bluuebunny/crossref_metadata_2025 huggingface dataset:
Landscape Maintenance Firms: II. Pest Management Practices
Authors: Garber M.P. , Bondari K.
Published: August 2020

Landscape maintenance firms in Georgia were surveyed to obtain information regarding pesticide usage and factors that would facilitate adoption of non-chemical pest control measures. The trend in pest control from 1988 to 1993 was toward greater usage of non-chemical control measures. The usage trend for chemicals during that period was an increase for fungicides/bactericides and herbicides and a decrease for insecticides, with growth regulator use remaining steady. Over half (55%) of the pesticides were used for turf management. All firms expect to use about the same amount of pesticides over the next 5 years while increasing the use of non-chemical control measures. Opportunities were identified for landscape architects and university personnel to help landscape maintenance firms reduce the need for pesticides. The two most frequently identified opportunities for university personnel were to sponsor local workshops with specific training for workers on integrated pest management (IPM) practices (35.6%) and seasonal or regular newsletters with IPM reminders (30.0%). The most frequently identified opportunities available to the landscape architects to help reduce pesticide use included: (1) improved plant selection, particularly pest resistant varieties (51.8%), (2) proper site selection/location of plants (14.8%), and (3) more spacing between plants and consideration of final size (13.7%).
Propagation of Quercus phillyreoides by Stem Cuttings
Authors: McGuigan Patrick J. , Blazich Frank A. , Ranney Thomas G.
Published: August 2020

Stem cuttings of two clones (clones 1 and 2) of seedling origin of Quercus phillyreoides A. Gray (ubame oak) in the adult growth phase were taken on four dates that represented four growth stages (semi-hardwood, hardwood, softwood, and transitional growth between softwood and semi-hardwood). All cuttings were treated with selected concentrations and formulations of indolebutyric acid (IBA) and placed under intermittent mist for rooting. Greatest rooting for both clones was achieved with softwood cuttings with 97% and 56% rooting for clones 1 and 2, respectively, treated with 8000 ppm (0.8%) IBA in talc. Six weeks later when cuttings were in a softwood/semi-hardwood condition, rooting of clone 1 was still comparable to softwood cuttings whereas clone 2 rooted poorly. For both clones, rooting of semi-hardwood cuttings was poor, which was the same for hardwood cuttings of clone 2. Moderate rooting of 58% was noted for nontreated hardwood cuttings of clone 1. Auxin treatments generally increased root number. As mean root number increased mean root length decreased. Greater overwinter survival was observed for rooted softwood cuttings, which produced a flush of new growth following rooting in comparison to softwood/semi-hardwood cuttings that did not flush following rooting.
Fertilizer, Irrigation and Root Ball Slicing Affects Burford Holly Growth after Planting
Authors: Gilman Edward F. , Yeager Thomas H. , Weigle Diane
Published: August 2020

Dwarf burford holly (Ilex cornuta ‘Burfordii Nana’) fertilized with 22.1 g N/container/yr of nitrogen during production in the nursery generated more new shoot weight but less root weight after transplanting to a landscape than those receiving 14.8 g N/container/yr. Slicing the root ball at planting, compared to not slicing, resulted in comparable regenerated root weight but reduced new shoot number, new shoot dry weight and new shoot:regenerated root dry weight ratio when irrigation was not applied daily after transplanting. Although irrigation frequency did not impact total weight of regenerated roots into landscape soil, more roots grew from the bottom half of the root ball when plants were irrigated periodically after planting than when plants received daily irrigation. Plants irrigated other than daily produced fewer shoots and less shoot weight than those receiving irrigation daily after transplanting. When plants were without irrigation for 4 or 6 days in the first week after transplanting, those planted without the nursery container on the root ball were more stressed (more negative xylem potential) than those planted with the container still on the root ball. However, two weeks later, plants without the nursery container were less stressed due to root growth into landscape soil.
Growth of Three Bedding Plant Species in Soilless Mixes With Alkaline Stabilized Sewage Sludge
Authors: Logan Terry J. , Lindsay Billie J.
Published: August 2020

Three bedding plant species (‘Cooler Grape’ Vinca (Vinca rosea L.), ‘Roc Mix’ Pansy (Viola × Wittrochiana Gams.), and ‘Impulse Red’ Impatiens (Impatiens Wallerana Hook.f.) were grown in soilless mixes: aged N-Viro Soil from the City of Toledo, OH, aged N-Viro Soil blended with sphagnum peat (N-Viro Soilipeat, 3:1 by vol), BioBlend (composted leaf yard waste: N-Viro Soil, 2:1 by vol), and Sunshine Mix LC1. The N-Viro Soil-based media were high in pH (8.3–8.9), soluble salts (3.2–9.6 dS/m) and exchangeable Ca, Mg and K, compared to Sunshine mix. Total porosity was lower in the N-Viro Soil media (62 to 74%) compared to Sunshine (90%), while available water holding capacities were higher in Sunshine mix and N-Viro Soil-peat (7.4 and 7.6% H2O by volume, respectively) than in aged N-Viro Soil and BioBlend (5.4 and 5.9% H2O by volume, respectively). Differences among the media in growth index of impatiens were significant (p = 0.054). This reflected the low index for aged N-Viro Soil compared to the other three media. Pansy growth index differences among the media were significant (p = 0.031), with the aged N-Viro Soil and BioBlend indices being significantly lower than that of Sunshine mix. There were no significant differences in vinca growth index. There were no significant differences in top growth weights among the four soil media for all three species. The results suggest that aged N-Viro Soil can be blended with peat or fresh N-Viro Soil can be composted with yard waste to produce soilless plant growth media that are comparable in performance to commercial peat-based mixes.
Effect of Cupric Hydroxide-treated Containers on Bougainvillea Propagation and Growth after Transplanting
Authors: Aldrich James H. , Norcini Jeffrey G. , Roddenberry William E.
Published: August 2020

