bluuebunny/crossref_metadata_2025 huggingface dataset:
Drought stress reactions of different populations of Quercus robur L. and Tilia cordata Mill.1
Authors: Selig Malte , Bohne Heike
Published: August 2020

Locally adapted trees and shrubs are suggested to show higher fitness at their site of origin than non-locally adapted ones. The production in tree nurseries could take this into account to improve outplanting performance. However, separate production of specific ecotypes in nurseries increases the costs of production and may reduce the availability of a specific species. In this study, we investigated drought stress reactions of 2 year-old container-grown seedlings of Quercus robur L. and Tilia cordata Mill. from four and three different populations, respectively, each from a different site of origin. Slow- and fast-developing drought stress treatments were applied in a greenhouse study to determine any difference in drought tolerance. Control plants were well irrigated. Depending on the species and stress development, only marginal interpopulation differences in particular physiological (pre-dawn water potential, stomatal conductance, relative water content) and/or biochemical (glucose, fructose, sucrose, starch, proline) reactions to drought existed. These differences did not consistently reflect precipitation conditions at the population sites of origin, indicating only low level of local adaptation for populations of the target species.

Index words: adaptation, carbohydrates, pedunculate oak, provenances, proline, small-leaved lime.

Species used in this study: pedunculate oak (Quercus robur L.); small-leaved linden (Tilia cordata Mill.).
Effect of Pre-plant Phosphate Charge and Leaching on Phosphorus Longevity in Soilless Substrate1
Authors: Compton Horner Amy J. , Niedziela Carl E. , Nelson Paul V. , Dickey David A.
Published: August 2020

There is little information addressing the impact of quantity of pre-plant phosphate charge in soilless substrate and leaching during production on soluble phosphate longevity when post-plant phosphate is omitted. Two experiments were conducted growing Petunia ×hybrida ‘Primetime White' seedling crops over a 42-d period in a sphagnum peat moss-perlite substrate. Phosphate-phosphorus (P) charge levels of 0.03, 0.06, 0.12, and 0.18 kg.m−3 (0.05, 0.10, 0.20 and 0.30 lbs·yd−3, respectively) and 0, 20, and 50% leaching were tested. The first experiment was conducted in winter (late November through December) and the second in spring (mid-March through April). The minimum-targeted, soluble-bulk-solution phosphate-P level of 3 mg.L−1 (ppm) was achieved for 41 d in the winter with a phosphate-P charge of 0.06 kg.m−3 (0.10 lbs·yd−3) and 20% leaching. Longevity for this treatment was 4 d less in the spring. At 0% leaching, the soluble-bulk-solution phosphate-P level was above the minimum target level of 3 mg.L−1 (ppm) for the entire 42-d period in both seasons. Increasing the leaching from 20 to 50% resulted in a loss of longevity by 4 d in the winter and 6 d in the spring.

Index words: soilless media, bedding plants, floriculture, Petunia ×hybrida, plant nutrition.

Species used in this study: petunia (Petunia ×hybrid var. multiflora Vilm.).
Efficacy of Bio-based Liquid Mulch on Weed Suppression and Water Conservation in Container Nursery Production1
Authors: Shen Kate , Zheng Youbin
Published: August 2020

To assess the effectiveness of bio-based liquid mulch at different application rates and binder loading types for weed suppression and evaporation reduction in container nursery production, a study was conducted outdoors in the summer of 2015 in Ontario, Canada. Three application rates [0.5 1.25, or 2.0 kg·m−2 (0.20 lb·ft−2)] and two binder loading types (AMP753 with 3.5% binder loading or AMP153 with 7% binder loading) of the liquid mulch were used in the trial. The evaporation rates (ER) from the container growing substrate were quantified daily for three 7-day cycles. All mulched treatments reduced total ERs starting from the second cycle compared to the no-mulch control, with the exception of the treatment binder loading type 3.5% with 0.5 kg·m−2 mulch. All mulched treatments had an equivalent effect at reducing weed numbers compared to the control. The 1.25 and 2.0 kg·m−2 rates were more effective for weed control than the low application rate (0.5 kg·m−2) and there were no differences between binder loading types. No negative effects on overall plant health, flower or branch number, total aboveground biomass, leaf area, or plant growth index were observed on Hydrangea paniculata ‘Jane' from the applied mulch. A major shortcoming with the product as tested was that it dried and shrunk within a couple of days of application. This caused a gap of approximately 10 to15 mm (0.39-0.59 inch) between the wall of the pots and the actual dried mulch. The 1.25 kg·m−2 rate of either binder loading type (3.5% or 7%) could be recommended if the shrinking issue of this mulch could be resolved.

Index words: Evaporation, witchgrass, Powell's amaranth, green foxtail, little lime hardy hydrangea.

Chemicals used in this study: Bio-based Liquid Mulch.

Species used in this study: witchgrass (Panicum capillare L.), Powell's amaranth (Amaranthus powellii S. Watson), green foxtail (Setaria viridis (L.) Beauv.), common groundsel (Senecio vulgaris L.), little lime hardyhydrangea (Hydrangea paniculata L. ‘Jane').
Responses of Ten Weed Species to Microwave Radiation Exposure as Affected by Plant Size1
Authors: Rana Aman , Derr Jeffrey F.
Published: August 2020

There is interest in alternative weed control methods to herbicide use, especially among those interested in organic approaches. The use of microwave radiation as a weed control method appears to be a good alternative because it does not produce chemical residues in the environment. A study was conducted to determine the impact of plant age on weed control using microwave radiation. Ten weed species, representing monocots and dicots, were selected for this study: southern crabgrass (Digitaria ciliaris (Retz.) Koeler), dallisgrass (Paspalum dilatatum Poir.), false green kyllinga (Kyllinga gracillima Miquel), fragrant flatsedge (Cyperus odoratus L.), yellow nutsedge (Cyperus esculentus L.) common ragweed (Ambrosia artemisiifolia L.), white clover (Trifolium repens L.), pitted morningglory (Ipomoea lacunosa L.), henbit (Lamium amplexicaule L.) and field bindweed (Convolvulus arvensis L.). In general, weed species become more tolerant of microwave treatments as they increased in size, as 8 to 10 week-old plants were injured less than 4 to 6 week-old plants. Most grass species regrew when treated at 90 and 180 joules.cm−2 of microwave radiation. Pitted morningglory and common ragweed showed the highest susceptibility to microwave radiation among all treated weed species. The increase in a weed's biomass over time probably increases the amount of microwave radiation necessary for heating samples to the thermal threshold required for control.

