bluuebunny/crossref_metadata_2025 huggingface dataset:
Nontarget Losses of Granular Herbicide Applied to Container-grown Landscape Plants
Authors: Porter Wayne C. , Parish Richard L.
Published: August 2020

Nontarget losses of granular material applied over widely spaced containers were reduced from 87% with a broadcast rotary applicator to 72–86% with a drop-type spreader and to 48–75% with a drop spreader modified to band apply the material. Plant species and container spacing configuration had a significant effect on material loss. With a drop spreader, losses ranged from a low of 10% with pot-to-pot spaced juniper to 86% with liriope on 30-cm centers. With a pot-to-pot hexagonal configuration, the losses varied from 10.2% with juniper to 19.9% with liriope. With a pot-to-pot square configuration, the losses varied from 15.1% with azalea to 31% with liriope. There were no significant differences in loss with the wide-spaced configuration with respect to plant species.
Chemically Induced Branching of Vinca minor
Authors: Foley James T. , Keever Gary J.
Published: August 2020

Application of Pro-Shear (BA), Accel (PBA), Promalin (BA + GA4+7) or Atrimmec (dikegulac) was tested for its ability to induce branching of Vinca minor L. ‘Alba.’ In the first experiment, plants receiving a single foliar spray of 62.5, 125 or 250 ppm Pro-Shear or Accel; 125, 250 or 500 ppm Promalin; or 1000, 2000 or 3000 ppm Atrimmec were compared to controls. Promalin at 250 or 500 ppm resulted in more runners throughout the experimental period. Atrimmec initially suppressed runner development, but treated plants had more runners 8 and 10 weeks after treatment. Application of Pro-Shear or Accel did not affect the development of runners. In a second experiment, foliar sprays of 250,500 or 1000 ppm Promalin or Atrimmec applied 7 weeks apart were compared to controls. Application of Promalin increased primary and secondary runner numbers and secondary runner lengths. Atrimmec at the higher rates increased primary runner numbers 16 weeks after initial treatment but rate had no effect on numbers or lengths of secondary runners.
Potential for Integration of Chemical and Natural Enemy Suppression of Azalea Lace Bug (Heteroptera: Tingidae)
Authors: Balsdon Julie A. , Braman S. Kristine , Pendley Andrew F. , Espelie Karl E.
Published: August 2020

Efficacies of nine insecticides were compared for suppression of azalea lace bug (ALB) and effect on natural enemies. Examination of leaf samples collected weekly revealed reduced ALB populations in all treatments while six of the tested products required multiple applications for effective control. Acephate was the most cost effective treatment. Emergence of Anagrus takeyanus, an egg parasitoid of ALB, was observed in all treatments and increased during the study period.
Herbicide Use During Propagation Affects Root Initiation and Development
Authors: Gilliam Charles H. , Eakes D. Joseph , Olive John W.
Published: August 2020

Two studies were conducted to evaluate the influence of herbicides on root initiation and development from stem cuttings of three woody landscape species. In the first experiment, Rhododendron obtusum ‘Hino Crimson’ rooting percentage was suppressed with Rout 3G (oxyfluorfen + oryzalin). Both root quality ratings and root lengths were lower for stem cuttings when herbicides were applied compared to untreated controls. Rooting percentages of Rhododendron × ‘Trouper’ and Gardenia jasminoides ‘August Beauty’ were not affected by herbicide application. Root quality ratings and root lengths were generally lower with Rout 3G, OH-2 3G (oxyfluorfen + pendimethlin), Snapshot 2.5TG (trifluralin + isoxaben), and Southern Weed Grass Control 2.68G (pendimethlin) when compared to untreated controls. In the second experiment, depth of sticking Gardenia jasminoides ‘August Beauty’ cuttings and herbicide treatments were evaluated. Cuttings in Rout 3G and Snapshot 2.5 TG treatments had improved root quality ratings when stuck to a depth of 2.5 cm (1.0 in) compared to 1.3 cm (0.5 in); however, all other herbicide treatments had similar root quality ratings to the untreated controls, regardless of depth of sticking.
Host Plant Suitability of the Orangestriped Oakworm (Lepidoptera: Saturniidae)
Authors: Coffelt Mark A. , Schultz Peter B.
Published: August 2020

Orangestriped oakworm, Anisota senatoria (J. E. Smith), suitability for oak (Quercus sp.) was determined by tree defoliation, percentage survival, developmental rate, pupal weight and oviposition. Suitable hosts, from the greatest to the least, were determined for the following oak species grown in southeastern Virginia: pin oak (Quercus palustris), scarlet oak (Q. coccinea), willow oak (Q. phellos), northern red oak (Q. rubra borealis), and sawtooth oak (Q. acutissima); intermediate in swamp white oak (Q. bicolor), chestnut oak (Q. prinus), southern red oak (Q. falcata), bur oak (Q. macrocarpa), and water oak (Q. nigra); and least in white oak (Q. alba), Planting less suitable species in the urban landscape, like white oak (Q. alba), may contribute to lower A. senatoria populations.
Changes in Physical and Chemical Properties of a Loamy Sand Soil When Amended With Composted Poultry Litter
Authors: Warren Stuart L. , Fonteno William C.
Published: August 2020

