bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of Butterfly Bush with Postemergence Herbicides
Authors: Altland James , Ream Julie
Published: August 2020

Butterfly bush (Buddleja davidii) is classified as invasive in several parts of the United States. Two experiments were conducted to evaluate the effectiveness of four herbicides and two application methods on postemergence butterfly bush control. The four herbicides included: Roundup (glyphosate), Aquamaster (glyphosate), Garlon (triclopyr), and Arsenal (imazapyr). Application methods included spraying foliage with a CO2 backpack sprayer, and applying herbicide concentrate to recently cut stems (cut-stump method). Plants were treated in September with the maximum labeled rate for each herbicide. Cut-stump rates were determined such that the same amount of active ingredient was applied as in the spray treatments. Applications were made to plants several months after planting to simulate control of small recently germinated plants, and again to plants over 1 year old to simulate control of larger and more established plants. Summarizing results over both plant sizes and from two repetitions of the experiment, Roundup and Aquamaster provided higher levels of control compared to Garlon and Arsenal early in the experiment. Cut-stump applications provided more rapid control than spray applications. Despite differences in control when evaluated several weeks after application, all treated plants were dead when evaluated the following spring.
Effect of IBA Treatments, Bottom Heat, Stock Plant Location, and Cutting Type on the Rooting of Spigelia marilandica Cuttings
Authors: Pill Wallace G. , Goldberger Brian
Published: August 2020

Spigelia marilandica (India pink, pinkroot), a herbaceous perennial native to the United States, is underused in the nursery trade, in part because it is difficult to propagate. We found from the first of two studies conducted during winter 2007 that stem-tip cuttings collected from greenhouse-grown stock plants submersed in 3000 or 6000 ppm (mg·liter−1) potassium salt of indole-3-butyric acid (IBA) for one minute had greater percentage rooting (average 76.6) than cuttings not treated with IBA (46.9). Bottom heat [average 27.2C (81F)] compared to no bottom heat [23C (73F)] increased rooting percentage from 48 to 85%. The second winter 2007 study determined that rooting percentage according to method of application of 3000 ppm IBA was in the order: solution dip (60.1) > powder dip (49.8) ≥ solution submersion (46.6) ≥ control (42.7). During summer 2009, bottom heat and the same methods of application of 3000 ppm IBA described above were applied to terminal (stem tip) or subterminal cuttings collected from greenhouse-or field-grown stock plants. While IBA application method had no effect on rooting of cuttings from greenhouse-grown stock plants (average 54.1%), it affected cuttings from field-grown stock plants in the order: solution submersion (80.1%) > solution dip (54.4%) > powder dip = control (average 29.5%). Solution submersion cuttings from field-grown stock plants had much greater rooting (80.1%) than those from greenhouse-grown stock plants (47.2%). Control and powder dip cuttings from greenhouse-grown stock plants had greater rooting percentage than those from field-grown stock plants. Cutting type had no effect on rooting of field-grown cuttings (average 48.4%). Terminal cuttings from greenhouse-grown stock plants had greater rooting (73.3%) than subterminal cuttings (34.8%).
Response of Two Salix L. Species to Water Deficit
Authors: Zhivotovsky Olena P. , Kuzovkina Yulia A.
Published: August 2020

Physiological responses and growth of two Salix species — S. miyabeana and S. cinerea — were compared during one and two drought cycles. Photosynthetic rate (Asat), stomatal conductance (gs), and transpiration (E) were determined for each species. The highest total biomass and root: shoot ratio were recorded for S. cinerea. After two drought cycles, S. cinerea had significantly higher Asat at wilting and recovery stages compared to S. miyabeana. In addition, after two drought cycles, the stem water potential and water use efficiency were higher in S. cinerea than in S. miyabeana. Based on the results obtained in this study, S. cinerea is more drought tolerant than S. miyabeana.
Remediation of Nitrogen and Phosphorus from Nursery Runoff during the Spring via Free Water Surface Constructed Wetlands
Authors: White Sarah A. , Taylor Milton D. , Chandler Stewart L. , Whitwell Ted , Klaine Stephen J.
Published: August 2020

Agricultural operations face increasing pressure to remediate runoff to reduce deterioration of surface water quality. Some nursery operations use free water surface constructed wetland systems (CWSs) to remediate nutrient-rich runoff. Our objectives were twofold, first to examine the impact of two hydraulic retention times (HRT, 3.5 and 5.5 day) on CWS performance, and second to determine if increased nutrient loading from internal CWS and nursery sources during the spring contributed to nutrient export in excess of regulatory limits. We quantified nutrient loading and removal efficiency in a free water surface CWS from late winter through late spring over three years and monitored various water quality parameters. Total nitrogen in runoff was reduced from 20.6 ± 2.8 mg·liter−1 (ppm) to 4.1 ± 1.3 mg·liter−1 (ppm) nitrogen after CWS treatment. Phosphorus dynamics in the CWS were more variable and unlike nitrogen dynamics were not consistently influenced by water temperature and hydraulic loading rate. Phosphorus concentrations were reduced from 1.7 ± 0.8 mg·liter−1 (ppm) PO4-P in influent to 1.2 ± 0.6 mg·liter−1 (ppm) PO4-P in CWS effluent, but substantial variability existed among years in both phosphorus loading and removal rates. The CWS was able to efficiently remediate nitrogen even under high spring loading rates.
Irrigation Pond Characterization and Analysis: Impact of Weather and Management
Authors: Fox Laurie J. , Struik Paul C. , Appleton Bonnie L. , Nowak Jerzy E.
Published: August 2020

