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Auburn Univ.'s shade tree evaluation is an ongoing study comparing a moderately diverse range of species, varieties and cultivars of larger-growing trees. Initiated in 1980, there were 250 tree selections planted in three replications located at the Piedmont Substation near Camp Hill, Ala. Among the published “fruits” of the evaluation have been critical comparisons of 10 Acer rubrum selections with respect to growth and fall color characteristics; growth rate and aesthetic characteristics of fourteen Quercus selections; growth and fireblight susceptibility of 10 Pyrus calleryana selections; and the best performing trees overall in the first 12 years of the study. The shade tree evaluation has served as an important precedent for initiation of six additional landscape tree tests in Alabama. Besides its benefits as a research project, the shade tree evaluation has provided a living laboratory for a wide range of educational audiences including landscape and nursery professionals, county extension agents, urban foresters, Master Gardeners, garden club members, and horticulture students. Knowledge gained from the shade tree evaluation has also been shared through presentations at many meetings and conferences.

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The effects of selected environmental factors [temperature, photosynthetic photon flux (PPF), and photoperiod] that contribute to optimal vegetative growth of Canary Island ivy (Hedera canariensis Willd.) were investigated. Experiments were conducted in growth chambers at constant day/night temperatures of 16 and 26 °C. The greatest number of leaves (6.1) and plant height (38.0 cm) were achieved with PPF of 210 μmol·m-2·s-1 and an 8-hour photoperiod at 16 °C. The greatest branch number (3.9), leaf area (41.4 cm2) and leaf chlorophyll content (1.02 mg·cm-2) were achieved with a PPF of 210 μmol·m-2·s-1 with a 12-hour photoperiod at 16 °C. Under normal greenhouse or field conditions, Canary Island ivy rarely branches; however, a PPF of 210 μmol·m-2·s-1 also induced branching.

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The effects of overhead and drip tube irrigation on twospotted spider mite (TSMs) (Tetranychus urticae Koch) and predatory mite (PMs) (Phytoseiulus persimilis Athias-Henriot) populations, as well as the biological control of TSMs by PMs, were investigated on Impatiens wallerana Hook. f. `Impulse Orange'. To determine the effects of the two irrigation methods on TSM populations, plants were inoculated with female TSMs 6 weeks after seeding. Plants were then irrigated twice every three days, and TSM counts were taken 3 weeks later. To assess the effects of irrigation method on PMs, plants were inoculated with TSMs 6 weeks after seeding, PMs were released 10 days later, plants were irrigated about once per day, and the number of predatory mites on plants was counted 3 weeks after release. To assess the effects of irrigation method on the biological control of TSMs by PMs, plants were inoculated with TSMs and PMs were released as before, but then plants were irrigated either three times every 2 days or three times every 4 days using either drip or overhead irrigation. The number of TSMs on plants and the number of leaves showing TSM feeding injury were measured 3 weeks after predator release. Overhead watering significantly reduced TSM and PM populations as much as 68- and 1538-fold, respectively, compared to drip irrigation with microtubes. Perhaps more important, overhead watering with or without predators significantly reduced the number of leaves sustaining TSM feeding injury as much as 4-fold compared to drip irrigation. These results confirm the common observation that TSM infestations and injury may be reduced by irrigation systems that wet plant foliage. However, predators still reduced TSMs even though overhead irrigation had a suppressive effect on predatory mites. Predators are particularly useful for reducing TSM injury when plants are watered infrequently. Overhead watering could be used in tandem with biological control as a component of an integrated crop management program for TSMs in ornamental greenhouses by rapidly lowering TSM population levels in hot spots before PMs are released.

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Pecan [Carya illinoinensis (Wangenh.) C. Koch `Melrose'] and pear (Pyrus calleryana Decne. `Bradford') trees in the nursery grew more in containers designed to hold water in the lower portion. The water-holding reservoir was obtained either by placing 76-liter containers in a frame holding water to a depth of 6 cm or by using containers with drainage holes 6 cm from the bottom. Continuous waterlogging at the bottom of containers resulted in root pruning and root death in the lower portion of the containers, but roots grew well above the constantly wet zone. Fresh weight of plant tops and trunk diameters were greater after two growing seasons in the containers with water reservoirs compared to those grown in similar containers with no water reservoirs. Total root dry weight was unaffected.

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Before analyzing the responses of Alabama garden center employees about the training they had received, we determined how satisfied 100 Alabama Master Gardeners were with the employee-s who helped them in the store from which they most often purchased plants for their homes, landscapes, or gardens. We mailed the primary survey to 472 employees of 130 retail garden center businesses in Alabama to determine the percentage of employees who received job training and the amount, frequency, and methods of training they received while working for their current employers (37% responded). Employees were categorized as managers (28%) or subordinate employees (72%) and full-time (72%) or part-time (28%). Forty-four percent of the employees had received some training at the time they were hired. Training continued for 68% of the respondents. Only 39% of the employees had a written description of their job responsibilities discussed with them. Most (85%) believed the training they received had prepared them to do their jobs well, but 82% said more training would increase their confidence in their work performance. Most employees were trained by one-on-one instruction (60%) and small-group sessions (5 or fewer persons) (65%). Few employees received training from videotapes (5%) or educational seminars (26%), and most that did were managers and full-time employees.

