bluuebunny/crossref_metadata_2025 huggingface dataset:
Determining the Microwave Radiations Exposure Level Needed for Weed Control Using a Stationary and Running Belt Microwave Radiations Applicator System1
Authors: Rana Aman , Derr Jeffrey F.
Published: August 2020

There is a demand for nonchemical weed control strategies, with microwave radiations one possible option. Accurately measuring a weed's exposure level to microwave radiations is a challenge when there is a gap between when electricity is applied to the magnetron and actual production of microwave radiations. This gap causes an error in the calculation of actual energy needed for weed management. Any misinterpretation over-estimates the required energy load, adversely affecting the perceived value of the technology. Studies were conducted to eliminate the existing lag period. A running belt prototype was built for this purpose using two magnetrons producing 900 watt each installed on a treadmill with a power supply. There was significant improvement in the precision for calculations of total energy required for weed control. These anatomically diverse weeds showed more uniform thermal injuries and greater control using the running belt prototype system than a stationary unit. The LD50 for broadleaf weeds treated with microwave radiations using the running belt system ranged from 31.2 joules.cm−2 for common ragweed (Ambrosia artemisiifolia L.) to 36.8 joules.cm−2 for pitted morningglory (Ipomoea lacunosa L.). In comparison, treatment of weeds with microwave radiations using the stationary mode system resulted in a range of LD50 values of 64.5 joules.cm−2 for common ragweed to 155.1 joules.cm−2 for white clover (Trifolium repens L.). Similarly, the LD50 values for grasses treated with microwave radiations using the running belt system ranged from 34.3 for dallisgrass (Paspalum dilatatum Poir.) to 69.5 joules.cm−2 for southern crabgrass [Digitaria ciliaris (Retz.) Koeler]); in comparison, the range in LD50 values for grasses treated with stationary system was 136.1 to 182 joules.cm−2. The LD50 values for sedges treated with microwave radiations using the running belt system ranged from 29.2 joules.cm−2 for yellow nutsedge (Cyperus esculentus L.) to 78.1 joules.cm−2 for fragrant flatsedge (Cyperus odoratus L.); in comparison, the range in LD50 values for the stationary mode system was 119.4 joules.cm−2 for fragrant flatsedge to 145.9 joules.cm−2 for yellow nutsedge.

Index words: Nonchemical control, weed control, efficacy, prototype, weed management.
Effects of Tree Production Method and Transplanting on Root Hydraulic Conductance1
Authors: Yin Jingjing , Harper Richard W. , Bassuk Nina L.
Published: August 2020

The objective of this study was to investigate the post-transplant, root specific hydraulic conductance (KS) of two oak species (Quercus bicolor Willd. and Quercus rubra L.). Q. bicolor and Q. rubra trees responded differently to transplanting across the differing types of production methods. Overall, higher post-transplant fine root KS resulted in a larger leaf area after transplanting. Container-grown (CG) trees had the highest root KS immediately after transplanting compared to balled-and-burlapped (BNB), in-ground fabric (IGF), and bare-root (BR) trees, but KS in CG trees was largely reduced at the end of the first growing season after transplanting. Post-transplant variations of fine root KS also differed between the two tree species. Fine root KS remained similar in BNB and IGF Q. bicolor trees after transplanting, but increased with time after transplanting in Q. rubra trees. The increase in KS was especially greater in BNB and BR Q. rubra trees than IGF Q. rubra.

Index words: transplanting, root hydraulic conductance, tree production method, Quercus bicolor, Quercus rubra, oak.

Species used in this study: Swamp white oak (Quercus bicolor Willd.); northern red oak (Quercus rubra L.).
Dimethenamid Persistence and Leaching Potential in a Soilless Mix1
Authors: Robertson Lori , Derr Jeffrey F.
Published: August 2020

Dimethenamid and the granular combination product pendimethalin plus dimethenamid are herbicides registered for use in nursery production and landscape maintenance. The objectives of this study were: (1) to compare the effectiveness of sprayed dimethenamid and the granular combination of pendimethalin plus dimethenamid in container nursery production, (2) to determine the impact of formulation on leaching of dimethenamid in soilless media versus field soil and (3) to determine the influence of irrigation volume on herbicide leaching. Dimethenamid is less mobile in pine bark than field soil, while pendimethalin is more mobile in pine bark. The leaching profile for the granular pendimethalin plus dimethenamid combination product was similar to dimethenamid in field soil and similar to pendimethalin in pine bark. There was no significant difference in herbicide movement in pine bark or field soil after doubling the irrigation volume from 17.8 cm (7 in) to 35.6 cm (14 in). Compared to pendimethalin, dimethenamid leaches less in pine bark, explaining its greater effectiveness for weed control in container production.

Index words: Herbicide leaching, soilless mix, pine bark, ornamentals, adsorption.

Species used in this study: southern crabgrass [Digitaria ciliaris (Retz.) Koel.]; spotted spurge [Chamaesyce maculata (L.) Small].

Chemicals used in this study: dimethenamid (Tower); dimethenamid plus pendimethalin (FreeHand); pendimethalin (Pendulum 2G).
Shallow Substrates Support the Growth of Contrasting Plant Types Installed in Irrigated, Arid-Climate Green Roofs1
Authors: Forrest Lauren , Gioannini Rachel , VanLeeuwen Dawn M. , Hilaire Rolston St.
Published: August 2020

Extreme evaporative demand makes substrate depth a critical design factor in arid-climate green roofs. The objective of this study was to determine whether a shallow irrigated substrate could support the growth of hens and chicks (Sempervivum calcareum L.) and iceplant [Delosperma nubigenum (Hook.f.) L.Bolus] in an arid environment. First, an experiment was conducted in the greenhouse that established that plants survived in 10 cm (3.9 in), 15 cm (5.9 in), and 20 cm (7.9 in) substrate depths, which then lead to a second experiment in an outdoor environment. The substrate was heat-expanded clay:sand:worm castings (6:3:1, by volume) in a greenhouse experiment and heat-expanded clay:zeolite:worm castings (6:3:1, by volume) in an outdoor experiment. In the greenhouse experiment, deep root length density (RLD) was significantly greater in the 10 cm-deep (3.9 in) substrate, while outdoors, deep RLD was highest for plants grown in the 15 cm-deep (5.9 in) substrate. Outdoors, iceplant had significantly greater mean coverage and shoot dry weight than hens and chicks. Lack of significant differences in quality and coverage due to substrate depth, coupled with higher RLD in the 10 cm (3.9 in) and 15 cm (5.9 in) depths in both experiments provides evidence that shallow irrigated substrates support the growth of both taxa.

