bluuebunny/crossref_metadata_2025 huggingface dataset:
Disease Resistance and Adaptability of Stellar and Flowering Dogwood Cultivars at Two Alabama Sites
Authors: Hagan A.K. , Akridge J.R. , Ducar J. , Bowen K.L.
Published: August 2020

Stellar® dogwood (Cornus florida × kousa) cultivars Aurora®, Constellation®, Celestial™, Ruth Ellen®, and Stellar Pink® were compared with selected flowering dogwood (Cornus florida) cultivars Cherokee Brave®, ‘Cherokee Princess’, ‘Cloud 9’, and ‘Rubra’ in a simulated landscape planting at sites in southwest (USDA Hardiness Zone 8a) and northeast Alabama (USDA Hardiness Zone 7a) for their reaction to the diseases spot anthracnose, powdery mildew, and Cercospora leaf spot. Tree longevity as influenced by the occurrence of the dogwood borer (Synanthedon scitula) and an ambrosia beetle (Xylosandrus sp.) was also assessed at both sites. All Stellar® dogwood cultivars generally proved resistant to the bract and leaf spot phases of spot anthracnose as well as powdery mildew and Cercospora leaf spot. While Cherokee Brave® was the only flowering dogwood with partial resistance to powdery mildew at both sites; this and the other flowering dogwood cultivars were equally susceptible to spot anthracnose and Cercospora leaf spot. Insect damage levels were higher at the southwest site than the northeast Alabama site. Within 3 years of establishment at the southwest Alabama site, incidence of tunneling damage attributed to dogwood borer and an ambrosia beetle was higher on the Stellar® dogwood than flowering dogwood cultivars, which also had higher values for tree longevity. In contrast, tree longevity was equally high and insect damage equally low at the northeast Alabama site for both the Stellar® and flowering dogwood cultivars. Superb resistance to the diseases spot anthracnose, powdery mildew, and Cercospora leaf spot translated into superior aesthetics and fall color for the Stellar® compared with the flowering dogwood cultivars at the northeast Alabama site. Hardiness of Stellar® dogwood cultivars in Alabama and possibly other southern states below USDA Hardiness Zone 7a is questionable due to tree vulnerability to the dogwood borer and ambrosia beetle.
Miscanthus × giganteus Can be Propagated from Stem Cuttings
Authors: Meyer Mary Hockenberry , Hong Jeong
Published: August 2020

Giant miscanthus was successfully propagated with 1 or 2-node basal stem cuttings in July and 2-node basal stem cuttings in September. Upper single nodes, especially those 3rd and 4th most distal from the crown, rooted very poorly. There were no consistent differences among peat, perlite, peat: perlite and vermiculite media; however, in July 2007, cuttings in peat: perlite had significantly higher root dry weights than those in other media; and in July 2006, both peat and peat: perlite had significantly higher dry weights than did vermiculite or perlite. Single-node cuttings produced a higher proportion of plants, but 2-node cuttings had significantly more roots, longer roots and higher dry weights. Two-node September cuttings showed a higher percentage of rooting from the upper nodes than did July cuttings of either size. Although 2-node cuttings require larger propagation space and more materials, they produce less waste and a larger finished product than do single-node cuttings.
The Range and Response of Neonicotinoids on Hemlock Woolly Adelgid, Adelges tsugae (Hemiptera: Adelgidae)
Authors: Joseph Shimat V. , Kristine Braman S. , Quick Jim , Hanula James L.
Published: August 2020

Hemlock woolly adelgid (HWA), Adelges tsugae Annand is a serious pest of eastern and Carolina hemlock in the eastern United States. A series of experiments compared commercially available and experimental insecticides, rates, application methods and timing for HWA control in Georgia and North Carolina. Safari 20 SG (dinotefuran) provided an average of 79 to 87% suppression of adelgid populations within one month after spring application. Arena 50 W (clothianidin) and Merit 75 WP (imidacloprid) were slower acting but provided longer-term adelgid suppression than dinotefuran. However, 26 months after application in spring 2006 HWA re-colonized trees treated with dinotefuran while imidacloprid treatments were still effective. High volume treatments like soil drenches of dinotefuran did not improve adelgid control over low volume applications such as soil injection. Evaluation in July 2008 of a fall 2007 application of Tristar 30 SG (acetamiprid) using arborjet trunk injectors showed no reduction of nymphal populations. Treatment timing and rates did not affect HWA relative to untreated check. The Xytect 75 WSP (imidacloprid) soil injection treatments applied during May, August, or November 2007 and Xytect root-flare micro injection system treatment in November 2007 provided 99 to 100% control in all treatments.
Effect of Repeated Short Interval Flooding Events on Root and Shoot Growth of Four Landscape Shrub Taxa
Authors: Jernigan Kathryne J. , Wright Amy N.
Published: August 2020

Research was conducted to screen four landscape shrub taxa for tolerance to repeated flooding events. Plants of Fothergilla × intermedia ‘Mt. Airy’ (dwarf witchalder), Ilex verticillata ‘Winter Red’ (winterberry), Clethra alnifolia ‘Ruby Spice’ (summersweet), and Viburnum nudum Brandywine™ (possumhaw) were flooded repeatedly over six weeks for 0 (non-flooded), 3, or 6 days with a draining period of 6 days between each flooding event. The experiment was repeated for a total of two runs. With the exception of F. × intermedia ‘Mt. Airy’, all taxa showed good visual quality and no reduction in root growth in either run, and effects on shoot growth were minimal. Size index of Clethra alnifolia ‘Ruby Spice’ was 27% higher in plants flooded for 0 or 3 days than in plants flooded for 6 days in run 1 only. Shoot dry weight of Ilex verticillata ‘Winter Red’ was actually 11% higher in plants flooded 6 days days than in plants flooded for 0 or 3 days in run 2. Size index of Viburnum nudum Brandywine™ increased with increasing flood length, and plants flooded for 6 days had a 9% higher SI than plants flooded for 0 days in run 1. With the exception of Fothergilla × intermedia L. ‘Mt. Airy’, all taxa appeared tolerant of and even thrived during flooding and would be appropriate shrub selections for a southeastern United States rain garden.
Rooting of Semi-Hardwood Peach Cuttings as Affected by Basal Fungicide, Mist, and Anti-Transpirant Treatments
Authors: Lyons C.G. , Byers R.E. , Yoder K.S.
Published: August 2020