Cupric hydroxide (100g Cu(OH)2/liter; 13.3 oz/gal) in a latex paint was sprayed to the interior of propagation cups to evaluate the effects on rooting of Bougainvillea glabra Choisy ‘Sanderiana’ cuttings and their growth after transplanting. Forty-two-day-old rooted cuttings propagated in Cu(OH)2-treated cups had a compact rootball with no root circling and tended to have more primary roots. From 91 to 144 days after transplanting 42-day-old rooted cuttings into non-treated 3.8 liter (1 gal) containers, transplants from the Cu(OH)2-treated cups had a greater growth index, principally due to increased height, than transplants from non-treated cups. However, the CU(OH)2 treatment did not significantly affect shoot or root fresh and dry weights 144 days after transplanting.
Preemergence Herbicide Effects on Nursery Crop Root and Shoot Growth
Authors: Derr Jeffrey F. , Salihu Sydha
Published: August 2020

The effects of preemergence herbicides on root and shoot growth of redtip photinia (Photinia × fraseri Lindl.), abelia (Abelia× grandiflora × A. Schumannii Rehd.), azalea (Rhododendron obtusum Planch. ‘Tradition’) and Japanese holly (Ilex crenata Thunb.‘Helleri’) were evaluated in container studies. Experimental design was a randomized complete block with four replications and five containers of each species per plot. Root and shoot weights were recorded five weeks after either one, two or three herbicide applications. Ronstar (oxadiazon) and Ornamental Herbicide II [OH2 (oxyfluorfen plus pendimethalin)] had essentially no adverse effect on shoot or root development of the four species. Rout (oxyfluorfen plus oryzalin), Surflan (oryzalin), Gallery (isoxaben), and Factor (prodiamine) decreased root and/or shoot development of certain species, especially at the first two harvests. Plant size at treatment may be a factor in the extent of stunting caused by preemergence herbicides, with larger plants being more tolerant. Stunting of shoot and root growth appeared to be temporary.
Evaluation of Newer Chemicals for Control of Foliar Nematode on Begonia
Authors: Walker Jerry T. , Oetting Ronald D. , Johnston-Clark Marcia , Melin John B.
Published: August 2020

Eight new chemical compounds were evaluated for control of foliar nematode (Aphelencoides fragariae) on several cultivars of begonia (Hiemalis group). Two greenhouse experiments were conducted in 1993, one in 1994, and one in 1995, using foliar nematode-infested begonia cultivars, and treating them with abamectin, azadirachtin, bifenthrin, carbosulfan, cyromazine, diflubenzuron, fenoxycarb or imidacloprid. Oxamyl was included for comparison because of its known activity against this nematode. None of the newer chemicals was effective in reducing the population of foliar nematodes at the rates tested, whereas one application of 10% granular oxamyl at 0.12 g/l5 cm (0.004 oz/6in) pot was as effective as higher rates or multiple applications in suppressing the populations.
Economic Feasibility of Micro-Irrigating Container-Grown Landscape Plants
Authors: Haydu J.J. , Beeson R.C.
Published: August 2020

While past research has examined certain technical efficiencies, little effort has been directed at the economic feasibility of various irrigation systems for container-grown landscape plants. Two irrigation systems, cyclic micro-irrigation and overhead impact sprinkler, were examined to determine economic advantages of one system over the other for container-grown landscape plants. Seedlings of Acer rubrum L. and Quercus virginiana Mill. produced in #3, #7, #10 and #15 (10.2, 26.5, 37.8, and 56.8 liter) polyethylene containers were considered. A two-step methodology was used to establish the biological and economic parameters of the study. Three major conclusions were arrived at in this paper. First, with the exception of the smallest container size, there was little difference in initial investment costs and variable costs of production between the two systems. Second, water costs were shown to be prohibitive for larger container sizes when reclaimed water is used in conjunction with overhead systems. Third, the potential impact of cyclic microirrigation on a firm's economic returns were shown to be positive. Cyclic micro-irrigation markedly speeds up the production process, utilizes less material inputs and a fraction of the water of an overhead system.
Sequential and Tank-Mixed Dimension (Dithiopyr) and MSMA Treatments for Large Crabgrass Control in Bermudagrass Turf
Authors: Johnson B. Jack
Published: August 2020

A field experiment was conducted during 1995 and 1996 in Georgia to determine the influence of Dimension (dithiopyr) and MSMA applied as sequential and tank-mixed treatments on large crabgrass [Digitaria sanguinalis (L.) Scop.] control in common bermudagrass [Cynodon dactylon (L.) Pers.]. Large crabgrass control by late August was equal to or higher when Dimension and MSMA were applied in a single tank-mixed application after weeds emerged in early May than when Dimension was applied as preemergence late February followed by MSMA as postemergence early June. Full season control ranged from ≥73% for tank-mixes of Dimension plus MSMA at 0.14 + 1.1 kg/ha (0.12 + 1.0 lb/A) to ≥93% when applied at 0.28 + 2.2 kg/ha (0.25 + 2.0 lb/A). The injury to common bermudagrass was due to MSMA and not related to Dimension. MSMA applied in May caused only slight discoloration but injury in June ranged from from ≤42% in 1995 and ≤25% in 1996. The higher injury in 1995 was related to higher air temperature following treatments. When injury was observed, recovery occurred within 2 to 3 weeks.
Incorporation of a Hydrophilic Polymer into Annual Landscape Beds
Authors: Boatright Jennifer L. , Balint Donna E. , Mackay Wayne A. , Zajicek Jayne M.
Published: August 2020