Index words: iceplant, hens and chicks, plant coverage, root length density, quality, zeolite, heat expanded clay.

Species used in this study: hens and chicks (Sempervivum calcareum L.); iceplant [Delosperma nubigenum (Hook.f.) L. Bolus].
Long-term Weed Control for Landscape Pecan (Carya illinoinensis) Trees1
Authors: Hand Lavesta C. , Foshee Wheeler G. , Monday Tyler A. , Sibley Jeff L.
Published: August 2020

Studies were conducted at the E.V. Smith Research Center in Shorter, AL (32°43′N, -85°89′W) in 2013 and 2014 to evaluate herbicides suitable for providing season-long weed control in pecan orchards. Herbicide treatments included: (1) glyphosate applied at 1.12 kg ae·ha−1 (1.0 lb ae·A−1), (2) glyphosate at 1.12 kg ae·ha−1 + indaziflam at 73.1 g ai·ha−1 (1.04 oz ai·A−1), (3) glyphosate at 1.12 kg ae·ha−1 + flumioxazin at 422 g ai·ha−1 (6.02 oz ai·A−1) + pendimethalin at 4.25 kg ai·ha−1 (3.79 lb ai·A−1), and (4) a nontreated control. Glyphosate + indaziflam provided the highest weed-free area at all rating dates, but at 150 DAT (69%) it wasn't acceptable. Glyphosate + flumioxazin + pendimethalin provided a similar weed-free area to glyphosate + indaziflam 30 DAT (88%).

Index words: landscape weed control, shade trees, pecan, edible landscape.

Species used in this study: Carya illinoinensis (Wang.) K. Koch ‘Desirable'.

Chemicals used in this study: indaziflam (Alion®), glyphosate (Cornerstone Plus), flumioxazin (Chateau ®), pendimethalin (Prowl H20®).
Increasing amounts of coir dust in substrates do not improve physical properties or growth of tree seedlings in a novel air-pruning propagation tray1
Authors: Munroe Ryan , McGrath Darby , Henry Jason
Published: August 2020

Air-pruning can improve tree seedling root quality in propagation by subjecting root tips to desiccation, thereby avoiding deflections, but also increases substrate dry-out rates. Several studies have indicated that coconut (Cocos nucifera L.) coir dust can enhance water holding properties, possibly benefiting trees grown in air-pruning trays. However, water availability characteristics are influenced by particle size. In this experiment, coir dust was added into a sphagnum peat-perlite substrate mix at rates of 10, 15 and 20%. An industry standard peat-perlite mix was tested as a fourth substrate type. Red oak (Quercus rubra L.), red maple (Acer rubrum L.), quaking aspen (Populus tremuloides Michx.) and eastern white cedar (Thuja occidentalis L.) were grown from seed in these four substrate types. Physical and chemical properties of all substrate types were analyzed pre-experiment. The particle size distribution was finer and more even in the peat-perlite mix compared to the three coir mixes. The higher proportion of coarse particles in the 20% coir mix may have reduced water availability. Seedlings grown in the 15 and 20% coir mixes had lower above and below-ground growth compared to the 10% coir and peat-perlite mixes in all species except red oak.

Index words: soilless media, water holding capacity, air space, particle size distribution, chlorophyll content, tree growth.

Species used in the study: red oak (Quercus rubra L.); red maple (Acer rubrum L.); quaking aspen (Populus tremuloides Michx.); eastern white cedar (Thuja occidentalis L.).
Insights from Southeastern US Nursery Growers Guide Research for Sterile Ornamental Cultivars 1
Authors: Bechtloff Allison , Adams Dr. Carrie Reinhardt , Wilson Dr. Sandra , Deng Dr. Zhanao , Wiese Christine
Published: August 2020

Some ornamental plants important to the nursery and landscape industries escape cultivation, spread to natural areas, and become invasive, outcompeting native plants in those ecosystems. Development of sterile cultivars of these problematic species can be one way to continue their sales yet limit their invasive potential and protect natural areas. To maximize the economic (and ecological) impact of this approach, sterile cultivar research and development should directly address grower needs. We conducted a survey of southeastern US growers to quantify sales of five popular yet invasive ornamentals (Coral ardisia, Chinese privet, Japanese honeysuckle, Heavenly bamboo, and Mexican petunia). Firms ranged from small businesses to large operations with up to $30M in gross annual sales. Respondents expressed a largely positive opinion of sterile cultivar research (74%) and a willingness to sell the sterile cultivars once created. Most (40%) recommended that sterile cultivar research on Heavenly bamboo was most critical, while 30% suggested that Chinese privet was the most important research target of the five species. The industry's willingness to adopt sterile cultivars documented in this survey positions the southeastern US to lead development of sterile cultivars and reduce invasiveness of economically important plants; research and development will be most effective if guided by industry input revealed here.

Index words: Invasive species, invasive ornamental, sterile cultivar, ornamental plants, non-invasive, non-native, survey, nursery production, economic impacts.