Dipping semi-hardwood Prunus persica ‘Harmony’ and ‘Cresthaven’ cuttings in a Captan-Benomyl mixture following an IBA quick dip treatment increased rooting compared to cuttings not receiving the fungicide treatment. Fungicide treated cuttings rooted as well or better in moist sand with daily watering as they did under intermittent mist. An anti-transpirant dip did not improve rooting and was deleterious to rooting in some treatments.
Propagation of Rhododendron chapmanii by Stem Cuttings
Authors: Gensel William H. , Blazich Frank A.
Published: August 2020

Two experiments were conducted to determine the feasibility of propagating Chapman's rhododendron (Rhododendron chapmanii A. Gray) by rooting stem cuttings. In the first experiment, semi-hardwood terminal cuttings taken from native plants, rooted in moderate percentages (43 to 63%) with the percentage of commercially acceptable cuttings (cuttings having a distinct root ball) being less (22 to 53%). The second experiment used hardwood terminal and subterminal cuttings taken from containerized stock plants that originated from cuttings rooted in the first experiment. Percent rooting for total and commercially acceptable cuttings ranged from 81 to 94% and 39 to 64%, respectively. For both experiments, indolebutyric acid (IBA) treatments resulted in an increase in the percentage of commercially acceptable cuttings.
Development of Lonicera Cultivars Resistant to the Honeysuckle Aphid (Hyadaphis tataricae)
Authors: Pellett H. , Moe S. , Vogel K. , Mainquist L.
Published: August 2020

Lonicera taxa growing in collections at the University of Minnesota Landscape Arboretum have been evaluated and observations are given for resistance to the honeysuckle witches broom aphid, Hyadaphis tataricae. A breeding program is in progress to develop superior resistant cultivars of honeysuckle for landscape use in informal hedge, screen, and windbreak plantings. A resistant selection has been approved for introduction to fill the nursery and landscape needs until better cultivars can be developed.
Plants Showing Tolerance of Urban Stress
Authors: Flint Harrison L.
Published: August 2020

Temperature, wind, water, compacted soil and reduced sunlight are environmental stresses that are commonly magnified when landscape plants are grown in urban situations, as contrasted to rural or suburban areas. With careful selection, landscape plants which are tolerant to adverse conditions can and should be considered for use in urban landscape environments.
Foliar Nutrient Diagnosis of Urban Sugar and Red Maples in the Great Lakes Region
Authors: Smiley E. Thomas , Hart James B. , Kielbaso J. James
Published: August 2020

Samples were collected from 293 urban Acer rubrum L. and Acer saccharum Marsh. in Michigan, Ohio, Illinois and Wisconsin. Foliar analysis indicated that healthy urban maples contained lower than expected levels of N and Mn; intermediate levels of Al, Cd, Cu, Fe, Mg and Zn; and high levels of B, Ca, K, Na and P. Guides to fertilization and diagnosis are presented.
Influence of Trickle Irrigation on Six Field-Grown Woody Landscape Species Based on Net Evaporation
Authors: Eakes D.J. , Gilliam C.H. , Ponder H.G. , Webster W.B. , Evans C.E. , Pounders C.
Published: August 2020

Six woody landscape species were field-grown with 4 irrigation rates based on 0%, 25%, 50%, and 100% replacement of net evaporation from a class A pan. Optimum irrigation rates varied by species. Japanese holly ‘Petite Point’ (Ilex crenata ‘Petite Point’), flowering dogwood (Cornus florida), green ash (Fraxinus pennsylvanica), and river birch (Betula nigra) had greater growth when irrigated compared to non-irrigated plants. Increases in caliper due to trickle irrigation occurred during the second growing season for 3 tree species. Growth of Pyrus calleryana ‘Bradford’ (‘Bradford’ pear) and pin oak (Quercus palustris) was similar regardless of irrigation rates. Only ‘Petite Point’ Japanese holly had improved livability as a result of trickle irrigation.
Evaluation of Selected Cotoneaster spp. for Resistance to Hawthorn Lace Bug
Authors: Schultz Peter B.
Published: August 2020

Four Cotoneaster species were evaluated for resistance to hawthorn lace bug. In a preference study using adults, the lace bugs preferred C. x watereri Exell. ‘Brandekeir’ when compared to the other 3 species, C. lacteus W.W.Sm., C. nitens Rehd. & E.H. Wils. and C. acutifolius Turcz. Significantly fewer nymphs completed development on foliage of C. lacteus than on C. x watereri ‘Brandekeir,’ C. nitens and C. acutifolius. The presence of dense pubescence is suggested as a factor in this reduced development.
Influence of Incubation Time on Phosphorus Leaching from a Container Medium
Authors: Yeager Thomas H. , Barrett James E.
Published: August 2020