The incorporation of a hydrophilic polymer into annual landscape beds was found to buffer temperature changes by as much as 3C (37F) during daylight hours. Under dry conditions, hydrophilic polymer incorporation increased the growth and flowering of petunias by as much as 64% and 75%, respectively. Vinca and marigold flowering did not increase with polymer incorporation. However, in the case of marigolds, the medium rate of polymer incorporation resulted in an average of 40% higher dry weights compared to control plants. Under nonlimiting water conditions, the advantage of using polymers were less pronounced than under dry conditions. In addition, plant growth and flowering were not affected. The findings suggest that drought-sensitive plants such as petunia may benefit from the addition of a hydrophilic polymer in areas receiving little or sporadic rainfall in addition to elevated temperatures.
Stem and Flower Bud Hardiness of Deciduous Azaleas
Authors: Väinölä Anu , McNamara Steve , Pellett Harold
Published: August 2020

Stem and flower bud hardiness of five deciduous azalea (Rhododendron sp.) clones were compared on six dates during the dormant period of 1992–1993. Visual evaluation and a specific conductance technique were compared on four dates as methods of evaluating freezing injury of stems. With a single exception, stems were always more hardy than the corresponding florets. Stems acclimated more rapidly in the fall and were from 3–15C (5–27F) more hardy than florets on two November sampling dates. Stems and florets of all clones achieved their maximum hardiness levels in January. With the exception of ‘Spicy Lights’, the maximum midwinter hardiness obtained by florets was 2–4C (4–7F) less than that of the corresponding stems. Midwinter stem hardiness was greatest in ‘White Lights’ and ‘Mandarin Lights’ [−40C (−40F)] while ‘Spicy Lights’ exhibited the greatest floret hardiness [−40C (−40F)]. Florets deacclimated substantially more than stems between January 25 and March 17. Rates of deacclimation in stems and flower buds were similar between March 17 and April 14, but stems were still significantly more hardy than florets on April 14. Visual ratings and specific conductance measurements provided similar estimates of hardiness in most, but not all cases. Use of visual observation for evaluating freezing injury of azalea stems is recommended based upon the relative ease and efficacy of this technique.
Ozone Sensitivity of Selected Southeastern Landscape Plants
Authors: Findley Douglas A. , Keever Gary J. , Chappelka Arthur H. , Gilliam Charles H. , Joseph Eakes D.
Published: August 2020

Twenty-six species and/or cultivars commonly used in landscapes of the southeastern United States were exposed to three ozone (O3) levels for 3-week periods during spring and summer 1994. Thirteen species or cultivars exhibited visible foliar injury at the highest rate, 2.5× ambient, and two cultivars exhibited foliar injury with ambient O3 concentrations. The most sensitive were two cultivars of buddleia or butterfly bush (Buddleia davidii Franch. ‘Black Knight’ and ‘Royal Red’), with visible injury under ambient and 2.5× ambient O3 levels, and ‘White Star’ zinnia (Zinnia angustifolia HBK ‘White Star’) with visible injury observed under 2.5× ambient O3 levels. Seven other cultivars of buddleia and three cultivars of red maple (Acer rubrum L. ‘Autumn Flame’, ‘October Glory’, and ‘Franksred’ (Red SunsetTM)) exhibited minor foliar injury under 2.5× ambient O3 levels. Visible injury was not present on flowering dogwood (Cornus florida L. ‘Stokes Pink’), hollies (Ilex crenata Thunb. ‘Green Luster’, I. cornuta Lindl. & Paxt. ‘Carissa’, I. x attenuate Ashe ‘Fosteri #2’), cultivars of crapemyrtle (Lagerstroemia indica L. ‘Byers Wonderful White’ and ‘Carolina Beauty’), glossy abelia (Abelia x grandiflora (Andre) Rehd.), southern waxmyrtle (Myrica cerifera L.), sawtooth oak (Quercus acutissima Carruth), begonia (Begonia semperflorens-cultorum Hort. ‘Pizzazz Red’), petunia (Petunia x hybrida Hort. Vilm.-Andr. ‘Celebrity Red’), salvia (Salvia splendens Sello. ‘Hotline’), or gomphrena (Gomphrena globosa L. ‘Strawberry Fields’).
Effect of Shade Levels and IBA During the Rooting of Eight Tree Taxa
Authors: Zaczek J. J. , Heuser C. W. , Steiner K. C.
Published: August 2020

Softwood shoot cuttings of Acer griseum, A. rubrum ‘Bowhall’, A. rubrum ‘Franksred’ Red Sunset™, A. saccharum ‘Legacy’, Cornus kousa, Quercus alba, Q. ellipsoidalis, and Q. palustris were subjected to hormone treatments (IBA and control) and placed in a fog-humidified polyethylene tent rooting chamber under one of three levels of shade (83% or control, 91%, and 97% of ambient sun). Percentage rooting, the number of roots per cutting, and the number of days to root were significantly influenced by shade levels and hormone treatment, but responses were dependent on species or cultivar. For most taxa, percentage rooting was greatest at 91% or 97% shade. Only for A. griseum was the control shading treatment best for rooting. Generally, under the greater shade levels, the IBA treated cuttings rooted more often, had more roots, and rooted faster than cuttings without IBA. However, in some cases, the hormone treatment did not provide a clear advantage. Results of this study demonstrate that high shade levels in the rooting environment can increase the rooting performance of cuttings of a number of woody plant taxa.
Shearing and Growth of Five Intermountain Native Shrub Species
Authors: Rupp Larry , Kjelgren Roger , Ernstsen Jerriann , Varga William
Published: August 2020

We investigated growth of native Intermountain West shrub species sheared yearly. Five shrub species with potential for use in naturalized landscapes and roadside reclamation, silver sage (Artemesia cana), rabbitbrush (Chrysothamnus nauseosus), red-stem dogwood (Cornus sericea), chokecherry (Prunus virginiana), and curlleaf mountain mahogany (Cercocarpus ledifolius), were planted as seedlings in summer 1989. From 1991–1993, half of the plants were sheared to within 0.15 m (0.5 ft) of the ground every spring prior to or at budbreak. Crown height and crown cross-sectional area were measured every year prior to pruning. Significant shearing effects were detected in some shrubs the first year after shearing, with crown area affected more than height. Height of three species with a multistemmed habit, C. nauseosus, A. cana, and C. sericea, was unaffected by shearing both years. Crown area of all species except C. sericea was reduced by shearing. All species were able to regrow to at least 50% of the crown area and 70% of the height of the unsheared plants, suggesting they would be able to tolerate shearing as a management tool with little to no loss of vigor.
Growth of Dianthus and Petunia in Media Amended with Composted Urban Waste
Authors: Klock Kimberly A.
Published: August 2020