Species used in this study: Coral ardisia (Ardisia crenata Sims); Chinese privet (Ligustrum sinense Lour.); Japanese honeysuckle (Lonicera japonica Thunb.); Heavenly bamboo (Nandina domestica Thunb.); Mexican petunia (Ruellia simplex C.Wright).
Optimizing Temperature and Humidity for Rooting Hybrid Hazelnuts from Hardwood Stem Cuttings1
Authors: Braun Lois , Wyse Donald
Published: August 2020

Hybrid hazelnuts are being developed as a new crop for the Upper Midwest for their ecological and economic value, but lack of economically viable propagation methods is a significant bottleneck to their wide scale adoption. In previous trials we found that hardwood stem cuttings could be propagated in low cost humidity tents constructed of molded plastic tubs covered with white 70% shade plastic. When the plastic was sealed tightly at the sides, these tubs maintained relative humidity near saturation, but also tended to overheat. This trial experimented with the use of ordinary household humidifiers as an alternative way of maintaining humidity while avoiding overheating. We found that it is not necessary to maintain RH near 100% as we had been doing when we kept the humidity tents tightly sealed. Stem survival and, as a consequence, rooting were improved in vented tents in which humidity was maintained with humidifiers, though these required much more management than the sealed tents.

Index words: Propagation, Corylus americana (Walter), Corylus avellana (L.), rooting, indole-3-butyric acid

Chemicals used in this study: indole-3-butyric acid (IBA)

Species used in this study: hybrid hazelnuts [Corylus americana (Walter) x Corylus avellana (L.)]
Effects of Fertilizer Placement on Greenhouse Gas Emissions from a Sun and Shade Grown Ornamental Crop1
Authors: Murphy Anna-Marie , Runion G. Brett , Prior Stephen A. , Torbert H. Allen , Sibley Jeff L. , Fain Glenn B. , Pickens Jeremy M.
Published: August 2020

The level to which ornamental plant production impacts rising atmospheric greenhouse gas (GHG) concentrations remains unknown. Research to date has focused on developing baseline estimations of GHG emissions from plant-pot production systems and their contribution to global warming potential. To date, pot size, irrigation delivery method and fertilizer application method have been evaluated in the production of common woody ornamental crops. In this study, two perennial herbaceous plants, full-sun-grown ‘Stella D'Oro' daylily (Hemerocallis × ‘Stella D'Oro' L.) and shade-grown ‘Royal Standard' hosta (Hosta × ‘Royal Standard') (Hosta plantaginea Aschers × Hosta sieboldiana N.Fujita) were grown utilizing one of three common fertilizer application methods (dibbled, incorporated or top-dressed). Plants were grown in 3.8 L (1 gal) nursery containers in a 6:1 pinebark:sand substrate with standard amendments. Gas samples were collected in situ according to standard GRACEnet protocols weekly for five months. Cumulative emissions for both CO2 and N2O were least for plant-pot systems using the dibbled fertilizer method, regardless of species. Cumulative CO2 emissions were highest for plants fertilized by incorporation, followed by those fertilized by top-dressing. No differences were observed between N2O efflux measurements for systems fertilized by either the incorporated or top-dressed methods. Results suggest that dibbling fertilizer could significantly decrease both CO2 and N2O emission.

Index words: carbon dioxide, nitrous oxide, methane, trace gas.

Species used in this study: ‘Stella D'Oro' daylily (Hemerocallis × ‘Stella D'Oro' L.); ‘Royal Standard' hosta [(Hosta × ‘Royal Standard') (Hosta plantaginea Aschers × Hosta sieboldiana N.Fujita)].
Research Priorities of the Environmental Horticultural Industry Founded through Consensus1
Authors: Owen James S. , LeBude Anthony V. , Calabro Jill , Boldt Jennifer K. , Gray Jennifer , Altland James E.
Published: August 2020

Environmental horticulture production (EHP) generates and employs approximately one-third of all specialty crop revenue and workforce, respectively. In recent years, however, EHP received only 12% of federal funds earmarked for specialty crops research from the USDA-Agricultural Research Service or the USDA-Specialty Crops Research Initiative. To increase leverage and accumulate more resources for EHP, stakeholder-driven consensus of research priorities needed to be constructed. Therefore, the Horticultural Research Institute led a professionally facilitated stakeholder roundtable discussion to achieve these priorities. Stakeholders identified trends and forces affecting EHP, its current state, a vision, and outcomes needed for success. Through consensus, four equal research priorities were constructed: 1) quantitate and validate the ecosystem services and benefits of plants on human health and wellness, 2) develop innovations in biological, mechanical, and technological systems that provide efficient, productive, and profitable solutions relevant to producer size and segment, 3) evaluate consumer-driven preferences that optimize industry-wide profitability and growth, and 4) solve ongoing and emergent industry challenges. These priorities and the successful future of EHP will be made possible by strong leaders and advocates positioned throughout industry, successfully communicating the human health, social, and economic benefits of plants, state-of-the-art technological and efficiently-designed systems, and an understanding of current and future consumers.

Index words: forces, greenhouse, innovation, nursery, roadmap, stakeholders, trends, vision.
Implementation of Soil Moisture Sensor Based Automated Irrigation in Woody Ornamental Production1
Authors: Wheeler William D. , Chappell Matthew , van Iersel Marc , Thomas Paul
Published: August 2020

A soil moisture sensor-based automated irrigation system was trialed in a commercial ornamental nursery over the 2014-2015 growing seasons. In both years, use of the sensor-based system resulted in an approximate 50% reduction in irrigation application (volume) when compared to grower-managed irrigation. No differences in growth and equivalent or slightly reduced crop losses were noted when comparing the sensor-based irrigation system to grower-managed irrigation in production of Pieris japonica, Hydrangea quercifolia, and Kalmia latifolia. In 2014, Rhododendron catawbiense had equivalent canopy size and reduced mortality when comparing sensor-based irrigation to grower-managed irrigation. However, in 2015 irrigation control with the sensor-based system resulted in significant (>50%) Rhododendron losses. High mortality was thought to have resulted from use of averaged (across crop species) soil moisture readings to establish irrigation set points. Canopy structure of Rhododendron obstructed water capture to a greater degree than the other three species due to canopy architecture. This effect, combined with precision irrigation applications, resulted in persistent drought conditions within the Rhododendron block. Soil moisture sensor-based automated irrigation can be an effective means of automating irrigation. Support from crop consultants is highly desirable to minimize disruption and maximize adoption during implementation.