Index words: Nonchemical control, microwave, weed age, weed maturity, thermal weed control.

Species used in this study: southern crabgrass (Digitaria ciliaris (Retz.) Koeler); dallisgrass (Paspalum dilatatum Poir.); false green kyllinga (Kyllinga gracillima Miquel); fragrant flatsedge (Cyperus odoratus L.); yellow nutsedge (Cyperus esculentus L.); common ragweed (Ambrosia artemisiifolia L.); white clover (Trifolium repens L.); pitted morningglory (Ipomoea lacunosa L.); henbit (Lamium amplexicaule L.); field bindweed (Convolvulus arvensis L.).
Spray Penetration and Natural Enemy Survival in Dense and Sparse Plant Canopies Treated with Carbaryl: Implications for Chemical and Biological Control1
Authors: Yeary Whitney , Fulcher Amy , Zhu Heping , Klingeman William , Grant Jerome
Published: August 2020

Ornamental plant producers often rely on chemical control to manage insect pests. However, cultural practices, such as pruning, can influence plant architecture which may, in turn, affect pesticide penetration. Spray penetration was studied to determine the effect of canopy density on beneficial insect survival following insecticide application and to better understand the implications of canopy density on pest management. Regardless of canopy density or plant species, the interior position of the canopy received less than 8% spray coverage. The middle position of sparse canopies received 288 to 513% more coverage than the middle position of dense canopies. The middle and interior position of dense canopies protected greater than 50% of the convergent lady beetle (Hippodamia convergens (Guérin-Méneville) population while only the interior position of dense canopies protected greater than 50% of green lacewing (Chrysoperla rufilabris Burmeister) populations.

Index words: beneficial insect, nursery crop, pesticide, plant architecture, woody ornamental.

Species used in this study: China Girl® holly (Ilex ×meserveae ‘Mesog'); ‘Alice' Oakleaf hydrangea (Hydrangea quercifolia Bartr. ‘Alice'); convergent lady beetle [Hippodamia convergens (Guérin-Méneville)]; green lacewing [Chrysoperla rufilabris (Burmeister)].

Chemicals used in this study: carbaryl (1-naphthyl N-methylcarbamate, Sevin® SL, Bayer CropScience, Durham, NC).
Early Postemergence Control of Woodland Bittercress (Cardamine flexuosa With.) and Yellow Woodsorrel (Oxalis stricta L.) with Dithiopyr and Isoxaben Combinations1
Authors: Saha Debalina , Marble S. Christopher , Chandler Annette
Published: August 2020

The objective of this research was to evaluate dithiopyr and isoxaben combinations and indaziflam (Marengo) for early postemergence control of woodland bittercress (Cardamine flexuosa) and yellow woodsorrel at 4 different early growth stages. Herbicides evaluated included sprayable formulations of isoxaben, dithiopyr + isoxaben, dithiopyr, indaziflam, and prodiamine + isoxaben without any surfactants. Woodland bittercress growth stages included seed production (extra-large), recently flowered (large), 6 to 9 leaf (medium) or in 2 to 5 leaf stage (small), while yellow woodsorrel growth stages included 8 to 12 leaf stage (extra-large), 4 to 6 leaf stage (large), 2 to 4 leaf stage (medium) and cotyledon to 1 leaf stage (small). Shoot fresh weight data showed all treatments provided ≤98% of woodland bittercress at the small stage. Dithiopyr + isoxaben (98%), isoxaben (90%), and indaziflam (93%) provided the highest level of woodland bittercress control at the medium stage and were the only treatments providing acceptable control (≥80%). In the large stage, dithiopyr + isoxaben provided acceptable control (80%) and outperformed other treatments. All treatments with the exception of isoxaben generally provided acceptable control of yellow woodsorrel up to the large growth stage. Only indaziflam (86% control) provided acceptable control at the extra-large stage.

Index words: herbicide, postemergence weed control, container-grown plants, phytotoxic damages.

Herbicides used in this study: isoxaben (Gallery® 4SC) N-[3-(1-ethyl-1-methylpropyl)- 5-isoxazolyl]-2,6-dimethoxybenzamide; dithiopyr (Dimension® 2EW) S,S'-dimethyl 2-(difluoromethyl)-4- (2-methylpropyl)-6-(trifluoromethyl)- 3,5-pyridinedicarbothioate; indaziflam (Specticle® FLO) N-[(1R,2S)-2,3-dihydro-2,6-dimethyl-1H-inden-1-yl]-6-(1-fluoroethyl)-1,3,5-triazine-2,4-diamine; prodiamine + isoxaben (Gemini® SC) 2,4-dinitro-N3,N3-dipropyl-6-(trifluoromethyl)-1,3-benzenediamine + N-[3-(1-ethyl-1-methylpropyl)- 5-isoxazolyl]-2,6-dimethoxybenzamide; dithiopyr + isoxaben (Dimension® + Gallery®) S,S'-dimethyl 2-(difluoromethyl)-4- (2-methylpropyl)-6-(trifluoromethyl)- 3,5-pyridinedicarbothioate + N-[3-(1-ethyl-1-methylpropyl)- 5-isoxazolyl]-2,6-dimethoxybenzamide.