The objective of this study was to determine the effects of composted poultry litter (CPL) on the physical and chemical properties of a loamy sand soil. To accomplish this, a loamy sand soil, amended with 0, 10, 20, 30, 40 and 50% by volume with CPL, was placed in 3.8-liter (#1) container for 13 weeks. Substrate pH increased with increasing rates of CPL. For most landscape plants, pH was in the recommended range (5.5 ≤ pH ≤ 6.5) at 10% to 30% CPL incorporation. Cation exchange capacity, available P, exchangeable K, Ca, and Mg increased linearly with increasing rates of CPL. The 20% amendment rate raised the available P, exchangeable K, Ca, and Mg to levels within the recommended range for landscape plants (N.C. Dept, of Agr.). Total porosity and unavailable water increased linearly with increasing rate of CPL amendment from 42% to 55.5% and 4% to 30.2%, respectively. Bulk density decreased linearly with increasing CPL concentration. Water content and available water capacity increased with increasing CPL rates. CPL amended soil had a 100% to 116% increase in available water capacity, compared to unamended soil. Amending soil with CPL reduced air space 3% to 36% with the largest decrease occurring between 20% and 30% CPL. This data supports the use of composted poultry litter to improve the chemical and physical properties of a loamy sand soil.
Effect of Copper-Treated Containers on Transplant Survival and Regrowth of Four Tree Species
Authors: Struve Daniel K.
Published: August 2020

Northern red oak (Quercus rubra L.), scarlet oak (Q. coccinea Muenchh.), sweetgum (Liquidambar styraciflura L.), and ‘Autumn Flame’ red maple (Acer rubrum L.) liners were produced in copper-treated (100 gm Cu(OH)2/1 white latex paint) or untreated black plastic 3.8 1 containers (Lerio C-700) in 1989. In spring 1990, liners were transplanted into field plots. Half the liners produced in untreated containers were root pruned just before transplanting, half were not. Liners grown in copper-treated containers were not root pruned before transplanting. Survival percentage was high for all species ranging from 92% for red maple to 65% for scarlet oak. Three years after transplanting, red and scarlet oak liners produced in copper-treated containers had higher survival rates (but not statistically significant) and greater regrowth (taller, greater trunk caliper and percent central leader formation) than liners produced in untreated containers, whether root pruned or not before transplanting. Regrowth of red maple and sweetgum were not affected by container type used during liner production. The study demonstrates species differences to transplanting; each species responds to transplant via a unique combination of growth characteristics. Transplant responses are expressed up to three years after transplanting.
Cold Hardiness Estimates of Woody Taxa From Cultivated and Wild Collections
Authors: Dirr Michael A. , Lindstrom Orville M. , Lewandowski Rick , Vehr Matthew J.
Published: August 2020

Twenty woody taxa from cultivated and wild collections were laboratory tested for midwinter and/or late winter cold hardiness using leaf and/or stem tissue. Potential introductions from Acer rubrum, Cedrus libani, Gardenia jasminoides, and Osmanthus americanus were more cold hardy than their species zone ratings. ‘Alice’ and ‘Alison’ oakleaf hydrangea, Hydrangea quercifolia, and three clones of Osmanthus americanus, although similar in ornamental characteristics, showed large differences in cold hardiness. Clones of Cornus florida and C. mas from Spring Grove, Cincinnati, Ohio, were cold hardy to at least−30°C (−22°F) in January. Wild-collected Camellia japonica, Staphylea bumalda and Styrax obassia from Korea were at least one zone hardier than typical for the species.
Importance of Red Oak Mother Tree to Nursery Productivity
Authors: Struve Daniel K. , McKeand Steven E.
Published: August 2020

Acorns from 19 red oak (Quercus rubra L.) trees were collected in fall 1988. Whips were produced in 1989 and field planted in 1990. Mother tree identity was maintained throughout the study. Growth during the whip production phase was rapid; the average height growth for the 19 families was 122 cm (approximately 4 ft). The best family averaged 167 cm (5.5 ft), the worst 73 cm (2.5 ft) with average individual whip values of $11.20 and $2.80, respectively. When transplanted to nursery fields, the whips had high survival and rapid growth rates. Average individual tree value at the end of three growing seasons ranged from $38.60 to $11.20 for families 6 and 12, respectively. All the traits measured in this study: height, caliper, % acceptable and individual tree value, have relatively high heritability estimates, indicating that traits are under genetic control and thus subject to manipulation by nursery mangers and breeders. The family that produced the highest value whips, did not produce the highest value finish stock. Average finish stock value for a family was determined more by the percentage of the acceptable trees (a measure of quality), than by plant height or caliper (measures of growth).
Effects of Contrasting Climate and Paclobutrazol on the Growth and Water Use of Two Container-Grown Landscape Plants
Authors: Ruter John M. , Martin Chris A.
Published: August 2020

A study was conducted under contrasting climates [southwestern Georgia (humid, temperate) and central Arizona (arid, Sonoran desert)] to evaluate the effects of paclobutrazol on the growth and water use of container-grown Feijoa Sellowiana O. Berg and Ligustrum japonicum Thunb. Plants grown in Georgia were taller, had approximately twice as many leaves and five times more canopy leaf area, a lower shoot:root ratio, and generally higher water use compared to plants grown in Arizona. Differences in meteorological factors such as higher maximum and minimum temperatures and increased solar radiation in Arizona compared to Georgia were coincident with smaller plant size and lower water use of plants grown in Arizona compared to those grown in Georgia. Paclobutrazol inhibited height growth of plants grown in Arizona; however, this growth inhibition was not affected by application concentration. In Georgia, paclobutrazol inhibited height growth of all plants; however, Ligustrum treated with 250 ppm paclobutrazol appeared to begin to overcome growth suppression after five months. Paclobutrazol reduced canopy leaf area and water use for all plants except for Arizona Feijoa.
Seasonal Cold Hardiness Differences of Three Woody Plant Taxa during the Production Stage and as Established Landscape Plants
Authors: Lindstrom Orville M. , Dirr Michael A.
Published: August 2020

