bluuebunny/crossref_metadata_2025 huggingface dataset:
Transpiration and Drought Stress Recovery of Three Zinnia Cultivars1
Authors: Roberts Bruce R. , Wolverton Chris
Published: August 2020

Transpiration and drought stress recovery were investigated in three container-grown zinnia cultivars [Zinnia elegans Jacq. (‘Lilliput' and ‘Thumbelina') and Z. haageana Reger (‘Persian Carpet')] by measuring daily changes in the normalized transpiration ratio (NTR) of well-watered (control), water-stressed, and water-stressed/re-watered plants. Transpiration of plants grown in gradually drying substrate did not decline until the fraction of transpirable substrate water (FTSW) reached 0.16 to 0.12. Symptoms of plant-water stress (i.e. foliar wilt) were first observed on the leaves of ‘Persian Carpet', which was also the cultivar with the highest average daily transpiration rate. By comparison, the remaining two cultivars (‘Lilliput' and ‘Thumbelina') exhibited lower average daily transpiration rates and took significantly longer to reach the same dry-down endpoint (NTR ≤0.15). Drought stress recovery was assessed by comparing xylem water potential and root and shoot dry weight in well-watered and in drought-stressed plants following a 7-day stress amelioration period. Xylem water potential of all three drought-stressed cultivars increased (i.e. became less negative) one week after re-watering. Root biomass and root:shoot ratio were both significantly greater in water-stressed plants than in well-watered plants of the same cultivar, a finding that suggests the likelihood of osmotic adjustment in response to drought.

Index words: normalized transpiration ratio, fraction of transpirable substrate water, foliar wilt, containerized horticultural crops.

Species used in this study: ‘Lilliput' and ‘Thumbelina' zinnia (Zinnia elegans Jacq.), ‘Persian Carpet' zinnia (Zinnia haageana Reger).
Efficacy of preemergence herbicides over time
Authors: Altland James E.
Published: August 2020

Preemergence herbicides are applied to container-grown nursery crops repeatedly throughout the year, often in 8 to 10 week intervals. Preemergence herbicide efficacy may decline over time, resulting in reduced weed control several weeks after application if weed seed density remains high. The objective of this research is to evaluate efficacy of preemergence herbicides on creeping woodsorrel (Oxalis corniculata L.) and flexuous bittercress (Cardamine flexuosa With.) by applying weed seed from 0 to 10 weeks after herbicide application. Granular formulations of pendimethalin, prodiamine + isoxaben, oxyfluorfen + pendimethalin, and flumioxazin were applied at their maximum labeled rates to separate groups of containers every two weeks for ten weeks. After the herbicide application at 10 weeks, 40 seeds of creeping woodsorrel and flexuous bittercress each were applied to all containers. All herbicides provided effective control when seed were applied within 2 weeks of herbicide application. Herbicides containing oxyfluorfen or flumioxazin provided effective preemergence bittercress and creeping woodsorrel control when seed were applied up to 8 to 10 weeks after herbicide application. Other herbicide products resulted in reduced control as the time between herbicide and seed application increased.

Index words: weed control, container crops, substrates.

Species used in this study: flexuous bittercress (Cardamine flexuosa With.), creeping woodsorrel (Oxalis corniculata L.).

Chemicals used in this study: pendimethalin (Pendulum 2G), prodiamine + isoxaben (Gemini G), pendimethalin + oxyfluorfen (OH2), and flumioxazin (BroadStar).
Japanese Stiltgrass (Microstegium vimineum) Germination Pattern and its Impact on Control Strategies1
Authors: Payne Geoffrey , Evans Jim , Derr Jeffrey , Murdock Ethan
Published: August 2020

Field trials were conducted by Virginia Master Naturalists to determine the germination period for Japanese stiltgrass and its impact on timing of postemergence herbicide applications. Germination rates declined from April to June, with no germination seen after mid-June. Glyphosate applications in early May significantly reduced Japanese stiltgrass cover that month, but post-treatment germination resulted in approximately 25% cover by October, with 78% cover seen in untreated plots. However, no Japanese stiltgrass was observed in October when glyphosate was applied in either the third week of June or the third week of July. A single application of glyphosate was effective for Japanese stiltgrass control if applications are made in June after new germination had ceased, verified by multi-year herbicide field trials. Field trials conducted by Virginia Tech showed preemergence applications of prodiamine reduced Japanese stiltgrass stand from 30 to 94%, depending on rate and timing, but even in the most effective treatment there was still at least 19% cover by August. Prodiamine treatments that utilized May applications were more effective for crabgrass (Digitaria spp.) control than for Japanese stiltgrass, supporting the earlier germination pattern for Japanese stiltgrass. Inclusion of this work in this paper provides a more complete picture of the treatment options for Japanese stiltgrass. A timed postemergence herbicide application may be a better control option for this weed than use of a preemergence herbicide application.

Index words: herbicide application, invasive plants, weed control.

Chemicals used in this study: Glyphosate [N-(phosphonomethyl)glycine)], prodiamine (2,6-Dinitro-N,N-dipropyl-4-(trifluoromethyl)-1,3-benzenediamine).

