bluuebunny/crossref_metadata_2025 huggingface dataset:
Metering Nonuniform Vegetable Seed
Authors: Parish Richard L. , Bracy Regina P.
Published: December 2018

Selecting the proper seeder setup to meter a given seed lot effectively can be very difficult for a vegetable grower, especially if the seed lot is not graded for size uniformity. A belt-type seeder should effectively singulate the seeds if the seeds are spherical and uniform because the holes are specifically sized. Seeds that are not graded for size uniformity may not be singulated effectively by a belt-type seeder. A vacuum-type seeder should uniformly meter a wider range of seed sizes better than a belt-type seeder since the holes in the seed plate must only be smaller than the smallest seeds in the lot. Seed lots (graded and ungraded) of two turnip (Brassica rapa L. rapifera group) cultivars were metered with a belt seeder using belts with holes 6/64 inch (2.4 mm) or 7/64 inch (2.8 mm) in diameter or with a vacuum seeder. Neither the belt nor vacuum seeder satisfactorily singulated any of the seed lots. With the larger (7/64 inch) belt holes, there were excessive incidences of multiple seeds per drop. With the smaller (6/64 inch) belt holes, multiple drops and missed seed were excessive. The vacuum seeder also resulted in excessive misses and multiples.
Evaluating Seed-covering Devices and Presswheels for Directly Seeding Mustard and Cabbage
Authors: Bracy Regina P. , Parish Richard L.
Published: December 2018

Stands of brassica crops obtained with precision seeders are sometimes inadequate or nonuniform. Although several types of covering devices and presswheels are available from precision seeder manufacturers, the effects of covering devices and presswheels on plant emergence of direct-seeded Brassica crops have not been determined. In Spring and Fall 1996, six crops of mustard [Brassica juncea (L.) Czerniak] and four crops of cabbage (Brassica oleracea L. capitata group) were direct seeded with a precision belt seeder using four covering devices and four rear presswheels. All of the covering devices and presswheels evaluated were adequate for direct seeding mustard and cabbage under the soil moisture conditions and soil type (silt loam or fine sandy loam) found in these experiments. Although poor stands were obtained with all seed covering devices and presswheels when 7.8 inches (199 mm) of rain occurred within 3 days of planting, plant stand of cabbage was greater when the paired arm device was used than with drag-type or no covering devices.
MACRONUT: Calculation Software for Custom-mixed Nursery Fertilizers
Authors: Harrington John T. , Glass Patrick A.
Published: December 2018

MACRONUT, a software program for microcomputers, calculates mixing rates of 17 commonly used nutrient sources of six mineral macronutrients for custom-mixed fertilizers. The software alleviates the need for the cumbersome calculations required to develop or adjust custom mixed fertilizers. The software can be used by field professionals and as an instructional tool for teaching horticultural students how to develop custom fertilizers for container nursery crops.
Potted Sunflower Growth and Flowering Responses to Foliar Applications of Daminozide, Paclobutrazol, and Uniconazole
Authors: Whipker Brian E. , Dasoju Shravan
Published: December 2018

Plant growth retardant (PGR) foliar sprays (in mg·L−1) of daminozide at concentrations from 1,000 to 16,000; paclobutrazol from 5 to 80; and uniconazole from 2 to 32 were applied to `Pacino' potted sunflowers (Helianthus annuus L.) to compare their effectiveness at chemical height control. Plants were grown in 650-mL or 1.2-L pots. When the first inflorescence started to shed pollen, number of days from seeding until anthesis, total plant height measured from the pot rim to the top of the inflorescence, inflorescence diameter, and plant diameter were recorded. There was no significant difference in plant height between `Pacino' plants grown in 650-mL or 1.2-L pots. Total plant height, plant diameter, inflorescence diameter, and days until flowering were significant for the PGR treatment main effect. Marketable-sized plants grown in the 1.2-L pots were produced with uniconazole concentrations from 16 to 32 mg·L−1 or with daminozide concentrations from 4,000 to 8,000 mg·L−1. Paclobutrazol foliar sprays up to 80 mg·L−1 had little effect, and higher foliar spray concentrations or substrate drench treatments may be needed to effectively control height.
Iowa State University Extension: Evaluation of Programs and Services Offered to Iowa's Turfgrass, Nursery, and Landscape Plant Installation and Maintenance Industries
Authors: Iles Jeffery K. , Padgitt Steven C. , Petrzelka Peggy , Wintersteen Wendy K.
Published: December 2018

A survey was conducted to evaluate the effectiveness of Iowa State University (ISU) extension programs and services to the turfgrass, nursery, and landscape plant installation and maintenance industries in Iowa. Completed questionnaires were received from 294 individuals (55% response rate). Respondents indicated they have a continuing need for pest identification and management information and that ISU extension is an important source for this information. In general, most respondents said quality of information provided by ISU extension was better than that offered by horticultural consultants or product suppliers; however, only 48% said extension was doing very well delivering programs and information in a timely manner. Demand for on-site visits with extension specialists was greater than that for distance learning opportunities, suggesting that extension must do a better job of marketing and making relatively new communication technologies palatable.
Echinacea: Cultivation and Medicinal Value
Authors: Li Thomas S.C.
Published: December 2018