Index words: Pieris Japonica D. Don ex G. Don ‘Prelude', Hydrangea quercifolia W. Bartram ‘Jet Stream', Rhododendron catawbiense Michx. ‘Roseum Elegans', Kalmia latifolia L. ‘Sarah', irrigation groupings, automation, canopy structure, irrigation capture, technology transfer, outreach, education, precision irrigation

Species used in this study: Japanese andromeda ‘Prelude' (Pieris Japonica D. Don ex G. Don); Oakleaf hydrangea ‘Jet Stream' (Hydrangea quercifolia W. Bartram); Rhododendron ‘Roseum Elegans' (Rhododendron catawbiense Michx.); Mountain laurel ‘Sarah' (Kalmia latifolia L.)
Physiological Response to Water Deficit Stress with Restricted Rooting in Tall Fescue and Zoysiagrass
Authors: Culpepper Travis , Young Joseph , Montague David T. , Sapkota Manish , Escamilla Eduardo , Wherley Benjamin
Published: August 2020

Urban soils may restrict turfgrass rooting depth with shallow soil layers in high sand content soils, which may influence water conservation. A greenhouse study sought to quantify water usage and determine the physiological response of turfgrasses at four irrigation levels. ‘ATF-1434′ tall fescue (Schedonorus arundinaceus (Schreb.) Dumort. nom. cons.; syn. Festuca arundinacea Schreb.), ‘Jamur' Japanese lawngrass (Zoysia japonica Steud.), and ‘Zeon' Manilagrass [Zoysia matrella (L.) Merr.] were established in 10 cm (4 in) diameter by 17.8 cm (7 in) tall containers. Each species was irrigated with 16.5, 21.9, 27.3, or 32.7 mm.wk−1 (0.65, 0.86, 1.1, or 1.3 in.wk−1). Gravimetric water loss was determined by pre- and post-irrigation pot weights. Turf quality, leaf discoloration, percent green cover, and gross photosynthesis were evaluated weekly and root parameters were measured at the conclusion of each trial. Although root mass was similar among species, water deficit stress and leaf discoloration occurred sooner in tall fescue than the two Zoysia species, reducing turf quality and green cover. Japanese lawngrass and Manilagrass had greater stomatal conductance, resulting in 109 and 89% higher gross photosynthesis relative to tall fescue. Both zoysiagrasses maintained acceptable turf quality with 27.3 mm water.wk−1. However, tall fescue quality was not acceptable at any irrigation level.

Index words: Photosynthesis, gravimetric water loss, tall fescue, Japanese lawngrass, Manilagrass.

Species used in this study: Tall fescue (Schedonorus arundinaceus (Schreb.) Dumort. nom. cons.; syn. Festuca arundinacea Schreb.); Japanese lawngrass (Zoysia japonica Steud.); Manilagrass [Zoysia matrella (L.) Merr.].
Water Savings and Return on Investment of a New Drought Resistant Turfgrass
Authors: Minor Josh , Campbell Benjamin , Waltz Clint , Berning Joshua
Published: August 2020

Bermudagrass is a commonly used turfgrass for home lawns and sports fields. Given increasing pressure to conserve water throughout the U.S., there is a desire by many homeowners to incorporate more drought-tolerant turfgrasses into their landscape. ‘TifTuf' is a new cultivar of bermudagrass that has increased drought tolerance compared to similar cultivars. ‘TifTuf' is currently sold at a premium price compared to other bermudagrass cultivars. However, there is currently no information regarding the payback period and potential water savings for ‘TifTuf'. In this study, we developed a model to evaluate potential cost savings for ‘TifTuf' relative to a conventional bermudagrass. We found cost and water savings are highly dependent on geographic location and water rates. Within the Southeast, the average water savings per year is 12.88 cm with water cost savings around $799 per 0.41 ha. Payback period for a new lawn in the Southeast (recoup only the $0.05 per 0.09 m2 premium) is around 3-4 years, while a payback period for a replacement lawn (recoup the full cost of the lawn, $0.36 per 0.09 m2) is around 21 years. In the Southwest, the water savings and cost savings are higher, implying a shorter payback period.

Index words: bermudagrass, ‘TifTuf', drought tolerance.

Species used in this study: Cynodon dactylon x C. transvaalensis: DT-1 ‘TifTuf'.
Establishment and Distribution of Ailanthus altissima in the Urban Environment
Authors: Pan Elizabeth , Bassuk Nina
Published: August 2020

An Ailanthus altissima (Miller) Swingle population in Ithaca, New York was found to be comprised of individuals from all size classes suggesting its continued potential for regeneration. Dispersal of seeds as intact panicles and strong root suckering contributed to its grouped formation in urban habitats. Ailanthus inhabited a range of urban sites that had a limited amount of exposed surface soil. The successful growth of Ailanthus into such sites was attributed to its simple rope-like lateral roots.
Comparison of Chemical and Cultural Controls for Pales and Northern Pine Weevils in Tree Stumps
Authors: Shetlar D.J. , Bennett L.W. , Heller P.R.
Published: August 2020

Selected insecticides were applied in kerosene or water to Scotch pine (Pinus silvestris L.) stumps in a Christmas tree plantation. Other stumps were treated by covering with black plastic mulch, roof sealer or hot caps plant protectors. The black plastic was considered to be as effective as the registered insecticides in controlling production of northern pine weevil, Pissodes approximatus Hopkins, and pales weevil, Hylobius pales (Herbst) (Coleoptera: Curculionidae). The use of black plastic was cost comparable to applying the insecticide lindane.
Evaluation of Pine Bark, Pine Bark With Wood, and Pine Tree Chips as Components of a Container Plant Growing Media
Authors: Laiche A.J. , Nash V.E.
Published: August 2020