Columns (4 × 15 cm; 1.5 × 6 in) of a pine bark: moss peat: sand (2:1:1 by vol) medium amended with 32P-superphosphate (8.7% P) and incubated for 0, 15, or 30 days, were leached daily with 16 ml (0.5 in) deionized water. Leachate 32P concentration (1092 ppm) was lower on day 1 for the medium incubated 30 days than for unincubated medium (1343 ppm), while on day 21 leachate 32P concentration for the unincubated medium (10 ppm) was lower than the medium incubated 30 days (21 ppm). A minimum of 86% of the 32P amendment leached in 21 days regardless of incubation time, indicating holding mixed media for a period of time prior to potting is not a practical means of reducing P leaching from a superphosphate-amended medium.
Distilled Eastern Redcedar (Juniperus virginiana L.) as an Alternative Substrate in the Production of Greenhouse-Grown Annuals
Authors: Vandiver Taylor A. , Fain Glenn B. , Murphy Anna-Marie , Gilliam Charles H. , Sibley Jeff L.
Published: August 2020

Peat moss is the main component used in soilless greenhouse substrates and is thus in high demand commercially. Due to both perceived environmental and economic concerns associated with peat harvest and production, an increased search for alternative substrates has occurred. A majority of the viable alternatives available to growers are wood-based substrates. These substrates are readily available and could be considered more sustainable, depending on geographic location, than peat moss. One example of these wood-based substrates is eastern redcedar (Juniperus virginiana L.). The objectives of these experiments were to evaluate post-distilled, milled eastern redcedar shavings, in varying volumetric concentrations, as a substrate component, and to compare its effectiveness to a grower's standard peat-lite mix. Petunia ×hybrida Vilm. ‘Celebrity Blue’ and Impatiens walleriana Hook.f. ‘Extreme Violet’ grown in substrates containing up to 40% eastern redcedar product had equal or greater growth index than in the standard peat-lite mix, although bloom count was reduced in one experiment. Therefore, growers could amend their substrates with up to 40% eastern redcedar shavings and see little to no change in marketable plant growth for these two annual species.
Control of Beach Vitex (Vitex rotundifolia) with Foliage and Cut Stem Herbicide Applications
Authors: Whitwell Ted , Briggs Jeanne A. , Cousins Matthew M.
Published: August 2020

The many invasive characteristics of Vitex rotundifolia L. f. [beach vitex (BV)] and the ecological concerns surrounding its presence along the coast have necessitated the development of effective control methods. The purpose of these studies was to evaluate various herbicides using cut stem and foliar application methods to develop effective control strategies. An observational case study on a beach dune site indicated that beach vitex regrowth occurred three years after the initial cut stem glyphosate (treatments at 2.4 g ai·cm−1 (0.2 oz ai·in−1) and served to direct experiments using both greenhouse and field studies. Glyphosate, imazapyr, and triclopyr were evaluated in greenhouse studies. An imazapyr solution at 1.2 g ai·cm−1 (0.1 oz ai·in−1) applied to recently cut stems effectively controlled beach vitex in both greenhouse and field studies. Foliar applications of imazapyr in greenhouse and field studies confirmed that it effectively controlled beach vitex at rates of 1.0, 1.4 and 2.0 kg ai·ha−1 (0.89, 1.25 and 1.79 lb ai·A−1). Imazapyr effectively controlled beach vitex in these studies whether applied either as a cut stem treatment or as a foliar spray application. Ineffective control was observed from glyphosate and triclopyr applications, which resulted in beach vitex regrowth.
Physical Properties of Peat-based Substrates Amended with a Mature Dairy Cow Manure Compost Before and After Plant Cultivation
Authors: Jeong Ka Yeon , Nelson Paul V. , Niedziela Carl E. , Brinton William F. , Fonteno William C.
Published: August 2020

Initial and final physical properties of four substrates based on a sphagnum peat moss:perlite (3:1 v/v) substrate where mature dairy manure compost (DMC) was partially substituted for peat moss at 0, 16, 26, or 33% DMC of total substrate volume (equivalent to DMC to peat moss ratios of 0, 1, 2, or 3 on a dry weight basis, respectively) were evaluated during a 12-week crop of ‘Macumba’ pot chrysanthemum [Dendranthema × grandiflora (Ramat.) Kitam]. The impact of time on physical properties was similar in all substrates, indicating that DMC was as stable as peat moss. Addition of DMC to substrates increased bulk density (Db) and lowered total porosity (TP) and air space (AS). Compared to peat moss plus perlite without DMC, container capacity (CC) increased with 16 and 26% DMC and was similar at 33% DMC. Addition of DMC at 33% resulted in a decrease in available water (AW). Plant shoot dry weight was higher in all substrates containing DMC, with the maximum at 26% DMC, compared to peat moss plus perlite without DMC.
Effects of Woody Mulches and Dimethenamid-P on Container Grown Ligustrum japonicum and Viburnum macrocephalum
Authors: Bartley Paul C. , Wehtje Glenn R. , Murphy Anna-Marie , Foshee Wheeler G. , Gilliam Charles H.
Published: August 2020

Current weed control practices in nursery container plant production consist primarily of hand weeding and application of preemergence herbicides. Non-chemical weed control methods, such as mulches, could reduce herbicide use, reduce potential environmental concerns from offsite herbicide movement, and decrease the expense of weed control. Before implementation, alternative methods of weed control must be evaluated for effects on the growth of common container-grown species. Mulches made from readily available tree species, including eastern red cedar (Juniperus virginiana), ground whole loblolly pine (Pinus taeda), Chinese privet (Ligustrum sinense), and sweetgum (Liquidambar styraciflua), were evaluated at multiple depths with and without the herbicide dimethenamid-P (Tower®). Wax-leaf ligustrum (Ligustrum japonicum) and snowball viburnum (Viburnum macrocephalum) treated with dimethenamid-P, averaged over mulch treatments, had up to 7% less growth compared to non-herbicide treated plants, but marketability was not affected. Mulch species and depth had no effect on plant growth. Results indicate that these readily available mulch species can be applied at depths up to 10.2 cm (4 in) for weed control in container plant production.
Assessing Alternative Organic Amendments as Horticultural Substrates for Growing Trees in Containers1
Authors: Sax Miles Schwartz , Scharenbroch Bryant C.
Published: August 2020