Echinacea species, a popular medicinal herb throughout the world, have been used by indigenous Americans for hundreds of years as an effective immunostimulant. The cultivated acreage in the United States and Canada is increasing because of the great demand for Echinacea products. Better cultural methods and standardization and quality control of the value-added products are needed to increase the confidence of growers, producers, and consumers in this promising medicinal herb. Echinacea can be propagated from seed, crown division, and root sections. Seed stratification for 4 to 6 weeks at 34 to 40 °F (1 to 4 °C) before planting can improve germination. Echinacea thrives under cultivation in moderately rich and well-drained loam or sandy loam soil with regular irrigation and weed control. Roots are harvested in the fall after 3 to 4 years of cultivation. The best stage to harvest flowers has yet to be determined. Leaves are a source of valuable active ingredients, but no information is available in the literature on leaf harvesting. Active ingredients in Echinacea include polysaccharides, flavonoids, caffeic acid derivatives, essential oils, polyacetylenes, and alkylamides.
Successful Strategies for Reducing Pesticide Use in the Landscape: Examples from California
Authors: Kabashima J. , Paine T.D. , Redak R.
Published: December 2018

Pesticide use in the landscape has been reduced through the implementation of integrated pest management (IPM) (Holmes and Davidson, 1984, Olkowski et al., 1978; Smith and Raupp, 1986). IPM emphasizes prevention, identifying pests and their symptoms, regular surveying for pests, determining action thresholds and guidelines, and using sound management methods. Monitoring techniques such as pheromone traps, degree-day models, and ELISA kits, in addition to traditional methods, have enabled pest managers to determine accurately when to apply IPM techniques. Examples of serious California landscape insect pests successfully controlled through IPM include the ash whitefly [Siphoninus phillyreae (Halliday)], the Nantucket pine tip moth [Rhyacionia frustrana (Comstock)], and the eucalyptus longhorned borer (Phoracantha semipunctata F.).
Achieving Adoption of Integrated Pest Management by Landscape Managers
Authors: Shaw David A.
Published: December 2018

Achieving adoption of integrated pest management (IPM) practices by professional landscape managers is a common goal of university research and extension personnel, governmental and regulatory agencies, industry, and the public. IPM is developed and promoted through cooperation of university, state, and industry groups in research and educational programs. Publications and educational events are major means of promoting IPM to landscape professionals. While large theater-style seminars may provide the advantage of reaching as many as 500 people at one time, landscape clientele have shown favor for the smallgroup, hands-on type of seminar for application technology and IPM methodologies. The impact of research and educational programs on IPM adoption tends to be variable, depending on the pest, the potential for effective control, the control practices to be undertaken, and economic consequences. Adoption of several biological control programs has been indicated. The pesticide-use data collected from 1992 to 1994 indicate trends in reduced use of some pesticides and shifts to less toxic materials. Unfortunately, these data do not account for variability in pest activity from year to year, and not all pesticide applicators are reporting. Pressure from the public to control pests while minimizing the use of pesticides also indicates adoption of IPM. Additional evaluations are necessary to assess adoption of current and future IPM programs.
In-ground Fabric Containers as an Alternative Nursery Crop Production System
Authors: Cole Janet C. , Kjelgren Roger , Hensley David L.
Published: December 2018

Nursery crops have traditionally been grown in the field and harvested as balled and burlapped or bareroot plants or grown in above-ground containers. A relatively recent product, the in-ground fabric container, has allowed producers to combine advantages of field production with those of container production. The effect of these containers on plant growth, transplant establishment, plant chemical composition, and water relations appears to be species and site specific.
Kenaf-based Fiber Mat as a Substrate for Establishing Soilless Sod
Authors: Hensler K.L. , Baldwin B.S. , Goatley J.M.
Published: December 2018

A truly soilless turfgrass sod may be produced on kenaf-based (Hibiscus cannabinus L.) fiber mat that offers the integrity of field-cut sod without the use of mineral soil growing medium. This research was conducted to determine the feasibility of producing warm-season turfgrass sod on such a biodegradable organic mat. Seeded turfgrass plots contained 4.9 lb/1000 ft2 (24 g.m−2) of pure live seed planted on a 66-lb/1000 ft2 (325-g.m−2) organic fiber mat carrier placed atop either 66- or 132-lb/1000 ft2 (325- or 650-g.m−2) organic fiber mats. In an experiment using vegetative material, stolons were applied at rates of 16.4 ft3/1000 ft2 (0.82 L.m−2) over 132- or 198-lb/1000 ft2 (650- or 975-g.m−2) organic fiber mats and covered with a rayon scrim. All plots were placed on 6-mil black plastic. Nitrogen was applied at 0.9 lb/1000 ft2 (4.4 g.m−2) weekly in addition to a monthly micronutrient application. Bermudagrass (Cynodon σππ.) had quicker establishment than other grasses in the study, with stolonized and seeded plots achieving ≈100% coverage by 9 weeks in 1995 and 6 weeks in 1996, respectively. By 15 weeks after planting in 1995, the plot coverage ratings for seeded centipedegrass [Eremochloa ophiuroides (Munro) Hack. `Common'] and all stolonized grass plots of centipedegrass, zoysiagrass (Zoysia japonica Steud. `Meyer'), and St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze `Raleigh'] were 91% or higher. The results were much less favorable in 1996 than 1995 due to a later planting date and an irrigation failure.
Influence of Bulb Packing Systems on Forcing of Dutch-grown Hippeastrum (Amaryllis) as Flowering Potted Plants in North America
Authors: De Hertogh A.A. , Gallitano L.B.
Published: December 2018