Species used in this study: Japanese stiltgrass (Microstegium vimineum (Trin.) A Camus.).
Micropropagation of Rhododendron chapmanii
Authors: Blazich Frank A. , Giles Cheryl G. , Haemmerle Carole M.
Published: August 2020

Shoot tips excised from Chapman's rhododendron (Rhododendron chapmanii A. Gray) were surface sterilized, the terminal portions were removed (decapitated) and the shoots placed in liquid Woody Plant Medium (WPM) supplemented with 8 μM (1.6 ppm) 6(γ, γ-dimethylallylamino)-purine (2iP). Within 2 to 3 months axillary shoots excised, decapitated and cultured on agarsolidified WPM supplemented with 49 μM (10 ppm) 2iP. Multiple shoot formation consisting of adventitious and axillary shoots was observed within 4 to 6 months. These shoots were transferred to WPM supplemented With 8 μM (1.6 ppm) 2iP and cultured under reduced light levels to stimulate shoot elongation. Shoots ≥ 10 mm (0.4 in.) were harvested (microcuttings) and rooted using non-in vitro procedures. Enhancement of axillary shoot multiplication was achieved by culturing decapitated axillary shoots under reduced light levels in a horizontal position on WPM supplemented WIth 8 μM (1.6 ppm) 2iP.
Dehydration Effects on Germination of Live Oak Seed
Authors: Morgan David L. , Brubaker Timothy P.
Published: August 2020

Mature live oak, Quercus virginiana Mill., acorns were collected from four trees in Dallas, Texas, dried at 35°C (95°F) to 0 to 30% weight loss, and allowed to germinate. Drying reduced germination, but the relationship of percent germination to weight loss varied from tree to tree. In general, the smallest acorns had the lowest germination rate. Drying time was closely related to percent weight loss in all seeds. Results suggest that growers should select live oaks with larger seeds which have demonstrated high germinability.
Evaluation of Ericoid Mycorrhizae and Media, on Establishment of Micropropagated, Rhododendron chapmanii, Gray
Authors: Barnes Lee R. , Johnson Charles R.
Published: August 2020

Rooted microcuttings of Chapman's rhododendron (Rhododendron chapmanii Gray) were transplanted into MetroMix-500 (M500) and fired montmorillonite clay: Canadian peat [(2FMC: 1CP) by vol] and half the plantlets were inoculated with the ericoid mycorrhizal fungus, Pezizella ericae Read. Plantlet survival was improved with mycorrhizal colonization after 16 weeks in 2FMC: 1CP medium, but no differences were observed for plants grown in the M500 medium. Plant growth parameters after 16 weeks were greater for all plants grown in the M500 medium and there were no beneficial mycorrhizal growth responses in either media. Mycorrhizal colonization appeared to be of no benefit to growth of rooted R. chapmanii microcuttings except improved survival in high pH 2FMC:1CP medium.
Relationship of Soil Temperature and Moisture to Development of Phytophthora Root Rot of Azalea
Authors: Benson D.M.
Published: August 2020

Temperature and moisture effects on development of Phytophthora root rot of azalea caused by Phytophthora cinnamomi was compared for plants growing in containers and a landscape bed in both sun and shade environment. Symptoms of Phytophthora root rot developed earlier and disease severity was greater on plants grown in the landscape bed where soil temperature and moisture in the root zone of infected plants favored disease development. Disease severity was similar for plants in the bed regardless of exposure to the sun or shade. In container culture, disease severity was greater on plants in the shade where medium temperature was lower and moisture was greater, than on similar plants exposed to the sun.
Use of Foliar-Applied Neem (Azadirachta indica A. Juss.) Seed Extract for the Control of the Birch Leafminer, Fenusa pusilla (Lepeletier) (Hymenoptera:Tenthredinidae)
Authors: Larew Hiram G. , Knodel J.J. , Marion D.F.
Published: August 2020

The effect of 1.0% neenl (Azadirachta indica A. Juss.) seed extract applied as a foliar spray against the birch leafminer (Fenusa pusilla (Lepeletier)) was compared to sprays of water and Metasystox-R™. Sprays were applied against the season's first generation, at oviposition (V-3-86) or early instar (V-10-86). Sprayed foliage was harvested and weighed at late instar, and adults were reared. The extract caused significantly more leafminer mortality than did water, and caused as much mortality as Metasystox-R™. Observations suggested that the extract took longer to kill leafminer larvae than did Metasystox-R™ thereby allowing for more foliar damage. There were no differences in efficacy between times of extract application.
Genetic Variability in the Propagation of Eucalyptus sideroxylon by Stem Cuttings
Authors: Burger D.W. , Lee C.I.
Published: August 2020

Stem cuttings from mature trees and coppice regrowth of three red ironbark eucalyptus (Eucalyptus sideroxylon A. Cunn. ex Woolls) genotypes were used to study the rooting response over time. Mature tissues failed to root, but coppice regrowth from the same trees showed a range in rooting response from 0 to nearly 100 percent. The two genotypes that formed adventitious roots maintained this ability for the duration of the study. The one genotype that exhibited the greatest potential for adventitious root formation formed a greater number of roots per cutting and had a greater mean root length.
Do Mycorrhizae Influence the Drought Tolerance of Citrus?
Authors: Graham James H. , Syvertsen James P.
Published: August 2020

The benefits of vesicular-arbuscular mycorrhizal (VAM) fungi for increasing drought tolerance have been demonstrated under nutrient-limiting conditions, particularly in low phosphorus (P) soils. Horticultural plants grown in soilless media, under greenhouse fertilizer regimes, are usually non-mycorrhizal, but have optimum P and the desired size and nutritional characteristics available when transplanted. Since plant nutrition can influence responses to environmental stress, potential benefits of VAM fungi for reducing transplant stress, such as drought, should be evaluated where growth and nutrition of mycorrhizal and non-mycorrhizal plants are similar at time of outplanting. In this way, nutritional and any unique non-nutritional effects of mycorrhizae on stress tolerance of plants can be identified. Non-nutritional effects of VAM fungi on drought tolerance of woody horticultural plants have not yet been clearly demonstrated.
Effect of Cutting Size on Rooting and Subsequent Growth of Acer rubrum ‘Red Sunset’ Cuttings
Authors: Smalley Timothy J. , Dirr Michael A.
Published: August 2020