Conventional substrates for nursery plant production typically are soilless media that are comprised of low bulk density material with either organic or synthetic components. These mixes aim to provide a lightweight medium that provides acceptable water holding capacity and nutrient retention and create a suitable environment for root proliferation and biomass growth. In an effort to identify alternatives to traditional container substrates, a comparative amendment study was conducted to observe changes in media qualities and plant growth response of Aronia melanocarpa ‘Viking' and Acer saccharum over a period of 16 months. Materials used to amend traditional medium included composted green waste, biosolids and wood chips, biochar, aerated compost tea and vermicompost. The results of this study found that all amendments performed equally as well as control (NULL) treatments for root, shoot and total biomass production for both Aronia melanocarpa ‘Viking' and Acer saccharum. After a period of 16 months, significant changes in biochemical properties had occurred in mediums amended with biochar, wood chips, composts and biosolids. This study provides data on a variety of alternative materials that can be used as substitutes for traditional greenhouse medium in production of nursery tree stock.

Index words: aerated compost tea, biochar, biosolids, carbon to nitrogen ratio, compost, dissolved organic carbon, electrical conductivity, fertilizer, microbial biomass carbon, control, active carbon, microbial respiration, leaf fluorescence, soil water tension, total nitrogen, total organic carbon, volumetric water content, wood chips, water holding capacity.

Species used in this study: ‘Viking' black chokeberry [Aronia melanocarpa (Michx.) Elliott]; sugar maple (Acer saccharum Marshall).
The Effects of Relative Humidity and Substrate Moisture on Rooting of Hybrid Hazelnuts from Hardwood Stem Cuttings1
Authors: Rusnak Tyler , Braun Lois
Published: August 2020

Hybrid hazelnuts (Corylus americana Walter x C. avellana L.) are currently being bred for use as a cold-hardy perennial crop that could produce profits for Midwestern farms while supporting agroecosystem sustainability. However, asexual propagation techniques for producing germplasm for breeding and dissemination purposes have proven difficult. This study was one of a series attempting to develop a protocol for hardwood stem cutting propagation. This study assessed the impact that relative humidity (RH) and substrate moisture has on rooting of hardwood stem cuttings propagated in low-cost humidity tents. Hardwood stem cuttings retrieved from 14 hybrid hazelnut genotypes were planted into enclosed humidity tents, each housing 64 cuttings. Treatments were RH thresholds of 30%, 50%, 70%, and 90%, which were maintained by daily monitoring and watering to saturate the substrate when a tent's RH fell below its specified RH threshold. Cuttings propagated in 50% and 70% RH tents showed the highest rates of rooting at 16% and 12% respectively, whereas only 7% of cuttings rooted at 90% RH and 3% at 30% RH. By showing that intermediate RH levels and watering regimes are optimal for rooting, these results suggest daily monitoring is not necessary for hardwood stem cutting propagation of hybrid hazelnuts.

Index words: propagation, relative humidity, substrate moisture, hardwood stem cuttings, hazelnuts, adventitious rooting.

Chemicals used in this study: IBA (indole-3-butyric acid).

Species used in this study: hybrid hazelnuts (Corylus americana Walter x C. avellana L.).
Greenhouse Gas Emissions from an Ornamental Crop as Impacted by Two Best Management Practices: Irrigation Delivery and Fertilizer Placement1
Authors: Murphy Anna-Marie , Runion G. Brett , Prior Stephen A. , Torbert H. Allen , Sibley Jeff L. , Gilliam Charles H.
Published: August 2020

Agriculture is one of the largest contributors of greenhouse gas (GHG) emissions. To date, much work on reducing GHG emissions has centered on row crops, pastures, forestry, and animal production systems, while little emphasis has been placed on specialty crop industries such as horticulture. In this horticulture container study, Japanese boxwood (Buxus microphylla Siebold & Zucc.) was used to evaluate the interaction of irrigation (overhead vs drip) and fertilizer placement (dibble vs incorporated) on GHG emissions (CO2, N2O, and CH4). Plants were grown in 11.4 L (#3) containers with a 6:1 pine bark:sand substrate with standard amendments. All containers received 6.35 mm (0.25 in) water three times daily. Gas samples were collected in situ using the static closed chamber method according to standard protocols and analyzed using gas chromatography. Total cumulative CO2 loss was not affected by differences in irrigation or fertilizer placement. Total cumulative N2O efflux was least for drip-irrigated plants, regardless of fertilizer placement. For overhead-irrigated plants, N2O efflux was greatest for those with incorporated fertilizer. Efflux of CH4 was generally low throughout the study. Findings suggest that utilizing drip irrigation could decrease N2O emissions, regardless of fertilizer placement. However, when limited to overhead irrigation, dibbled fertilizer placement could decrease N2O emissions.

Index words: carbon dioxide, methane, nitrous oxide, trace gas

Species used in this study: Japanese boxwood (Buxus microphylla Siebold & Zucc.)
Impact of Mowing Height and Nitrogen Fertility on Crabgrass Cover in ‘RTF' Tall Fescue1
Authors: Cutulle Matthew , Derr Jeffrey , McCall David , Nichols Adam , Horvath Brandon
Published: August 2020

Tall fescue (Festuca arundinacea Shreb.) has exceptional utility as a low maintenance lawn in the transition zone. However, during the summer smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.] infestations can reduce the aesthetic value and function of the turf and lead to a thinning of the tall fescue stand, noticeable after the crabgrass plants have senesced. Research was conducted to evaluate the impact of mowing height and nitrogen fertility on smooth crabgrass plant counts and tall fescue cover in Virginia Beach, VA. Plots were mowed at either 6 cm (2.5 in) or 10 cm (4 in) and received 49, 171, or 220 kg of nitrogen annually per hectare (44, 152, and 196 lb.A−1). Mowing at 10 cm with the highest level of fertility resulted in the most turfgrass cover among all the treatment combinations. Mowing at 10 cm as opposed to 6 cm resulted in less smooth crabgrass plants, regardless of nitrogen fertilization rate.