Dutch-grown Hippeastrum bulbs (`Apple Blossom' and `Red Lion') were packed in five readily available and economical packing systems and after transport and storage were evaluated as flowering potted plants. After being harvested and graded, bulbs were specially packed and placed in perforated cardboard boxes, shipped by boat to Raleigh, N.C., and stored in the original packing materials for 84 days at 48 °F (9 °C). At planting time, the best old basal root system and lowest disease incidence for both cultivars was obtained when bulbs were packed with hout-wol, a type of excelsior, in perforated polyethylene bags and placed in perforated cardboard boxes. Plants from bulbs with this system and those packed loose in polyethylene bags flowered the earliest. At full flower, the longest leaves were obtained with the hout-wol, box only, and wood chip systems. There were no significant effects of the five packing systems on floral stalk length, number of flowers produced per stalk, flower diameter, strength of the first floral stalk or leaves, or overall plant quality. After flowering, the root systems were harvested. The hout-wol packing system significantly increased the fresh weights of the old basal roots retained, secondary roots produced, and total weights of the root system. there were significant differences between cultivars. `Apple Blossom' produced fewer roots and lower quality plants (shorter leaves and taller floral stalks) than `Red Lion'. Other significant cultivar differences, e.g., days to flower, were attributed to genetic variation. Based on the most desirable forcing characteristics, the superior packing system for shipping and storing Dutch-grown Hippeastrum bulbus was hout-wol combined with perforated polyethylene bags.
Establishment of Tetranychid Mites in vitro
Authors: Hadi Masood Z. , Bridgen Mark P. , Sanderson John P.
Published: December 2018

Procedures were developed to determine if live, adult two-spotted spidermites (Tetranychus urticae Koch) could be surface disinfested before being introduced into in vitro cultures of torenia (Torenia fournieri L.). Three time periods (5, 10, and 15 minutes) and five levels of sodium hypochlorite (0.05% to 0.25%) were evaluated. Surface disinfestation was accomplished by agitating 2 × 3 cm pieces of infested bean leaves in sodium hypochlorite solutions and then drying in a mite drier apparatus. All sodium hypochlorite concentrations disinfested the mites completely, however high concentration levels were lethal to the mites. Exposure periods of 10 and 15 minutes also significantly increased mortality. For optimum disinfestation of two-spotted spidermites with minimum mortality, a concentration of 0.05% sodium hypochlorite and 0.05% Tween-20 for 5 minutes should be used.
Flowering of Cold-treated Field-grown Astilbe
Authors: Runkle Erik S. , Heins Royal D. , Cameron Arthur C. , Carlson William H.
Published: December 2018

In 1996 and 1997, eight cultivars of cold-treated field-grown Astilbe were grown in a 20 °C green-house with short days (SDs = 9-h natural days) or long days (LDs = 9-h natural days with night interruption with incandescent lamps from 2200 to 0200 hr) to determine how photoperiod influences flowering. Cultivars studied were Astilbe × arendsii Arends `Bridal Veil', `Cattleya', `Fanal', and `Spinell'; A. chinensis Franch. `Superba'; A. japonica A. Gray `Deutschland' and `Peach Blossom'; and A. thunbergii Miq. `Ostrich Plume'. Flowering percentage was highest (≥90%) for `Cattleya', `Deutschland', `Fanal', `Ostrich Plume', and `Peach Blossom', regardless of photoperiod. Photoperiod did not affect the time to visible inflorescence or flower number for any cultivar studied. The time from visible inflorescence to first flower took 27 to 36 days, irrespective of photoperiod. Time to flower varied by cultivar; `Deutschland' was the earliest to flower (31 to 41 days) and `Superba' was the last to flower (51 to 70 days). `Fanal' and `Ostrich Plume' flowered slightly but significantly faster (by 1 to 6 days) under LDs than SDs. For five cultivars, the inflorescence was taller under LDs than SDs. All cultivars reached visible inflorescence and flower significantly faster (by 1 to 15 days) in 1997 than in 1996.
Producing Print-on-demand Publications for Instructional and Extension Materials
Authors: McConnell James , Pangelinan Maria I.D.
Published: December 2018

Print-on-demand (POD) publications are being produced from computer to printer to increase the diversity of printed extension and educational materials. The layouts are stored in libraries on the computer and text files and digital images are added to the layouts. Images can be edited before insertion into the layouts to enhance the image. The completed materials are stored in portable document format (PDF) on disk and are printed as needed or distributed over computer networks. Printing materials as needed greatly increases the diversity of materials and gives greater flexibility in revising publications than bulk printing.
A Continuously Diluting Injector for Applying Fertilizer to Experimental and Demonstration Plots
Authors: Lancaster Mark E. , Davis Jeanine M. , Sanders D.C.
Published: December 2018

Small-scale research plots and demonstrations of fertilizer application through a drip-irrigation system have inherent characteristics that make using commercial fertilizer injection systems difficult. Uniform fertilizer application, without excessive water, is essential for meaningful results in these small-scale, rate-specific studies. An inexpensive, easy to build, continuously diluting fertilizer injector is described. This injection system was reliable and provided uniform application under the confines of a low flow rate.
A Business Profile of Australian Nurseries
Authors: Brumfield Robin G. , McSweeney Peter F.
Published: December 2018