Bedding plant growers have the opportunity to utilize composted urban waste as a component in bedding plant media. Growth of Dianthus chinensis L. (dianthus) and Petunia × hybrida Hort. (petunia) was evaluated in media with 0, 30, 60, or 100% compost made from biosolids and yard trimmings. Dianthus and petunia shoot dry mass, size, and height increased as the percentage of compost in the medium increased from 0 to 60% but decreased at 100% compost. However, dianthus and petunia growth was greater in 100% than 0% compost. Initial nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and soluble salt concentrations linearly increased as the percentage of compost in the medium increased from 0 to 100%. Soluble salt concentrations in 100% compost were 28× greater than in 0% compost and 2× greater than in 30 and 60% compost. Media containing compost made from biosolids and yard trimmings produced larger dianthus and petunia plants than plants grown in peat, vermiculite, perlite medium. The best dianthus and petunia growth was in the medium containing 60% compost.
Preemergent Control of Common Vetch (Vicia sativa L.) and Black Medic (Medicago lupulina L.)
Authors: Norcini Jeffrey G. , Aldrich James H. , Martin Frank G.
Published: August 2020

Preemergence applied herbicides, Barricade 65 WDG (prodiamine), Derby 5G (metolachlor + simazine), Pendulum 60 WDG (pendimethalin), Snapshot DF (isoxaben + oryzalin), and Snapshot TG (isoxaben + trifluralin) were evaluated for control of common vetch (Vicia sativa L.) and black medic (Medicago lupulina L.) in 2.5 liter (0.7 gal) containerized soilless medium. Herbicides were applied at label rates in November 1993 (experiment 1) and 1994 (experiment 2). Common vetch was controlled up to 16 weeks after treatment (WAT) by both Snapshot formulations. Pendulum and Barricade, or Derby provided excellent and good control of vetch for 8 WAT (experiment 1), respectively, but only 4 WAT in experiment 2. Both Snapshot formulations resulted in excellent control of black medic for the entirety of both experiments. Pendulum provided excellent control up to 12 WAT (experiment 2) and good control up to 16 WAT (experiment 1). Further studies should evaluate the turfgrass/landscape herbicide Gallery (isoxaben), the common active ingredient in both Snapshot formulations.
Evaluation of Lonicera Taxa for Honeysuckle Aphid Susceptibility, Winter Hardiness and Use
Authors: Herman Dale E. , Davidson Campbell G.
Published: August 2020

One-hundred-thirty-five honeysuckle (Lonicera L.) taxa were evaluated in North Dakota, Manitoba and/or reviewed in the literature for relative honeysuckle aphid [Hyadaphis tataricae (Aizenberg)] susceptibility, winter hardiness and landscape characteristics. Sixty taxa are rated susceptible to highly susceptible, 13 lightly susceptible and 55 with apparent resistance to aphid attack. Lonicera tatarica L.,L. morrowii Gray. and L. ruprechtiana Reg., including cultivars and hybrids derived from these species, were particularly susceptible. Taxa with apparent aphid resistance were evaluated for hardiness zone assignment and landscape qualities. Only 3 taxa are rated in the high recommendation category for landscape planting in USDA hardiness zones 2 through 5. These include L. x brownii (Reg.) Carr. ‘Dropmore Scarlet’, L. x xylosteoides Tausch. ‘Miniglobe’ and L. xylosteum L. ‘Emerald Mound’. Sixteen taxa received an average recommendation and 27 taxa a low recommendation. The 60 taxa which proved susceptible or highly susceptible to honeysuckle aphid, plus 17 additional taxa, are placed in the non-recommendation category. These 77 taxa represent 57% of the taxa evaluated in this study. Eleven taxa are recommended for potential use in shelterbelt or conservation plantings as replacements for aphid susceptible honeysuckles.
Diagnosis of X-Disease Phytoplasma in Stone Fruits by a Monoclonal Antibody Developed Directly from a Woody Plant
Authors: Guo Y. H. , Cheng Z.-M. , Walla J. A. , Zhang Z.
Published: August 2020

A monoclonal antibody was produced by using enriched antigen from an infected chokecherry plant, and was used to detect the X-disease phytoplasma using both ELISA and immunofluorescence staining. The monoclonal antibody reacted with five of seven tested phytoplasmas in the X-disease phytoplasma cluster, and one of four phytoplasmas (pigeon pea witches'-broom phytoplasma) outside that cluster. The efficiency of the monoclonal antibody for detection of X-disease phytoplasmas was verified through assays of infected stone fruit plants. The efficacy of the monoclonal antibody was confirmed by X-disease phytoplasma-specific nested-polymerase chain reaction. Development of the monoclonal antibody represents a substantial improvement in the potential for commercial diagnosis of X-disease phytoplasma infection in nurseries and orchards and for screening large numbers of stone fruit plants for X-disease phytoplasma infection in breeding programs.
Effects of Nursery Container Type on Root Growth and Landscape Establishment of Acer rubrum L.
Authors: Marshall Michael D. , Gilman Edward F.
Published: August 2020