Index words: fertilization, turfgrass, weed control.

Species used in this study: Smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.]; tall fescue [Festuca arundinacea Shreb. synonym Schedonorus phoenix (Scop.) Holub].
Optimizing IBA Concentration and Stem and Segment Size for Rooting of Hybrid Hazelnuts from Hardwood Stem Cuttings
Authors: Braun Lois , Wyse Donald
Published: August 2020

Germplasm improvement of woody crops through plant breeding depends on effective methods of vegetative propagation, both for evaluation of candidate germplasm and for dissemination of improved varieties. Hybrid hazelnuts [Corylus americana (Walter) x C. avellana (L.)] are being developed as a new crop for the Upper Midwest for their ecological and economic value, but lack of economically viable propagation methods is a significant bottleneck to their wide scale adoption. This paper describes two trials to optimize propagation from hardwood stem cuttings in low-cost humidity tents, using dormant crown suckers collected in the fall. We found that: 1) 2 g.L−1 (2,000 ppm) indole-3-butyric acid (IBA) in a 50% ethanol solution is the best concentration for rooting cuttings of a range of sizes and 2) rooting declines with increasing basal diameter of stems, but increases with increasing length of stem. The thicker cortex of large diameter stems may present a physical barrier to emergence of adventitious roots. Conversely, longer stems have larger stores of carbohydrates, which are essential both for keeping the stems alive until roots can be developed, and for providing the building blocks for growing those roots.

Index words: Propagation, Corylus americana (Walter), Corylus avellana (L.), rooting, indole-3-butyric acid.

Chemicals used in this study: indole-3-butyric acid (IBA).

Species used in this study: hybrid hazelnuts [Corylus americana (Walter) x Corylus avellana (L.)].
Optimizing Pre-germination Techniques for Kentucky Bluegrass and Perennial Ryegrass1
Authors: Campbell Julie H. , Henderson Jason J. , Inguagiato John C. , Wallace Victoria H. , Minniti Anthony
Published: August 2020

Many intensively trafficked areas such as athletic fields and golf courses require constant overseeding to maintain suitable turfgrass cover. Rapid seed germination and development are critical to managing these high wear areas. The objectives of this research were to determine the effect of water aeration, seed soaking duration, and water temperature on mean germination time (MGT) and final germination percentage (FGP) of Kentucky bluegrass (Poa pratensis L., KBG) and perennial ryegrass (Lolium perenne L., PRG). Two separate controlled environment studies were conducted. PRG soaked in aerated water from 8 to 48 h had a 20% decrease in MGT compared to an untreated control, while treated KBG decreased MGT by only 10% compared to an untreated control. Soaking duration and water temperature had significant effects on KBG. KBG MGT was optimized at 20 C (68 F) water temperature with a soaking duration of 24 h. MGT of PRG was optimized when soaked for 8 h while water was aerated. There was no significant difference in FGP for any of the treatments tested.

Index words: turfgrass, aeration, seed soaking.

Species used in this study: Kentucky bluegrass (Poa pratensis L.); perennial ryegrass (Lolium perenne L.).
Evaluation of a novel endophytic Pseudomonas lactis strain for control of boxwood blight1
Authors: Kong Ping
Published: August 2020

Boxwood blight, caused by Calonectria pseudonaviculata (Cps) (Synonyms: Cylindrocladium buxicola, Cylindrocladium pseudonaviculatum), is a devastating disease which affects boxwood (Buxus) in private and public gardens worldwide. SW, an endophyte identified as a strain of Pseudomonas lactis, was isolated along with seven other bacterial strains from symptom-reversed boxwood leaves infected by Cps. SW had the largest population among the 8 isolates. SW inhibited Cps culture growth similar to three other antagonistic isolates but was the strongest suppressor of Cps conidial germination and germling development. When the cell-free supernatant (CFS) from SW liquid cultures was used to treat boxwood plants 48 h prior to inoculation with Cps, it resulted in a 69.4% disease reduction; suggesting involvement of its metabolites in disease suppression. Boxwood blight control efficacy was further evaluated with resuspended SW cell at 108-9 cfu.ml−1 at different treatment lead times. When SW was applied 2 or 10 days before inoculation with Cps, boxwood blight disease decreased by 72% and 67%, respectively. Further extending the lead time to 20 and 30 days, the efficacy was reduced to 26-27%. However, with its features of moderate control efficacy, high population in plant tissue and safety towards humans, SW shows great potential as a biocontrol agent for boxwood blight.

Index words: Biocontrol agent, endophyte, plant pretreatment, Calonectria pseudonaviculata suppression.