Three woody landscape species, Rhododendron indica ‘President Clay’, Ligustrum sinense ‘variegata’, and Ilex crenata ‘compacta’, were grown in media prepared from fresh pine bark, pine bark with wood, and pine tree chips. Although media were variable in physical properties, all exhibited very high hydraulic conductivity and low water holding capacity. The capacity of these media materials to hold fertilizer elements was very low. Nitrogen, potassium, and phosphorus were rapidly removed by leaching while calciuum and magnesium were retained longer because of the low solubility of dolomitic limestone. Pine bark was the best growth media tested for all plant species. Pine bark with wood was less satisfactory than pine bark and growth was poorest in pine tree chips. More research is needed on the use of the organic amendments with greater amounts of wood before being widely used as organic components of growth media.
Cultural Practices Can Influence Root Development for Better Transplanting Success
Authors: Watson Gary W.
Published: August 2020

Stress in transplanted nursery stock is caused primarily by the drastic reduction of the root system. Unsatisfactory soil conditions at the planting site reduces root regeneration and prolongs the stress. Root pruning can be used effectively to increase the amount of fine root surface area in the root ball. Careful preparation of the planting site will provide a favorable environment for root growth following transplanting.
Effect of Experimental Bactericides on Three Bacterial Diseases of Foliage Plants
Authors: Chase A.R.
Published: August 2020

Several experimental bactericides were compared with standard bactericides for efficacy on several floral and foliage crops: Erwinia chrysanthemi on Philodendron selloum, Xanthomonas campestris pv. hedera on Brassaia actinophylla and Hedera helix, and Pseudomonas cichorii on Chrysanthemum morifolium and B. actinophylla. Compounds tested were Kocide 101 77WP (cupric hydroxide) alone and in combination with Manzate 200 80WP (mancozeb), Ciba Geigy experimental compounds 448, 115944 and 151731, and Agri-Strep 1721.2% (streptomycin sulfate). In the majority of trials, compound 115944 provided disease control equivalent to that achieved with streptomycin sulfate. Disease control following application of 151731 was variable, while treatment with compound 448 resulted in poor control. Moderate disease control was achieved with cupric hydroxide applied alone or with mancozeb for Erwinia blight or Xanthomonas leaf spot.
Effects of Pruning on Root and Shoot Growth of Ilex crenata ‘Compacta’
Authors: Gilliam Charles H. , Cobb Gary S. , Fare Donna C.
Published: August 2020

In 2 experiments, shoot pruning at potting reduced root growth of transplanted rooted cuttings (liners). However, tip pruning of plants increased root growth compared to severe pruning (50% of shoots) and increased shoot numbers compared to nonpruned plants. In experiment 1 severe shoot pruning of transplanted liners in September resulted in increased shoot numbers compared to nonpruned plants, while in a second experiment, severe shoot pruning in May had no effect on shoot numbers.
Host Suitability of Three Asiatic Elms to the Elm Leaf Beetle (Xanthogaleruca luteola) (Coleoptera: Chrysomelidae)
Authors: Hall Richard W. , Young Curtis E.
Published: August 2020

Larval and adult elm leaf beetle, Xanthogaleruca luteola (Muller) were fed leaves of Ulmus pumila L., U. parvifolia Jacq. and U. wilsoniana Schneid. to determine host suitability. U. pumila was a suitable host, while U. parvifolia and U. wilsoniana were found to be poor hosts. U. parvifolia and U. wilsoniana should be considered for urban plantings where elm leaf beetle defoliation is severe, and as sources of resistance in elm breeding programs.
Response of 17 Species of Container-Grown Woody Landscape and Foliage Plants to Four Postemergence Herbicides
Authors: Gilreath P.R. , Gilreath J.P.
Published: August 2020

Postemergence applications of 2 rates of Whip [fenoxaprop-ethyl) (ethyl 2-[4-[(6 chloro-2-benzoxazolyl) oxy]-phenoxy] propanoic acid), Assure (quizalofop-ethyl) (2-[4-[6-chloro-2-quinoxalinyl) oxy]-phenoxy]-propanolc acid, Fusilade 2000 (fluazifop-p-butyl) (R-butyl 2-[4-(5) trifluoromethyl-2-pyridyloxy)-phenoxy] propanoic acid), and Poast (sethoxydim) (2-[1-(ethoxyamino) butyl]-5-[2-(ethylthio) propyl 1]-3-hydroxy-2 cyclohexene-l-one) were evaluated for phytotoxicity to 17 species of container-grown woody landscape and foliage plants and control of large crabgrass (Digitaria sanguinalis L.). Crabgrass plants were treated at the 2 to 4 and 8 to 10 leaf stages and were grown under both full sun and 40% shade. Each herbicide injured at least one species. Fusilade 2000 injured the fewest species, while Poast injured the most. Under 40% shade, control of crabgrass with 2-4 leaves was acceptable with all herbicides except 0.28 kg/ha (0.25 lb/A) Whip. All herbicides were effective when applied in the 8-10 leaf stage of growth. In full sunlight, excellent control of crabgrass at the 2-4 leaf stage was obtained with all herbicide treatments except Poast. Two weeks after application to the 8-10 leaf stage, the best control was obtained with Whip; however, by the end of 8 weeks, all treatments, except Poast, provided excellent control.
Use of Antitranspirants for Control of Powdery Mildew on Field Grown Roses
Authors: Hagiladi A. , Ziv O.
Published: August 2020

Antitranspirants Wilt Pruf, Vapor Gard and Folicote protected garden roses from powdery mildew. The coating polymers were stable in the field for about 30 days.
Fingerprinting Apple Cultivars by Electrophoretic Isozyme Banding Patterns
Authors: Menendez R.A. , Larsen F.E. , Fritts R.
Published: August 2020