Rooting and subsequent overwinter survival and growth of single-node (5 cm; 2 in), triple-node (15 cm; 6 in), and tip cuttings (15 cm; 6in) of Acer rubrum L. ‘Red Sunset’ were compared. Triple-node cuttings had significantly more roots and total length of roots than single-node and tip cuttings, but no difference in percent rooting or percent survival existed among the cutting types. The triple-node and tip cuttings had significantly greater caliper after the first year of growth than the single-node cuttings, but the difference was minor (1 to 2 mm; 0.04 to 0.08 in). No difference in first year height existed among the cutting types. The single-node cuttings were straighter and had significantly fewer lateral budbreaks than the triple-node and tip cuttings.
Reducing Moisture Stress in Cornus f1orida
Authors: Williams J.D. , Ponder H.G. , Gilliam C.H.
Published: August 2020

Two experiments were conducted to evaluate potential means for reducing moisture stress in Cornus florida. In experiment 1, the antitranspirant (Folicote), and defoliation treatments were applied before inducing stress and after withholding water for 1 week. Folicote was not effective at either application time in reducing moisture stress; plants treated with Folicote had similar shoot water potentials as untreated. Defoliation at both times reduced moisture stress compared to control plants. In experiment 2, two defoliants, (2 chloroethyl) phosphonic acid (ethephon) and 2,3 dihydro-5,6-dimethyl-1,4-dithiin 1,1,4,4, tetroxide (Harvade), were compared at 3 rates each. Percent defoliation of dogwood was similar among treatments after 26 days, with defoliation ranging from 78 to 94 percent.
Association of Nematodes with Dogwood Canker and Stem Malformations on Other Trees
Authors: Santamour Frank S. , McArdle Alice Jacot
Published: August 2020

Two nematodes, one stylet-bearing and allied to the Aphelenchoides fragariae complex and the non-stylet species Panagrolaimus subelongatus, were isolated from the disrupted bark on main trunks and branches of young flowering dogwood (Cornus florida L.) trees exhibiting symptoms of “dogwood canker” disease. Similar nematodes were isolated from burls on the trunks of Siberian elm (Ulmus pumila L.), Higan cherry (Prunus subhirtella Miq.), red oak (Quercus rubra L.) and black locust (Robinia pseudoacacia L.), whereas only the Panagrolaimus species was found in abnormal tumorous growths on the trunks of the Green Mountain cultivar of sugar maple (Acer saccharum Marsh. ‘Green Mountain’). Nematodes were recovered 2 months after inoculation into young dogwood stems in June, 1983 but none could be detected after the inoculated trees had been subjected to winter temperatures as low as −22°C (−4°F) even though nematodes in established cankers survived under the same conditions. Inoculations made in July, 1984 into callus tissue developed after wounding in 1983 or 1984 produced canker-like symptoms but the nematodes were not reisolated in 1985. The total number of nematodes per canker was low and older cankers often yielded no nematodes, even though the canker persisted.
Selective Post-Emergence Control of Oxalis corniculata in Cymbidium hybrida
Authors: Colvin Shawn , Rice Robert P.
Published: August 2020

This investigation was performed to determine the effectiveness of selective post-emergent herbicides for control of Oxalis corniculata L., creeping woodsorrel in container grown cymbidium orchids. Triclopyr, [(3,5,6-trichloro-2-pyridimyl)oxy] acetic acid, (Turflon) and 2,4-D Amine, (2,4-dichlorophenoxy)acetic acid (Weedar 64) were applied as spot and broadcast treatments. Weed and crop phytotoxicity were monitored. Turflon (Triclopyr) at 1.12 kg/ha (1.0 lb ai/A) provided complete oxalis control with both spot and broadcast treatments. No crop phytotoxicity was noted. Weedar 64 (2,4-D amine) spot treated at 4 gm ai/l reduced oxalis populations by 60% after 8 weeks, with no observed crop injury.
Effect of Autumn and Spring Propagation of Two Taxus Cultivars on Summer Growth Rate
Authors: McGuire John J.
Published: August 2020

Two cultivars of Taxus media (cvs. Nigra and Densiformis) rooted outdoors in April, produced liners equal or superior to those propagated by conventional methods. The spring propagation method requires no cost for fuel and only eight weeks for propagation.
Tolerance of Selected Bluegrass and Fescue Taxa to Simulated Human Foot Traffic
Authors: Evans G. E.
Published: August 2020

Cultivars of Poa pratensis L., Festuca rubra L., subsp rubra, and Festuca arundinaceae Schreb. were subjected to simulated foot traffic and three irrigation regimes. Soil compaction was evaluated by soil bulk density measurements.

Clipping yields of 16 bluegrass species and cultivars increased with increasing soil moisture. Highest yielding bluegrass cultivars were those with either upright growth habit or rapid vertical growth. The conclusion is drawn that, unless evaluated upon the percent yield change, clipping weights are not an accurate method of assessing trampling resistance of certain strongly rhizomatous, prostrate growing cultivars of Kentucky bluegrass during moderate, continuous trampling. Under the experimental conditions of this study, Poa pratensis L cultivars ‘Merion’, ‘Newport’, and ‘Windsor’ appeared to have greatest resistance to trampling; Poa ampla and Poa trivialis L. having least trample resistance.

Clipping yields of seven cultivars of F. rubra also increased in most cases with increasing irrigation level. Significant yield differences, assumed to represent growth rate differences, occurred among cultivars. Interactions between cultivar and trample level were taken as measures of differential wear tolerance. Festuca rubra L. subsp. rubra ‘Pennlawn’ was significantly higher in trample resistance than all others. F. ovina L. KO-16 had better apparent trample resistance than others which had equal resistance to trampling.