Trees of red maple (Acer rubrum L.) were planted into seven container types evaluated for their ability to reduce number of roots deflected by the container wall. Seedlings were grown 70 weeks (production phase) in seven container types to a mean trunk diameter of 3.9 cm (1.5 in) and were transplanted into a sandy soil and grown with frequent or periodic irrigation for 24 weeks (landscape phase). There was no effect of container type on total root mass, trunk diameter or height during the production phase. Total deflected root length was less in low-profile plastic containers, chemical root pruning containers, air root pruning containers (ARPC), and wood boxes than in standard black plastic containers (SBPC). Trees produced in the SBPC had the most horizontally-oriented deflected root length while the ARPC and SBPC had the most vertically-oriented deflected root length. Trees grown in the ARPC had less roots on the inside of the root ball than all other container types. Container type did not influence root and shoot growth, but impacted stem water potential in the first five months after transplanting to the landscape. Trees frequently irrigated during the landscape phase had greater trunk diameter, height, and generated more new root mass than those which were infrequently irrigated.
Susceptibility of Cultivars of Several Dogwood Taxa to Powdery Mildew and Spot Anthracnose
Authors: Hagan A. K. , Hardin B. , Gilliam C. H. , Keever G. J. , Williams J. D. , Eakes J.
Published: August 2020

Incidence of powdery mildew (Microsphaera penicillata) and spot anthracnose (Elsinoe corni) was assessed on 37 selections or cultivars of flowering dogwood (Cornus florida), kousa dogwood (C. kousa), hybrid dogwood (C. kousa x florida and C. nuttallii x florida) and giant dogwood (C. controversa). Across all cultivars, the flowering dogwood and C. nuttallii x florida ‘Eddie's White Wonder’ are more susceptible to powdery mildew and spot anthracnose than the kousa, C. kousa x florida hybrids and giant dogwood. Among the cultivars of flowering dogwood screened, ‘Cherokee Brave’, ‘Cherokee Chief’, ‘Welch's Bay Beauty’ and ‘Weaver's White’ were partially to highly resistant to both diseases. With few exceptions, the kousa dogwood and C. kousa x florida hybrids, and giant dogwood suffered very little powdery mildew or spot anthracnose-related damage.
Effects of Gallery Applied at Different Growth Stages to Dwarf Burning Bush (Euonymus alatus ‘Compacts’)
Authors: Salihu Sydha , Derr Jeffrey F. , Hatzios Kriton K.
Published: August 2020

The effect of Gallery application timing on dwarf burning bush tolerance was determined in field trials. Gallery was applied foliarly at 0.84, 1.69 and 3.39 kg ai/ha (0.75, 1.5 and 3 lb ai/A) to dwarf burning bush at different growth stages. Gallery applied at the dormant stage and two months after bud-break did not injure dwarf burning bush. Plants treated one month after bud-break with all three rates were injured approximately 30 to 45% at one and three months after herbicide application. Injury symptoms were manifested as decreased leaf size and leaf distortions. Gallery applied at 0.84 and 1.69 kg/ha (0.75 and 1.5 lb/A) one month after bud-break decreased plant width. Shoot-dieback was also observed in plants treated with Gallery at all rates one month after bud-break. Gallery at all three rates applied one month after bud-break caused 60 to 75% of the leaves to defoliate six weeks earlier in the fall compared to the other application timings.
Effect of Lifting Date and Time of Storage on Survival and Die-Back in Four Deciduous Species
Authors: Lindqvist Hans
Published: August 2020

Woody landscape plants transplanted in urban areas frequently show poor establishment and high mortality rates. The importance of lifting date in combination with cold storage was tested in a trial with four species, European white birch (Betula pendula Roth.), redosier dogwood (Cornus sericea L. ‘Flaviramea’), singleseed hawthorn (Crataegus monogyna Jacq.) and English oak (Quercus robur L.). Plants were lifted at 14-day intervals during the fall and divided for different purposes including assessment of root growth potential (RGP) before and after four months of cold storage; evaluation of survival and damages after four months of cold storage; and for evaluation of survival, damage and shoot growth in a field trial. Early lifting in combination with cold storage was negative for the survival and damage to the four species. A longer period of cold storage had a further negative effect on plants lifted early. RGP assessed in the fall could indirectly be used to predict lifting date of European white birch, English oak and red-osier dogwood. RGP after storage could be used to predict field performance in European white birch and English oak. Singleseed hawthorn did not show any differences in RGP.
Effects of Cyclic Micro-irrigation and Substrate in Pot-in-pot Production
Authors: Fain Glenn B. , Tilt Ken M. , Gilliam Charles H. , Ponder Harry G. , Sibley Jeff L.
Published: August 2020

This study was conducted to evaluate production techniques for increasing irrigation application efficiency [(water volume applied − water volume leached) / water volume applied] for large container trees. Three irrigation treatments (single, three cycle and six cycle) and three substrate treatments [pinebark, pinebark:coir (4:1 by vol), and pinebark:peat (4:1 by vol)] were evaluated for effects on irrigation application efficiency and growth of Acer rubrum ‘Franksred’ in a pot-in-pot production system in Auburn, AL. Substrate pH, electrical conductivity and leachate total inorganic nitrogen (N) content were measured. Cyclic irrigation reduced total N lost by a minimum of 89% when compared to a single irrigation application. Irrigation application efficiency increased with cyclic irrigation compared to a single irrigation application and for the pinebark: coir substrate compared to the pinebark. Growth was greater when irrigation was applied in six cycles than in a single irrigation application. Trees grown in pinebark: peat substrate had greater shoot dry weight than those grown in the pinebark substrate.
Cyclic Irrigation and Grass Waterways Combine to Reduce Isoxaben Losses from Container Plant Nurseries
Authors: Briggs Jeanne , Whitwell Ted , Riley Melissa B. , Lee Tracy
Published: August 2020