Weed species evaluated: woodland bittercress (flexuous bittercress) (Cardamine flexuosa With.); yellow woodsorrel (Oxalis stricta L.).
Effects of Three Fertilization Methods on Weed Growth and Herbicide Performance in Soilless Nursery Substrates1
Authors: Stewart Cody J. , Marble S. Christopher , Jackson Brian E. , Pearson Brian J. , Wilson P. Christopher
Published: August 2020

Research objectives were to determine the effect of fertilization method (incorporation, subdress, and topdress) on weed growth and the performance of preemergence herbicides applied to soilless substrates. Nursery containers were filled with a pine bark:peat substrate and fertilized at two different rates [4.4 and 9.5 kg.m−3 (8.9 and 19.2 lb.yd−3)] via topdressing, subdressing, or incorporating. Containers were treated with either dimethenamid-P for spotted spurge (Euphorbia maculata L.), flumioxazin for eclipta (Eclipta prostrata L.) or prodiamine for large crabgrass (Digitaria sanguinalis L.). A control was established for each fertilizer rate/placement and weed species that was not treated. Incorporating or subdressing fertilizer resulted in reduced large crabgrass and spotted spurge growth in non-treated containers. Weeds grew larger at the higher fertility rates in both topdress and incorporated treatments but fertilizer rate did not affect growth of spotted spurge or large crabgrass when fertilizers were subdressed. Herbicides generally provided commercially acceptable weed control regardless of fertilizer treatment, but results varied with species. Results suggest that in the absence of herbicides, topdressing may result in greater weed growth compared with subdressing or incorporating fertilizers; however, fertilizer placement will have less impact on herbicide performance if proper herbicides are chosen and applied correctly.

Index words: topdress, subdress, incorporate, large crabgrass, eclipta, spotted spurge, preemergence

Chemicals used in this study: Flumioxazin (SureGuard®); 2-[7-fluoro-3,4-dihydro-3-oxo-4-(2-propynyl)-2H-1,4-benzoxazin-6-yl]-4,5,6,7-tetrahydro-1H-isoindole1,3(2H)-dione; Dimethenamid-P (Tower) 2-chloro-N-[(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl)acetamide; Prodiamine (Barricade) 2,4-dinitro-N3, N3-dipropyl-6-(trifluoromethyl)-1,3-benzenediamine (Barricade®)

Species used in this study: Large crabgrass (Digitaria sanguinalis L.); Eclipta (Eclipta prostrata L.); Spotted spurge (Euphorbia maculata L.)
Eriophyoid Mites Found on Healthy and Rose Rosette Diseased Roses in the United States1
Authors: Otero-Colina Gabriel , Ochoa Ronald , Amrine James W. , Hammond John , Jordan Ramon , Bauchan Gary R.
Published: August 2020

Phyllocoptes fructiphilus (Keifer), known as the rose bud mite, is an eriophyoid mite that has been shown to be the vector of Rose rosette virus (RRV), an Emaravirus, and the causal agent of rose rosette disease (RRD). Studies were conducted of mites found on roses, using various microscopy techniques including wide field, phase contrast and differential interference contrast light microscopy, and table top and low temperature scanning electron microscopy. Surveys of roses from several states within the US indicate the presence of three species of eriophyid mites: Phyllocoptes fructiphilus, Eriophyes eremus (Druciarek & Lewandowski), and Callyntrotus schlechtendali (Nalepa). Phyllocoptes fructiphilus was found primarily under the petioles (stipules), inside the flower sepals appressed to the ovary/seeds, and on the surface of the leaves. It was collected on plants with or without symptoms of RRD and often hides amongst the dense simple and bulbous, glandular hairs or under the stipules/petioles. Eriophyes eremus was found under the stipules of roses and is now recorded for the first time in the Americas. Callyntrotus schlechtendali was found on the open surface of the older leaves. The latter two species were not observed to be associated with obvious plant injury. In addition, predatory mites were found associated with these mites which may be useful as biological control agents of the eriophyid mites.

Index words: insect vectors, disease spread, predatory mites, viruses

Species used: Rose bud mite [Phyllocoptes fructiphilus (Keifer)]; Roses (Rosa spp.)
An Update of the Literature Supporting the Well-Being Benefits of Plants: Part 2 Physiological Health Benefits
Authors: Hall Charles R. , Knuth Melinda J.
Published: August 2020

This paper focused on providing evidence from the literature regarding the physiological health benefits associated with plants, thereby influencing the physiological, psychological, and cognitive well-being constructs affecting quality of life. These benefits are segmented and discussed using the following categories: better sleep, increased birthweights, decreased diabetes, decreased ocular discomfort, enhanced immunity, improved circadian functioning, improved rehabilitation, decreased cardiovascular and respiratory disease, decreased mortality, improved digestion, decreased allergies, increased physical activity, and improved cognitive development. This research should be strategically incorporated into both industry-wide and firm-specific marketing messages that highlight the quality of life value proposition in order to maintain the industry's sense of value and relevance to residential landscape consumers of the future. These findings also present evidence that municipal leaders and policymakers can use in justifying green infrastructure-related funding decisions, as well as grounds for the construction industry using biophilic design principles in ensuring the built environment offers opportunities for green space interactions. The green industry can play a pivotal role not only in providing plants of high quality for these applications but educating stakeholders regarding the benefits discussed herein.

Index words: benefits of plants, emotional health, mental health
Control of Insects and Diseases with Intelligent Variable-rate Sprayers in Ornamental Nurseries
Authors: Chen Liming , Wallhead Matthew , Zhu Heping , Fulcher Amy
Published: August 2020

Intelligent spray technology can reduce pesticide use and safeguard the environment; however, its ability to effectively control insects and disease must be validated before its adoption by growers. Comparative tests for two different laser-guided variable-rate intelligent sprayers and the same sprayers with conventional constant-rate mode were conducted to control pests at two ornamental nurseries in two growing seasons in Ohio. Crabapple [Malus ‘Sutyzam’ (Sugar Tyme®), M. sargentii], apple (Malus pumila), maple [Acer ×freemanii ‘Jeffersred' (Autumn Blaze®), A. rubrum ‘Franksred' (Red Sunset®) and A. rubrum], birch (Betula nigra and Betula populifolia ‘Whitespire'), London planetree (Platanus ×acerifolia ‘Bloodgood') and dogwood (Cornus florida) were used as the test plants. Intelligent spray technology reduced pesticide use by 56.1% and 51.8% on average at the two nurseries, respectively. Compared to conventional air-assisted sprayers, severity of scab on apple trees and powdery mildew in dogwood was reduced on intelligent spray-treated plants at one nursery, and there were equal or fewer leafhoppers in maple trees and aphids in birch trees when sprayed using intelligent spray technology at both nurseries. These results suggest that intelligent, variable-rate sprayers achieve equivalent or greater insect and disease control in ornamental tree nurseries compared to conventional, constant-rate sprayers.

