression compared to treatments applied individually. The results indicated that NVS application was effective at suppressing RKN populations through the accumulation of ammonia to levels lethal to the nematode in soil.
Imidacloprid Insecticide Slows Development of Phony Peach and Plum Leaf Scald
Authors: Dutcher James D. , Krewer Gerard W. , Mullinix Benjamin G.
Published: December 2018

Observations in controlled field experiments over 5 years indicated that imidacloprid, applied as a soil drench around the trunks of peach (Prunus persica), nectarine (P. persica var. nectarine) and japanese plum (P. salicinia) trees at planting and in the early spring and mid-summer for two subsequent seasons (0.7 g/tree a.i.), slowed the development of symptoms of phony peach disease (PPD) and plum leaf scald (PLS) (Xylella fastidiosa) in the trees. After 3.5 years, the percentage of peach trees showing PPD symptoms was 8.5% for the imidacloprid-treated trees compared to 34.3% for untreated trees. After 4.5 years, the percentage of peach trees showing PPD symptoms was 13.1% in the treated trees and 71.4% in the untreated trees. After 3.5 years, nectarine trees in untreated and treated plots showed PPD symptoms in 8.3% and 0.9% of the trees, respectively. After 4.5 years, PPD symptoms in nectarine were found in 32.3% of the untreated trees and 8.5% of the treated trees. Development of PLS disease in plum was also slowed by the trunk drench with imidacloprid in two japanese plum varieties. After 3.5 years, dieback was observed in 55% of the twigs of untreated and 23% of the twigs of treated trees of `Au Rosa' plum and 33% of the twigs of untreated and 12% of the twigs of treated trees of `Santa Rosa' plum.
An Innovative Vegetative Propagation System for Large-scale Production of Globe Artichoke Transplants. Part II. Propagation System Validation
Authors: Cardarelli Mariateresa , Rouphael Youssef , Saccardo Francesco , Colla Giuseppe
Published: December 2018

Research was conducted at the University of Tuscia (central Italy) to validate the propagation system for globe artichoke (Cynara cardunculus var. scolymus) described in a previous paper for a 1-year production cycle. The resulting globe artichoke plants were used in a 2-year field trial to investigate the field response of plantlets obtained with our propagation technique in comparison with plantlets produced by in vitro propagation and by offshoots harvested in commercial fields. The total number of artichoke plantlets obtained with our propagation system was 62.7 plantlets/m2 per year. In the first year, the globe artichoke production (bud number and fresh bud weight) was higher in plants obtained with our propagation system and by micropropagation than in those obtained from offshoots harvested in commercial fields. The production cost of plantlets obtained with our propagation technique was 52% lower than those of the micropropagated plantlets. This could lead to a significant reduction of production costs for artichoke growers, while preserving the advantages of in vitro propagation (disease-free plants and plant uniformity).