A 1995 study of 22 Australian nurseries 1) developed a profile of production, management, and profitability; 2) compared their performance to relevant U.S. benchmarks; and 3) identified trends and potential areas of improvement in the management of Australian nursery enterprises. The study confirmed that Australian nurseries incur high labor costs (38.8% of sales) comparable to United States nurseries, while costs of materials and supplies were lower than in the United States. Australian managers were concerned with marketing and recruiting and keeping labor rather than increasing capital investment to enhance production efficiency. Capital expenditures were funded from internal cash flow rather than external financing. Many of the nursery managers used relatively simple performance indicators, and most business objectives were stated in general terms. Concerns about the viability of the industry included oversupply, the growth in chain stores' business, factors eroding the demand for nursery products, and greater regulation.
Paclobutrazol Drenches Control Growth of Potted Sunflowers
Authors: Dasoju Shravan , Evans Michael R. , Whipker Brian E.
Published: December 2018

Paclobutrazol drenches were applied at 0, 2, 4, 8, 16, or 32 mg a.i./pot to potted sunflowers (Helianthus annuus L. `Pacino') to determine its effect on growth. Plant height was shorter as paclobutrazol dose increased up to 16 mg; however, additional increases in dose had little effect on height. Severe height retardation of `Pacino' plants was evident at 16 and 32 mg. Plants treated with 2 mg of paclobutrazol were 17% and 25% smaller in diameter than untreated plants in Expts. 1 and 2, respectively. Plant diameter was smaller as paclobutrazol dose increased up to 16 mg, with additional increases in dose having little effect on plant diameter in Expt. 2. Plants treated with 16 or 32 mg of paclobutrazol exhibited phytotoxicity symptoms including crinkled leaves and stunted growth, and smaller and greener leaves. Sunflower plant growth was greater in the summer (Expt. 1) than in winter (Expt. 2). In the summer higher doses of paclobutrazol will be required than in winter for growth control. Marketable sized plants grown in 15- to 16.5-cm-diameter pots were produced with doses of paclobutrazol at 2 and 4 mg in both seasons, and doses up to 8 mg can also be used in summer for growth control.
A Web Site for Urban Horticulture: Meeting Increasing Demands with Decreasing Resources
Authors: Bradley Lucy K. , Stutz Jean C.
Published: December 2018

The Univ. of Arizona Cooperative Extension home horticulture World Wide Web site for Maricopa County, “Environmentally responsible gardening and landscaping in the low desert,” provides the public with timely, research-based, regionally appropriate information. This delivery method enables self-service access to prepared text information and high-quality images that could not be economically distributed via traditional print methods, and interactive opportunities for submitting questions.
ASHS HortBase—Opportunities for Change
Authors: Green James L.
Published: December 2018

ASHS HortBase provides opportunities for change—change in how we author and deliver information to meet the needs of the inquirer for 24-hour access to specific, concise information for planning and decision support; change from individual autonomy to global collaboration to meet more economically the increasing needs for quality horticultural information with decreasing resources; change, by adding ASHS peer review, to meet the inquirer's need for validated information and to strengthen the educator's efforts in developing scholarly, shared information resources; change to strengthen the interaction between the educator and inquirer; change to broaden and enhance ASHS's role in providing validated, up-to-date horticultural information. HortBase is a service that ASHS is uniquely qualified to provide to its members and to worldwide horticultural inquirers. HortBase's unique characteristic is the dynamic pool of ASHS members who will serve as volunteer authors and reviewers, as well as users of HortBase. ASHS members will be the continuous infrastructure to sustain HortBase and to ensure its continuous evolution and renewal.
Weed Control and Phytotoxicity of Preemergence Herbicides Applied to Container-grown Herbaceous Plants
Authors: Staats David , Hillock David , Klett James E.
Published: December 2018

Five preemergence herbicides were applied to seven herbaceous perennials to evaluate weed control efficacy and phytotoxicity. Different species were used each year. The species used during 1992 were coneflower (Rudbeckia fulgida Ait. `Goldstrum'), common foxglove (Digitalis purpurea L. `Excelsior'), Shasta daisy (Leucanthemum ×superbum Bergmans `Alaska'), Stokes's aster (Stokesia laevis Greene `Blue Danube'), and avens (Geum Quellyon Sweet `Mrs. Bradshaw'). The species used in 1993 were woolly yarrow (Achillea tomentosa L.) and woolly thyme (Thymus pseudolanuginosus Ronn.). The herbicides and rates were napropamide (Devrinol 10G) at 4 and 8 lb a.i./acre; metolachlor (Pennant 5G) at 4 and 8 lb a.i./acre; oxyfluorfen+oryzalin (Rout 3G) at 3 and 12 lb a.i./acre; trifluralin (Treflan 5G) at 4 and 8 lb a.i./acre; and oxadiazon (Ronstar 2G) at 4 and 8 lb a.i./acre. Plants were grown in no. 1 containers and weed seeds were sown onto the substrate surface. Two control treatments, no herbicides but with weeds (weedy control), and no weeds or herbicides (weed-free control) also were evaluated. Weed control was effective and similar for all herbicides tested. Napropamide at 8 lb a.i./acre caused stunting in foxglove (20% to 45% less growth compared to weed-free control). Oxyfluorfen + oryzlain at 12 lb a.i./acre caused severe phytotoxicity (≈80% to 95% of plant injured) and stunted the growth (70% to 80% less growth, sometimes plant death) of woolly yarrow. Woolly thyme was stunted by all herbicides when applied at the recommended rates (42% to 97% less growth compared to control) except for oxadiazon and oxyfluorfen + oryzlain. Woolly thyme appeared to be more susceptible to phytotoxicity due to its less-vigorous growth habit and shallow, adventitious roots that were in contact with the herbicide.
Field Sampling Short-day Onions for Bulb Pungency
Authors: Randle W.M. , Kopsell D.A. , Kopsell D.E. , Snyder R.L. , Torrance R.
Published: December 2018