Index words: aphid, apple scab, environmental protection, leafhopper, precision spray, powdery mildew, sustainable.

Species used in this study: apple (Malus pumila Mill), birches (Betula nigra L, Betula populifolia Marsh. ‘Whitespire'), crabapples [Malus ‘Sutyzam' (Sugar Tyme®), M. sargentii Rehder], dogwood (Cornus florida L.), maples [Acer ×freemanii E. Murray ‘Jeffersred' (Autumn Blaze®), A. rubrum L. ‘Franksred'(Red Sunset®) and A. rubrum L.], London planetree [Platanus ×acerifolia (Ait.) Willd. ‘Bloodgood'].
Evaluation of Variation in Switchgrass (Panicum virgatum L.) Cultivars for Rust (Puccinia emaculata) Resistance1
Authors: Cheng Qunkang , Windham Alan S. , Lamour Kurt H. , Saxton Arnold M. , Windham Mark T.
Published: August 2020

Eleven switchgrass cultivars (eight ornamental and three agronomic) were inoculated with 40 switchgrass rust isolates collected from the southeastern U.S. to study host resistance, rust virulence and host/pathogen interactions by measuring urediniospore germination percentage, latent period, and the number of uredia and urediniospores produced per cm2 of leaf surface. In general, ornamental switchgrass cultivars had reduced number of uredia and urediniospores produced per cm2 than did agronomic cultivars. Rust isolates were variable for virulence in culture (on grass blades in petri dishes); however they could not be segregated into groups based on collection locations or years. The results of this study will provide information concerning durable horizontal resistance in switchgrass for the ornamental industry.

Index words:, Switchgrass, leaf rust, resistance.

Species used in the study: switchgrass (Panicum virgatum L., rust (Puccinia emaculata).
Changes in Tree Root Architecture Resulting from Field Nursery Production Practices1
Authors: Watson Gary , Hewitt Angela
Published: August 2020

Nursery production practices subject tree root systems to mechanical and environmental factors that are not imposed on plants regenerated naturally from seed. Architecture of undisturbed root systems of nine trees species commonly planted in urban landscapes was compared to root architecture of these tree species produced using common field nursery production practices. When young nursery production seedlings are root-pruned prior to replanting, the loss of the lower portion of the main root and lateral roots emerging from it, and initiation of adventitious roots from the cut end, alter the root system architecture. Nursery production plants have 7 to 48 percent fewer natural lateral roots that could develop into flare roots than undisturbed plants. New roots initiated from the cut end of the main root on nursery production plants can substitute for the loss of lateral roots, if accepted practices are followed. Root architecture of trees is established early. With minor exceptions attributed to the loss of small roots less than 1 mm diameter, there were no significant changes in the number of lateral roots over the 4 year period in both nursery production and undisturbed plants. This consistent number of roots also suggests that pruning the main root did not stimulate additional lateral roots above the pruning cut. Root architecture of liner stock produced in nurseries can be equivalent to undisturbed root systems.

Index words: Structural roots, root pruning, bare root, root depth, taproot, root flare.

Species used in this study: Norway maple (Acer platanoides L.); green ash (Fraxinus pennsylvanica Marsh.); littleleaf linden (Tilia cordata L.); red maple (Acer rubrum L.); European white birch (Betula pendula Roth.); Kentucky coffee tree (Gymnocladus dioicus L.); domestic apple (Malus spp.); red oak (Quercus rubra L.); Siberian elm (Ulmus pumila Jacq.).
Temperate Zone Woody Plants for Interior Environments
Authors: Keever Gary J. , Cobb Gary S.
Published: August 2020

Japanese yew (Podocarpus macrophyllus ‘Maki’) and Wheeler's Dwarf pittosporum (Pittosporum tobira ‘Wheeler's Dwarf’) grown outdoors under 3 production light levels and shade-grown fatsia (Fatsia japonica), dwarf gardenia (Gardenia jasminoides ‘Radicans’), variegated pittosporum (Pittosporum tobira ‘Variegata’), leatherleaf mahonia (Mahonia bealei), and Chinese mahonia (Mahonia fortunei) adapted well to interior conditions following production. Quality of asiatic jasmine (Trachelospermum asiaticum), Okinawan holly (Ilex dimorphophylla), and dwarf Japanese euonymus (Euonymus japonica ‘Microphylla’) grown under the 3 production light levels and all species grown in full sun, except the Japanese yew and Wheeler's Dwarf pittosporum, were judged unacceptable.
Temperate Woody Species as Interior Landscape Plants
Authors: Friendship R.A. , Tsujita M.J. , Ormrod D.P.
Published: August 2020

The feasibility of employing temperate woody species in the interior landscape was examined. The indoor performance of deciduous and evergreen plants was observed. Selected species of Taxus, Caragana, Cornus, Ilex, Acer and Euonymus showed potential for indoor use. Condition of plants at the time of introduction to the interior environment was investigated, including adjustment to light level of the plants before indoor placement. Installation of dormant plants was more successful than the installation of actively growing material.
Micropropagation of Meconopsis befonicifolia Franch. from Immature Seeds
Authors: Qu Yong , Norton Colin R.
Published: August 2020