Weather and management practices were monitored to assess the impact on water quality at four stormwater retention ponds used for irrigation. Two retention ponds were located at Bayville Golf Club (BGC) in Virginia Beach, VA, and two were located at Knotts Creek Nursery (KCN) in Suffolk, VA. Total dissolved N concentrations were examined at increasing depths and over time at the pond inflows and middles. Multiple fertilizer products with variable analyses were applied more frequently at BGC, but N concentrations were consistently higher at KCN. In 2002, a drought year, water temperatures fluctuated little over the season or with depth, regardless of location. N concentration ranges were 1.0—3.5 mg·liter−1 (ppm) at BGC and 2.5—6.0 at KCN. Nitrogen concentrations fluctuated as water depth increased. In 2003 rainfall was above average. Water temperatures fluctuated more over the season than in 2002 and with increasing depth. N concentration ranges were 0.75—4.2 mg·liter−1 (ppm) at BGC and 0.5—6.0 at KCN; and were consistent as water depth increased. Both water temperatures and N concentrations fluctuated dramatically at the inflow locations compared to the middles of the ponds.
Green Roof Growing Substrates: Types, Ingredients, Composition and Properties
Authors: Ampim Peter A.Y. , Sloan John J. , Cabrera Raul I. , Harp Derald A. , Jaber Fouad H.
Published: August 2020

Although development of low (extensive) and high (intensive) maintenance green roof systems has progressed significantly, studies on the function of the growing substrate as a living constituent are lacking. The objective of this review paper is to summarize current scientific knowledge on the components, composition, and characteristics of green roof substrates and to identify future research needs. Due to variations in climate and desired plant types, there is no universal growing substrate. An appropriate substrate is expected to provide permanent physical support for plants and possess a fine balance between free drainage and adequate plant available water and nutrient retention. Typical substrate components include minerals in natural or modified forms such as sand, lava rock, or expanded shale, clay and slate; recycled waste materials like crushed bricks or tiles, crushed or aerated concrete and subsoil; stabilized organic matter such as composts; and plastic materials and slow release fertilizers. Proportions of components vary among substrates based on target vegetation, green roof type, and other considerations. Better green roof management for maximum benefits will require characterizing, quantifying and understanding the impacts of plant species and building attributes such as aspect, slope, height and heating on substrate performance, and should be considered for future research.
Entomosporium Leaf Spot Control on Red-tip Photinia in the Landscape
Authors: Hagan A.K. , Arkidge J.R.
Published: August 2020

In 2006, 2007, and 2008, efficacy of the soil-applied fungicide drench All-In-One Rose & Flower Care [All-In-One] (tebuconazole) was compared with the foliar-applied fungicides Daconil Weather Stik (chlorothalonil), Immunox Multipurpose Fungicide (myclobutanil), RosePride Disease Control Concentrate (triforine), and Disease Control for Roses, Flowers & Shrub Concentrate (tebuconazole) for the control of Entomosporium leaf spot on field-grown red-tip photinia (Photinia × fraseri ‘Birmingham’). While the label rate of All-In-One drench was poured over the soil surface around the base of each plant at monthly intervals, the foliar applied-fungicides were applied at label rates at 2-week intervals to runoff. Over the study period, drenches of All-In-One failed to protect photinia from Entomosporium leaf spot, while the foliar-applied fungicides significantly reduced disease levels. Defoliation on the non-fungicide treated controls was similar to the All-In-One drench and ranged over the study period from 25 to nearly 75%. In contrast, little if any leaf spotting and no defoliation occurred in any of the study years on the photinia treated with Daconil Weather Stik, Immunox Multi-purpose Fungicide, RosePride Disease Control Concentrate, and Disease Control for Roses, Flowers & Shrub Concentrate. Poor efficacy of the All-In-One was attributed to an inadequate concentration of the fungicide component tebuconazole when applied at the label drench rate.
Evaluation of Powdery Mildew Resistance in Hydrangea macrophylla
Authors: Windham Mark T. , Reed Sandra M. , Mmbaga Margaret T. , Windham Alan S. , Li Yonghao , Rinehart Timothy A.
Published: August 2020

Powdery mildew, Erysiphe polygoni DC, can be a significant problem on Hydrangea macrophylla (Thunb.) Ser. in the landscape in late summer to fall and during greenhouse propagation or production of potted plants. Because very little information related to sources of resistance is available, 90 H. macrophylla cultivars were evaluated for resistance to powdery mildew over a 3-year period. This included 69 H. macrophylla ssp. macrophylla and 18 H. macrophylla ssp. serrata (Thunb.) Makino cultivars, along with three cultivars that are hybrids between the two subspecies. Significant differences among cultivars to powdery mildew were found in all three study years. Three cultivars, ‘Amagi Amacha’, ‘Shirofuji’ and ‘Veitchii’, were among the most resistant each year. ‘Diadem’, ‘Komachi’, and ‘Omacha’ were highly resistant in 2006 and 2008, but only moderately resistant in 2007. ‘Komachi’ and ‘Shirofuji’ were considered unsuitable for breeding purposes as they do not appear to produce fertile flowers. ‘Veitchii’ was the only member of H. macrophylla ssp. macrophylla with a high level of powdery mildew resistance; while all other resistant cultivars were members of H. macrophylla ssp. serrata, not all members of this subspecies are resistant. Results of this study will be useful in breeding powdery mildew resistant H. macrophylla.
Physical and Chemical Properties of Green Roof Media and Their Effect on Plant Establishment
Authors: Olszewski Michael W. , Young Courtney A.
Published: August 2020