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The unprecedented, yet sustained, growth of undergraduate enrollment in the Department of Horticulture at Auburn University can be attributed to many factors, including an increased industry demand for horticulture graduates nationwide. Perhaps the basis of some of Auburn's growth, while appearing to be unique, may be of value in other programs. This paper chronicles the growth of the Auburn Department of Horticulture undergraduate program and highlights some of the traditional teaching methods employed within the department as well as some unique methods that contribute to the program. The paper offers ideas and practices that may be beneficial to other horticulture programs and may encourage teaching faculty at other institutions to publish similar departmental profiles that may prove beneficial to colleagues.

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The influence of three shade levels on propagation of golden barberry (Berberis koreana Palib. × B. thunbergii DC.) selection `Bailsel' was evaluated in studies initiated 29 Apr. and 18 Sept. 1998. After 57 days, root ratings were higher in plants under 70% and 80% shade treatments than 60% shade for both studies. In study one, viability was lower among plants under the 60% shade level than those under 70% or 80% shade levels. Viability among treatments was similar in study two. Based on visual observations, leaf retention appeared greater under the 70% and 80% shade treatments than the 60% shade treatment for both studies. Cuttings rooted under 70% and 80% shade levels generally had a uniform golden hue, whereas the foliage of those rooted under 60% shade often had a red hue and showed signs of desiccation for both studies. Root dry weights were greater for cuttings under the 60% shade levels than 70% or 80% shade.

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Managed turfgrass species require frequent inputs to maintain an acceptable level of density and appearance. Among these inputs, the N supply is often the most limiting input in terms of growth and development of the turfgrass stand. However, N fertilization has been linked to nonpoint source (NPS) pollution of groundwater and natural water bodies. White clover (WC), which would provide N in mixed turfgrass swards, could help reduce NPS pollution from N fertilization of turf. To test the feasibility of introducing WC into existing turf, a field study was designed to determine the best method of incorporating WC in mature stands of two cool-season grasses. Two varieties of WC, ‘Dutch White’ (DW), and ‘Microclover’ (MC), were sown (24.4 kg·ha−1) into existing stands of kentucky bluegrass (KBG) (Poa pratensis L.) and tall fescue (TF) (Festuca arundinacea Schreb.). Establishment techniques tested included core aeration (CA), scalping (SC), and vertical mowing (VM) compared with direct sowing into the turfgrass stand. Establishment treatments were performed in April, July, and October of 2012–13 to examine for any seasonal timing effect on establishment. No significant difference in plant numbers (individual clover plants per square meter) was found between WC varieties among planting dates and techniques. The SC treatment resulted in the highest individual clover plant numbers. However, turfgrass recovery was significantly slower from the SC treatment than all other treatments. The summer planting date yielded the highest WC plant numbers. Recovery of the turfgrass from all preplanting treatments was also highest at the spring and summer planting dates.

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The Auburn University Shade Tree Evaluation is an ongoing trial of a moderately diverse range of species, and varieties of larger-growing trees. The study was initiated in 1980 with the planting of 250 selections in three replications of three trees each, located at the Alabama Agricultural Experiment Station, Piedmont Substation in east-central Alabama. Among the fruit of the investigation have been an evaluation of 10 red maple (Acer rubrum) selections with respect to growth and fall color characteristics; a comparison of growth rate and aesthetic characteristics of 14 oak (Quercus) selections; a comparison of the growth and fireblight (Erwinia amylovora) susceptibility of 10 callery pear (Pyrus calleryana) selections; and a 12-year evaluation of the overall best performing trees. The Shade Tree Evaluation has served as a precedent for six additional landscape tree evaluations in Alabama. It has provided a living laboratory for a wide range of educational audiences including landscape and nursery professionals, county extension agents, urban foresters, Master Gardeners, garden club members, and horticulture students. Knowledge gained from the Shade Tree Evaluation has been shared through presentations at meetings and conferences.

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Biological and chemical control strategies for the twospotted spider mite (TSM; Tetranychus urticae) were evaluated in a greenhouse experiment replicated over time in mixed production of ivy geranium (Pelgargonium peltatum ‘Amethyst 96’) and two impatiens cultivars (Impatiens wallerana ‘Impulse Orange’ and ‘Cajun Carmine’). Chemical control using the miticide bifenazate was compared with two release strategies for biological control using the predatory mite, Phytoseiulus persimilis. Specific treatments included 1) a single application of bifenazate at 0.3 g·L−1 formulation (22.6% a.i.); 2) a single release of predatory mites at a 1:4 predator to pest ratio based on sampled pest density; 3) a weekly release of predatory mites at numbers based on the area covered by the crop; and 4) an untreated control. TSM populations were monitored for 4 weeks. After another 4 weeks, when plants were ready for market, plant quality ratings were recorded. The number of TSM per leaf dropped for all treatments on all genotypes but increased in the untreated plants. On ivy geranium, the fact that there were significantly more TSM on untreated plants was not reflected in average plant quality, but it did reduce the proportion of containers rated as salable at full price compared with both chemical and biological control. On impatiens, both treatment and cultivar had significant effects on the mean plant quality rating and on the proportion of containers rated as salable at full price. The use of a sampling plan to determine the appropriate number of predators to release was as effective as the currently recommended management treatments for TSM in bedding plants.

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