Festuca arundinaceae ‘Goars’ was observed to have superior trample resistance to the others studied which were equal. With a single exception, clipping yields of tall fescue decreased with decrease in irrigation levels.
Chemical and Biological Stability of Indole-3-Butyric Acid (IBA) After Long-term Storage at Selected Temperatures and Light Regimes
Authors: Robbins James A. , Campidonica Mark J. , Burger David W.
Published: August 2020

Concentrated [4.9 mM (1,000 ppm) and 24.6 mM (5,000 ppm)] IBA solutions in 50% isopropyl alcohol were stored in amber and clear glass bottles at 3 temperatures [22–25°, 6°, O°C (72–77°, 43°, 32°F)]. No significant change in biological activity of the solutions or breakdown of IBA was observed for solutions stored for 4 and 6 months. Solution color changed during storage. Color development was dependant on storage temperature, but not on exposure to light. Chemical names used: IAA = indole-3-acetic acid; IBA = indole-3-butyric acid; NAA = 1-naphthaleneacetic acid
Characterization of Quince (Cydonia) Cultivars Using Polyacrylamide Gel Electrophoresis
Authors: Sanchez E.E. , Menendez R.A. , Daley L.S. , Boone R.B. , Jahn O.L. , Lombard P.B.
Published: August 2020

An investigation of available Cydonia (Cydonia oblonga Mill., quince, membrillo) germplasm by isozyme staining of anionic polyacrylamide gradient electrophoresis gels is described. The isozymes of acid phosphatase, esterase, peroxidase and phenol oxidase showed most diversity and usefulness for this purpose. Eleven groups of quince and two groups of x Pyronia (quince-pear crosses) were distinguished by their isozyme patterns. These patterns distinguish between groups of clonal accessions, and the patterns were constant for each accession during the test period (December, 1986 to August, 1987). Thus, these patterns were considered to represent genetic characteristics suitable for identification purposes. The diversity of isozyme patterns was much less than in Corylus and Pyrus populations previously sampled; and less than that of a restricted pool of apple cultivars previously examined.
Nursery Marketing Can Be Improved
Authors: Gineo Wayne M.
Published: August 2020

The socioeconomic factors influencing consumer demand for landscape plants and services and nursery sector growth were investigated. Data that shows a shifting age composition, gains in consumer inconle, higher education levels, and increases in construction starts provides a socioeconomic rationale for continued expansion of the nursery industry. Through surveys and a review of published information it was revealed that the industry needs additional information on production costs, pricing strategies, profit margins for individual plants, product distribution and market planning. Research aimed at incorporating these components into appropriate economic analyses and models designed to investigate production and marketing of landscape plants and related services would assist the industry in capitalizing on the anticipated growth in demand.
Cambial Peroxidase Enzymes Related to Graft Incompatibility in Red Oak
Authors: Santamour Frank S.
Published: August 2020

Variation in cambial isoperoxidase banding patterns was greater in northern red oak (Quercus rubra L.) than in any of the other oak species studied, with all combinations of the 3 major anodal bands (A,B,C) being present (A,B,C,AB,AC,BC,ABC). Barkring grafts between seedlings of similar enzyme constitution were successful and xylem vascular continuity was restored across the graft union. When the isoperoxidase pattern in the bark-ring donor differed from that of the stock, no common cambium was formed and normal vascular connections did not occur. The graft “failures” (not incompatibility) that have been common in the propagation of ‘Crownright’ and ‘Sovereign’ pin oaks are probably caused by the hypersensitivity of these scion cultivars to a virus transmitted by soil-borne nematodes. The disruption at the graft union was more severe when stock and scion had different isoperoxidase constitutions. Propagation problems engendered by isozyme incompatibility and virus hypersensitivity can be solved by developing “seed orchards” for the production of desirable seedling rootstocks.
Effects of Rate and Repeat Application of Flurprimidol on the Growth of Photinia × fraseri and Ilex crenata ‘Compacta’
Authors: Laiche Adolph J.
Published: August 2020

Flurprimidol, α-(1-Methylethyl)-α-[4-(trifluoromethoxy)phenyl]-5-pyrimidine-methanol, was applied to three month plants of Photinia × fraseri in 5.6 L (6 qt) containers and Ilex crenata ‘Compacta’ in 2.8 L (3 qt) containers as foliar sprays at 0, 33, 66, 132, 264, 528, 1056, 2112, 4224, and 8448 ppnl. Growth-medium drench applications with flurprimidol were applied at 0, 2, 4, 8, 16, 32, 64, 128, 256, and 512 ppm solution, 0.5 L (17 oz) per 5.6 L (6 qt) container to Photinia. The initial foliar spray treatments and the growth medium drench treatments were applied on July 14, 1983. All test plants were planted in soil on December 9, 1983. Foliar spray treatments were repeated on July 19, 1985.

Flurprimidol at low concentrations as a spray and drench substantially reduced plant size with little or no phytotoxicity. Duration of growth suppression increased as rate increased. Flurprimidol at low rates reduced growth for the remainder of the growing season in which it was applied. At higher rates growth was also reduced in the following growing season. Minor leaf distortion of smaller leaves was obtained at low rates and leaf distortion appeared to increase slightly at higher rates. Shoot growth after the effects of flurprimidol were no longer apparent appeared normal. Results indicate that flurprimidol alone and in conjunction with pruning can be helpful in maintaining woody landscape plants to a desirable size.
Growth Response of Selected Container-grown Bedding Plants to Paclobutrazol, Uniconizole, and Daminozide
Authors: Banko Thomas J. , Stefani Marcia A.
Published: August 2020