Anionic electrophoretic isozyme patterns of peroxidase, esterase and acid phosphatase and cationic peroxidase isozyme patterns from shoot bark protein extracts were used to identify clonal apple scion cultivars. Each of the 21 cultivars included in this study developed a unique combination of isozyme patterns which allowed it to be distinguished from the others. Sports within cultivars exhibited identical patterns of enzymes, with the exception of ‘Wijcik’, a natural compact mutant of ‘McIntosh’ which could be distinguished from the latter, although it was indistinguishable from the cultivar ‘Spartan’. Isozyme patterns remained constant when samples were taken from wood of different ages, at several times of the year and with trees growing in different locations and on different rootstocks.
Effects of Wounding, IBA and Basal Trimming on Rooting of Boxwood Cuttings
Authors: Banko Thomas J. , Stefani Marcia A.
Published: August 2020

Wounding, indole butyric acid (IBA) and trimming of cuttings to a basal node were evaluated for their effects on rooting of Buxus sempervirens L. (American boxwood), B. sempervirens L. ‘Suffruticosa’ (English boxwood), B. microphylla var. koreana Nakai. (Korean boxwood), and B. microphylla var. japonica (Müll. Agr.) Rehd. and Wils. (Japanese boxwood) cuttings. Rooting of all cultivars was improved by a 5 second dip in a 0.4% aqueous solution of the potassium salt of IBA. Wounding the basal end of the cuttings only improved rooting for Korean and Japanese boxwoods. However, the combination of wounding and IBA dip gave the best results for all cultivars. Trimming the cuttings to a basal node was beneficial only to Korean boxwoods.
Root Regeneration, Starch Content, and Root Promoting Activity in Tilia cordata Cultivars at Three Different Digging-Planting Times
Authors: Witherspoon Wm. Robert , Lumis Glen P.
Published: August 2020

Three-year-old, 250 cm (8 ft) bareroot-dug Tilia cordata cultivars were planted at three different digging-planting times: (1) fall-dug and fall-planted, (2) fall-dug and spring-planted following winter storage, and (3) spring-dug and spring-planted. Fall-dug, fall-planted trees had a significantly higher number of new roots initiated than trees from either of the other two digging-planting times. Differences in root starch content were not significant enough to account for the reduced amounts of root regeneration in the two spring-planted groups. Extracts from cut root tips of spring-dug, spring-planted trees had the greatest ability to promote rooting of mung bean cuttings. This result did not correspond to the actual field performance of the trees. Other factors that may have influenced the root regeneration of spring-planted trees are discussed.
Effect of Root-Applied IBA on Root and Shoot Growth of Dwarf Peach Trees
Authors: Starbuck C.J. , Preczewski J.L.
Published: August 2020

Roots of 1-year old dwarf (Prunus persica ‘July Elberta’ budded on Prunus tomentosa) peach trees were dipped in solutions of 100 ppm indole-3-butyric acid (IBA) with and without starch-polyacrylate gel in the treatment solution prior to planting in beds of 1:1 peat:perlite or in the field. Four weeks after treatment, plants treated with 100 ppm IBA with or without gel had 4 to 5 × the dry weight of new roots as did controls. Treatment with 100 ppm IBA plus gel increased the number of new roots by 62% over controls. During the first season in the field, plants treated with gel with or without IBA produced longer shoots than controls. During the second season, plants originally treated with 100 ppm IBA alone produced significantly longer shoots than any other treatment while those treated with IBA/gel were not different from controls. In a separate expenment, DMSO (dunethyl sulfoxide) and DMF (dimethyl formamide) at 0.4% in the treatment solution had no apparent influence on IBA-induced root initiation.
Influence of Pruning at Transplant Time on Growth and Establishment of Liquidambar styraciflua L., Sweet Gum
Authors: Hummel Rita L. , Johnson Charles R.
Published: August 2020

Pruning of container-grown sweet gum trees by heading 20, 30, and 50% of the top at transplant time produced no significant positive influence on growth and establishment when compared to nonpruned trees. Total growth of plants pruned 30 and 50% was restricted. Heading impaired the natural excurrent (conical) form of sweet gum. However the lost leader of some trees was replaced by a clearly dominant, upright lateral branch. Results of fall and spring transplanting were similar. Supplemental irrigation during prolonged dry periods produced significantly larger, more desirable landscape trees.
Evaluating Ways to Reduce the Harmful Effects of Irrigating Nursery Crops with Water High in Soluble Salts
Authors: Iles A.M. , Klett J.E.
Published: August 2020

The effects of watering technique on container grown Lonicera tatarica L. ‘Zabelii’ and Philadelphus x virginalis Rehd. irrigated with water high in soluble salts were investigated during the 1982 and 1983 growing seasons. Hand, mini-sprinkling, and sprinkler irrigation were compared. The quality of irrigation water used in this experiment included: A) EC 0.12 mmhos/cm, pH 6.6, SAR 0.3 (city water); B) EC 1.42 mmhos/cm, pH 7.5, SAR 2.0; and C) EC 2.48 mmhos/cm, pH 7.8, SAR 2.9. Mini-sprinkling resulted in significantly greater growth of Philadelphus x virginalis when compared to sprinkler irrigation. This increase in growth was attributed to greater media moisture, prevention of leaf contact with irrigation water, and the possible leaching of salts by the spotspitter type of mini-sprinkling utilized.
Phomopsis Shoot Blight of Colorado Blue Spruce
Authors: Sanderson Peter G. , Worf Gayle L.
Published: August 2020

A Phomopsis spp., identified as P. occulta Trav. was demonstrated to be the causal agent of a tip blight of Colorado blue spruce (Picea pungens Engelm.) that affects both nursery and landscape trees in Wisconsin. The disease was characterized by the downward curling and necrosis of expanding shoots. Stem cankers and sap exudate commonly occurred on infected shoots. Greenhouse studies showed that disease severity was greatest under warm temperatures (28 °C/78 °F) and relatively humid conditions (75-95% RH). When four species of spruce and two species of fir (Abies spp.) were artificially inoculated, P. pungens expressed severe disease symptoms while P. obovata, P. glauca cv. ‘Densata,’ and P. abies were less severely affected. A. balsamea and A. concolor were symptomless. Sirococcus strobilinus Preuss was also reported as a pathogen on Colorado blue spruce for the first time in Wisconsin.
Effects of Irrigation Frequency and A Water-Absorbing Polymer Amendment on Ligustrum Growth and Moisture Retention by a Container Medium
Authors: Ingram Dewayne L. , Yeager Thomas H.
Published: August 2020