There are few research reports on components of green roof media. Better elucidation will allow landscape installers to select the ideal medium for individual or regional situations. The present study examined the effects of heat-expanded clay media components on: (1) physical and chemical properties and (2) growth of Sedum floriferum (stonecrop) and Dianthus gratianopolitanus (dianthus) plugs on a green roof. The addition of fine grade components caused an increase in bulk density and a decrease in total porosity, aeration porosity, and aeration porosity at applied suction pressure of 6.3 kPa. Container capacity reached a maximum following the addition of 40–60% (by vol) fine grade particles. Stonecrop and dianthus plugs were planted in early summer (June 29, 2010) into 6.4 cm (2.5 in) depth media containing 10–60% fine or medium grade heat-expanded clay located in a green roof garden. By early autumn (October 3, 2010), dianthus cover and plant weight were greatest in media containing 50–60% fine grade heat-expanded clay or 60% medium grade heat-expanded clay while stonecrop growth was inadequate regardless of media type.
Characterization of Hydrangea macrophylla Cultivars by the Anthocyanin Content in their Sepals
Authors: Schreiber Henry D. , Wade Samantha E. , Mayhew Kelly M. , Cobb Jason A.
Published: August 2020

In order to ascertain the role of anthocyanin content on the color and brightness of Hydrangea macrophylla sepals, anthocyanin contents of different colored sepals were measured for numerous commercial cultivars. Anthocyanin contents were primarily determined by extraction of the pigment, then measurement by differential spectrophotometry. Concentrations ranged from about 25 to over 400 μg delphinidin-3-glucoside per g of fresh sepal, with the magnitude roughly proportional to the perceived intensity of sepal coloration for that Hydrangea macrophylla cultivar. However, the anthocyanin content was independent of the sepal color, being the same for red, purple, or blue sepals of the same cultivar. Even though significant sepal-to-sepal variation in color intensity existed within a single inflorescence, the extractable anthocyanin content was constant for a specific cultivar. Accordingly, Hydrangea macrophylla cultivars were classified in terms of their color brightness or anthocyanin content in sepals as blush (very light colored, 25 to 60 μg·g−1), cold-hardy (light colored, 80 to 120 μg·g−1), classic (medium colored, 140 to 190 μg·g−1), vivid (deep colored, 230 to 270 μg·g−1), or vibrant (very deep colored, >300 μg·g−1) at peak bloom. The anthocyanin content of the sepals steadily increased as the inflorescence approached peak bloom, remained constant for a week or more, then decreased. The cultivar-dependent anthocyanin contents of the sepals can be used, in part, to rationalize the relative bluing capability of the various Hydrangea macrophylla cultivars.
Propagation of Osmanthus heterophyllus ‘Variegatus’ by Stem Cuttings
Authors: Lambert Christopher R. , Blazich Frank A. , LeBude Anthony V.
Published: August 2020

Nontreated softwood cuttings of Variegatus' osmanthus [Osmanthus heterophyllus (G. Don) P.S. Green ‘Variegatus’] collected in early June 2009 and late May 2010 rooted at > 70%. Treatment of cuttings with solutions of the potassium (K) salt (K-salt) of indolebutyric acid at 500 to 2000 mg·liter−1 (ppm) was generally ineffective and does not appear to be necessary for satisfactory rooting.
Preference and Performance of Black Cutworm (Lepidoptera: Noctuidae) on Poa Species
Authors: Hong Seung Cheon , Chris Williamson R. , Held David W.
Published: August 2020

Black cutworm (Agrotis ipsilon Hufnagel) is a destructive pest of golf course turf. Previous work suggests that Poa pratensis ‘Midnight’ is resistant to black cutworm, but it is not known if resistance also exists among other Poa species and cultivars. This study compared preference and performance of black cutworm on Poa species and cultivars to a susceptible host plant, creeping bentgrass (Agrostis stolonifera L. ‘Penncross’) in laboratory choice feeding assays and rearing experiments. Seven-and 14-day-old larvae were used in performance feeding tests. Larvae reared on all Poa spp. exhibited significantly lower developmental and survival rates than larvae fed creeping bentgrass. Young (7 days old) larvae did not survive to pupation. Although older (14 days old) larvae pupated and eclosed on Poa, larval weight gain was significantly lower than those reared on creeping bentgrass. In choice feeding bioassays, regardless of larval stage, black cutworm preferred creeping bentgrass over all Poa species and cultivars. The results of this research suggest that although Poa species are generally resistant to black cutworm, the resistance varies among cultivars and insect growth stage.
Nitrogen, Phosphorus and Potassium Fertilization of Brassaia actinophylla, Calathea makoyana and Chrysalidocarpus lutescens
Authors: Poole Richard T. , Conover Charles A.
Published: August 2020

Data indicated a 5-1-2 ratio of N-P-K with N level of 2.5 kg/100m2 (0.5 lbs/100 ft2) a month produced the highest quality B. actinophylla and C. makoyana. A 2-1-2 ratio with N level of 1 kg/100m2 (0.2lbs/100 ft2) a month produced the highest quality C. lutescens.
Weed Control in Newly Planted Azaleas
Authors: Beste C.E. , Frank J. Ray
Published: August 2020