A study was conducted to compare the growth-retarding effects of paclobutrazol (Bonzi), uniconizole (XE-1019, Sumagic), and daminozide (B-Nine) on container-grown bedding plants. Seedlings of Begonia semperflorens ‘Olympia’, ‘Scarletta’, and ‘Vodka’, Catharanthus roseus ‘Little Bright Eye’, Impatiens sultani ‘Blitz Orange’, and Zinnia elegans ‘Yellow Marvel’ were treated with a paclobutrazol spray at 0.15, 0.3 or 0.45 mg ai/plant, or a drench of 0.15 mg ai/pot. Uniconizole was applied as a spray at 0.025, 0.05, or 0.075 mg ai/plant, or a drench of 0.025 mg ai/pot. The daminozide was applied only as a 5000 ppm spray. Paclobutrazol and uniconizole were very effective in controlling the height of begonia, catharanthus (vinca), and impatiens at relatively low rates compared to daminozide. The height of zinnia was controlled by daminozide, but not by the other compounds at the rates tested.
Preemergent Weed Control in Container-grown Herbaceous Perennials
Authors: Schuett Julie , Klett James E.
Published: August 2020

This study was conducted to evaluate several preemergence herbicides for weed control, effects on plant growth, and phytotoxicity to container-grown herbaceous perennials. Surflan (Oryzalin) was applied at 0, 2.24, 4.48, 6.72 kg ai/ha (0, 2, 4, 6 lb ai/A), Ronstar (Oxadiazon) at 0, 4.48, 8.96, 13.44 kg ai/ha (0, 4, 8, 12 lb ai/A), and Rout (Oxyfluorfen + Oryzalin) at 0, 3.36, 6.72, 10.08 kg ai/ha (0, 3, 6,9 lb ai/A) to container-grown Ajuga reptans atropurpurea L. (carpet bugle), Campanula garganica major (Ten.) Fiori (bellflower), and Liatris spicata (L.) Willd. (spike gayfeather). Additionally, Devrinol (Napropamide) and Treflan (Trifluralin) were each applied at 0, 4.48, 8.96, 13.44 kg ai/ha (0, 4, 8, 12 lb ai/A) to Astilbe × arendsii Arends. (false spirea) and Dicentra spectabilis (L.) Lem. (bleeding heart). Plants were grown in 2.54 1 (#1) containers in a medium of sand, topsoil, and sphagnum peat (1:1:1 by vol). Weed control was acceptable with all herbicides except Surflan at 2.24 kg ai/ha (2 lb ai/A) which did not control shepardspurse. Surflan applied at either 4.48 (41b ai/A) or 6.72 kg ai/ha (61b ai/A) rate resulted in phytotoxicity of carpet bugle, while the 6.72 kg ai/ha rate (6 lb ai/A) significantly reduced plant growth.
Response of Codiaeum variegatum ‘Gold Star’ as Influenced by Slow-Release Fertilizer
Authors: Chase A.R. , Poole R.T.
Published: August 2020

Codiaeum variegatum ‘Gold Star’ croton were grown at different nutritional levels of 3.3, 6.6, 9.9, 13.2, 16.5 and 19.8 g of slow-release 19N-3P-10K (19-6-12) per 12.5 cm (5 in) pot. Plant grade was highest with levels of 3.3–9.9 g per pot, with corresponding leachate electrical conductivity of approximately 200–1100 μmhos·cm−1.
Effect of Fertilizer Level on Severity of Xanthomonas Leaf Spot of Pilea spruceana
Authors: Chase A.R.
Published: August 2020

Severity of Xanthomonas leaf spot of Pilea spruceana was highest for plants receiving intermediate fertilizer rates (recommended to 5 times the recommended rate) and decreased at rates of 6–9 times recommended rate. Plant growth responded similarly with highest quality plants most susceptible to Xanthomonas campestris. Tissue nutrient content for highest quality plants was as follows: N (2.2%), P (0.37–0.38%), K (1.2–1.4%), S (1.00–1.06%), Mg (1.03–1.24%), Ca (2.07–2.30%), Fe (62–76 mg/kg), Mn (358–370 mg/kg), B (50–55 mg/kg), Cu (10 mg/kg), and Zn (348–357 mg/kg). Leachate electrical conductivity for highest quality plants was approximately 200 μmhos/cm. The results indicate that optimizing the nutrient status for highest quality foliar growth of P. spruceana may result in conditions which maximize severity of Xanthomonas leaf spot.
Fertilization of Four Indoor Foliage Plants With Osmocote or Nutricote
Authors: Poole Richard T. , Conover C.A.
Published: August 2020

Aphelandra, Dieffenbachia, Pilea and Chamaedorea grew equally in containers when fertilized with Osmocote or Nutricote incorporated or surface applied. There was slight indication that plants grew better at higher than recommended rate, but increased fertilizer costs and potential for ground water contamination suggest higher rates should not be used.
Propagation of Quercus L. Species by Cuttings
Authors: Drew John J. , Dirr Michael A.
Published: August 2020

Ten species of oak, Quercus L., were used to determine the feasibility of rooting oak cuttings. Cuttings were taken from the first, second, and third growth flushes from seedling stock plants (2 to 3-year-old) and treated with 1.0% potassium 1H-indole-3-butanoic acid (K-IBA), 5-sec. dip and placed under mist. Rooting ranged from 0% to 80% with Q. phellos L., Q. robur L., and Q. lyrata Walter rooting 80%,69%, and 43%, respectively, on the first date. Generally, rooting decreased with progressive flushes. Quercus alba L. and Q. suber L. rooted 2% or less over all dates. No consistent pattern of rooting was observed for white oak compared to red oak groups. Rooting was strongly species specific.
Damage Caused by Wind-Borne Salts to Landscape Plants and its Prevention by a Wind-Controlled Sprinkler System
Authors: Hagiladi A. , Ben-Jaacov J. , Eliasaf A.
Published: August 2020