Seasonal cold hardiness levels of Crape myrtle (Lagerstroemia L. ‘Natchez’), Leyland cypress [× Cupressocyparis leylandii (A.B. Jacks. and Dallim.) Dallim. and A.B. Jacks.] ‘Haggerston Gray’ and Lacebark elm (Ulmus parvifolia Jacq. Allee™) were determined for nursery production and established landscape plants grown at the same location. Differences in cold hardiness between the growth treatments were taxon specific. During October, November and December, nursery-grown crape myrtle plants were up to 11°C (20°F) less cold hardy than those established in the landscape. Differences in Leyland cypress cold hardiness were detected, but were not as great as in crape myrtle. During October, November and December newly transplanted Leyland cypresses were from 3 to 6°C (5 to 11°F) less cold hardy compared to established landscape plants. Differences occurred between nursery production and established landscape plants of lacebark elm in January and February.
Establishment of White Oak Seedlings with Three Post-Plant Handling Methods on Deep-Tilled Minesoil during Reclamation
Authors: Kjelgren Roger , Cleveland Brenda , Foutch Mike
Published: August 2020

Three methods to improve first-year establishment of bare-root white oak on compacted minesoil during reclamation were investigated. We applied tree-shelter, hydrophilic-polymer, and nitrogen-fertilization treatments to seedlings planted on deep- and untilled soil. Predawn and midday water potential, and midday stomatal conductance (gs) were measured in early, mid, and late season. Leaf area, trunk diameter growth, and survival were measured in early fall. Single-row deep tillage loosened the soil to 0.7 m (2.3 ft), but outward from the midrow the effect dissipated rapidly. Water stress increased in all treatments during an extended mid-summer dry period. Deep tillage resulted in higher initial gs but differences in water stress between tillage treatments were not sustained during the dry period. Trees in shelters, however, were able to delay water stress longer than those in the other handling treatments. While there were no differences in trunk diameter growth among all treatments, trees on deep-tilled soil had greater leaf area and survival than those on unfilled soil. Among handling treatments, only trees in shelters had leaf area and survival significantly greater than the control. Both deep tillage and shelters contributed to improved survival, and the greatest effect occurred with shelters on deep-tilled soil.
Row Cover Management of Field-Grown Cercis canadensis and Lagerstroemia (indica x fauriei) ‘Muskogee’
Authors: Newman Steven E. , Baldridge Leila P.
Published: August 2020

Field-grown Cercis canadensis and Lagerstroemia (indica x fauriei) ‘Muskogee’ with or without trickle irrigation and three row cover management systems, including a summer leguminous cover crop, pine bark mulch or bare cultivation, were evaluated. Cercis plants grown with lespedeza clover as a row cover had less plant growth than those bare cultivated or mulched with pine bark, even with supplemental irrigation. Mulched plots exhibited higher stomatal conductance rates attributable to high canopy temperatures. Lagerstroemia plants with no cover grew as well as those with a cover of mulch or clover, when sufficient water was available from either rainfall or irrigation. Clover interplantings decreased the height and number of branches in Lagerstroemia without supplemental irrigation, but did not affect the water relations significantly.
Choice of Nursery-Appropriate Marketing Channels in the Landscape Plant Industry
Authors: Hinson Roger A. , Turner Steven C.
Published: August 2020

Producers of landscape plants utilize different marketing channels based on various factors including the age, size, region, and corporate status of firm, number of trading methods used, competitive pressures, and negotiating attitudes. This study identified significant influences on market channel choice as negotiation propensity, use of various transaction methods, competitive pressures, and the region of the country where the nursery was located. These results lend support and empirical evidence to the hypothesis that marketing channel choice is influenced by trading attitudes and styles as well as economics.
Preemergence Herbicide Evaluations on Selected Spring and Summer Flowering Bulbs and Perennials
Authors: Skroch W.A. , Catanzaro C.J. , De Hertogh A.A. , Gallitano L. B.
Published: August 2020

Nine species of field-grown flowering bulbs and perennials were screened for tolerance to the preemergence herbicide products Dacthal (DCPA), Gallery (isoxaben), Pennant (metolachlor), PRE-M (pendimethalin), Stakeout (dithiopyr), Derby (metolachlor + simazine) and Snapshot (isoxaben + oryzalin). Herbicides were applied at recommended rates three to five times over two to three years. No detrimental effects on growth, development or flowering were observed. Most products controlled large crabgrass, horseweed and prostrate spurge. However, control of crabgrass and spurge was poor with Gallery at 0.84 kg ai/ha, and control of horseweed and spurge was poor with Dacthal.
Influence of Dates and Frequency of Drive Treatments On Large Crabgrass Control in Tall Fescue Turf
Authors: Johnson B. Jack
Published: August 2020

When postemergence (POST) herbicides are used to control large crabgrass [Digitaria sanguinalis (L.) Scop.] in turfgrasses, it is desirable to maintain a high level of control with minimum number of applications. A field experiment was conducted during 1992 and 1993 to determine the influence of timing and frequency of applications with Drive (quinclorac) on large crabgrass control in tall fescue (Festuca arundinacea Schreb.) turf. Drive (quinclorac) applied as a single application at 0.84 kg/ha (0.75 lb/A) on June 11 controlled 98% large crabgrass throughout the summer in tall fescue turf. The control was consistently higher than when the herbicide was applied earlier (April 12 or May 3) at the same rate. There was no increase in large crabgrass control with multiple Drive (quinclorac) applications, when compared to a single application made on June 11. Drive (quinclorac) applied on June 11 caused a maximum of 35% injury to tall fescue in 1992, but the turfgrass recovered to an acceptable level (<20%) within one week. Maximum turfgrass injury was only 13% when the herbicide was applied at the same date in 1993. Tall fescue treated with multiple applications of Drive (quinclorac) was injured similarly to that reported from a single application, but the turfgrass required a longer recovery period.
Propagation of Maackia amurensis Rupr. & Maxim, by Softwood Cuttings
Authors: McNamara Steve , Graves William R. , Pellett Harold
Published: August 2020