Goal (oxyfluorfen) [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene] or Ronstar (oxadiazon) [2-tert-butyl-4(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin-5-one] each at 2.2 kg ai/ha (2.0 lb/A) controlled 87% and 70% of the summer annual weeds in newly planted liners of ‘Hershey Red’ azaleas (Rhododendron obtusum Planck) when applied at planting in June 1980 and reapplied in March 1981. Ronstar at 4.5 kg/ha (4.0 lb/A) controlled 80% or more of Pennsylvania bittercress (Cardamine pensylvanica Muhl.), common purslane (Portulaca oleracea L.), spotted spurge (Euphorbia maculata L.), common yellow woodsorrel (Oxalis stricta L.), and common groundsel (Senecio vulgaris L.). Devrinol (napropamide) [2-(a-naphthoxy)-N,N-diethylpropionamide] applied at 4.5 or 9.0 kg/ha (4.0 or 8.0 lb/A) was the only effective treatment for controlling common chickweed [Stellaria media (L.) Cyrillo] (81%). Goal at 2.2 kg/ha (2.0 lb/A) and Devrinol at 9.0 kg/ha (8.0 lb/A) were the most effective treatments for controlling large crabgrass [Digitaria sanguinalis (L.) Scop.]. No significant differences were observed in size of the azaleas after two years.
Coverings for Overwintering Container Grown Plants in Northern Regions
Authors: Pellett Norman E. , Dippre Daphne , Hazelrigg Ann
Published: August 2020

Several methods were compared for moderating temperatures and protecting container-grown nursery plants from winter injury. Three layers of microfoam covered by 1 layer of 4 mil white copolymer (poly) and 30 cm (12 in) straw between 2 layers of white poly greatly moderated minimum temperatures of growing medium. The straw-between-white poly treatment prevented rapid rise of air temperatures under the cover in early spring. All covers resulted in minimal winter injury to most plant species, but growing medium temperatures in containers under 1 layer of microfoam or 1 layer white poly dropped below −10°C (14°F), the temperature shown to be injurious to root systems of some plants.
A Production System and Costs for Propagating Dogwood Cultivars from Softwood Cuttings
Authors: Badenhop M.D. , Glasgow Thomas
Published: August 2020

Propagation of flowering dogwood (Cornus florida L.) cultivars from softwood cuttings offers a successful alternative method to producing cultivars by field budding of dogwood seedlings. The total cost to produce an acceptable rooted cutting is $0.34. A 9-month propagation period, mid-July to mid-April, is required. Variable costs comprised 79% of total costs with labor being the most important variable cost item. Rooting dogwood cultivars is economically practical and in the future more growers will be producing dogwoods by this propagation method.
Growth of Hardy Chrysanthemums in Containers of Media Amended with Composted Municipal Sewage Sludge
Authors: Gouin Francis R.
Published: August 2020

Four hardy Chrysanthemum X morifolium (Ramat) (chrysanthemum) cultivars were grown in peat sand media amended with 2 sources of sewage sludge compost at 50, 60 and 67% of the media by volume. Chrysanthemums growing in the 50% to 60% by volume composted sewage sludge treatments and top dressed with complete or only N slow-release fertilizers were comparable to plants growing in a commercially available potting medium with a complete fertilizer. Media containing 50 and 60% compost with a pH range of 6.2 to 6.9 supplied trace elements and most of the P and K necessary for normal plant growth. The use of a surfactant increased the fresh weight in some compost blends.
Phosphorus Requirement of Rhododendron ‘Victor’ and Cotoneaster adpressa praecox Grown in a Perlite-Peat Medium
Authors: Havis John R. , Baker John H.
Published: August 2020

Rooted cuttings of Rhododendron ‘Victor’ (a PJM cultivar) and Cotoneaster adpressa praecox were grown in the greenhouse with phosphorus (P) levels ranging from 0 to 15 ppm in a perlite-peat medium. Shoot growth of Rhododendron was equal at P levels from 2.5 to 15 ppm. Maximum growth of shoots and roots of Cotoneaster was at 10 ppm. Maximum Rhododendron leaf P content occurred at 5 ppm in the medium and remained the same at higher P levels. The P content of Cotoneaster leaves increased throughout the range of P levels in the growing medium. A P level of 10 ppm in soilless media solution is suggested for most nursery crops.
Amended Backfills: Their Cost and Effect on Transplant Growth and Survival
Authors: Hummel Rita L. , Johnson Charles R.
Published: August 2020

Amendment of backfill soil at planting with peat moss, fired montmorrilonite clay or a “superabsorbent” gel had no significant positive influence on growth and establishment of container grown Liquidambar styraciflua L., sweet gum, plants placed in well-drained Arredondo fine sand soil. A cost estimate indicated the addition of amendments to backfill soil would increase installation costs 27 to 30% over those for control plants.
Propagation of Hybrid Lilacs Using Stock Plant Etiolation
Authors: Miske Diane M. , Bassuk Nina L.
Published: August 2020

Outdoor grown stock plants of French hybrid lilacs, (Syringa vulgaris), were allowed to leaf out under dense shade. The resulting etiolated shoots were banded at the base with black tape to retain their etiolated condition, after which time shade was removed and the tops were allowed to green up. Cuttings from shoots treated this way rooted significantly better over a longer period of time than did the controls. Localized blanching of the shoots with black tape without prior shade treatment also had a favorable effect on rooting. Cuttings taken from stock plants forced during the winter in a greenhouse rooted as well as the best etiolation treatment outdoors. Shading or IBA treatment did not improve the rooting of these greenhouse grown plants. Only localized banding with black tape increased rooting significantly in the greenhouse grown cuttings.
Survival and Growth of Paulownia Seedlings are Enhanced Through Weed Control
Authors: Beckjord P.R. , Melhuish J.H. , Kundt J.F.
Published: August 2020

Four treatments of preemergence herbicide and a water control were compared in circular plots around cut off stumps of l-year-old field-grown Paulownia tomentosa seedlings. Tree survival and growth were significantly increased with the use of Princep (simazine), 0.45 and 0.90 kg/ha (0.40 and 0.80 lb) active ingredient/acre (ai/A) and Velpar (hexazinone), 0.50 and 1.00 kg/ha (0.45 and 0.90 lb ai/A) for weed control. Velpar at the high rate significantly reduced weed cover over all other herbicide treatments.
Cultural Treatment and Cutting Type Affects Growth of ‘Heritage’ Birch Rooted Cuttings
Authors: Struve Daniel K.
Published: August 2020