This study evaluated the remediating effects of the combination of cyclic irrigation and grass waterways on pesticide loads in runoff water. Cleary's 3336 (thiophanate-methyl), Dursban (chlorpyrifos), and Snapshot TG (trifluralin plus isoxaben) were applied to container nursery beds. The two treatments were continuous irrigation (90 min duration) with runoff emptying through a clay/gravel waterway and cyclic irrigation (three 30 min cycles with 90 min between cycles) with runoff emptying into a grass waterway. Samples of runoff water were collected at the end of the waterways on the day of application and 1, 2, 4, and 8 days after application. Cyclic irrigation reduced runoff water volume 15% compared to continuous irrigation. All pesticides were detected in runoff water on the day of application from both treatments. Isoxaben was detected in runoff water through 8 days after application from both treatments. Isoxaben concentrations and amounts were reduced by the cyclic irrigation/grass waterway treatment on the day of application and as a total for the duration of the study.
Pre-emergence Applied Herbicides for Container-Grown Liriope after Division
Authors: Hayes Christine K. , Gilliam Charles H. , Olive John W. , Keever Gary J. , Eakes D. Joseph
Published: August 2020

Three experiments were conducted to evaluate the effects of preemergence-applied herbicides on growth of liriope [Liriope muscari (Decne.) L.H. Bailey ‘Big Blue’ and ‘Variegata’] when applied immediately after division. Overall, most herbicides caused no injury or suppression of root or shoot development. Surflan (oryzalin) and a Surflan + Gallery (isoxaben) combination inhibited root and shoot growth. Predict (norflurazon) caused foliar injury characterized by bleached bands or spots on both old and new foliage.
Supercooling in Dormant Flower Buds of Forsythia, and the Correlation between Pistil Size and Bud Hardiness
Authors: Flinn Cindy L. , Ashworth Edward N.
Published: August 2020

Experiments were conducted to determine if dormant buds of Forsythia taxa exhibit the deep supercooling characteristic. Specimens were collected from thirteen Forsythia taxa including: F. suspensa (Thunb.) Vahl, F. x intermedia cv. Spectabilis (Koehne), F. x intermedia cv. Lynwood (G.E. Peterson), F. europaea (Degen and Baldacci), F. giraldiana (Lingelsh), F. japonica (Makino) var. saxatilis (Nakai), F. mandshurica (Uyeki), F. ovata (Nakai), F. suspensa var. fortunei (Lindl.), F. viridissima (Lindl.), F. x intermedia cv. Arnold Giant (Sax), F. cv. Arnold's Dwarf, and F. cv. Meadowlark (Flint). Buds and attached stem segments, were cooled at 2C (3.6F) per hour, and the temperature at which freezing occurred was determined by thermal analysis. Typically, two distinct freezing events were detected within Forsythia buds. The first freezing event, or high temperature exotherm, occurred just below 0C (32F), while the second freezing event, or low temperature exotherm, occurred between −16C (3.2F) and −28C (−18.4F). The low temperature exotherm corresponded to the freezing of supercooled water within dormant buds, and the detection of low temperature exotherms in buds of all 13 Forsythia taxa indicated that deep supercooling is common among members of this genus. In nine of the 13 Forsythia taxa, the temperature of the low temperature exotherm was an accurate indicator of bud freeze-tolerance (LT50), as determined by a laboratory freeze-stress protocol. The discrepancies noted in the other four taxa were apparently due to the occurrence of field freezing injury prior to conducting these laboratory studies. Evidence indicated a relationship between the extent of supercooling and the size of the pistil in dormant Forsythia buds.
Yellow Nutsedge Control and Nursery Crop Tolerance with Manage as Affected by Adjuvant Choice
Authors: McDaniel Gary L. , Fare Donna C. , Witte Willard T. , Flanagan Phillip C.
Published: August 2020

Adjuvants combined with one-half rate (18 g ai/ha, 0.26 oz ai/A) of Manage (MON 12051, halosulfuron) were evaluated for phytotoxicity on five species of landscape plants grown in containers and for effectiveness of yellow nutsedge (Cyperus esculentus L.) control. Adjuvants tested at 0.25 and 0.5% (v/v) were: X-77 (non-ionic), Scoil (methylated soybean seed oil), Sun-It II (methylated sunflower seed oil), Agri-Dex (paraffin crop oil concentrate), and Action “99” (non-ionic organosilicone). Manage combined with each adjuvant injured Japanese holly (I. crenata Thunb. ‘Bennett's Compacta’), forsythia (Forsythia x intermedia Zab. ‘Lynwood Gold’), green liriope (Liriope muscari Bailey ‘Big Blue’), and weigela (Weigela florida Bunge ‘Pink Lady’), but not ‘Blue Girl’ holly (Ilex x meserveae S.Y. Hu ‘Blue Girl’). Manage with Scoil produced moderate phytotoxicity on forsythia and weigela and reduced growth of all landscape plants. Manage plus Action “99” caused severe phytotoxicity to weigela and reduced growth on all plants tested. Manage plus Agri-Dex treatment resulted in moderate to severe growth reduction to all plants, with severe marginal necrosis of foliage on forsythia and weigela. Manage with Sun-It II resulted in less growth reduction and fewer phytotoxic symptoms of the test species, compared to other adjuvant plus Manage combinations. Initially, foliar chlorosis was observed on all species except ‘Blue Girl’ holly with the Manage plus Sun-It II treatment, but most plants had recovered by 8 weeks after treatment (WAT). Yellow nutsedge control at 4WAT was greater when Manage (18 g ai/ha, 0.26 oz/A) was combined with Scoil, Sun-It II, Agri-Dex, or Action “99” adjuvants. By 8WAT, Manage combined with Sun-It II resulted in 98–100% control of nutsedge. Manage plus the adjuvants Scoil or Sun-It II resulted in superior yellow nutsedge control compared to X-77, Action “99”, or Agri-Dex and had little effect on growth of these landscape plants.
Shading and IBA Treatment Do Not Improve Rooting of Stem Cuttings of Quercus phillyraeoides ‘Emerald Sentinel’
Authors: Griffin Jason J. , Blazich Frank A. , Ranney Thomas G.
Published: August 2020