The marketing of onions (Allium cepa L.) based on bulb pungency as a measure of overall flavor intensity is being considered by the onion industry. Pungency is highly variable within and among fields due to genetic and environmental factors. Therefore, a study was undertaken to develop a sampling procedure to estimate onion pungency means and variances from field-grown onions with predetermined degrees of accuracy and confidence. Two shortday onion cultivars, commonly grown in the Vidalia, Ga., area, were each randomly sampled from four different fields. The sampled bulbs were analyzed for enzymatically formed pyruvic acid (EPY) and soluble solids content (SSC) to assess pungency and sugars, respectively. EPY concentration and SSC varied between the two cultivars, among the four fields within cultivars, and among the fifty samples within each field. In a combined analysis of all eight fields, at least 1.3 ten-bulb samples would be needed per acre to come within ±0.5 μmol EPY of a field's true EPY mean with 95% confidence. If the accuracy of the estimation was lowered to ±1.0 μmol EPY of a field's true mean, then at least 0.4 ten-bulb samples would be needed per acre. Because SSC was less variable than EPY, the number of ten-bulb samples needed per acre to estimate a field's true mean was lower than the number required to estimate EPY. Establishing a sampling method to estimate an onion field's EPY and SSC will provide the mechanism to standardize onion flavor in the market place and instill greater consumer confidence in purchasing onions.
Nitrogen Source Affects Growth and Quality of Bougainvillea
Authors: Broschat Timothy K.
Published: December 2018

Container-grown Bougainvillea Comm. Ex Juss. `Brasiliensis' were fertilized with ammonium sulfate, sodium nitrate, or ammonium sulfate plus sodium nitrate as N sources. Plants fertilized with sodium nitrate were stunted, extremely chlorotic, and produced few flowers compared to those receiving ammonium sulfate. In a second experiment bougainvilleas were fertilized with 12 different controlled-release or soluble ammonium, urea, or nitrate fertilizers as N sources. Plants grown with only nitrate N were chlorotic, stunted, and produced fewer flowers compared to those receiving N from urea or ammonium salts. High substrate pH, associated with nitrate fertilization, was believed to be a cause of the chlorosis, but possible toxicity symptoms (small necrotic lesions and premature leafdrop) were also observed on nitrate-treated plants. Plants receiving controlled-release urea or potassium nitrate were of higher quality than those receiving similar uncoated fertilizers.
A Study of Tomato Ringspot Virus and Prune Brown Line Resistance in Twenty-five Rootstock-Scion Combinations
Authors: Kommineni K.V. , Gillett J.M. , Ramsdell D.C.
Published: December 2018

In a greenhouse study, fifty 1-year-old `Stanley'/`Myrobalan 29C' plum (Prunus sp.) trees were inoculated with tomato ringspot nepovirus (ToRSV) by either nematode inoculation or slash inoculation to compare how inoculation effects the onset of the prune brown line (PBL) disease. In six tests (over 2 years), slash-inoculated trees had a higher percentage of ToRSV infection than nematode-inoculated trees when root and bark samples were tested by enzyme-linked immunosorbent assay (ELISA). ELISA differences between the two treatments were significant by chi-square analysis. None of the ToRSV positives by ELISA developed a brown line at the graft union. In a second experiment, five rootstock (`Myrobalan 29C', `Marianna 4001', `Marianna 2624', `Marianna GF8-1', and `St. Julian 655-2') and five scion (`Carolyn Harris', `New York 58.900.12', `Stanley', `Valor', and `70031') combinations (total combination = 25) were established in a field plot in Traverse City, Mich., and infected with ToRSV by slash and nematode inoculation. All five rootstocks were infected, with incidences of 40% to 60% ToRSV infections after 3 years. `Marianna 2624' had the lowest incidence of PBL (5%) compared to `Myrobalan 29C', which had the highest incidence (30%). The scion 70031 in combination with either `Myrobalan 29C' or `Marianna 4001' rootstocks, produced PBL in 100% of the trees. ToRSV was detected by ELISA and northern hybridization assays. ELISA consistently detected more positives when root or bark tissues were tested, and northern hybridization assay consistently detected more positives when rootstock sucker leaves were used.
Chemical Treatments to Control Erwinia Soft Rot of Calla Rhizomes
Authors: Kuehny Jeff S. , Branch Patricia C. , Holcomb Gordon E. , Chang Wen-Chy
Published: December 2018