Ocean spray carried by wind was shown to be the main cause of leaf scorching of vegetation along the Mediterranean coast of Israel. An overhead sprinkling system was designed to be activated when wind velocity reached a critical level. It was shown to reduce leaf scorching. The degree of protection depended on plant species. Plants showed different degrees of sensitivity to wind-borne salts in the following increasing order: Japanese Pittosporum (Pittosporum tubira Ait.), Thorny Elaeagnus (Elaeagnus pungens Thunb.), Common Oleander (Nerium oleander L.), Tamarisk, Athel (Tamarix aphylla Karst.).
Lowering of Calcareous Soil pH in Field-Grow Containers
Authors: Kidder G. , Holsinger M.J. , Yeager T.H.
Published: August 2020

Wettable sulfur (S) mixed with a Pineda fine sand (an Arenic Glossaqualf with 7.8 pH and 1.5% calcium carbonate equivalent) quickly acidified the soil, but the effect was lost within 8 weeks at low application rates and within 21 weeks at the highest rate (1 g S/kg soil or 1 lb S/1000 lb soil). Granular S mixed with the soil took one year to produce maximum pH reduction of 0.3, 0.4, and 0.9 pH units at 250, 500, and 1000 mg S/kg soil (1/4, 1/2, and 1 lb S/1000 lb soil), respectively . Wettable sulfur (S), surface-applied at 100 g/m2 (0.036 oz/10 ft2), lowered the pH of the upper 5 cm (2 in) of soil to the 5.6 to 5.8 range for one to two months before the pH returned to > 7.0; granular S took about five months to lower the pH to 6.7 but the soil pH was 6.2 two years after application. Wettable S at 20 g/kg soil (0.32 oz S/lb soil) in a small cylindrical zone resulted in a temporary depression of pH within the treated zone but had no effect on pH in other areas of the container. Mixing up to 1.0 g iron sulfate/kg soil (0.016 oz/lb soil) failed to reduce soil pH. Live-oak trunk diameter and plant height were not affected by any of the soil treatments in the two-year experiment.
Desiccation Tolerance of Deciduous Plants During Postharvest Handling
Authors: Murakami Paul , Chen Tony H.H. , Fuchigami Leslie H.
Published: August 2020

Nurserymen consider Washington hawthorn (Crategus phaenopyrum Med.) sensitive and Norway maple (Acer platanoides L.) tolerant to postharvest practices. The desiccation tolerance, cold hardiness and water potential at various growth stages were monitored on field-grown Washington hawthorn and Norway maple. There were no differences between these two species in the rate of water loss in the root, shoot or whole plants. Hawthorn, however, was more sensitive to desiccation stress than maple throughout all growth stages. The roots lost water at a faster rate than the stems in both species. Hawthorn plants acquired rest and cold hardened later in the fall and attained less dormancy and less freezing tolerance than did maple.
Insecticidal Bark Bands for Reduction of Defoliation by Elm Leaf Beetle (Coleoptera: Chrysomelidae)
Authors: Hall R.W , Nielsen D.G. , Young C.E. , Hamerski M.R.
Published: August 2020

An experiment was conducted to evaluate the effectiveness of carbaryl (Sevin XLR +) applied to elm bark for prevention of defoliation by elm leaf beetle, Xanthogaleruca luteola (Müller). Trunks of trees were treated with 2% carbaryl applied as a 1 m (3.3 ft) wide band. First generation larvae were killed when descending treated trees as they moved toward pupation sites. Insecticide bands were generally effective in preventing defoliation at treated sites. However, defoliation by first generation larvae at one treated site caused unacceptable aesthetic damage.
Variation among Picea pungens Progenies grown in Ohio
Authors: Townsend A.M , Douglas L.W.
Published: August 2020

Wide variation in foliage color, height, and form was found among progenies of blue spruce (Picea pungens Engelm.) grown in Ohio from seed collected from 32 provenances. Data were collected seven and 12 years after permanent field planting of 3-3 stock. Broad differences also occurred among 4 geographic regions, each made up of anywhere from 4 to 12 provenances. Trees from the region (Region 3) of southern Colorado, northern New Mexico, and northern Arizona averaged the fastest growth, bluest color, and most symmetrical form. Those trees from Utah and Wyoming (Region 2) most often had the slowest growth rate and least desirable form and color. The average performance of trees from northern Colorado (Region 1) and southern New Mexico and southern Arizona (Region 4) was generally intermediate between that of Region 2 and Region 3. Although regional differences were significant, great variability existed among provenances across the entire range of the species. Nurserymen desiring to grow blue spruce with improved growth rate, color, and form at a lower cost should consider collecting seed from those seed sources which have consistently proven themselves to be superior in this and other studies.
Minimizing Disease Injury To Hybrid Poplars
Authors: Ostry Michael E. , McNabb Harold S.
Published: August 2020

Poplars (Populus L.) are among the most versatile of trees, but many poplar hybrids have often failed to grow as advertised because of their high susceptibility to several diseases. Chemical and cultural controls have been developed that can minimize disease incidence in hybird poplars, but planting resistant clones is believed to be the best long-term management strategy. Nursery operators need to produce these disease resistant clones in order to increase market acceptability.
Water Absorption of Hydrophylic Polymers (Hydrogels) Reduced by Media Amendments
Authors: Foster William J. , Keever Gary J.
Published: August 2020

Water absorbency of 4 commercially available hydrophylic polymers (hydrogels) (Agrosoke, Liqua-gel, Mizuace and Terra-sorb HB) in response to 4 media amendments (Micromax, Osmocote 18N-2.6P-10.0K (18-6-12), gypsum and dolomitic limestone) and the combination of 4 amendments was determined. Water absorbency of 4 hydrogels was reduced by all amendments except Osmocote added to Liqua-gel. Generally, hydrogel absorbency was reduced most by Micromax and the combination of media amendments, followed by gypsum, Osmocote, and dolomitic limestone. None of the hydrogels functioned as advertised.
Retail Target Markets for Landscape Plants
Authors: Turner Steven C. , Dorfman Jeffrey H.
Published: August 2020