Rooted cuttings of Betula nigra ‘Heritage’ originating from short shoots were either staked and lateral shoots pruned to a 3 node length or were unstaked and unpruned. One hundred and twenty-five days following propagation, the pruned and staked plants had higher net assimilation rates and lower leaf area ratios than unstaked and unpruned plants. No differences in relative growth rates, total dry weight, root/shoot ratios or shoot length were observed between control and treated plants. Pruned and staked plants had, relative to unstaked and unpruned, less leaf surface area composed of fewer but larger leaves which produced more grams of dry weight per cm2 leaf surface area per day. Pruning and staking maximized economically important dry matter production without reducing total dry weight.

Plants originating from long shoots had greater root, shoot and total dry weights, and required less staking to produce upright growth than plants originating from short shoots. By exploiting the beneficial topophysis growth of long shoots, nursery productivity can be increased.
Phosphorus Availability in Peat-Sand Media Fertilized with Several Phosphorus Sources
Authors: Havis John R. , Baker John H.
Published: August 2020

Treble superphosphate 20% P (0-46-0), MagAmp 7N-17.6P-5K (7-40-6) and Osmocote 18N-2.6P-10K (18-6-12) failed to maintain phosphorus (P) at a level of 10 ppm in peat:sand media extracts during a full growing season under nursery conditions. A single surface application of Osmocote 14N-6.2P-11.6K (14-14-14) supplied the desired P level for 18 weeks.
Dikegulac Sodium Concentration and Application Number Affects Branching of Blackgum and Southern Sugar Maple during Container Production
Authors: Keever Gary J. , Kessler J. Raymond , Hoffman L. Heath , Stephenson James C.
Published: August 2020

A study was conducted under nursery production conditions to evaluate multiple concentrations of dikegulac sodium (dikegulac) (0, 800, and 1,600 ppm) applied either once or twice as a foliar spray to blackgum grown at two locations in Alabama and to southern sugar maple grown at a single location. Mid-season and end-of-season shoot counts increased linearly in response to increasing dikegulac concentrations in both species and at both locations. Shoot counts also were greater when dikegulac was applied twice compared to a single application, except when 800 ppm dikegulac was applied to blackgum at one location. Both southern sugar maple and blackgum were visibly more branched and compact following treatments with dikegulac than nontreated control plants, although the branching response was much greater in blackgum. Effects of dikegulac application on plant height and caliper varied with species, concentration, application number, and time after application. Southern sugar maple exhibited temporary reddening of immature foliage that dissipated over time, while immature foliage of blackgum yellowed at one location and cupped and developed necrotic lesions at the second location. No phytotoxicity was evident 6 weeks after dikegulac application.
Quantifying Water and Nutrient Losses with Hose Irrigation
Authors: Andiru G.A. , Pasian C.C. , Frantz J.M.
Published: August 2020

The amount of water, nitrogen (N), phosphorous (P), and iron (Fe) lost from potted impatiens (Impatiens wallerana Hook. f.) plants fertilized with either controlled-release fertilizer (CRF) of varying longevities or a water-soluble fertilizer (WSF), with irrigation provided with a hose in all treatments, was quantified. The plants were grown in a sphagnum peat-based soilless substrate containing either CRF [Osmocote Plus 16-9-12 (16-3.9-10-0.46 N:P:K:Fe), 5 to 6 month and or 8-to 9 month longevities] incorporated (6.8 kg·m−3 or 11.5 lb·yd−3) throughout the substrate and compared with plants fertigated with a WSF [Peters Professional 20-10-20 (20-4.4-1.66-0.1 N:P:K:Fe) at 150 mg·L−1 (150 ppm) N]. The container-grown plants were placed on top of plastic cups and located inside a plastic box. Municipal water or mineral nutrient solution leached from each container and lost between containers was captured, quantified and analyzed for N, P, and Fe concentrations. As an average for the three treatments, 25.6% of the total water applied was leached out of the pots and 34% fell between the pots. Six weeks after starting the experiment, leachate from pots fertilized with WSF had approximately a 92% higher concentration of N, 96% more P, and 69% more Fe than the concentrations in leachate from CRF-fertilized pots. These results quantify the assumed inefficiencies of using a hose as the primary fertilizer delivery method.
Cultural and Chemical Practices for Quality Improvement of Overseeded Bermudagrass [Cynodon dactlyon (L.) Pers. × C. transvaalensis Burtt-Davy] and Annual Bluegrass (Poa annua L.) Suppression
Authors: Aldahir Philipe C. F. , McElroy J. Scott , Flessner Michael L. , Baird James H. , Magni Simone , Grossi Nicola , Lulli Filippo , Volterrani Marco
Published: August 2020