A system for micropropagation of Meconopsis betonicifolia Franch. was developed. Strength of Murashige and Skoog salts, 2,4-dichlorophenoxyacetic acid and cytokinin were varied to determine optimal treatments. Seedlings were used as explant material after root removal. One-third-strength Murashige and Skoog media produced greater survival than the same medium at full strength. Two or 5 mg 1−1 benzyladenine, kinetin or isopentenyladenine combined with 0.2 mg 1−1 2,4-dichlorophenoxyacetic accid induced the formation of multiple meristems and multiple shoots in Meconopsis. In the second subculture, explants originally cultured on benzyladenine or kinetin containing medium produced more multiple meristems and shoots than those originally cultured on isopentenyladenine containing media.
Automated Fertilizer Applicator for Potting Machines
Authors: Parish Richard L. , Constantin Roysell J. , Brown William L. , Wayne Wells D.
Published: August 2020

An automatic fertilizer metering device was designed, built, and mounted on a nursery potting machine. The device senses the presence of a container under the fertilizer spout, and automatically deposits a metered charge of fertilizer into the planting hole in the medium in the container. Fertilizer rate is readily adjustable. Operation is fully automatic.
Influence of Ten Ground Cover Systems on Growth and Market Value of Eastern Hemlock and Eastern White Pine
Authors: Skroch W.A. , Shribbs J.M. , Bir R.E. , Shelton J.E.
Published: August 2020

Growth, mineral nutrient content, and market value of young eastern hemlock (Tsuga canadensis L.) and eastern white pine (Pine strobus L.) were evaluated using 10 ground cover treatments over a 4 to 5 year growing cycle. Hemlocks were taller and had greater market value when managed with straw mulch, bare ground, and cultivation than with tall broadleaf complex, orchardgrass (Dactylis glomerata L.), or ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.). Hemlocks grown with blackberry (Rubus spp.), short broadleaf complex, nimblewill (Mulenbergia schreberi J.F. Gmel.), or Kentucky bluegrass (Poa pratensis L.) ground covers were intermediate. Mulched white pine had greater height, stem diameter, branches per node, and market value compared to trees in tall fescue. Higher P and K concentrations in needles were associated with poor growth. Straw mulch, short broadleaves and nimblewill have the potential for replacing Kentucky bluegrass, orchardgrass and tall fescue in conifer planting systems.
Ectomycorrhiza Formation on Sawtooth Oak by Inoculation with Basidiospore Chips of Pisolithus tinctorius and Scleroderma citrinum
Authors: Beckjord Peter R. , Melhuish John H. , Hacskaylo Edward
Published: August 2020

Basidiospores of the ectomycorrhiza-forming fungi Pisolithus tinctorius and Scleroderma citrinum incorporated into an organic hydrocolloid and stored up to five years can be used successfully in inoculations. Container-grown sawtooth oak seedlings were inoculated with basidiospores that were incorporated and stored in chips of compressed sand and peat moss. Basidiospore chips were manufactured each year after several collections of sporocarps from two locations and stored up to five years. This study showed that sufficient basidiospores remained viable in chip form for ectomycorrhiza formation of sawtooth oaks.
Growth Response of Umbrella Pine as Influenced by Temperature, Photoperiod and Chilling
Authors: Blazich Frank A. , Wright Robert D.
Published: August 2020

Two experiments were conducted to accelerate growth of umbrella pine [Sciadopitys verticillata (Thunb.) Siebe & Zucc.]. Seedlings were grown in controlled-environment chambers at 22°/18°C (71.6°/64.4°F), 26°/22°C (78.8°/71.6°F) and 30 °/26 °C (86.0 °/78.8 °F) under short day (SD) and long day (LD) photoperiods. By 28 weeks, LD seedlings at 22 °/18 °C (71.6°/64.4°F) and 26°/22°C (78.8°/71.6°F) exhibited slightly greater growth. At this time, all plants except 30 °/26°C (86.0°/78.8 °F) SD were chilled 8 weeks at 4°C (39.2 °F) and returned to their respective growth chambers. Chilling substantially increased growth. At 22°/18°C (71.6°/64.4°F) and 26°/22°C (78.8°/71.6°F), the LD photoperiod produced more growth than the SD treatment. In the second experiment, plants from the first study grown at 22 °/18 °C (71.6 °/64.4 °F) SD and LD and 26 °/22 °C (78.8°/71.6°F) LD were divided into 2 groups. One group was placed back in the growth chambers in which they had been maintained during the first experiment. Remaining plants were chilled 8 weeks at 4°C (39.2 °F) and returned to their respective chambers. Excluding leaf length, growth at 22 °/18 °C (71.6 °/64.4 °F) LD, coupled with chilling, produced the largest values for all growth parameters.
Identification of Red-Fruited Pears by Fourth Derivative Spectroscopy of Intact Lamina
Authors: Daley Larry S. , Menendez Ricardo A. , Stebbins R.L.
Published: August 2020

Intact lamina (leaf blade) of young leaves from red-fruited pears were analyzed by fourth derivative attenuance (~absorption) spectroscopy. This method was used to extend electrophoresis based identification procedures. When the two methods were used in combination before fruit development, red-fruited pears were distinguished from the non-red-fruited parent cultivars, and these from other red-fruited and non-red-fruited pear cultivars.
Effect of Pot Lip Shape on Soil Surface Evaporative Losses
Authors: Whitlow T.H. , Mudrak L.Y.
Published: August 2020

Small pots containing a loam soil were monitored in a growth chamber and wind tunnel to determine the effect of 13 different lip shapes on evaporation from the soil surface. In the growth chamber, pots with modified lips showed evaporative losses ranging from 52-95% of the unmodified control during the first 24 hrs following watering. The same trend was observed during the second 24 hrs following watering but not during the third 24 hr period. In the wind tunnel, nine treatments showed significant reductions in evaporation in comparison to the control 24 hrs after watering; no differences were observed after three days of drying.
A Comparison of Light Acclimatization Methods for Reduction of Interior Leaf Drop in Ficus spp.
Authors: Turner Melanie A. , Reed David Wm. , Morgan David L.
Published: August 2020