Amending a 2 pine bark: 1 Canadian peat: 1 sand (by vol) container medium with 0, 1.2, 2.4, 3.6 or 6 kg/m3 (0, 2, 4, 6 and 10 lbs/yd3) of a water-absorbing polymer, Moisturite3, did not influence the volume of water held at tensions less than 100 cm (39 in). Greenhouse-grown Ligustrum japonicum wilted when irrigated (920 ml/application; 31 oz) every 12 days; however, more frequent irrigation treatments (every 6 and 3 days) reduced shoot and root dry weights. Dry weights were not affected by polymer amendment rates nor were container medium temperatures different 1, 2 or 3 days after irrigation.
Growth and Chemical Composition of Populus deltoides × nigra Grown in Field-grow Fabric Containers
Authors: Chong C. , Lumis G.P. , Cline R.A. , Reissmann H.J.
Published: August 2020

Growth and chemical composition of popular (Populus deltoides × nigra, DN 69) grown in field-grow fabric containers (FGFC) was evaluated. Unrooted hardwood cuttings were grown in 0.6, 2.4, 6.0, and 14.0 L (0.2, 0.6, 1.6, and 3.7 actual gal) custom-made FGFC inserted in 3, 6, 12 and 24 L (#1,2,3 and 6 trade size) plastic nursery containers, resp. A 3.5 cm (1.4 in) layer of the same medium was placed under the between the FGFC and the walls of the nursery container. Each bag was filled with a medium of pine bark; spruce bark (3:1 by vol.). Control plants were grown in containers of all sizes without FGFC in the same medium. Plant growth increased with increasing container size. Root dry weight of plants grown in FGFC were 21% less than plants without FGFC. However, there was no difference in top growth between FGFC and control plants. Soluble sugars concentration was 7% higher in leaves of FGFC grown plants, but leaf N, P, and K concentrations were similar. Roots outside the FGFC contained more N, P, and K than roots inside the FGFC. Soluble sugars and starch concentrations were greater inside the FGFC than outside.
Sensitivity and Time of Application of Fusilade 2000 to Azaleas
Authors: Gilliam C.D. , Cobb G.S. , Fare D.C.
Published: August 2020

Application of Fusilade 2000 (fluazifop-P-butyl) (R-butyl ± 2-[4-[5- (trifluoromethyl)-2-pyridinyl] oxyl] phenoxy] propanoic acid) on September 3 reduced flowering of ‘Hino-Crimson’ azalea by 60% and 25% compared to those treated on August 1 and nontreated control plants. Off-Shoot-O (methyl esters of C6-C12 fatty acids) treated plants responded similarly. ‘Hino-Crimson’ azaleas treated with Fusilade 2000 on July 2 and August 1 had greater flower numbers the following spring than comparable plants treated with Off-Shoot-O. Only azaleas sensitive to Fusilade 2000 respond as such. Sensitive azalea cultivars tested include: ‘Hino-Crimson,’ ‘Hinodegiri,’ ‘Sherwood Red,’ ‘Girard's Scarlet’ and ‘Girard's Rose.’
Influence of Chilling Hours on Flower Bud Growth and Rooting Ability of Blueberry Budsticks
Authors: Austin Max E. , Bondari K.
Published: August 2020

Budsticks from 3 rabbiteye blueberry cultivars (‘Baldwin,’ ‘Brightwell,’ and ‘Tifblue’) and 2 highbush blueberry cultivars (TH-275 and ‘Georgiagem’) were subjected to 0 to 650 hrs at 4.4 °C (40°F) to determine the effects of accumulated chilling on terminal flower bud growth and rooting ability. The cultivar X chilling hours interaction was significant for both flower bud growth and rooting ability. The 2 highbush cultivars had wider flower buds than the 3 rabbiteye cultivars. ‘Baldwin’ and ‘Georgiagem’ produced the best overall root systems. Chilling requirements ranged from 350 to 550 hr for the rabbiteye cultivars and 350 to 450 hr for the highbush. Except for rooting score of clone TH-275, the functional relationships between flower bud width or rooting score and chilling hours were non-linear. In general, chilling hours enhanced the growth of terminal flower buds and increased the rooting ability.
Propagation of Osmanthus X fortunei by Softwood Cuttings
Authors: Blazich Frank A. , Acedo Juan R.
Published: August 2020

Moderate rooting (64%) was achieved with nontreated, softwood cuttings of Fortune's osmanthus (Osmanthus X fortunei Carr.). Treatment of cuttings with 2500 ppm indolebutyric acid (IBA) significantly increased percent rooting (92%). Higher auxin concentrations resulted in rooting comparable to the nontreated cuttings. None of the treatments had any influence on root number or root length.
Effect of Endomycorrhizal Inoculum on Root Initiation and Development of Viburnum dentatum L. Cuttings
Authors: Verkade Stephen D. , Hamilton David F.
Published: August 2020

Viburnum dentatum L. cuttings were inoculated with Glomus fasciculatum (Thaxter) Gerdemann and Trappe spores, hyphae and associated soil and root segments at 5 spores/cm3 of medium. Fresh weight of roots, number of roots, and mycorrhizal condition were determined on the fourth and each subsequent week for 5 additional weeks. Inoculation during propagation resulted in uniform mycorrhizal infection (30-50%) and increased root development. A positive interaction between mycorrhizal development and root initiation also was observed.
High Soil Temperature and Water Relations of Endomycorrhizal Nursery Crops2
Authors: Newman Steven E. , Davies Fred T.
Published: August 2020