Dormant bermudagrass (Cynodon dactlyon (L.) Pers. × C. transvaalensis Burtt-Davy) is overseeded with perennial ryegrass (Lolium perenne L.) to maintain green color through the fall and winter. Annual bluegrass (Poa annua L.) control is critical for overseeding success, as this weed can greatly decrease aesthetic quality and playability of turfgrass due to excessive seedhead production. Research was conducted to evaluate the influence of pre-seeding cultural practices (scalping, solid-tine aerification, vertical mowing, and vertical mowing plus scalping) on overseeding establishment. The effect of increasing overseeding rates of perennial ryegrass (111, 222, 444, and 888 kg pure live seed·ha−1; 100, 200, 400, and 800 lb·A−1) and roughstalk bluegrass (Poa trivialis L.) (55, 111, and 222 kg pure live seed·ha−1; 50, 100, and 200 lb·A−1) on annual bluegrass populations was also investigated. Additionally, plant growth regulators (PGRs) were evaluated for annual bluegrass seedhead suppression and turf injury. Mefluidide at 0.056 kg ae·ha−1 (0.05 lb ae·A−1), and paclobutrazol, flurprimidol, trinexapac-ethyl, and trinexapac-ethyl plus ethephon at 0.28, 0.42, 0.382, and 0.095 plus 3.82 kg ai·ha−1 (0.25, 0.37, 0.34, 0.085 plus 3.4 lb ai·A−1), respectively, were applied twice, sequentially with a four-week interval. Contrary to previous research, pre-seeding cultural practices did not improve overseeding success. Annual bluegrass density decreased with increasing perennial ryegrass overseeding rates from 50% in the non-overseeded to 14 to 17% when overseeded with rates up to 222 kg pure live seed·ha−1, and 4 to 8% when overseeded with rates between 444 and 888 kg pure live seed·ha−1. Roughstalk bluegrass overseeded reduced annual bluegrass density from 50% in the non-overseeded, to 7 to 13% when overseeded with 55, 111, or 222 kg pure live seed·ha−1, regardless of the overseeding rate. Overseeding bermudagrass with roughstalk bluegrass or perennial ryegrass increased turfgrass green cover during winter, especially 100 days after seeding. Paclobutrazol, flurprimidol, and trinexapac-ethyl were successful at suppressing annual bluegrass seedheads and were not injurious to perennial ryegrass. Mefluidide resulted in efficient annual bluegrass seedhead suppression; however, unacceptable turfgrass injury occurred in 2012.
Substrate pH and Butterfly Bush Response to Dolomitic Lime or Steel Slag Amendment
Authors: Altland James E. , Zellner Wendy , Locke James C.
Published: August 2020

Steel slag (SS) is a fertilizer amendment with a high concentration of calcium oxide, and thus capable of raising substrate pH similar to dolomitic lime (DL). Steel slag, however, contains higher concentrations of some nutrients, such as iron, manganese, and silicon, compared to DL. The objective of this research was to determine the effect of SS rate on pH in a substrate composed of 80 pine bark:20 sphagnum peatmoss (v:v), as well as growth and nutrient concentration of butterfly bush (Buddleja davidii ‘Pink Delight’ Franch.). The base substrate was amended with either DL or SS at rates of 0, 0.6, 2.4, 4.8, 9.5, or 14.3 kg·m−3. Substrates were placed into 12-L nursery containers and potted with a single butterfly bush per container. Dolomitic lime amendment resulted in higher substrate pH at rates from 0.6 to 4.8 kg·m−3 while the SS amendment caused a greater increase in pH at rates higher than 4.8 kg·m−3. Butterfly bush responded well to all but the highest SS rate applied. As the rate of SS increased to 14.3 kg·m−3, decreased Mg availability may have reduced shoot growth. Based on the results of this experiment, SS could be used as an alternative to DL. However, incorporation rates would need to be adjusted slightly higher for SS compared to DL to achieve a desired pH in the range of 6 to 6.5.
Survey of Reclaimed and Non-reclaimed Irrigation Water Use for Production of Container-grown Plants in Florida
Authors: Yeager Thomas H. , von Merveldt Joseph K. , Irani Tracy A. , Larsen Claudia A.
Published: August 2020

A descriptive survey was conducted of container plant growers using reclaimed water (processed sewage) for irrigation of nursery crops and growers whose businesses were located in areas where reclaimed water was available but not used for irrigation. Surveys were completed during site visits except when participants wanted to complete the survey at a later time. Nurseries using reclaimed water produced trees, shrubs, perennials, bedding plants, foliage plants, and potted flowering plants. Average area outdoors or under shade irrigated with overhead sprinklers was 3.5 ha (8.6 A) and 10,777 m2 (116,000 ft2) for greenhouses. Participants responded that reclaimed water quality (67%) and quantity (50%) were consistent over time. All reclaimed water users were satisfied with both quality and quantity of reclaimed water. Most growers (83%) not using reclaimed water were using well water as the primary source of water. Seventy-one percent of non-reclaimed users responded that expense of connection to reclaimed water was a limitation, while 57% indicated that unknown water quality and health or safety concerns were limitations. Results from this survey indicated acceptance of reclaimed water among active users and the need for education about reclaimed water for non-reclaimed users.
Developmental Stage of ‘Snow White’ Indian Hawthorn and ‘Sky Pencil’ Holly Affects Response to Cyclanilide
Authors: Williamson Zoe , Keever Gary J. , Kessler J. Raymond , Olive John W.
Published: August 2020