Two acclimatization methods at 5 light intensities were investigated for indoor maintenance of Ficus benjamina and F. stricta. Plants were either grown at 5 production shade levels of full-sun (1685 μEm−2s−1) to 80% shade (340 μEm−2s−1) for 8 wks then placed directly into a simulated interior environment for 12 wks, or were grown in full-sun for 8 wks then acclimatized for 6 wks at 5 post-production shade levels prior to placement indoors. Photosynthetically active radiation (PAR) in the interior was set at 10.5 μEm−2s−1 (78 ft-c). For F. benjamina, the full-sun treatment caused the highest degree of defoliation and as production or post-production shade level increased, defoliation decreased. F. stricta showed similar effects under post-production shade, but under production shade levels there was a poor correlation between percent shade and leaf drop. There appeared to be two or three periods of leaf drop after placement indoors as opposed to a constant rate of defoliation.
Seed Germination of Cyeas revoluta
Authors: Frett John J.
Published: August 2020

Cycas revoluta seeds commonly take from a few months to a year or more to germinate and germination percentages are normally quite low. In an effort to improve germination, several seed treatments were tested. Seeds germinated better in dark than in the light. Removal of the pulp from seeds increased percent germination as compared to seeds with the pulp intact. Treatment of seeds or 0.5, 1.0, 1.5 or 2 hr with concentrated sulfuric acid increased seed germination. The application of gibberellic acid at concentrations of 500, 1000 or 5000 ppm did not affect germination as compared to controls. Seeds stored at room temperature for 6 months germinated more readily than seeds planted immediately. It is suggested that seeds stored at room temperature and scarified with concentrated sulfuric acid for 1 hr will exhibit improved germination.
Chemical Defoliation of Fig Nursery Stock Using Ethephon, Harvade, and D-WK Surfactant
Authors: Dozier W.A. , Gilliam C.H. , Knowles J.W.
Published: August 2020

Application of harvade (2,3 Dihydro-5, 6-dimethyl-l, 4-dithiin 1,1,4 tetroxide) and ethephon (2-chloroethyl phosphonic acid) in combination with Dupont-WK (D-WK) surfactant (principle functioning agent the dodecyl ether of polyethylene glycol) resulted in significant leaf abscission of Ficus carica. Two applications at weekly intervals of 200 ppm harvade or 400–800 ppm ethephon in combination with 20% D-WK surfactant resulted in acceptable defoliation without plant injury in two tests. In one test, defoliation was achieved with lower rates of harvade or ethephon but significant plant injury occurred. Plant injury was as great with D-WK applied alone as with the addition of harvade or ethephon.
Nursery Container Design for Improved Root Environments
Authors: van de Werken Hendrik
Published: August 2020

Of the $2 billion wholesale production of nursery plants grown in the U.S., about 50% are produced in containers. Freeze damage to the roots of container grown plants is the largest single cause of crop loss in the nursery industry. Differences in cold hardiness between roots and tops of woody plants can be as much as 16.7°C (30°F). A container designed for research on the utilization of soil heat to prevent low container temperatures eliminated freeze damage to the roots of otherwise hardy plants. The new container design also allows for improved drainage, rooting-out control and other advantages of concern to growers.
Influence of Timing and Rate of Glyphosate Applications on Conifer Growth
Authors: Neal J.C. , Skroch W.A.
Published: August 2020

Glyphosate [N-(phosphonomethyl)glycine] was applied at four rates, 0.4, 0.8, 1.5 and 3.0 kg ai/ha (0.36, 0.71, 1.34 and 2.7 lb ai/A) each at four dates, May 26, July 14, September 10, and October 27, 1982, over Fraser fir (Abies fraseri (Pursh) Poir.), Norway spruce (Picea abies (L.) Karst.), and Canadian hemlock (Tsuga canadensis (L.) Carriere). Plants were treated in 1982 and evaluated in 1983 and 1984. Plant height best described the treatment effects for hemlock and fir. Plant height plus budset on the terminal best described treatment effects for spruce. Fir and spruce were tolerant to September and October applications of glyphosate, however, May and July treatments resulted in significant phytotoxicity. Hernlock plants were injured by May, July and September glyphosate treatments, but not bv similar applications in October. Injury to all species persisted into the 1984 season from single applications in 1982.
Water Requirements of Five Container-Grown Acer Species
Authors: Roberts Bruce R. , Schnipke Virginia M.
Published: August 2020

Relative water demand, RWD, of 2-year-old containerized seedlings of red maple (Acer rubrum L.), sugar maple (A. saccharum Marsh.), silver maple (A. saccharinum L.), Norway Maple (A. platanoides L.) and boxelder (A. negundo L.) was determined by comparing potential evapotranspiration rates and actual water consumption values with growth rates for each species. Based on differences in growth rate, each species was determined to be either fast growing (red maple, silver maple, boxelder) or slow growing (sugar maple, Norway maple). Fast growing species used the most water over the 3-month experimental period (June-August), and had the higher RWD. The actual irrigation demand for each species was closely correlated with monthly potential evapotranspiration rates as determined by the Thornthwaite equation.
Effects of Container Geometry and Media Physical Properties on Air and Water Volumes in Containers
Authors: Bilderback T.E. , Fonteno W.C.
Published: August 2020

Data derived from soil moisture retention curves of two media were combined with geometric descriptions of four containers to produce calculated values of air and water volumes for each medium-container combination. The volume air space ranged from 28% in a #1 container to 12% in a bedding plant cell (BPC). Water volume after drainage increased from 43% (#1) to 59% (BPC). The same trend occurred in these containers with the peatlite mix. These calculations were also used to mathematically model four simulated containers and to calculate the air and water contents in the resultant container-medium combinations.
Effects of Harvest Date, Storage Temperature, and Moisture Status on Postharvest Needle Retention of Fraser Fir
Authors: Mitcham-Butler Elizabeth J. , Eric Hinesley L. , Pharr David M.
Published: August 2020