Dimethyl ammonium chloride (DAC, `Triathlon'), sodium hypochlorite, formaldehyde, and streptomycin (`Agri-mycin 17') were used as dips to treat Zantedeschia rehmannii superba Engl., Zantedeschia elliotiana ×maculata (Hook.) Engl., and Zantedeschia albomaculata (W.Wats.) Baill. rhizomes to control Erwinia soft rot. A 30 min 200 ppm (mg·L−1) streptomycin dip provided the best control of Erwinia soft rot for all three Zantedeschia species and a 1-hour 10% formaldehyde dip provided the second best control of inoculated rhizomes. Rhizomes inoculated with Erwinia required more days to emerge. Chemical treatments did not affect days to emergence or final plant growth.
Determining Nutrient Stress in Lettuce Plants with Machine Vision Technology
Authors: Giacomelli G.A. , Ling P.P. , Kole Jaco
Published: December 2018

The rate of change of top projected leaf area (TPLA) of lettuce (Lactuca sativa L.) seedlings was determined with machine vision technology. Differences of TPLA between control and treatment plants were detectable with this technique within 48 hours from the onset of an imposed nutrient stress. The nutrient stress treatments were 0%, 50%, 150% of the control (100%). There were no differences for the 50% and 150% treatments compared to the control plants, even after a 6-day observation period. However, the 0% treatment caused different TPLA expansion within 48 hours and required a recovery period of 3 or 4 days after being returned to normal EC levels before again attaining prestressed growth rates.
Tomato Transplant Production Using the Float System and Cupric Hydroxide
Authors: Wyatt Jim E.
Published: December 2018

Comparisons were made between conventional and float system growing methods for tomato (Lycopersicon esculentum Mill.) transplants and subsequent production. Effects of cupric hydroxide application to the interior surface of plant-growing trays were compared to untreated controls. Tomato transplants grown in the float system had higher fresh and dry weights; were larger after establishment in the field; and produced higher early yields of small, medium, and large tomatoes than plants grown by conventional methods. Mean fruit weight was higher from conventionally grown transplants early in the season. Total number of fruit and total yield were not affected by transplant production method. Transplants grown in cupric hydroxide-treated trays were larger and had fewer roots emerging through the bottom of the trays than transplants grown in untreated trays. Cupric hydroxide treatment had no effect on tomato earliness, yield, or mean fruit size.
Producing Horticultural Crops Using Hydroponic Tobacco Transplant Systems
Authors: Frantz Jonathan M. , Welbaum Gregory E.
Published: December 2018

Intensive, deep-batch, hydroponic systems that use float beds (FBs) are used extensively by the tobacco industry to produce transplants. FBs and a modified FB system with separate drying and flooding stages called ebb-and-flood (EF) beds were used to grow 12 diverse horticultural crops to maturity. Beds were filled with 570 L of water with 114 mg·L−1 N and 143 mg·L−1 K or 66 mg·L−1 N and 83 mg·L−1 K in 1994 and 1995, respectively. The EF beds were flooded for 6 hours, then drained for a 6-hour dry stage each 12 hours in 1994, and flooded for 1 hour and dried for 5 hours each 6-hour period in 1995 from May through August. Although both systems were suitable for producing Chinese water spinach (Ipomoea aquatica Forssk.—see footnote in Table 1), vegetable amaranth (Amaranthus tricolor L.), zinnia (Zinnia elegans Jacq.), and sweet basil (Ocimum basilicum L.), the EF system provided greater control over water availability and higher oxygen concentration in the root zone.
Fungus Gnat Population Development in Coconut Coir and Sphagnum peat-based Substrates
Authors: Evans Michael R. , Smith James N. , Cloyd Raymond A.
Published: December 2018

Coir and peat-based substrates were tested for their effectiveness in inhibiting the development of fungus gnat populations. The first experiment was conducted in July under relatively high temperatures (20 to 35 °C) and a second experiment was conducted in April under relatively low temperatures (20 °C). Euphorbia pulcherrima Willd. ex Klotzch `Freedom' plants were planted into 18-cm-diameter containers filled with substrates containing 80% sphagnum peat or coir, with the remainder being perlite. Half of the containers of each substrate were inoculated with fungus gnat larvae and sealed with either cheesecloth or thrips screen for Expts. 1 and 2, respectively. After 6 and 8 weeks for Expts. 1 and 2, respectively, fungus gnat adult and larval populations were sampled. Adults and larvae were recovered from coir and peat-based substrates in both experiments. In Expt. 1, significantly more adults and larvae were recovered from coir-based than peat-based substrates. In Expt. 2, significantly more adults and larvae were recovered from the peat-based than coir-based substrates. In a third experiment, the peat- and coir-based substrates used in Expts. 1 and 2 were used as well as the Iowa State greenhouse substrate, which contained 40% Sphagnum peat, 40% perlite, and 20% loam (v/v). Helianthus annuus L. `Pacino' seeds were sown into 18-cm-diameter containers filled with the test substrates. Natural infestation was allowed to occur for 6 weeks, after which time potato disks were used to sample the fungus gnat larvae population. Larvae were recovered from all substrates, and there was no significant difference in the number of larvae collected from the three substrates. Based on the results of these experiments, we concluded that coir does not inhibit the development of fungus gnat larvae populations and, when presented with options, fungus gnats will infest coir-based substrates as readily as peat-based substrates.
An Alternative Method to Managing Olive Orchards: The Coppiced System
Authors: Cantini Claudio , Gucci Riccardo , Sillari Balilla
Published: December 2018