Softwood terminal stem cuttings were collected at two developmental stages from twenty mature trees of Amur maackia (Maackia amurensis Rupr. and Maxim) growing in Minnesota, Maryland, and Washington DC. Cuttings were treated with either 0 or 2500 ppm (0.25%) of a potassium salt formulation of indole-3-butyric acid (K-IBA) and stuck under intermittent mist with bottom-heat. Cuttings were evaluated for rooting after 12 weeks. Cutting collection date did not affect rooting of most genotypes. Treatment with K-IBA nominally improved root rating scores and root numbers. All trees exhibited the capacity for rooting with individual rooting percentages ranging from 19% to 92%. Based upon mean visual ratings, cuttings from 14 of the 20 trees produced root systems of acceptable quality. These findings indicate that mature Maackia amurensis trees can be propagated by softwood cuttings, but refinement of the rooting protocol may be required to achieve acceptable levels of rooting for some genotypes.
Seed Germination of Three Provenances of Rhododendron catawbiense: Influence of Light and Temperature
Authors: Rowe D. Bradley , Blazich Frank A. , Warren Stuart L. , Ranney Thomas G.
Published: August 2020

Seeds of three provenances of Rhododendron catawbiense Michx. (Catawba rhododendron) were collected during Fall 1992 from the following localities in the southeastern United States: Cherokee Co., GA [34°20′N, 84°23′W, elev. = 320 m (1050 ft)], Johnston Co., NC [35°45′N, 78°12′W, elev. = 67 m (220 ft)], and Yancey Co., NC [35°45′N, 82°16′W, elev. = 1954 m (6410 ft)]. Following drying for 1 month and storage at 4°C (39°F), seeds were removed from storage in January 1993 and germinated at 25°C (77°F) or an 8/16 hr thermoperiod of 25°/15°C (77°/59°F) with daily photoperiods of 0, ½, 1, 2, 4, 8, 12, or 24 hr. Regardless of temperature and provenance, seeds required light for germination. Negligible germination for all provenances in total darkness was overcome by daily photoperiods as short as ½ hr. All provenances commenced germination earlier at 25°C (77°F) than at 25°/15°C (77°/59°F). Mean germination at day 24 for both temperature treatments and for all photoperiods with the exception of total darkness was 98%, 90%, and 80% for the Yancey, Johnston, and Cherokee Co. provenances respectively. Light and temperature requirements for seed germination of all provenances were similar, although seeds of the higher elevation, Yancey Co. provenance exhibited greater vigor; they germinated at a faster rate with greater cumulative germination.
Ornamental Grasses For Minnesota
Authors: Meyer M. Hockenberry , White D. B. , Pellett H.
Published: August 2020

One hundred and sixty-five (165) species and cultivars of ornamental grasses and grass-like plants were investigated to determine winter survival in USDA Zone 4a from 1987 to 1993 at the Minnesota Landscape Arboretum, Chanhassen, MN. Eighty-five (85) entries survived and performed well all six years and are considered hardy under the conditions of the experiment. Additionally, 35 entries survived four or five of the six years and are considered marginally hardy. The remaining 45 entries survived no more than two winters and are not hardy in zone 4a. Hardiness varied within species of Miscanthus sinensis Anderss. and Pennisetum alopecuroides (L.) Spreng..Saccharum ravennae (L.) Murray, synonym (Erianthus ravennae); Imperata cylindrica L. ‘Red Baron’; and Chasmanthium latifolium (Mic.)Yat. were not considered hardy. Some popular genera such as Calamagrostis, Deschampsia, Molinia, and Spodiopogon were reliably hardy throughout the years of the investigation.
Early Lifting and Transplanting of Flowering Dogwood Seedlings Increases Survival in the Southern United States
Authors: Ruter J.M. , Garber M.P. , Moorhead D.J.
Published: August 2020

Effects of lift date and photoperiod on budbreak and survival of 1-0 flowering dogwood (Comus florida L.) seedlings were studied under greenhouse conditions while survival was evaluated on plants transplanted in field plots. Seedlings were lifted from field beds on October 3, 1990; October 31, 1990; November 28, 1990; December 18, 1990; and February 5, 1991 (0, 63, 192, 357, and 851 chill hours, respectively (<7°C, 45°F)) and were placed in photoperiod chambers (10, 12, and 14 hr) constructed in a greenhouse or planted in the field under natural conditions. Increasing photoperiod under greenhouse conditions decreased the number of days to budbreak across lift dates. Photoperiod had no effect of survival. Survival of greenhouse plants was greater than 85% for all but the February lift date (72%). Survival of plants in the field decreased to 50% for the December lift date compared to >90% for both October lift dates. Mean survival across lift dates for the greenhouse and field plants were 88% and 77%, respectively. No differences in shoot growth or root regeneration were seen between treatments for greenhouse-grown plants. Results of these studies suggest that bareroot seedlings of flowering dogwood should be lifted and planted in the fall for optimal survival in the warmer areas of the southern United States.
Mid-Season Reapplication of Controlled Release Fertilizers Affect ‘Helleri’ Holly Growth and N Content of Substrate Solution and Effluent
Authors: Shiflett Melinda C. , Niemiera Alex X. , Leda Carol E.
Published: August 2020