Fraser Fir (Abies fraseri (Pursh) Poir.) branches harvested Oct. 3 and Nov. 28, 1984 were stored with and without water at 9, 16, 23 and 30°C (48, 61, 73 and 86°F) for 6 weeks. Branches set in water exhibited minimal needle loss at all temperatures except 30°C (86°F) where 60 to 75% of the foliage detached. Branches without water retained needles better at lower temperatures where the drying rate was slower. Branches without water which were harvested Nov. 28 exhibited less needle loss than those harvested Oct. 3, but storage temperature had more effect than harvest date. Branches with water maintained a moisture content of 120 to 140% (dry weight basis) except those at 30°C (86°F) which decreased to 66% moisture content after 2 weeks. Later harvest date and lower storage temperatures improved postharvest needle retention of Fraser fir.
Inheritance of Resistance to Fire Blight in Malus Crosses
Authors: Korban S. S. , Ries S. M. , Morrisey J. F. , Hattermann D.
Published: August 2020

In eight interspecific and intraspecific Malus crosses, segregation of seedlings after greenhouse inoculation with Erwinia amylovora indicated that resistance to fire blight was polygenically controlled. In certain interspecific and intraspecific crosses, high percentages of resistant seedlings were recovered suggesting that sources of fire flight resistance are available in the cultivated apple as well as in other small-fruited Malus species.
Growth Reduction of Eastern Redbud (Cercis canadensis L.) Seedlings Caused by Interaction with a Sorghum-Sudangrass Hybrid (Sudex)
Authors: Geneve R. L. , Weston L. A.
Published: August 2020

Growth of Eastern redbud (Cercis canadensis L.) seedlings was significantly reduced when co-cultivated with living sudex (Sorghum bicolor (L.) Moench × Sorghum sudanese (P.) Stapf. cv. FFR 201) and when sudex leaf material was incorporated into the growing medium. The reduction in redbud growth could not be reversed with increased fertilizer rates. Increasing the amount of fresh ordried sudex incorporated into the medium reduced redbud seedling growth in a linear manner. Sudex leaf material placed on the soil surface as a mulch had no effect on redbud growth.
Effects of Temperature and Preinoculation Light Level on Severity of Syngonium Blight Caused by Xanthomonas campestris
Authors: Chase A.R.
Published: August 2020

The effect of temperature on growth of Xanthomonas campestris pv. syngonii isolated from Syngonium podophyllum ‘White Butterfly’ and X. campestris pv. dieffenbachiae isolated from Anthurium andraeanum was tested n vitro. Growth of X. campestris pv. syngonii occurred between 18 (65) and 32°C (90°F) (optimum 26°C [79°C]); growth of X. c. pv. dieffenbachiae occurred from 18 (65) to 34°C (93°F) (optimum 22°C [72°F]). Severity of syngonium blight was greatest for plants maintained at 30°C (86°F); no symptoms developed at temperatures below 26°C (79°F). Preinoculation light levels from 1600 to 5000 ft-c did not affect subsequent disease development on plants inoculated with X. campestris pv. syngonii.
Evaluation of New Fungicides for Control of Rose Blackspot
Authors: Hagan A.K. , Gilliam C.H. , Fare D.C.
Published: August 2020

Daconil 2787, Spotless, Systhane, Maag RO15-1279, and Funginex were evaluated for blackspot control on field-grown roses. Weekly applications of Systhane at 0.16–0.20 g ai/l (0.021–0.027) oz ai/gal) and Maag RO15-1279 at 0.10 g ai/l (0.013 oz ai/gal) provided season-long blackspot protection equal to Daconil 2787. Lower rates of both Maag RO15-1279 and Systhane were less effective than the recommended rates of both fungicides. Spotless retarded shoot elongation while Systhane and Maag RO15-1279 did not.
Irrigation Frequency and Shading Influences on Water Relations and Growth of Container-Grown Euonymus japonica ‘Aureo-marginata’
Authors: Newman S.E. , Follett M.W.
Published: August 2020

Trickle irrigation frequency, shading, water relations, and plant growth of container-grown Euonymus japonica Thunb. ‘Aureomarginata’ was investigated. Plants were grown under a combination of 3 irrigation frequencies and 2 shade levels. Stomatal conductance (gs) was reduced when plants were irrigated 3 times per week compared to irrigation daily and twice daily after week 4 under full sun and after week 8 under shade. Few differences were detected in predawn shoot water potential (Ψshoot) under shade at any irrigation level. The predawn shoot water potential (Ψshoot) was reduced (rnore negative) for plants irrigated 3 times per week compared to irrigation daily and twice daily after week 8 for plants grown under full sun and week 10 for plants grown under shade. These values remained lower for the duration of the study. Plants grown under shade and irrigated once daily had greater plant dry weight and leaf area compared to plants irrigated either twice daily or 3 times per week. They were also larger than all plants grown under full sun. Plants grown under shade had greater chlorophyll levels per unit leaf area. Under shade, plant quality was not affected by irrigation rates. However, only plants grown under shade were of salable quality.
Phytotoxicity of Herbicides to Spring Flowering Bulbs
Authors: Skroch W.A. , Warren S.L. , De Hertogh A.A.
Published: August 2020

Biennial application for two years of nine commonly used turf and ornamental herbicides were evaluated for phytotoxicity to fourteen species of spring flowering bulbs. OH 2 significantly damaged foliage of Anemone ‘Rosea’, Crocus ‘Cream Beauty’, Endymion ‘Blue’, Hyacinthus ‘Ostara’, Iris reticulata ‘Harmony’, Muscari armeniacum, Narcissus ‘Geranium’, Ornithogalum umbellatum, Scilla ‘Spring Beauty’, Triteleia ‘Queen Fabiola’, and the Tulipa ‘Golden Apeldoorn’, ‘Purissima’, and ‘Paul Richter’. Ronstar damaged the foliage of Crocus ‘Cream Beauty’, Crocus ‘Remembrance’, Endymion ‘Blue’, Hyacinthus ‘Ostara’, Iris ‘Harmony’, Muscari armeniacum, Narcissus ‘Geranium’, Ornithogalum umbellatum, Scilla ‘Spring Beauty’, Trietleia ‘Queen Fabiola’, and the Tulipa ‘Golden Apeldoorn’, ‘Purissima’, and ‘Paul Richter’. Muscari foliage was damaged by Balan, Dacthal, Devrinol, Fusilade and Poast. Hyacinthus ‘Ostara’ foliage was damaged by Balan. Anemone ‘Rosea’ foliage was injured by Betasan and Pennant. Tulipa ‘Paul Richter’ foliage was deformed by Devrinol and Fusilade damaged Endymion.