An alternative method to managing olive (Olea europaea L.) orchards for oil production is described. Using the coppiced system, the orchard is divided into 10 plots and all trees in one plot are coppiced year 1, all trees in a second plot are coppiced year 2, etc. In this way, the olive orchard consists of 10 different-aged plots after 10 years. Then a new cycle is started by coppicing trees in plot 1 in year 11, those in plot 2 in year 12, and so on. Since hardly any pruning is done after coppicing, the main advantages of this innovative management method are to reduce labor costs and the need for skillful labor, without negative effects on fruit yield, oil yield, or alternate bearing. Pesticide application, weed control, and fertilization were performed according to standard commercial practice. As a result, this system is more convenient than other training systems used for olive trees, it is suitable for renewing old trees, and can be adopted under many cultural conditions. The coppiced management system is compatible with soils of low fertility and is sustainable for long-term olive oil production.
Factors Influencing Grape Juice Quality
Authors: Morris Justin R.
Published: December 2018

Interest in grape juice has risen as the public becomes more aware of natural foods and the specific evidence of healthful benefits of grapes. Among major preharvest conditions that influence quality of grape juice are climate, soil, cultivar, vineyard management, and maturity. Each of these factors exerts its own influence, but complex interactions among these factors must be recognized. For mechanically harvested juice grapes, cultivar takes on special importance to quality and yield as do the production system, harvest machines, postharvest handling systems, and processing method. Grape juice composition has been extensively studied, and production and processing methods have improved over the years. The following discussion deals with developments in grape juice production.
Water Management
Authors: Biernbaum John A. , Versluys Natasha Bos
Published: December 2018

Important components of water management for transplant production include water quality, the frequency and volume of water application, and the method of application. Water quality factors of concern are alkalinity, soluble salts including sodium absorption ratio (SAR), and ions at potentially toxic concentrations including boron and fluoride. The available water in individual transplant cells is influence by container size and geometry, medium particle size, medium moisture release characteristics, and wetting agents but is primarily determined by irrigation frequency and the amount of water applied at each irrigation. Irrigation scheduling can be done using several methods but is influenced by the crop stage, the water volume applied, and the frequency of drying desired. Transplants can be watered by hose and breaker, stationary sprinklers, traveling boom sprinklers, fog nozzles, or subirrigation. The outcome of experiments testing effects of transplant size, transplant age and fertilizer rates are all influenced by water management.
Controlling Height with Temperature
Authors: Berghage Robert
Published: December 2018

Temperature management has emerged as an important tool for plant height control in greenhouse production systems. This is particularly important in vegetable transplant production where chemical controls for plant height are limited or not legal. Plant height is a function of the number of nodes and the length of each internode, and both are strongly influenced by greenhouse temperatures. Node number, or formation rate, is primarily a function of the average greenhouse temperature, increasing as the average temperature increases. Internode length is strongly influenced by the relationship between the day and night temperature, commonly referred to as DIF (day temperature - night temperature). As DIF increases, so does internode length in most plant species studied. Although the nature and magnitude of temperature effects vary with species, cultivar, and environmental conditions, these two basic responses can be used to modify transplant growth. Although data are limited, controlling transplant height with temperature does not appear to adversely influence plant establishment or subsequent yield.
Transplant Growth Control through Water Deficit Stress—A Review
Authors: Liptay Albert , Sikkema Peter , Fonteno William
Published: December 2018

The theme of this review is modulation of extension growth in transplant production through restraint of watering of the seedlings. The purpose of the modulation is to produce transplants of 1) appropriate height for ease of field setting and 2) adequate stress tolerance to withstand outdoor environmental conditions. Physiological responses of the plant are discussed in relation to the degree of water deficit stress and are related to the degree of hardening or stress tolerance development in the transplants. Optimal stress tolerance or techniques for measuring same have not been fully defined in the literature. However, stress tolerance in seedlings is necessary to withstand environmental forces such as wind and sand-blasting after the seedlings are transplanted in the field. It is also imperative that the seedlings undertake a rapid and sustained rate of growth after outdoor transplanting. Water deficit stress applied to plants elicits many different physiological responses. For example, as leaf water potential begins to decrease, leaf enlargement is inhibited before photosynthesis or respiration is affected, with the result of a higher rate of dry matter accumulation per unit leaf area. The cause of the reduced leaf area may be a result of reduced K uptake by the roots with a concomitant reduction in cell expansion. Severe water deficits however, result in overstressed seedlings with stunted growth and poor establishment when transplanted into the field. In transplant production systems, appropriate levels of water deficit stress can be used as a management tool to produce seedlings conducive to the transplanting process.
Understanding Root Systems to Improve Seedling Quality
Authors: Nicola Silvana
Published: December 2018

Root architecture can be very important in plant productivity. The importance of studies on root morphology and development is discussed to improve seedling growth. Root systems of dicotyledonous species are reviewed, with emphasis on differences between growth of basal and lateral roots. The presence of different types of roots in plant species suggests possible differences in function as well. The architecture of a root system related to its functions is considered. Classical methods for studying root systems comprise excavation of root system, direct observation, and indirect analyses. While the first method is destructive and the third is effective in understanding root architecture only on a relatively gross scale, observation methods allow the scientist a complete a nondestructive architectural study of a root system. The three groups are reviewed related to their potential to give valuable information related to the root architecture and development of the seedling, with emphasis on the availability of a medium-transparent plant-growing system, enabling nondestructive daily observations and plant measurements under controlled environmental conditions. Effects of CO2 enrichment on seedling growth is reviewed, emphasizing the effects of CO2 on root growth.
Transplant Age in Vegetable Crops
Authors: Vavrina Charles S.
Published: December 2018