The objective of this study was to determine how a mid-season CRF (controlled release fertilizer) reapplication to container-grown Ilex crenata ‘Helleri’ Thunb. affected growth, substrate solution N content, and the amount on N leached compared to a single early season CRF application (control). ‘Helleri’ holly liners were initially fertilized (March 7) with an 8 to 9 month CRF, Osmocote 18N-2.6P-9.9K (18-6-12), or a 12 to 14 month CRF, Osmocote 17N-3.1P-9.9K (17-7-12). A subset of plants received a CRF reapplication (half rate) of the respective Osmocote formulation on July 19, August 2, or August 16. In addition, 12 plants received a water soluble fertilizer solution (WSF) with each irrigation starting on July 19. All effluent was collected and analyzed for N. Substrate solution N and electrical conductivity (EC) levels (via the pour-through method) and foliar N concentrations were determined every two weeks. Throughout the experiment, plants were irrigated with an irrigation amount that resulted in an ≈ 0.25 leaching fraction (LF). Plant width was determined on November 1. Plant width values were higher for the first and second reapplication and WSF treatments for both formulations than the control. However, in terms of commercial size grades, plants of all treatments were in the same grade. Thus, there was no economic advantage to reapplying CRF. We concluded that CRF reapplication was not necessary when substrate solution N and foliar N values were ≥ 20 mg N/liter and ≥ 2.3%, respectively. Irrigating at a LF of 0.2, the mid-season CRF application increased the amount of N lost from containers by 42% compared to a single, early season CRF application.
Nitrogen Nutrition of Containerized Cryptomeria japonica ‘Elegans Aurea’
Authors: Jull Laura G. , Warren Stuart L. , Blazich Frank A.
Published: August 2020

Containerized, rooted stem cuttings of ‘Elegans Aurea’ Japanese cedar [Cryptomeria japonica (L.f.) D. Don ‘Elegans Aurea’] grown in calcined clay, were fertilized three times weekly for 14 weeks with a complete nutrient solution containing 0, 25, 50, 100, or 200 mg N/liter supplied as ammonium nitrate. Top and root dry weights were not affected by N rate suggesting that 25 mg N/liter was adequate for maximizing growth. Nitrogen fertilization increased top and root dry weights by 149% and 20%, respectively, compared to the nontreated controls (0 mg N/liter). As N concentrations increased, root area and total root length decreased linearly. Nitrogen fertilization decreased root:top ratio by 50% compared to the nontreated controls. However, the root:top ratio was not affected by N rate. Percent top N concentration was increased by N compared to the nontreated control. Percent top K, Ca, and Mg decreased linearly with increasing N rates. There was a quadratic response in percent top P with a maximum at 50 mg N/liter.
Cold Hardiness of Landscape Pear Taxa
Authors: McNamara Steve , Pellett Harold
Published: August 2020

The cold hardiness of ten landscape pear cultivars and two pear species was evaluated in container- and field-grown plants during the dormant periods of 1991 through 1994. Timing and extent of acclimation by containerized plants overwintered in a temperature-moderated greenhouse was similar to that of plants growing in the field, indicating that containerized stock can be used for determining the hardiness of taxa lacking sufficient hardiness to survive outdoors in USDA Zone 4a. Among P. calleryana cultivars, ‘Autumn Blaze’ exhibited the best overall cold tolerance and greatest mid-winter hardiness [−34°C (−29°F)]. ‘Bradford’ was consistently the least hardy P. calleryana cultivar. All P. calleryana cultivars acclimated too slowly in the fall and or lacked sufficient mid-winter to survive in USDA Hardiness Zone 4a. Both P. salicifolia ‘Silver Frost’ and P. fauriei were hardier than the P. Calleryana cultivars on most sampling dates. P. ussuriensis was the hardiest taxon on all sampling dates and withstood −42°C (−44°F) by mid-December 1992. In field trials, only ‘Silver Frost’, P. fauriei, and P. ussuriensis survived exposure to −36°C (−32°F) in January of 1994.
Preference for and Suitability of Selected Elms, Ulmus spp. and Their Hybrids for the Elm Leaf Beetle, (Pyrrhalta luteola Coleoptera: Chrysomelidae)
Authors: Miller Fredric , Ware George
Published: August 2020

Selected elms Ulmus spp. and their hybrids growing at the Morton Arboretum, Lisle, IL were evaluated in the laboratory for feeding preference by the elm leaf beetle, Pyrrhalta luteola (Muller). Results from the single-choice and multiple-choice feeding studies showed that U. szechuanica was the least suitable for feeding and reproduction by the adult elm leaf beetle. The hybrids U. pumila x U. parvifolia and U. pumila x U. americana, and U. pumila (control) appeared to be highly suitable for feeding and reproduction by the adult elm leaf beetle. Adult longevity and the pre-ovipositional period appeared to be a function of suitability as adults feeding on U. szechuanica had the shortest longevity and the longest pre-ovipositional period. The converse was also true. Results from multiple-choice studies were consistent with the single-choice studies. The intermediately suitable species/hybrids of U. japonicawilsoniana x U. pumila, U. Japonica, U. macrocarpa, and U. wilsoniana show promise for further elm breeding programs. Further studies are needed to evaluate hybrid crosses of the intermediately and least preferred elms as potential sources of shade trees resistant to Dutch elm disease and not preferred by the elm leaf beetle.
Evaluation of Selected Herbicides on Field-Grown Woody Ornamentals
Authors: Reeder Jesse A. , Gilliam Charles H. , Wehtje Glenn R. , South David B. , Keever Gary J.
Published: August 2020

Six herbicides and selected combinations were evaluated on four field-grown woody landscape crops: live oak, ‘Mary Nell’ holly, ‘Chesapeake’ viburnum, and ‘Acoma’ crapemyrtle. All herbicide treatments provided excellent control of goosegrass (Eleusine indica (L.) Gaertn.). Treatments with Predict (norflurazon) provided adequate sicklepod (Cassia obtusifolia L.) control. Only Goal (oxyfluorfen)-containing treatments controlled cutleaf eveningprimrose (Oenothera laciniata Hill). Predict and Predict treatment-combinations bleached older foliage of crapemyrtle and viburnum when applied in the first year after planting; however, growth was not affected. Holly was not injured by any herbicide treatments. Pendulum (pendamethalin) and Surflan (oryzalin) had similar weed control activity and plant growth with no plant injury
Offset Stage of Development Affects Hosta Propagation by Stem Cuttings
Authors: Keever G.J. , Eakes D.J. , Gilliam C.H.
Published: August 2020