No flower injury was noted from use of Balan, Betasan, Dacthal, Devrinol, Pennant, Fusilade or Poast for two seasons on the 14 bulb species. OH 2 and Ronstardamaged flowers of Crocus ‘Remembrance’, Hyacinthus ‘Ostara’, Iris germanica and I. reticulata ‘Harmony’, Narcissus ‘Unsurpassable’, Ornithogalum umbellatum, Scilla ‘Spring Beauty’, Triteleia ‘Queen Fabiola’, and Tulipa ‘Purissima’ and ‘Paul Richter’. OH 2 damaged the flowers of Crocus ‘Cream Beauty’, Hyacinthus ‘Ostara’, Iris germanica, Iris reticulata ‘Harmony’, Muscari armeniacum, Narcissus ‘Unsurpassable’, Ornithogalum umbellatum, Scilla ‘Spring Beauty’, Triteleia ‘Queen Fabiola’, and Tulipa ‘Golden Apeldoorn’, ‘Purissima’, and ‘Paul Richter’.

Bulb numbers harvested after two years were unaffected by Balan, Betasan, Devrinol, Pennant or Fusilade. Poast and Dacthal reduced bulb numbers of Muscari armeniacum. OH 2 reduced bulb numbers of Crocus ‘Cream Beauty’, Crocus ‘Remembrance’, Hyacinthus ‘Ostara’, Iris reticulata ‘Harmony’, Muscari armeniacum, Triteleia ‘Queen Fabiola’, and ‘Paul Richter’ and ‘Purissima’ tulips. Ronstar reduced the number of bulbs harvested of Crocus ‘Cream Beauty’ and Crocus ‘Remembrance’, Hyacinthus ‘Ostara’, Iris reticulata ‘Harmony’, and Triteleia ‘Queen Fabiola’.
Chemical Removal of Premature, Unwanted Azalea Buds
Authors: Sanderson Kenneth C. , Martin Willis C. , Bruce Reed R.
Published: August 2020

Spray applications of 4.2% Off-Shoot-0 (a mixture of methyl ester of fatty acids C6, C8, C10, and C12) effectively destroyed flower bud scales and flower parts on the azalea (Rhododendron simsii Plachon.) cultivars ‘Prize’ and ‘Kingfisher’. The addition of ethephon to Off-Shoot-0 did not increase the destruction of bud scales and flower parts. Dikegulac-sodium and oxathiin alone or in combination with ethephon did not significantly destroy scales or flower parts. Destructive chemical pinching agents such as dimethyl dodecylamine and n-undecanol usually were as effective as Off-Shoot-0 in killing bud scales but not flower parts. Cultivars differed slightly in their response to chemicals designed to destroy unwanted flower buds.
Growth of Common Bermudagrass as Influenced by Plant Growth Regulators, Soil Type and Nitrogen Fertility
Authors: Devitt D. A. , Morris R. L.
Published: August 2020

An experiment was conducted on common bermudagrass [Cynodon dactylon (L.) Pers.] in the greenhouse using three soil types, four nitrogen(N) levels and three plant growth regulators. Growth response was compared to a control. Cutting biomass, cumulative height, turf color, and evapotranspiration were studied over a 9 week period. Cutless® (flurprimidol) reduced cumulative height by as much as 83% and water consumption by as much as 27%. Embark® (mefluidide) and Limit® (amidochlor) did not provide significant long-term height suppression at any rate or any N level on the three soils. Biomass, cummulative height and color ratings of the bermudagrass were higher on the loam and clay soils compared to the sandy loam soil after growth regulators were applied. Phytotoxicity was observed in the form of leaf tip dieback and discoloration only with Cutless®. Turf discoloration was offset by increased nitrogen levels. However, nitrogen reduced the efficacy of Cutless®. By the ninth week, on the sandy loam soil, color exceeded the acceptable rating for Cutless® only at the 1.5 kg ai/ha (1.34 lb ai/ac) level and 73 kg/halmo (65/lb/ac/mo) nitrogen.
Directed Application of Goal (Oxyfluorfen) to Container Grown Euonymus, to Minimize Phytotoxicity and Leaching
Authors: Horowitz M. , Elmore C.L. , Boquist D.
Published: August 2020

Goal 1.6E (Oxyfluorfen) was applied to rooted cuttings of Euonymus fortunei ‘Colorata’ planted in a U.C. Mix (peat:sand, 1:1 by vol), in 3.8 1 (#1) containers, either as a topical spray or mixed within the growth-medium to 2, 7 or 14 cm (0.8, 2.8, 5.6 in) depth. At comparable rates, phytotoxicity was much lower in layered treatments than when sprayed over-the-top. With an identical concentration of Goal in the growth medium, there was no difference in phytotoxicity between a shallow top layer, exposing all but the base of the root ball to treated soil, and planting the root ball into an entire container profile of treated soil. Incorporation slightly reduced the herbicidal activity—as assessed by oversown grass weeds—compared to surface application. The presence of herbicide in the effluent, collected under the containers, was determined 1 and 8 weeks after the application, by bioassay based on germinating bentgrass. In the first bioassay, no appreciable amount of Goal was detected from surface sprays up to 3 kg/ha (2.75 lb/A), nor from 2 and 7 cm (0.8, 2.8 in) layers containing up to 19 mg/kg (17 lb/A). In the second bioassay, no herbicide was detected from shallow layers containing up to 192 mg/kg (172 lb/A). Goal at 19 mg/kg incorporated 2 to 7 cm (0.8, 2.8 in) deep, at planting time, is suggested as an alternative to overall application on containers.