Merchandisers of landscape plants can increase the effectiveness of their marketing strategies by identifying target markets. Using full information maximum likelihood tobit procedure, different types of retail outlets were shown to have different target markets in Georgia, The results lend support and empirical evidence to the premise that different retail outlet types have different target markets.
Growth Response of 13 Container-Grown Landscape Plants to Uniconazole
Authors: Warren Stuart L.
Published: August 2020

Uniconazole, an experimental plant growth regulator, was applied as a foliar spray and a medium drench to 13 and 7 species, resp. Shoot dry weight was determined at 60, 90, and 120 days after treatment. Sixty days after treatment, shoot dry weight of no species was affected by uniconazole. At 90 and 120 days, shoot dry weight of all species, except golden privet (Ligustrum × vicaryi), Russian-olive (Elaeagnus angustifolia), and waxleaf privet (Ligustrum lucidum), decreased with increasing rates of uniconazole, regardless of method of application. Degree of growth reduction varied by species, rate, and method of application. For most species, uniconazole was effective in suppressing growth for 120 days. Generally greater reduction of shoot growth resulted from drench application compared to foliar application.
Paulownia tomentosa Seedling Growth at Differing Levels of pH, Nitrogen, and Phosphorus
Authors: Melhuish J. H. , Gentry C. E. , Beckjord P. R.
Published: August 2020

This study examined the effects of various levels of acidity, nitrogen, and phosphorus on the survival and growth of Paulownia tomentosa seedlings. The seedlings grew within a pH range of 7.0 to 4.0, but little or no growth occurred at pH 3.0. The seedlings grew well with nitrogen at 50 to 200 ppm and phosphorus at 5 ppm, but growth was greatly reduced below 10 ppm nitrogen. Higher levels of phosphorus need to be investigated.
Influence of Spectral Filters on Height, Leaf Chlorophyll, and Flowering of Rosa × hybrida ‘Meirutral’
Authors: McMahon M.J. , Kelly J.W.
Published: August 2020

Growth of Rosa × hybrida ‘Meirutral’ under different spectral filters was evaluated. Two filters that altered far-red (730 nm)/red (660 nm) light (FR/R) were developed. One, a blue textile dye, increased FR/R by filtering out a portion of red light. The second, a salt (copper sulfate) decreased FR/R by filtering out a greater portion of far-red than red light. A third filter that did not alter light quality was the control. The filters were installed in specially built growth chambers. Photosynthetic photon flux (PPF) was adjusted to equal values in each chamber.

Plants were significantly shorter and had higher leaf chlorophyll when grown under the reduced FR/R filter. The number of flower buds and number of buds showing color at termination of the experiment was not affected by light quality treatments.
Tree Root Growth and Development. I. Form, Spread, Depth and Periodicity
Authors: Gilman Edward F.
Published: August 2020

Root form is governed by seedling genetics and soil characteristics including texture, compaction, depth to the water table, fertility, moisture content and other factors. Trees develop lateral roots growing parallel to the surface of the soil. These are generally located in the top 30 cm (12 in) of soil. Fine roots emerge from lateral roots and grow into the soil close to the surface. If soil conditions permit, some trees grow tap and other vertically oriented roots capable of penetrating several feet into the soil. Many trees, particularly those planted in urban landscapes, do not generate tap roots. Lateral roots spread to well beyond the edge of the branches. Their growth in governed by competition from other plants, available water, soil temperature, fertility, stage of shoot growth and other factors.
Evaluation of Thermal Properties and Effect of Irrigation on Temperature Dynamics in Container Media
Authors: Martin Chris A. , Ingram Dewayne L.
Published: August 2020

Thermal energy flows in pine bark, 4 pine bark: 1 sand (by vol), and 3 pine bark: 2 sand (by vol) media as a function of volumetric water content were studied. The predicted rate of movement of heat energy was greatest for the 3 pine bark: 2 sand medium if the volumetric water content was between 10% and 65%. Field experiments were conducted to evaluate the effects of irrigation volume and timing and container media composition on container media temperature dynamics using a spray stake delivery system. Irrigating 10-liter (#3) containers with water at 26°C (79°F) was most effective as a container medium coolant if the volume which was applied equaled or exceeded 3.0 liters (0.8 gal), the applications were made beginning at midday, and sand was in the container medium compared to pine bark alone.
Tolerance of Woody Nursery Stock to Classic (chlorimuron) and Harmony (thiameturon)
Authors: Derr Jeffrey F.
Published: August 2020

Classic and Harmony applied at rates ranging from 0.009 kg ai/ha (0.008 lb ai/A) to 0.067 kg/ha (0.06 lb/A) provided excellent preemergence and postemergence control of common groundsel (Senecio vulgaris L.) 5 weeks after application to container-grown nursery plants. Classic at 0.034 kg/ha (0.03 lb/A) and 0.067 kg/ha (0.06 lb/A) reduced yellow nutsedge (Cyperus esculentus L.) growth by 50 to 77% 5 weeks after preemergence or postemergence treatments. Harmony did not affect yellow nutsedge from either type of application. ‘Seagreen’ juniper (Juniperus chinensis L.), ‘Blue Pacific’ juniper (Juniperus conferta Parl.) and ‘Bennetts Compacta’ holly (Ilex crenata Thunb.) tolerated all rates of Classic and Harmony. ‘Girard's Rose’ (Rhododendron kaempferi Planch.) and ‘Coral Bells’ azale(Rhododendron obtusum (Lindl.) Planch.), and redtip photinia (Photinia × Fraseri Dress) were initially injured by these herbicides, but outgrew the foliar damage.
Influence of Moisture Loss During Storage on New Growth of Conifer Seedlings
Authors: Lefevre Roy E. , Cameron Arthur C. , Curtis Peterson N.
Published: August 2020