The research reviewed here represents the majority of the information available on transplant age to date. When the results of these studies are distilled down to the “ideal” transplant age for setting of a specific crop, we generally arrive at the recommendations found in the 1962 edition of Knott's Handbook for Vegetable Growers. The conflicting results in the literature on transplant age may be due to the different environmental and cultural conditions that the plants were exposed to, both in the greenhouse and in the field. The studies did reveal that the transplant age window for certain crops might be wider than previously thought. Older transplants generally result in earlier yields while younger transplants will produce comparable yields, but take longer to do so. Our modern cultivars, improved production systems, and technical expertise enable us to produce high yields regardless of transplant age. The data, in general, support the view that if a vegetable grower requires resets after an catastrophic establishment failure (freeze, flood, etc.), they need not fear the older plants usually on hand at the transplant production facility.
Seed Treatment and Cultural Practices Influence Seedling Growth of Hydroponic Lettuce
Authors: Korkmaz Ahmet , Pill Wallace G. , Cobb Bruce B.
Published: December 2018

Raw, pelleted or germinated seeds of `Cortina' lettuce (Lactuca sativa L.) were sown in phenolic foam cubes preplant soaked in water or fullstrength nutrient solution (2 mmho·cm−1, 2 dS·m−1). The seeds were left uncovered or covered with fine vermiculite (grade 5), and seedling emergence characteristics were subsequently determined. Shoot fresh masses and their coefficients of variation (cv) by 9 days after planting (1 or 2 true leaves) and by 31 days after planting (4 or 5 true leaves) also were determined. Soaking the cubes in nutrient solution rather than water increased seedling emergence percentage and rate, and increased shoot fresh masses by 9 or 31 days after planting. This increased shoot fresh mass was accompanied by lower cv of shoot fresh mass by 9 days after planting, but not by 31 days after planting. Covering seeds with vermiculite decreased emergence from 99% to 93%, but increased shoot fresh mass by 9 and 31 days after planting when cubes were soaked in water, but not in nutrient solution. Seed treatments influenced shoot fresh mass at 9 and 31 days after planting in the order germinated > pelleted > raw. Germinated seeds resulted in lower cv of shoot fresh mass (24%) than raw or pelleted seeds (29%) by 31 days after planting. Thus, sowing germinated seeds into foam cubes soaked in full-strength nutrient solution, with or without covering the seeds with vermiculite, produced the heaviest and most uniform seedlings.
Evaluating Leonardite as a Crop Growth Enhancer for Turnip and Mustard Greens
Authors: Duval John R. , Dainello Frank J. , Haby Vincent A. , Earhart D. Ron
Published: December 2018

The objectives of this study were to determine if the use of leonardite as a fertilizer supplement improved crop growth and if there was a residual effect from previous applications. Three planting sequences were established and leonardite applied at 0, 50, 100, 200, and 400 lb/acre (0, 56.1, 112.1, 224.3 and 445.6 kg·ha−1). Subplots were treated at the first, the first and second, or all at three planting sequences. `Purple Top White Globe' turnip (Brassica rapa L.) and `Florida Broadleaf' mustard greens (Brassica hirta L.) were used as the indicator crops in the first two and last sequences, respectively. No differences in plant growth were observed among number of applications or treatment rate. Differences in soil potassium and iron were observed.
The Effect of an Interdisciplinary Garden Program on the Environmental Attitudes of Elementary School Students
Authors: Skelly Sonja M. , Zajicek Jayne M.
Published: December 2018

Project GREEN (Garden Resources for Environmental Education Now) is a garden program designed to help teachers integrate environmental education into their classroom using a hands-on tool, the garden. The objectives of this research project were to 1) develop an interdisciplinary garden activity guide to help teachers integrate environmental education into their curricula and 2) evaluate whether children developed positive environmental attitudes by participating in the activities. Students participating in the Project GREEN garden program had more positive environmental attitude scores than those students who did not participate. Second-grade students in the experimental and control groups had more positive environmental attitudes than fourth-grade students. In addition, this research found a significant correlation between the number of outdoor related activities students had experienced and their environmental attitudes.
Using Isothiazolone Biocides to Control Microbial and Fungal Contaminants in Plant Tissue Cultures
Authors: Niedz Randall P.
Published: December 2018

Controlling bacterial and fungal contamination in plant tissue cultures is a serious problem. Antibiotics are currently used but are not always effective, can alter plant growth, and are costly, and resistant strains can result with extensive use. Plant preservative mixture (PPM) contains a mixture of two isothiazolones—methylchloroisothiazolinone and methylisothiazolinone, which are a class of broad-spectrum, widely used industrial biocides. The isothiazolones used in PPM are reported by the manufacturer to be nonphytotoxic at concentrations suitable for the prophylactic control of microbial contaminants in plant tissue cultures. Our results indicate that PPM can be routinely added to tissue culture medium to control air- and waterborne bacterial and fungal contaminants effectively.