Offset stem cuttings of Hosta sieboldiana at different stages of development (SOD) were removed from mother plants previously treated with BA; half of the cuttings at each SOD were treated with 1000 ppm IBA prior to placing under intermittent mist. Rooting percentages, primary and secondary root counts, root lengths, root rating, root dry weights, and final shoot SOD were greater for cuttings removed at a more advanced SOD. Rooting was greater than 85% for cuttings with 3 unfurled leaves, the most advanced SOD in this study. Treatment of cuttings with IBA increased primary root counts by 35%, but did not affect other measured characteristics.
Influence of Inoculant Form and Applied Nitrogen on Growth and Root Nodulation of Maackia amurensis
Authors: Giridhar J. , Pai B. , Graves William R.
Published: August 2020

We studied growth and nodulation of Maackia amurensis Rupr. & Maxim, treated with three forms of an inoculant of Bradyrhizobium (USDA 4349) and irrigated with solutions containing N at 1.8, 3.6, 7.2, or 14.3 mol·m−3(25, 50, 100, or 200 ppm). One inoculant (arabinose-gluconate liquid) was prepared in our laboratory, whereas the other two (Cell-Tech liquid and Cell-Tech peat powder) were obtained from a commercial source. Nodule dry mass of 10-week-old seedlings was similar regardless of inoculant form. Only plants supplied N at 1.8 and 3.6 mol·m−3 (25 and 50 ppm) nodulated consistently, and nodule dry mass of plants in these two treatments was not different. Laminar area and plant dry mass were highest among plants provided the two highest concentrations of N. Shoot N content was lowest and highest for plants provided N at 3.6 mol·m−3 (50 ppm) and 14.3 mol·m−3 (200 ppm), respectively, and it was not affected by form of inoculant. We conclude that liquid and peat-based inoculants cause a similar degree of nodulation. This study also demonstrated that providing N at concentrations of 7.2 mol·m−3 (100 ppm) or higher inhibits nodulation, and that inoculation with USDA 4349 does not substitute for applied N if maximal early seedling growth is desired.
Stimulation of Basal and Axillary Bud Formation of Container-grown Hybrid Tea Roses
Authors: Jayroe-Cournoyer Linda , Newman Steven E.
Published: August 2020

Two plant growth regulators, 6-benzylaminopurine (BA) and sodium salt of 2,3,4,6-bis-O-(1-methylethylidene)-a-L-xylo-2-hexulofuranosonic acid [dikegulac-sodium (DS)], were applied separately to container-grown two-year-old hybrid tea rose cultivars ‘Honor’, ‘Peace’, ‘Tournament of Roses’, ‘Touch of Class’, and ‘Prima Donna’ to study the effects on basal and axillary shoot production. Four rates of BA (0,75,125 and 250 ppm) or DS (0,250,500 and 1000 ppm) were applied as drenching sprays to the graft union or with floral foam applied basally or to the top of a cut cane. ‘Tournament of Roses’ had the greatest number of basal shoots when BA was applied at 75 ppm to a cut cane with a floral cube. ‘Peace’ and ‘Prima Donna’ had the greatest number of basal shoots when BA was applied at 250 ppm to a cut cane with a floral cube. Axillary shoots increased on ‘Honor’ when BA was applied as a basal floral foam. DS increased axillary shoots for ‘Peace’ only when applied as a drenching spray to the bud union. Otherwise, DS did not increase basal shoots for any other cultivar regardless of application method and rate. Neither chemical nor application method consistently promoted basal and axillary shoots in all five cultivars.
Frequency of Drive (Quinclorac) Treatments on Common Bermudagrass Tolerance and on Large Crabgrass Control
Authors: Jack Johnson B.
Published: August 2020

When a postemergence (POST) herbicide is used to control large crabgrass [Digitaria sanguinalis (L.) Scop.] in common bermudagrass [Cynodon dactylon (L.) Pers.], the herbicide should maintain optimum weed control for 8 to 10 weeks without causing undesirable injury to the turfgrass. A field experiment was conducted during 1993 and 1994 to determine the lowest rate of Drive (quinclorac) needed to control large crabgrass without causing undesirable injury to bermudagrass turf. Drive (quinclorac) applied at 0.28 kg ai/ha (0.25 lb ai/A) initially in early May and repeated at the same rate at a 2-week interval, controlled 85% large crabgrass for 16 weeks in 1993 and 70% for 10 weeks in 1994. The control in 1994 was 96% for 17 weeks when the herbicide was applied at 0.28 kg ai/ha (0.25 lb ai/A) in each of three applications on May 2, May 29, and June 13. The maximum bermudagrass injury in 1993 from Drive (quinclorac) applied at 0.28 kg ai/ha (0.25 lb ai/A) in each of two applications at 2- to 4-week interval was ≤ 27% compared to ≥ 33% when ≥ 0.56 kg ai/ha (≥ 0.5 lb ai/A) was applied as a single application. Bermudagrass treated initially with Drive (quinclorac) at 0.28 kg ai/ha (0.25 lb ai/A) was injured higher in 1994 (≤ 35%) than in 1993 (≤ 14%). Bermudagrass injury was ≥ 40% when the second application was delayed until mid- to late June either year or when the herbicide was applied in three applications during May and June 1994.
Effect of 2,4-D and Triclopyr on Annual Bedding Plants
Authors: Hatterman-Valenti Harlene , Christians Nick E. , Owen Micheal D.K.
Published: August 2020

Greenhouse trials were conducted to evaluate annual flower response to simulated drift of Weedar 64 (dimethylamine salt of 2,4-D) and Turflon Amine (triethylamine salt of triclopyr). Mature annual flowers responded differently to low concentrations of Weedar 64 and Turflon. The order for species from most sensitive to least sensitive was petunia > begonia = marigold =pansy =statice > geranium =impatiens =rose periwinkle =salvia. Rates less than 128 g ae/ha (0.11 lb ae/A) caused only slight injury. Injury was expressed in reduced flower production and callus. Turflon suppressed flowering 19% more than Weedar 64. Both herbicides reduced flowering at rates greater than 100 g/ha (0.088 lb/A).
Efficacy of Three Nitrogen and Phosphorus Sources in Container-Grown Azalea Production
Authors: Warren Stuart L. , Bilderback Ted E. , Tyler Helen H.
Published: August 2020