The relationship between moisture loss from bare-root 2-year-old seedlings of Colorado spruce (Picea pungens glauca Engelm.) and percent survival and performance after extended storage at 0°C (32°F) was investigated. Moisture loss was examined by percent weight loss and moisture content (g H2O/g FW) during postharvest handling and storage. To generate different levels of moisture loss, seedlings were stored in various packages that differed in water permeability with a 0 and 1 day delay at 20°C (68°F) prior to 5 or 7 months of storage at 0°C (32°F). Depending on treatment, percent weight loss of seedlings varied from 0 to 60% and seedling survival ranged from 0 to 100%. When percent weight loss was below 25% all bare-root seedlings survived 5 and 7 months storage. Seedlings expressed a great degree of tolerance to desiccation stress, as demonstrated by those few which survived nearly 60% weight loss. Between 20 and 40% weight loss there was no direct relationship between moisture loss and percent survival. Bare-root Colorado Spruce seedlings grew with 100% survival following 5 and 7 months storage at 0°C (32°F) if packaged in either unsealed perforated or nonperforated polyethylene film.
Response of Periwinkle to Composted Sewage Sludge Used as a Soil Amendment
Authors: Devitt D.A. , Morris R.L. , Bowman D.C.
Published: August 2020

An experiment was conducted in the greenhouse to investigate the effects of composted sewage sludge as a soil amendment on growth and mineral composition of ‘Bright Eyes’ periwinkle (Catharanthus roseus (L.) G. Dn.). Three desert soils (loamy sand, sandy loam, clay) were amended with two different composted sewage sludges (city and county) at rates of 0, 7.5, 15, 30 and 60% by volume. Plants were grown in the amended soils for four months. Composted city sludge had a positive effect on size, growth rate and number of flowers per plant in all three soils. Plants grown in soils amended with the county sludge grew poorly and developed an interveinal chlorosis. Tissue analysis suggested chlorosis was due to a calcium-induced manganese deficiency. Whole plant tissue Mn declined to as low as 23 mg/kg when the calcium in the soil extract exceeded 25 meq/liter.
Sumagic (Uniconazole) Enhances Flowering of ‘Shishi-Gashira’ Camellia
Authors: Keever Gary J. , McGuire John A.
Published: August 2020

Growth of Camellia sasanqua Thunb. [C. hiemalis Nakai] ‘Shishi-Gashira’ was either unaffected or was inhibited by single foliar sprays of Sumagic (uniconazole), while flower number was significantly greater. A 5 ppm spray of (Sumagic) uniconazole increased flower number 53% without influencing growth indices, days to flower or flower diameter. A 20 ppm spray increased flower number 113% without affecting days to flower or flower diameter; however, growth indices were reduced up to 21%.
Shade Tree Growth and Nutritional Status as Influenced by Fabric Container and Trickle Fertigation
Authors: Chong Calvin , Lumis Glen P. , Cline Robert A.
Published: August 2020

Five species of landscape shade trees, when grown in fabric containers, showed small but significant reductions in caliper and height compared to field-grown control trees after each of 3 growing seasons, 1988–1990. Reductions also were observed in certain leaf nutrients: N and Ca after the second year, and P and K after the third year. There were increased levels of leaf Mn (1989), Zn (1990), and starch (1989). Trees of all species receiving 5.7 L (1.5 U.S. gal) of water per day plus 200 ppm of supplementary N applied twice weekly had consistently larger caliper after each of the 3 growing seasons and tended to have higher leaf Mn content after the second year. There was inconsistent, little, or no difference in height, or in other leaf nutrients, due to fertigation treatments or to irrigation alone.
Asexual Propagation of Shepherdia canadensis and S. rotundifolia
Authors: Krishnan Sarada , Hughes Harrison
Published: August 2020

Shepherdia canadensis and S. rotundifolia were asexually propagated by hardwood cuttings and aseptic micropropagation. S. canadensis showed greatest rooting of 46.5% with 0.3% IBA. S. rotundifolia showed greater proliferation in woody plant media (WPM) with 0.89 μM BA and optimum rooting in WPM with 5.4 μM NAA.
Dolomitic Lime Particle Size and Container Medium pH
Authors: Leda Carol E. , Wright Robert D.
Published: August 2020

Boxwood liners, Buxus sempervirens ‘Suffruticosa’, were container-grown for two years in a pine bark/peat moss medium amended with various particle sizes of dolomitic limestone. Adjustment of pH was more effectively accomplished with the finer particles. All treatments resulted in greater plant growth than the untreated control. A surface application of a commercially available pulverized dolomitic limestone was also effective in increasing the pH above the control treatment, and plants grown with the surface applied treatment were as large as any of the incorporated treatments.
Measuring the Effects of Firm Promotion Expenditures on Green Industry Sales
Authors: Palma Marco A. , Hall Charles R. , Campbell Ben , Khachatryan Hayk , Behe Bridget , Barton Sue
Published: August 2020

This paper measures the effectiveness of green industry firms' promotion and advertising expenditures in enhancing sales. Specifically the paper addresses the following three questions: 1) Are promotion and advertising expenditures effective in increasing sales of green industry firms? 2) What are the types of promotion and advertising efforts that have the highest returns for their investment? 3) How does the answer to these two questions change depending on the size of the firm? In order to answer these questions, a model was specified to measure the increase in sales for green industry firms as a result of promotion activities and the associated elasticities of promotion were used to calculate a benefit cost ratio. The returns to promotion expenditures differed depending on media used and also by firm size with ranges from not significant to $7.5 returns per every $1 allocated to promotion and advertising.