Shoot tip cuttings of Quercus phillyraeoides A. Gray ‘Emerald Sentinel’ (‘Emerald Sentinel’ oak), in a transitional growth stage between softwood and semi-hardwood, were collected from containerized plants growing under uniform fertility on June 4, 1998. Cuttings were treated with talc formulations of indolebutyric acid (IBA), ranging from 0 to 8000 ppm (0.8%), and placed under intermittent mist with shade levels excluding 0%, 30%, 60% or 90% of full solar irradiance. After 14 weeks, percent rooting averaged 18% and was unaffected by either IBA concentration or shading regime. Similarly, both mean root number per rooted cutting and mean root length were unaffected by IBA concentration or shading. Roots per rooted cutting and mean root length averaged 2.6 and 41 mm (1.6 in), respectively. Results suggest that shading stem cuttings of ‘Emerald Sentinel’ during propagation does not affect rooting.
Effects of Herbicide and Time of Application on Pampas Grass Grown in Containers
Authors: Hayes Christine K. , Gilliam Charles H. , Keever Gary J. , Eakes D. Joseph
Published: August 2020

Two experiments evaluated the effects of preemergence herbicides on pampas grass [Cortaderia selloana (Schult. and Schult. f.) Asch. and Graebn.] growth. Herbicides were applied 1, 15, or 30 days after potting (DAP) from 36-cell packs into 3.8 liter (#1) containers. Ronstar (oxadiazon) applied at the manufacturer's recommended rate caused little or no injury when applied 1 or 15 DAP. Factor 65 WG (prodiamine) applied 1 DAP suppressed root growth compared to control plants; however, when applied 15 or 30 DAP root ratings of Factor treated plants were similar to control plants 60 and 75 DAP. Plant height at 90 DAP was about 10% greater when the herbicide application was delayed 30 DAP, compared to plants treated 1 DAP. In experiment 2, plant height and root ratings were greater when herbicides were applied 30 DAP than when applied 1 DAP. Pendulum 2G (pendimethalin), Pendulum 60 WDG (pendimethalin), and Factor 65 WG (prodiamine) suppressed root growth in the upper 5.1 cm (2 in) and lower 10.2 (4 in) of container medium. Plants treated with Factor 65 WG or Pendulum 60 WDG generally had the highest percent lodging and the most club roots in both experiments; Ronstar was the only herbicide that did not cause lodging or club root formation.
Biorational and Conventional Plant Protectants Reduce Feeding by Adult Japanese Beetles
Authors: Witt J. Dale , Warren Stuart L. , Ranney Thomas G. , Baker James R.
Published: August 2020

Nine commercial plant protectants were tested for efficacy against feeding by adult Japanese beetles (Popillia japonica Newman). Treatments included an endotoxin from a bacterium [Bacillus thuringiensis (Berl.) var. san diego]; microencapsulated pyrethrum extracted from pyrethrum [Tanacetum cinnerariifolium (Trev.) Schultz-Bip.], two extracts from neem (Azadirachta indica A. Juss); an extract from cayenne pepper (Capsicum annuum L. var. annuum Longum Group); an extract from garlic (Allium sativum L.); rotenone extracted from galedupa (Derris trifoliata Lour.) and barbasco [Lonchocarpus sericeus (Poiret) Kunth] or timbo (L. nicou Aublet D.C.); carbaryl (1-napthyl methylcarbamate); and the pyrethroid, fenpropathrin. Experimental plots were located at the Horticulture Field Laboratory (HFL), Raleigh, and the Mountain Horticultural Crops Research and Extension Center (MHCREC), Fletcher, NC. Himalayan birches [Betula utilis var. jacquemontii (Spach) Winkl.] were used as host plants. Treatments were applied twice, 2 weeks apart. Five weeks after initial application, trees treated with fenpropathrin averaged 2% defoliation vs. 40% defoliation for the control trees at HFL; and 3% defoliation vs. 100% defoliation for the control trees at MHCREC. Rotenone treatments averaged 10% defoliation at HFL and 92% defoliation at MHCREC. The following treatments were not significantly different from the control at week 5 at either location: garlic extract, neem extracts, cayenne pepper extract, microencapsulated pyrethrum, encapsulated bacterial endotoxin, and carbaryl.
Development of an In Ovolo Embryo Culture Procedure for Hydrangea
Authors: Reed S. M.
Published: August 2020

Panicle hydrangea (Hydrangea paniculata) is a potential source of cold hardiness that is needed for improvement of bigleaf hydrangea (H. macrophylla). Seeds have been produced from H. macrophylla × H. paniculata crosses, but seedlings derived from the few seed that germinated died at a very young age. The objective of this study was to investigate the use of in ovolo embryo culture for producing this interspecific hybrid. Six media, which differed in basal media formulation and sucrose concentration, were tested using H. macrophylla intraspecific ovules collected 3 to 4 and 5 to 6 weeks after pollination. The highest percent germination for both time periods was obtained on Gamborg's B-5 medium supplemented with 2% sucrose; therefore, this medium was chosen for culture of H. macrophylla x H. paniculata ovules. Plants germinated from interspecific ovules cultured 3 to 6 weeks after pollination, but all died before forming two sets of true leaves. A slow-growing bacterial contamination that was present in many of the interspecific cultures necessitated the elimination of cultures initiated 7 to 8 weeks after pollination, and may have been at least partially responsible for the death of the putative hybrids. A broad-spectrum biocide/fungicide was found to be 100% effective in controlling this endogenous contaminant, thereby allowing older ovules to be cultured. Putative H. macrophylla x H. paniculata hybrids have been obtained from ovules cultured 9 to 10 weeks after pollination.
Benzyladenine Improves Summer Quality of Hosta
Authors: Schultz Heather C. , Keever Gary J. , Kessler J. Raymond , Dute Roland R.
Published: August 2020