High root-zone temperatures can stress plants and reduce nursery productivity of container-grown crops. Predawn shoot water potential was initially increased (less water strain) by root-zone temperatures from 40° to 45°C (104° to 113 °F) and then subsequently declined after 3 days. Stomatal conductance (SC) was reduced at similar root-zone temperatures. Hydraulic root conductance (Lp) increased linearly in response to increasing root-zone temperatures for high temperature tolerant species, and quadratically for susceptible species. Endomycorrhizal fungi colonization enhanced high root-zone temperature stress tolerance at moderate temperatures from 35 ° to 40°C (95 ° to 104°F).
Growth Response and Mineral Uptake of Vegetable Transplants Growing in Composted Sewage Sludge Amended Medium.
Authors: Falahi-Ardakani A. , Gouin F.R. , Bouwkamp J.C. , Chaney R.L.
Published: August 2020

Six species of vegetable transplants were grown in market packs filled with peat moss, perlite and screened sewage sludge compost (equal parts by vol.). Compost was made from lime-dewatered sludge and woodchips. Seedlings were fertilized at 1, 2, 3 and 4 wks after transplanting in single, split and multiple applications of varying levels of N and K in factorial combinations. Fertilizer applications could be delayed 1 to 2 wks after transplanting without a loss of top growth. Lettuce, broccoli and cabbage plants were grown to marketable size with only N fertilizer. However, eggplants, tomato and pepper plants grew best when fertilized with both N and K. Acceptable levels of P, Ca, Mg, Md, Zn and Fe, as measured in tissues, were provided by the growth medium and tissue Cd levels wete within acceptable limits.
Post-Transplant Root System Expansion in Juniperus chinensis L. as Influenced by Production System Mechanical Root Disruption and Soil Type
Authors: Blessing Stephen C. , Dana Michael N.
Published: August 2020

Juniperus chinensis (L.) ‘Sea Green’ from 3.8 1 (#.1) containers (CG) and comparably sized field grown plants balled and burlapped (B&B) were planted in clay and loam soil in mid-June. Prior to transplanting, root balls of the CG plants were either mechanlcally disrupted by vertical cuts (D/CG) or left undisturbed (CG). Root growth beyond the original root ball and shoot extension growth in loam soil were determined at 8 and 12 weeks, while similar data were collected from loam and clay soils at 16 wks. B&B plants and D/CG plants produced greater dry weight of new roots, but less shoot growth at 8 wks than CG plants with an undisturbed root ball. By 16 wks, B&B plants had produced greater new root dry weight than either CG treatment and shoot growth was not different among treatments. In clay soil B&B plants produced greater dry weight of new roots than CG plants. Root ball disruption reduced new root growth in the heavy soil compared to CG plants. Shoot growth was not different among treatments in the heavy soil, but was significantly diminished compared to shoot growth on the lighter, loam soil.
Response of Bedding Plants and Weeds to Herbicides
Authors: Gilbertz D.A. , Johnson B.J.
Published: August 2020

Preemergence and postemergence herbicides were evaluated for summer weed control and for phytotoxicity of 6 commonly used annual bedding plant species. Dacthal (dimethyl 2,3,5,6-tetrachloro-1,4-benzenedicarboxylate), Enide (N,N-dimethyl-a-phenyl benzene acetamide), Devrinol (N,N-diethyl-2-(1-naphthalenyloxy) propanamide), Surflan (4-(dipropylamino)-3,5-dinitro-benzenesulfonamide), Ronstar (3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-1(1,1-dimethylethy1)-1,3,4-oxadiazol-2-(3H)-one), Kerb (3,5-dichloro(N-l, 1-dimethyl-2-propynyl)benzamide), and Treflan (2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl) benzenamine) at 3.3 kg/ha (3.0 lb/A) applied as preemergence treatments and Poast (2-[1-(ethoxyimino)-butyl]-5[2-ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one) and Fusilade (+)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid) applied as postemergence treatments effectively controlled large crabgrass [Digitaria sanguinalis (L.) Scop.] throughout a two-month period. Effective prostrate pigweed (Amaranthus blitoides S. Wats.) control was achieved by use of Dacthal at 14.0 kg/ha (12.5 lb/A), Surflan at 1.1 kg/ha (1.0 lb/A) and Ronstar at 3.3 kg/ha (3.0 lb/A) and postemergence application of Escort (2-[[[[(4-methoxy-6-methyl-1 ,3,5-triazin-2-yl)amino]carbonyl]-amino] sulfonyl]benzoic acid) at 0.07 kg/ha (0.06 lb/A). SC 1084 (methyl 3-hydroxy-4-[4-[[5-(trifluoromethyl)-2-pyridinyl]-oxy]-phenoxy]-pentanoate at 0.13 kg/ha (0.12 lb/A) was ineffective in controlling either weed. Plant vigor of salvia was reduced by Dacthal at 11.2 kg/ha (12.5 lb/A), while vigor of ageratum and geranium was reduced by Enide at 4.4 kg/ha (4.0 lb/A). The vigor of geranium and salvia was lower than untreated plants when treated with Devrinol at 3.3 kg/ha (3.0 lb/A). The vigor of petunia, marigold, and salvia was also lower than untreated plants when treated with Ronstar at 3.3 kg/ha (3.0 lb/A) while vigor of geranium, salvia, marigold, and zinnia was lower when treated with Surflan at 2.2 kg/ha (2.0 lb/A). Kerb at 1.6 kg/ha (1.5 lb/A) reduced the vigor of geranium, petunia, and salvia when compared with untreated plants. Poast at 0.28 kg/ha (0.25 lb/A) did not injure any of the annuals while marigold and zinnia were injured with Fusilade at 0.2 kg/ha (0.18 lb/A). Escort at 0.07 kg/ha (0.06 lb/A) and Oust (2-[[[[(4,6-dimethyl-2-pyrimidinyl)amino]-carbonyl]amino]sulfonyl]benzoic acid) at 0.07 kg/ha (0.06 lb/A) applied as postemergence applications severely injured all annuals.