A study was conducted to determine the role that plant developmental stage (DS) has on the efficacy of cyclanilide (CYC), a plant growth regulator (PGR) with cytokinin-like properties. In 2007, single foliar applications of 200 ppm CYC were applied to ‘Snow White’ Indian hawthorn (Rhaphiolepis indica (L.) Lindl. Ex Ker Gawl.) and ‘Sky Pencil’ holly (Ilex crenata Thunb.) at progressively later stages of lateral shoot development: bud break (DS 1), active shoot elongation (DS 2), or to recently matured shoots (DS 3). The experiment was repeated in 2008 and included an additional application to Sky Pencil holly before bud break (DS 0). In 2007 and 2008, Snow White Indian hawthorn treated with CYC at all DS formed more shoots than untreated plants, except in summer 2008 (DS 3 only) and fall 2008 (DS 1 only). New shoot counts of CYC-treated Indian hawthorn were 53 to 67% and 46 to 65% higher than those of untreated plants in summer and fall, respectively, in 2007 and 26 to 39% and 29 to 48% higher in summer and fall, respectively, in 2008. In the fall of 2008, the only effect of DS on shoot counts of Indian hawthorn was that plants treated at DS 3 formed 29% more new shoots than plants treated at DS 1; DS had no effect on shoot counts in 2007. Symptoms of foliar injury to Indian hawthorn included reddening, chlorosis, and cupping of new growth that appeared between 15 and 30 days after treatment (DAT) and, although not quantified in 2007, were generally less severe and more transitory as DS increased. In 2007, foliar injury lasted until about 90 to 120 DAT in DS 2 and DS 3 plants, but was more persistent in DS 1 plants. In 2008, foliar injury was also transient, regardless of DS, but was highest when CYC was applied at DS 1 or DS 2. CYC-treated Sky Pencil holly had formed more shoots than untreated plants by summer and fall of 2007. Although Sky Pencil holly treated at DS 2 in 2007 formed fewer shoots than DS 1 plants in fall, quality ratings were higher due to a larger canopy that was dense and compact. In the fall of 2008, shoot counts of CYC-treated Sky Pencil holly were greater than those of untreated plants, regardless of DS, and there were no effects of DS on shoot counts. Quality ratings of Sky Pencil holly treated at DS 2 or DS 3, but not at DS 0 and DS 1, were higher than those of untreated plants. In both years of the study, symptoms of foliar injury on Sky Pencil holly were minimal, suggesting a relatively high tolerance to foliar-applied CYC, and all plants were considered marketable.
Evaluation of Indaziflam for Greenhouse Use
Authors: Edwards Lucy , Marble S. Christopher , Murphy Anna-Marie , Gilliam Charles H.
Published: August 2020

Due to the relatively small market, volatility concerns, and high crop-value-per-acre associated with ornamental crops, no preemergence (PRE) herbicides are currently labeled for use in greenhouses containing plants. The objective of this study was to evaluate indaziflam SC for potential use as a PRE herbicide on gravel in greenhouses containing sensitive crops grown in extreme environmental conditions. Mini-greenhouses (MG) were designed and constructed to fit within gravel ground beds as an initial component to this study in order to evaluate herbicide volatility. Species evaluated included ‘Better Boy’ tomato (Lycopersicon esculentum Mill.), ‘Extreme Orange’ impatiens (Impatiens walleriana Hook. f.) and two species of petunia (Petunia × hybrida Juss. ‘Dreams White’ and ‘Dreams Neon Rose’). Indaziflam SC was applied at the manufacturer's labeled rate [40 g ai·ha−1 (0.04 lbs ai·A−1)] (1×) and at twice the labeled rate [80 g ai·ha−1 (0.07 lbs ai·A−1)] (2×). Each rate was applied using one of three different methods: 1) applied to only the gravel in ground beds with plants placed on gravel and covered with MG immediately following application; 2) applied over the top of plants on gravel inside the ground beds and covered with MG immediately application; and 3) applied over the top of plants outside the ground beds on adjacent gravel and left outside of MG. Two nontreated control treatments were maintained for each species and were placed either on nontreated gravel inside ground beds and covered with MG or placed outside ground beds on adjacent nontreated gravel and not covered with MG. Little to no injury was observed on any of the species after being placed on treated gravel and covered with a MG regardless of indaziflam rate. However when indaziflam was applied over-the-top, impatiens and tomatoes exhibited severe injury and death by 30 days after treatment (DAT). Additionally, fresh weights showed that all species receiving either over-the-top treatment were severely injured, while the plants placed on treated gravel inside the MG and both nontreated control treatments (both inside and outside of MG) exhibited no signs of injury or stunted growth. Results from this study indicate that while indaziflam may cause crop injury to ornamental species when applied over-the-top, it is likely that little to no injury will be observed as a result of volatility due to a gravel application in an enclosed structure.
Trade Flows within the U.S. Nursery Industry
Authors: Khachatryan Hayk , Hodges Alan W. , Palma Marco A. , Hall Charles R.
Published: August 2020

This study summarizes regional trade flows in the U.S. nursery industry by incorporating origin and destination (OD) sales data from a national survey of ornamental plant growers and dealers conducted in 2014. Specifically, we discuss: 1) regional annual sales reported by the green industry firms in 2013, 2) percentage distribution of OD trade flows by regions and states, and 3) differences in the percentage distribution of OD trade flows during the 5-year period by region. Of 32,000 questionnaires sent via mail and email, a total of 2,657 usable observations were received and used in the analysis. The OD trade flow results were then compared with those of 2008 estimates by eight United States regions. The highest proportion of inter-regional sales were reported by firms in the Appalachian (35.7%), followed by Mountain (25.4%), and Southeast (19.1%) regions, and the lowest inter-regional sales were in the Midwest (2.2%) and Great Plains (0.9%) regions. The results show considerable changes in both intra-state (within home state) and inter-regional (between states) trade flows from 2008 to 2013. Overall, intra-regional trade in the Great Plains, Midwest, Pacific, and Southeast regions increased by 9.9, 3.7, 1.6, and 7.8% from 2008 to 2013, respectively. However, the proportion of sales within Appalachian, Mountain, Northeast and Southcentral regions, decreased by 11.1, 8.3, 3.8 and 0.2%, respectively. Implications for relevant green industry stakeholders are discussed.
Bigtooth Maples from Three Geographically Different Origins Endure Root Zone Salinity
Authors: Bsoul Emad , Gioannini Rachel , St. Hilaire Rolston
Published: August 2020