A study was conducted to determine the effects of benzyladenine (BA) on improving summer quality of hosta in container production and in the landscape. For container production, stock plants of Hosta ‘Sum and Substance’, H. sieboldiana ‘Elegans’, H. ‘Francee’, H. sieboldiana ‘Frances Williams’, H. plantaginea, and H. ‘Tokudama’ were divided and potted. When they showed signs of summer dormancy or foliar decline, half the plants of each cultivar/species received a single foliar spray application of 3000 ppm BA. In the landscape, half the established field-planted hosta with 27–4 initial offsets (‘Francee’) or 0–3 initial offsets (‘Frances Williams’) received a single foliar spray application of 3000 ppm BA when plants began to show signs of summer dormancy. BA stimulated the outgrowth of axillary and rhizomic buds in all cultivars/species in both parts of the study. Offsets formed more leaves on plants treated with BA compared to the untreated hosta. Offset leaf number was dependent on cultivar in both locations, and initial offset number affected leaf number for ‘Frances Williams’ in the landscape. Generally, BA application improved plant appearance of cultivars/species in both parts of the study. Cultivar/species and BA influenced whole plant growth index in container production, but had no effect in the landscape.
Foliar Application of Plant Growth Retardants to Coreopsis rosea ‘American Dream’
Authors: Burnett S.E. , Keever G.J. , Kessler J.R. , Gilliam C.H.
Published: August 2020

In one experiment conducted in 1998 and two in 1999, Coreopsis rosea ‘American Dream’, or pink coreopsis, were treated with four plant growth retardants (PGRs): B-Nine from 2500 to 7,500 ppm, Cutless from 25 to 150 ppm, Sumagic from 10 to 40 ppm, and Bonzi from 25 to 100 ppm. The study was conducted to determine whether PGRs could be used to suppress growth of pink coreopsis without delaying flowering or causing phytotoxicity. Application of B-Nine, Cutless, or Sumagic suppressed plant growth 13–31% at first flower and when plants were marketable (one-third of flowers open) in all experiments and improved plant quality compared to controls. Plants treated with B-Nine, Cutless, or Sumagic had quality ratings 52–67% higher than those of control plants when marketable; treated plants appeared denser and more floriferous. Time to first flower and to a marketable stage were minimally affected by PGR application, and no phytotoxicity was observed. Bonzi did not significantly control growth or affect flowering of pink coreopsis in any of the three experiments.
Irrigation Regimens Differentially Affect Growth and Water Use Efficiency of Two Southwest Landscape Plants
Authors: Stabler Linda B. , Martin Chris A.
Published: August 2020

Growth and water use efficiency (WUE) of two, common Southwest landscape plants, red bird of paradise (Caesalpinia pulcherrima L.) and blue palo verde (Cercidium floridum Benth. Ex A. Gray), were studied in response to three irrigation regimens (frequent, moderate, and infrequent) that mimicked a range of residential landscape watering practices in Phoenix, AZ. During 50 to 58 and 138 to 147 days after the start of irrigation treatments (DAT), mid-day measurements of shoot water potential (Ψ), osmotic potential (Ψ0), and gas exchange were made. Concurrently, diurnal measurements of whole plant transpiration (T) and estimates of dry weight accrual were made to calculate WUE. More frequent irrigations increased shoot length of both species and dry weight of Cercidium. For both species, Ψ and Ψ0 showed patterns of osmotic regulation as the substrate dried between watering events for moderately and infrequently irrigated plants. Infrequently irrigated Caesalpinia and Cercidium had the lowest WUE, except for 138 to 147 DAT during which time infrequently irrigated Cercidium had the highest WUE. Instantaneous transpiration efficiency (ITE) was negatively correlated to the ratio of intracellular to ambient CO2 (Ci/Ca) in all treatments, suggesting that under more frequently irrigated conditions, WUE of Caesalpinia and Cercidium might be reduced by negative feedback effects of high Ci/Ca ratios on stomatal conductance.
Growth Regulation of Mexican Sage and ‘Homestead Purple’ Verbena During Greenhouse and Nursery Production
Authors: Burnett S. E. , Keever G. J. , Kessler J. R. , Gilliam C.H.
Published: August 2020

Salvia leucantha (Mexican sage) and Verbena canadensis ‘Homestead Purple’ were treated with the plant growth retardants (PGRs), Cutless, Sumagic, B-Nine/Cycocel tank mixes, or Pistill under both greenhouse and nursery conditions. Increasing rates of all PGRs applied to both species reduced plant size in the greenhouse for 6 weeks after treatment (WAT). Growth reduction of Mexican sage with the most effective rate (providing greatest growth control) of each PGR over this period averaged 11% with Cutless, 15% with Sumagic, 23% with B-Nine/Cycocel tank mixes, and 25% with Pistill. For verbena, size control with the most effective rate of each PGR averaged 15% with Cutless, 18% with Sumagic, 27% with B-Nine/Cycocel tank mixes, and 29% with Pistill. After transplanting greenhouse-grown plants into outdoor ground beds, only Mexican sage treated with B-Nine/Cycocel were significantly smaller 4 weeks after planting (WAP). Greenhouse-grown verbena treated with Sumagic, B-Nine/Cycocel tank mixes, and Pistill and planted in the landscape were 15—23%, 18–25%, and 0–20% smaller, respectively, than control plants at 2 WAP, but by 4 WAP, all PGR-treated verbena were similar in size to control plants. Under nursery conditions, Cutless and B-Nine/Cycocel tank mix reduced Mexican sage size up to 4 WAT. None of the PGRs affected plant size at 6 WAT. The most effective rate of each PGR (averaged over the duration that a PGR was significant) suppressed shoot growth 16% for Cutless, 12% with Sumagic, 20% for B-Nine/Cycocel tank mixes, and 29% for Pistill. For verbena only, Sumagic suppressed growth up to 10% at 2 WAT, and no PGR effectively controlled growth under nursery conditions 4 WAT.