Rooted stem cuttings of ‘Sunglow’ azalea (Rhododendron sp. ‘Sunglow’) were potted into 3.8 liter (#1) containers with a pine bark: sand (6:1 by vol) substrate and topdressed with 3.5 g (0.12 oz) N per container with resin-coated NH4 NO3 and P [Osmocote 18N–2.6P–10K (18–6–12)], urea and sulfur-coated P [Woodace 20N–1.8P–9.1K (20–4–11)], or composted turkey litter (CTL) [Sustane 5N–0.9P–3.3K (5–2–4)]. A container-grown plant production area was constructed and subdivided into nine separate plots, 7.6 × 1.8 m (25 × 6 ft), with a 2% slope and lined with black plastic. At 5:00 AM daily, 1.3 cm (0.5 in) of water was applied by overhead irrigation at a rate of 1.6 cm/hr (0.6 in/hr) resulting in a leaching fraction of approximately 0.1 to 0.2. All effluent was collected individually from each plot. At 8:00 AM daily, volume of effluent was measured and sub-sampled for analysis of NO3, NH4, and P. The experiment, a RCB design with 3 replications, was conducted for 100 days. Thirty containers were placed in each plot for a total of 90 containers per treatment. After 100 days, 13%, 12%, and 9% of the N applied was recovered in the effluent from containers fertilized with resin-coated NH4NO3, urea, and CTL, respectively. Of the P applied, 8%, 27%, and 15% was recovered in the effluent with resin-coated P, sulfur-coated P, and CTL, respectively. Resin-coated NH4NO3 and urea produced greater shoot growth and higher shoot N content compared to CTL. Shoot and root P contents were greatest with resin-coated P. Nutrient efficiency defined as grams of nutrient the plantabsorbed divided by total grams of nutrient found in effluent and plant resulted in resin-coated NH4NO3 and urea having the highest N efficiency (56%); while, resin-coated P had the highest P efficiency (43%).
Application of RAPD-PCR Markers for Identification and Genetic Analysis of American Elm (Ulmus americana L.) Selections
Authors: Kamalay Joseph C. , Carey David W.
Published: August 2020

We used randomly amplified polymorphic DNA (RAPD) markers from DNA polymerase chain reactions to differentiate selected American elms. DNA profiles made from leaf DNAs of parental trees were identical to profiles produced by DNA from leaves, roots, vascular tissues, callus or suspension-cultured cells from the same trees or their ramets. In addition, several variations in the technique did not appear to alter the genotype-specific DNA profiles from a given elm selection. RAPD polymorphisms were inherited as dominant Mendelian factors in the progeny of a cross between two American elm selections. We conclude that the construction of RAPD DNA profiles is a reliable and easy method for selection identification, genetic analysis, and the assembly of linkage maps in American elms.
Greenhouse Rose Production in Media Containing Coal Bottom Ash
Authors: Butler Susan H. , Bearce Bradford C.
Published: August 2020

Coal bottom ash was mixed with composted hardwood bark fines in proportions of 3:1, 2:1 and 1:1 (by vol) and with soil and peat in proportions of 1:1:1 (by vol). A mix of soil, sand and peat 1:1:1 (by vol) was used as the control root medium. Rosa × hybrida L. ‘Samantha’ plants were planted and cultured for one year and production indices recorded for four harvests. Flower stem lengths, flower bud diameters, production times, and numbers of flowers produced in media composed of ash and bark were equivalent to those in the control medium. Stem fresh weights of flowers produced in ash:bark media exceeded those in the control during third and fourth harvest. Foliar analysis showed increased B but decreased Mn and Cu in plants grown in the ash:bark media. Values of physical characteristics of all media were within acceptable ranges. Requirements for irrigation and fertilization were higher in the ash:bark media. The coal bottom ash:hardwood bark combinations showed potential as components of artificial root media for growing greenhouse roses.
Controlled Freezing of Twenty-three Container-grown Herbaceous Perennials
Authors: Herrick Todd A. , Perry Leonard P.
Published: August 2020

Twenty-three containerized herbaceous perennials were acclimated to ambient outdoor temperature and photoperiod until November 19, when they were moved into a greenhouse and held at 3C (37F) until February 15. At that time, plants were exposed for 30 minutes to a range of subzero temperatures, and returned to the greenhouse for forcing. Plants were rated for survival and salability following 6 weeks regrowth at 15C (59F), using a subjective scale of 1 to 5 (1 = worst, 5 = best, 3 and above considered salable). Of the 23 perennials studied, 15 survived after exposure to at least-8C (18F), however, 40% of the species and cultivars surviving at this temperature sustained a level of injury which rendered them unsalable. Most plants were rated salable at treatment temperatures 3 to 6 degrees warmer than their respective lowest survival temperatures (LST's). Phlox ‘Chattahoochie’, Phlox ‘Morris Berd’ and Tiarella ‘Laird of Skye’ remained salable after exposure to —11C (12F). Campanula takesimana, Heuchera americana ‘Dales Strain’, Penstemon fruticosus ‘Purple Haze’, Rosmarinus officinalis ‘Arp’, Tiarella ‘Running Tapestry’, and Tiarella cordifolia ‘Slick Rock’ remained salable after exposure to-8C (18F). Erodium reichardii ‘Roseum’, Hebe macrocarpa ‘Margaret’, and Verbena ‘Homestead Purple’ remained salable after exposure to-5C (23F). Only the unfrozen controls of Houttuynia cordata ‘Chameleon’ and Thelypteris kunthii remained salable. Treatment means for Ceratostigma plumbaginoides were not significantly different and all 6 Hibiscus cultivars (‘Blue River II’, ‘Disco Belle Pink’, ‘Disco Belle Rose Red’, ‘Disco Belle White’, ‘Lord Baltimore’ and ‘Southern Belle’) failed to survive any of the temperature treatments. In general, plants showed a gradual decline in salability with decreasing temperatures.
Generation and Identification of New Viburnum Hybrids
Authors: Hoch W.A. , Zeldin E.L. , Nienhuis J. , McCown B.H.
Published: August 2020