Species used in this study: Bacterium strain SW (Pseudomonas lactis). Plant species: Buxus sempervirens ‘Justin Brouwers'.
Field Pretreatment of Crown Suckers for Propagating Hybrid Hazelnuts
Authors: Braun Lois , Wyse Donald
Published: August 2020

Hybrid hazelnuts [Corylus americana (Walter) x C. avellana (L.)] are being developed for their ecological and economic value as a new crop for the Upper Midwest, but lack of economically viable propagation methods is a significant bottleneck to their wide scale adoption. Thus far, mound layering has been the primary propagation method, but layering cannot produce the numbers of plants needed for large-scale production. Rooting hardwood stem cuttings is a possible alternative. In a factorial experiment, we evaluated two pretreatments, blanching with sawdust and application of IBA, applied to rapidly growing first year collar suckers in the field five months ahead of collection for rooting. These treatments simulated mound layering, but without girdling. Sawdust by itself significantly increased both quantity and quality of subsequent rooting, but IBA pretreatment in combination with sawdust produced even better results. Stem cuttings were rooted in a growth chamber, set at 22 C (72 F) and 60% relative humidity, with PAR of 320 umol.m−2 s−1 for 16 hours per day. The lack of heat stress in the growth chamber likely also contributed to relatively high rooting relative to the humidity tents used in previous trials.

Index words: Propagation, Corylus americana (Walter), Corylus avellana (L.), rooting, etiolation.

Chemicals used in this study: indole-3-butyric acid (IBA).

Species used in this study: hybrid hazelnuts [Corylus americana (Walter) x Corylus avellana (L.)].
Fertilizer Source and Irrigation Depth Affect Nutrient Leaching During Coleus Container Production
Authors: Sanders Kayla R. , Beasley Jeffrey S. , Bush Edward W. , Conger Stacia L.
Published: August 2020

Nutrient leaching during nursery container production can have negative effects on plant growth and the environment. The objective of this study was to evaluate effects of fertilizer source at two irrigation depths on nutrient leaching during coleus [Plectranthus scutellarioides (L.) Codd] ‘Solar Sunrise' container production to develop best management practices. Coleus received no fertilizer, a controlled-release fertilizer (CRF), or a water-soluble fertilizer (WSF) applied at 0.30 kg N and P per m3 (0.02 lb per ft3) and were irrigated at 1.9 or 3.8 cm.day−1 (0.7 or 1.5 in.day−1) for 56 days after planting (DAP). Leachate was analyzed every 7 DAP for inorganic N and dissolved total P (DTP). At 56 DAP, root biomass, leaf quality, and plant growth index were similar between CRF and WSF treatments at both irrigation depths. Highest inorganic N and DTP losses occurred within 21 DAP. Application of WSF resulted in higher cumulative N and DTP losses compared to CRF applications. Coleus irrigated at 3.8 cm.day−1 and fertilized with WSF resulted in higher DTP losses compared to CRF applications regardless of irrigation depth. Reducing irrigation reduced inorganic N leaching for each fertilizer source. Application of CRF provided consistent growth while curbing nutrient losses across both irrigation depths compared to WSF.

Index words: controlled-release fertilizer, water-soluble fertilizer, nursery producers, best management practices.

Chemicals used in this study: Micronutrients mix (Micromax®); controlled-release fertilizer (Osmocote® Classic); water-soluble fertilizer (Grower's Special).

Species used in this study: Coleus [Plectranthus scutellarioides (L.) Codd] ‘Solar Sunrise'.
An Update of the Literature Supporting the Well-Being Benefits of Plants: Part 3 - Social Benefits
Authors: Hall Charles R. , Knuth Melinda J.
Published: August 2020

This paper provides evidence from the literature regarding the social benefits associated with plants and how they influence the physiological, psychological, and cognitive well-being constructs affecting quality of life. These benefits are segmented and discussed using the following categories: place or community attachment, reduced crime, disaster resilience, access to locally-produced foods, socialization of children and their school performance, and community therapeutic impacts. The equitable distribution of these green space benefits among local populations is also discussed. This research should be strategically incorporated into both industry-wide and firm-specific marketing messages that highlight the quality of life value proposition in order to maintain the industry's sense of value and relevance to residential landscape consumers of the future. These findings also present evidence that municipal leaders and policymakers can use in justifying green infrastructure-related funding decisions, as well as grounds for the construction industry using biophilic design principles in ensuring the built environment offers opportunities for green space interactions. The green industry can play a pivotal role not only in providing plants of high quality for these applications but educating stakeholders regarding the benefits discussed herein.

Index words:, benefits of plants, community, social benefits.
Seasonal Population Patterns of a New Scale Pest, Acanthococcus lagerstroemiae Kuwana (Hemiptera: Sternorrhynca: Eriococcidae), of Crapemyrtles in Texas, Louisiana, and Arkansas.1
Authors: Vafaie Erfan , Merchant Michael , Xiaoya Cai , Hopkins John D. , Robbins James A. , Chen Yan , Gu Mengmeng
Published: August 2020

The crapemyrtle bark scale, Acanthococcus lagerstroemiae, is an invasive scale insect pest of crapemyrtles. Crawler populations were monitored using double-sided sticky tape on established crapemyrtle trees in Tyler (TX), Huntsville (TX), Dallas (TX), College Station (TX), Shreveport (LA), and Little Rock (AR) from 2015 - 2017 to determine crawler activity and determine if degree-day models could predict the first peak in crawler activity. Difference in crawler densities on upper and lower branches of trees was also determined by using double-sided sticky tapes. The first peak in crapemyrtle bark scale crawler activity was between March 26th and May 22nd across all locations and years, with multiple subsequent peaks per season frequently found, suggesting multiple generations. Using the average date (May 2nd) to predict the first peak crawler activity resulted in the lowest variance and was subsequently considered a better predictor compared to any degree-day model. There was no apparent difference in crawler activity between upper and lower branches of crapemyrtle trees across an entire season. This study provides the first set of population dynamics data for crapemyrtle bark scale in the U.S. and will help with future bark scale management decisions.