The contiguous geographic range of bigtooth maple (Acer grandidentatum Nutt.) covers Utah, Idaho, Wyoming, Arizona, New Mexico, and Texas and suggests that this deciduous tree is a potential landscape plant for many regions. Using bigtooth maples selected from provenances in New Mexico (NM), Utah (UT) and Texas (TX), we evaluated physiological and growth traits of plants subjected to root zone salinity treatments at concentrations 0 (control), 2.5, 5.0 or 10.0 dS·m−1 (0, 1,600, 3,200, or 6,400 ppm). At harvest, foliar Kjeldahl nitrogen, potassium, magnesium, phosphorus, and calcium concentrations of salinity-treated plants were not different from control plants. Plants from the TX provenance had the highest leaf dry weight (DW) (15.7 g [0.55 oz]), larger stem diameter (11.4 mm [0.45 in]), less foliar injury, and less negative midday stem water potentials while accumulating three and two times more foliar sodium than plants from the UT and NM provenance plants, respectively. Total DW (95.9 g [3.4 oz]) of TX plants was triple that of the other two provenances. While bigtooth maples from the three provenances tolerated salinity, those from the TX provenance show enhanced resiliency to root zone salinity.
Ethyl Methanesulfonate and Caffeine Mutagenetic Treatment to Four Ornamental Silene Species
Authors: Jiang Li , Dunn Bruce L.
Published: August 2020

Mutagenesis breeding for horticultural crops is valuable not only for creating new cultivars, but also expanding the genetic pool for hybridization. Four Silene species were subjected to ethyl methanesulfonate (EMS) and/or caffeine mutagenesis to obtain valuable ornamental traits and to test the effects of different mutagens and combinations. Species responded differently to the mutagens. Generally, caffeine plus EMS treatments had a greater effect on mutation rate than either treatment applied alone. Caffeine alone was found to enhance seed vigor of S. floscuculi. Caffeine as a plant mutagen should be further investigated to determine the most efficient concentration as well as effects on other plant species, as several desirable mutants were obtained with leaf variegation.
Spray deposition inside multiple-row nursery trees with a laser-guided sprayer1
Authors: Zhu H. , Liu H. , Shen Y. , Liu Hengyu , Zondag R. H.
Published: August 2020

Multiple-row container-grown trees require specially designed sprayers to achieve efficient spray delivery. A five-port air-assisted sprayer with both automatic and manual control modes was developed to discharge adequate spray deposition inside multiple-row trees. The sprayer resulted from integration of a high-speed laser-scanning sensor with a sophisticated nozzle flow control system, an embedded computer with a touch screen, a Doppler speed sensor, a specially-designed algorithm and an air-assisted sprayer base. It was able to detect target tree presence and measure target tree size, shape and leaf density. The sprayer then controlled the spray output of each nozzle to match tree structures. The sprayer was tested for its sprayer deposition quality inside canopies in a four-row sterling silver linden (Tilia tomentosa 'Sterling Silver' Moench) field and another six-row northern red oak (Quercus rubra L.) field. Tests were conducted with the sprayer in variable-rate application (VRA) and constant-rate application (CRA) modes. The average spray deposit on foliage of trees was 1.37±0.47 μL cm−2 from VRA and 1.29±0.42 μL cm−2 from CRA in linden, and was 2.15±0.57 μL cm−2 from VRA and 2.72±0.94 μL cm−2 from CRA in red oak, respectively. In comparison, spray coverage on foliage of trees was 19.8±3.0% from VRA and 20.9±4.3% from CRA in the linden trial, and was 27.9±3.7% from VRA and 30.5±5.4% from CRA, respectively, in the red oak trial. The newly developed air-assisted sprayer in both VRA and CRA modes would be able to discharge adequate spray deposition inside multiple-row tree plants while conserving pesticide.

Index words: environmental protection, pest control, pesticide, precision sprayer, spray coverage.

Species used in this study: sterling silver linden (Tilia tomentosa 'Sterling Silver' Moench), northern red oak (Quercus rubra L.).
Effect of Propagation Tray Design on Early Stage Root Development of Acer rubrum, Quercus rubra, and Populus tremuloides 1
Authors: McGrath Darby , Henry Jason , Munroe Ryan , Agro Erin
Published: August 2020

This experiment investigated the effect of different plug-tray cell designs on root development of red maple (Acer rubrum), red oak (Quercus rubra), and quaking aspen (Populus tremuloides) seedlings. In April of 2015, seeds of each species were sown into three plug trays with different substrate volumes and grown for 17 weeks. Two trays had permeable walls for air-pruning, one with vertical ribs and one without. The third tray had impermeable plastic cell walls. Harvested seedlings were analyzed for root dry weight, length, volume, surface area and number of deflected roots. Root length per volume was highest in the impermeable-walled tray for red maple and quaking aspen. The total numbers of deflected root systems were higher for all species in the impermeable-walled tray. Seedlings grown in the air-pruning trays had smaller proportions of deflected root masses. Greater substrate volume did not influence root deflection development. The air-pruning tray without vertical ribs had the lowest total number of root masses with misdirected roots and lower proportions of root masses with misdirected roots for all species. These results indicate that improved root architecture in root-air pruning tray designs is achievable in tree propagation; however, vertical plastic structures in air-pruning trays can still cause root deflections.

Index words: Deflected roots, air-pruning, seedling, propagation, plugs, root architecture.

Species used in the study: red maple (Acer rubrum L.); red oak (Quercus rubra L.); quaking aspen (Populus tremuloides Michx.).