The controlled crossing of fragrant flowered viburnums (V. carlesii and its hybrids) with the hardier, rugose foliaged V. lantana is unattainable through traditional breeding methods due to incompatibilities within the developing seed. Hybrid plants from these crosses have now been obtained using embryo rescue techniques. Embryos were removed from developing seed 17 days following pollination and placed on WPM medium to promote continued maturation. Genotypes from two crosses, V. lantana ‘Mohican’ x V. carlesii ‘Aurora’ and V. lantana ‘Mohican’ x V. x juddii, were obtained and verified using RAPD markers. These plants are presently being evaluated for ornamental characteristics and cold hardiness.
Evaluation of Selected Preemergence Herbicides in Field-Grown Landscape Crops in Kentucky
Authors: Setyowati N. , Weston L. A. , McNiel R. E.
Published: August 2020

Research was conducted during 1990 and 1991 at the Horticultural Research Farm in Lexington, Kentucky, to evaluate the efficacy of herbicides available for use on woody landscape plants (simazine and oryzalin), newly labelled herbicides (isoxaben, isoxaben plus oryzalin, metolachlor and metolachlor plus simazine) and those not widely labelled for the nursery industry (oxyfluorfen and dithiopyr). Herbicide phytotoxicity was also evaluated in 10 species of woody nursery crops. Results 6 WAT (weeks after treatment) indicated that the standard of simazine at 1.1 kg ai/ha (1.0 lb/A) plus oryzalin at 3.3 kg ai/ha (3.0 lb/A) provided adequate control of most common broadleaf weeds (98%) and annual grasses (98%) but not yellow nutsedge (31%). Isoxaben plus oryzalin at 4.2 kg ai/ha (4.0 lb/A) (DF formulation) and isoxaben plus trifluralin at 4.2 kg ai/ha (4.0 lb/A) (granular formulation) gave excellent full-season control of nearly all broadleaf and grass weeds with the exception of galinsoga and field bindweed. In addition, yellow nutsedge control was acceptable, ranging from 63 to 96% in these treatments. Isoxaben alone also provided excellent broadleaf control (93%) 6 WAT in 1990 but poorer (<70%) control of giant foxtail, galinsoga and velvetleaf by 12 WAT. Dithiopyr (granular formulation) provided excellent full-season residual control of broadleaf weeds, nutsedge and grasses at the highest rate of 2.2 kg ai/ha (2.0 lb/A). Oxyfluorfen at the higher rate (2.2 kg ai/ha) (2.0 lb/A) also controlled all species except yellow nutsedge. Poor broadleaf control was obtained 12 WAT with 3.3 kg ai/ha (3.0 lb/A) metolachlor or metolachlor plus simazine at rates up to 4.4 kg ai/ha (4.0 lb/A) in both 1990 and 1991. Pronamide at 2.2 kg ai/ha (2.0 lb/A) did not provide adequate control of either broadleaf or grasses at 6 or 12 WAT. No visible phytotoxicity to woody ornamentals was observed in either season up to 8 weeks after application. However, growth reductions were noted in both common lilac and red oak stem or trunk diameter following treatment with isoxaben at 1.1 kg ai/ha (1.0 lb/A).
Evaluation of New Systemic Insecticides for Elm Insect Pest Control
Authors: Sclar D. Casey , Cranshaw Whitney S.
Published: August 2020

Use of systemic insecticides that can be injected either into the root system or trunk of woody plants provides several potential advantages, notably in control of drift during application. Recently, new classes of insecticides with systemic activity have been developed, which may supplant the organophosphate and carbamate systemic insecticides that have previously been available. To evaluate their potential to control insects affecting shade trees, studies were conducted using imidacloprid and abamectin on elm. Soil injections of imidacloprid appeared particularly effective, controlling all three of the target pest species in this study (elm leaf beetle, European elm scale, elm leaf aphid). Both imidacloprid and abamectin also were effective against at least some elm insects when injected into trunks. Persistence of irnidacloprid was unusually long, providing second season control of all elm insect pests, although root uptake following soil injections was slow.
Gas Exchange Rates for Selected Red Maple Cultivars Grown in Alabama
Authors: Sibley Jeff L. , Eakes D. Joseph , Gilliam Charles H. , Keever Gary J. , Dozier William A.
Published: August 2020

The objective of this study was to develop a rapid screening technique to characterize selected red maple (Acer rubrum L.) cultivars based on their gas exchange capacities. Evaluations were conducted in Alabama under ambient conditions on an established, irrigated field trial. In preliminary evaluations 9 red maple cultivars (‘Autumn Flame’, ‘Fairview Flam’, ‘Franksred’, ‘Karpick’, ‘Northwood’, ‘October Glory’, ‘Redskin’, ‘Schlesingeri’, and ‘Tilford’) and 3 Freeman maple (Acer x freemanii E. Murray) selections (‘Autumn Blaze’, ‘Morgan’, and ‘Scarsen’) were observed for differences in net photosynthesis (Pn), transpiration (E), and stomatal conductance (Cs). Based on these results, 4 cultivars of A. rubrum were selected and evaluated intensively over 2 years. Throughout the study, growth rates for the 4 selections failed to correspond with gas exchange observations.