Index words:, Crapemyrtle bark scale, invasive insect, population dynamics, Lagerstroemia spp

Species used in this study: Crapemyrtle bark scale (Acanthococcus lagerstroemiae Kuwana); Crapemyrtle (Lagerstroemia spp.)
Cambial Isoperoxidase Patterns in Castanea
Authors: Santamour F.S. , McArdle A.J. , Jaynes R.A.
Published: August 2020

Only 3 major and variable anodal isoperoxidase bands were found in the cambial zone of 10 Castanea species. Even though the numbers of plants tested in several taxa were low, it appeared that certain banding patterns could be characteristic for some species. Thus, C. dentata and other American species (C. alnifolia, C. ashei, C. ozarkensis, C. pumila) exhibited only band A. The Japanese chestnut (C. crenata) and C. seguinii had only band B. The isoenzyme phenotypes A, B, and AB were found in the European chestnut (C. sativa) while our single tree of C. henryii had both A and B bands. Chinese chestnut (C. mollissima) contained trees with 4 isoenzyme phenotypes (A, AB, B, BC). The distribution of isoperoxidase banding patterns, coupled with widespread sexual compatibility, indicated that the categorization of chestnut species into different taxonomic sections may have little importance from a genetic basis. The possible influence of enzyme phenotype on graft compatibility is discussed.
Influence of Stratification and Light on Germination of Sourwood (Oxydendrum arboreum (L.) DC.)
Authors: Barton S.S. , Bonaminio V.P.
Published: August 2020

Comparison of stratified and nonstratified seed demonstrated that at 25° C (77° F), as duration of stratification increased from 0 to 60 days, germination percentage also increased. However, an opposite effect occurred for seed exposed to alternating temperatures of 30/20° C or 25/15° C (86/68° For 77/59° F). There were no significant differences observed in the final germination percentage between seed stratified for 30 days and nonstratified seed. Stratification hastened germination and decreased the light required for germination.
Characterization of Pyrus Species and Cultivars Using Gradient Polyacrylamide Gel Electrophoresis
Authors: Menendez R.A. , Daley L.S.
Published: August 2020

A chemical identification procedure previously used to identify apple clones was tried with pear species and clones. Following electrophoresis, the peroxidase, esterase, and acid phosphatase isozyme patterns on anionic polyacrylamide gradient gels were determined. These patterns were found to vary with the species and clone, but not to change, within a clone during the growing season. Thus, these patterns were considered to represent genetic characteristics. The patterns were used to identify 37 selected Pyrus accessions at the National Clonal Germplasm Repository, Corvallis, Oregon. All species tested were distinguishable using this system. All the accessions of P. calleryana selected from the NCGR collection were distinct: however, one clone from outside the collection had an identical pattern to one inside the collection. Among the Chinese pear clones (complex hybrids of P. ussuriensis × P. pyrifolia) tested, three pairs of clones had the same combination. This technique appears to have the potential to readily identify pear specimens, and could be an important aid in the characterization of germplasm material.
Urban Integrated Pest Management in Kentucky—A Case Study
Authors: Hartman John R. , Lee Gerstle J. , Timmons Mark , Raney Harley
Published: August 2020

Integrated Pest Management (IPM) principles and techniques were applied to woody landscape plants and turfgrasses in the urban landscape in Louisville during the 1980-83 growing seasons. The program, at first directed towards professional horticulturists and institutional grounds maintenance persons, gradually grew to include commercial nurserymen and homeowners. Operating procedures, pricing strategies, and use of personnel changed each year of the program to take advantage of previous experience. Developing this program provided an opportunity to learn about the various ways that this and similar programs nlight succeed or fail.
Effects of Moisture Stress on Two Spotted Spider Mite Populations, Tetranychus urticae Koch (Acari: Tetranychidae) in Schefflera (Brassaia actinophylla Endl.)
Authors: Colijn Annette C. , Lindquist Richard K.
Published: August 2020

Studies were conducted to determine the effects of moisture stress and schleffera variety (Brasspia actinophylla Endl. and B. actinophylla ‘Amate’) on populations of twospotted spider mides (Tetranychus urticae Koch) grown under interior conditions.

After approximately 2 weeks, spider mite populations were significantly higher on moisture stressed B. actinophylla as compared with unstressed plants. Populations on rewatered plants were intermediate. Moisture stress did not affect mite populations on the cultivar ‘Amate’ in a consistent manner. The cultivar ‘Amate’ was more mite resistant than B. actinophylla. Mites feeding on ‘Amate’ laid fewer eggs, had lower survival and slower developmental rates than those feeding on B. actinophylla. Leaves of ‘Amate’ were 67% thicker and had lower percent total nitrogen than B. actinophylla leaves.
Effects of Moisture Content and Storage Temperatures on Germination of Quercus macrocarpa Acorns
Authors: Schroeder W.R. , Walker D.S.
Published: August 2020

Viability of bur oak Quercus macrocarpa Michx. acorns was determined after 6 months storage at − 2°C (28°F), 1°C (34°F) and 5°C (41°F) and moisture contents of either 17%, 27%, 37% or 44%. Viability was significantly affected by moisture content with optimum germination occurring for acorns stored at 44% moisture. Optimum storage temperature was 1°C (34°F) although acorns tolerated subfreezing temperatures to − 2°C (28°F) with little loss in viability. Acorn moisture content had a greater effect on viability than storage temperature. Storage for up to 6 months had no detrimental effects on germination of bur oak acorns.
Effect of Soil Compaction and Oxygen Content on Vertical and Horizontal Root Distribution
Authors: Gilman E.F. , Leone I.A. , Flower F.B.
Published: August 2020

Gleditsia triacanthos var. inermis seedlings were field planted in compacted and non-compacted soil in both normal oxygen and reduced oxygen soil atmosphere. Entire root systems were excavated and mapped. Compaction caused significantly shallower roots in normal and reduced oxygen areas. Roots in the reduced oxygen area were not significantly shallower than in normal oxygen areas. Root spread was correlated with stem diameter and branch spread. Lateral roots extended three times as far from the trunk as did the branches.
Effects of Fruit Maturity, Storage, Presoaking, and Seed Cleaning on Germination in Three Species of Palms
Authors: Broschat T.K. , Donselman H.
Published: August 2020

Green, half ripe and ripe fruit of queen [Arecastrum romanzoffianum (Cham.) Becc.], pygmy date (Phoenix roebelenii O'Brien) and royla palms [Roystonea regia (HBK) O. F. Cook] were cleaned or left uncleaned and were presoaked in 1000 mg/1 gibberellic acid (GA,) for 48 hr, water for 48 hr, were not presoaked. Queen palm seed germinated best if cleaned green or half-ripe seed was used, but pygmy date and royal palm seed germinated best when cleaned half-ripe or ripe seed was used. Cleaned seed of these palms can be stored in sealed polyethylene bags at 23°C (73°F) for 4 to 9 months. Depending on the species, and royal palm seed benefited from storage of up to 9 months, presumably due to immature seed embryos at time of harvest.
Effects of Curing Time on Physical and Chemical Properties of Composted Sewage Sludge Bind on the Growth of Selected Bedding Plants
Authors: Vega-Sanchez Fernando E. , Gouin Francis R. , Willson George B.
Published: August 2020

Raw sewage sludge treated with lime and ferric chloride was composted by the Beltsville Aerated Pile Method, screened and piled outdoors (cured) for 4, 6, 8, or 10 months. As curing time increased there was a decrease in CO2 and temperature, and an increase in O2 within the piles. The NH4 concentrations and electrical conductivity (EC) of the compost decreased while pH, NO3 + NO2, and extractable P increased with time. Curing time did not influence extractable K while bulk density (BD) and particle size distribution (PSD) exhibited only moderate changes. Marketable seedlings of Impatiens hybrida ‘Super Elfin Scarlet’ and Tagetes patula L. ‘Yellow Boy’ were produced in peat:vermiculite (v/v) amended with 10 or 20% compost, regardless of compost curing time. Seedlings of Coleus x hybridus Voss. ‘Saber Golden’ were stunted and unmarketable in all compost amended media. Increasing compost curing time decreased EC, pH, and extractable N and K of the media at transplant time, and resulted in increased dry weight of I. hybrida and T. patula. Increasing compost concentrations in the media decreased plant top dry weight and visual ratings, and increased EC, pH, and NH4, NO3 + NO2, and extractable N, P, and K.
Efficacy of Prodiamine for Weed Control in Container Grown Landscape Plants Under High Temperature Production Conditions
Authors: Duray Sharon A. , Davies Fred T.
Published: August 2020

Applications of preemergent herbicide prodiamine 65 WDG (wettable dry granule) (2,4-dinitro-N3,N3-dipropyl-6(trifluoromethyl)-1,3-benzenediamine) at 1.12, 2.24, 4.48, and 8.96 kg ai/ha (1.0, 2.0, 4.0 and 8.0 lb ai/A) controlled large crabgrass (Digitaria sanguinalis L. Scop.), bermudagrass (Cynodon dactylon L. Pers.), purslane (Portulaca oleracea L.), and red sorrel (Rumex acetosella L.) for 16 weeks after application. A granular application at 1.12 kg ai/ha (1.0 lb ai/A) resulted in unsatisfactory weed control and subsequently decreased shoot weight of container grown landscape plants. Prodiamine 65 WDG did not cause phytotoxic effects to landscape plants at any rate evaluated.
Available Water and Root Development Within the Micropores of Pine Bark Particles
Authors: Pokorny F.A.
Published: August 2020

Internal pore space, root development, and available water within pine bark particles were studied. Internal porosity constituted about 43% of a pine bark particle. Scanning electron microscopy (SEM) revealed that roots of Coleus blumei and Vaccinium ashei were attached to the exterior surface of pine bark particles and had invaded the micropores. Growth of Raphanus sativus seedlings in water-saturated bark pieces demonstrated that internally adsorbed water was utilized provided that root development occurred within the bark particle.
Increasing Production of New Roots by Potted Roses with Root Applied IBA
Authors: Starbuck C.J.
Published: August 2020

Dormant bare root rose (Rosa × hybrida ‘Las Vegas’) plants with roots dipped in a 500 ppm solution of indole-3-butyric acid (IBA) produced 50% more new roots than untreated plants. However, plants treated with 100 and 500 ppm IBA had fewer open flower buds 8 wks after potting and shorter average shoot length after 18 wks than did controls. Treatment with the potassium salt of IBA (KIBA) at 100 and 500 ppm also stimulated new root production and retarded flower bud development but did not reduce shoot length. Addition of starch-polyacrylate gel to treatment solutions counteracted the root promoting effect of IBA but not of KIBA. Gel itself also caused a reduction in average shoot length.
Effect of a Medium-Incorporated Hydrogel on Plant Growth and Water Use of Two Foliage Species
Authors: Wang Yin-Tung , Boogher Carol A.
Published: August 2020

A fully expanded hydrogel, Agrosoke, was used to replace 5% (1 ×) or 10% (2 ×) of the volume of a potting medium to determine its effect on plant growth and water use. Although irrigation frequency was unaffected by Agrosoke, spider plants (Chlorophytum comosum (Thunb.) Jacques ‘Vittatum’) grown in the 2 × medium were 50% larger and had more lateral shoots and better root systems than the control, demonstrating improved water use efficiency. Agrosoke had no effect on either irrigation frequency or on fresh weight of Boston fern (Nephrolepis exaltata (L.) Schott. ‘Rooseveltii’). Leachates from hydrogel-amended media had higher electrical conductivity indicating that more nutrients and other salts were held by these media.