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R.D. Berghage

Constructed wetland biofilters have been widely used in recent years to provide secondary or tertiary water treatment, effectively reducing BOD, TSS, nitrate and ammonium, and some organic pollutants from municipal, industrial, and agricultural waste sources. The greenhouse and nursery industries, like all agricultural enterprises, have found themselves under increasing pressure to reduce or eliminate discharge of contaminated wastewater. In response, many greenhouse and nursery operators have installed, and are using, a variety of runoff containment and recirculating irrigation systems. While effective in reducing or eliminating wastewater discharge, these systems can become contaminated themselves and require treatment of the water before it can be reused in the irrigation system. Further, if the water should become contaminated and unusable, environmental discharge of this spent water from a recirculating irrigation system is perhaps even more problematic than simply allowing the excess irrigation water to be dumped in the first place. Potential contaminants in a recirculating irrigation system could include pesticide and other organic residues, excess fertilizer and non-fertilizer salts, and plant pathogens. The primary concern in greenhouse and nursery discharge wastewater is usually fertilizer salts, although pesticide and other organic chemical residues may also be of concern. Biological filtration using constructed wetlands may be a simple low-cost method for greenhouses and nurseries to treat these contaminants.

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R.D. Berghage and D.J. Wolnick

Potential consumers were surveyed in the spring of 1996 to gain insight into preferences for flower and leaf color in New Guinea impatiens (Impatiens hawkeri Bull.). Survey participants indicated a preference for bright solid colors, and bicolor flowers. The most preferred solid flower colors were red-violet, and red. The least preferred solid flower colors were pink and blush. Potential consumers ranked bicolor flowers over their solid color counterparts. Red and variegated foliage were preferred to solid green. Foliage with solid red upper or lower surfaces were preferred 2:1 over variegated foliage.

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R.D. Berghage and N.K Lownds

Writing is an integral part of a career in horticulture. Most successful horticulturists write not only in communicating with peers, but also in keeping extensive journals or records of their activities. These tasks use different writing skills. Writing in horticulture classes should reflect, encourage, and provide practice in both types of writing. Assignments should reflect the students' career choices and provide writing practice in an appropriate genre.

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Martin R. McGann and Robert D. Berghage

The Pennsylvania State University Medieval Garden (PSMG) showcases varieties of medieval plants used as ornamentals, food crops, medicinal ingredients, and for household purposes in a stylized setting representing a medieval garden. Since its installation, various colleges within the university as well as community groups have used the garden as an alternative classroom for learning activities, educational demonstrations, and events related to the medieval period. This article focuses on the initial development of the garden design and how the installation and continued use as a classroom has contributed to meeting educational goals for students in the landscape contracting program at the Pennsylvania State University and the Pennsylvania Governor's School for Agricultural Sciences.

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M.J. Ricci, N.K. Lownds and R.D. Berghage

Studies were conducted to determine postharvest longevity of field grown Desert Marigold (Baileya multiradiata) and perennial Aster (Aster bigelovii) cut flowers. Flower stems were cut and placed into storage at 4, 7, 15 and 24C in the dark. Storage treatments included DI water, citric acid (CA), floralife (F), silver thiosulfate (STS) and modified atmosphere packaging (MAP). Flowers were rated daily using a scale of 1 (optimum condition) to 4 (unsaleable). Postharvest longevity of Baileya decreased quadratically with increasing temperature, (r2=0.67, P=0.001) between 4 and 24C. For Aster, postharvest longevity was greatest at 7C (13.3 days), slightly less at 4C (10.5 days) and only 5 days at 15 and 24C. Postharvest longevity of Baileya at 4C was doubled using STS, but was not affected by CA or F. MAP increased postharvest longevity of Aster 1.6- to 2.2-fold at each temperature. Other storage treatments for Aster were ineffective. The results suggest MAP may have potential as a storage technique for commercial cut flowers.

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N.K Lownds, M.G. White and R.D. Berghage

Previous work has shown that container grown landscape plants use, and likely need, much less water than is typically applied. Therefore, studies were conducted to quantify the relationships between water loss and water stress responses using several drought tolerant (Cassia corymbosa, Leucophyllum frutescens, Salvia greggii) and traditional landscape plants (Euonymus japonicus, Pyracantha coccinea). Water stress was induced by withholding water and water loss measured gravimetrically. The shape of the water loss curve was similar for all species being, Y = a + bx + cx2 (r2 > 0.95). The rate of ethylene production began to increase 24 hr after irrigation, reaching a maximum 36-48 hr after irrigation and then decreasing. Maximum ethylene production occured at 35-47% water loss irrespective of species or rate of water loss. Stress symptoms (wilting leaf discoloration and abscission) followed a similar pattern. The potential for monitoring gravimetric water loss to schedule container irrigation will be discussed.

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N.K Lownds, M.G. White and R.D. Berghage

Previous work has shown that container grown landscape plants use, and likely need, much less water than is typically applied. Therefore, studies were conducted to quantify the relationships between water loss and water stress responses using several drought tolerant (Cassia corymbosa, Leucophyllum frutescens, Salvia greggii) and traditional landscape plants (Euonymus japonicus, Pyracantha coccinea). Water stress was induced by withholding water and water loss measured gravimetrically. The shape of the water loss curve was similar for all species being, Y = a + bx + cx2 (r2 > 0.95). The rate of ethylene production began to increase 24 hr after irrigation, reaching a maximum 36-48 hr after irrigation and then decreasing. Maximum ethylene production occured at 35-47% water loss irrespective of species or rate of water loss. Stress symptoms (wilting leaf discoloration and abscission) followed a similar pattern. The potential for monitoring gravimetric water loss to schedule container irrigation will be discussed.

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R.D. Berghage, E.J. Holcomb and A.H. Michael

The New Guinea Impatiens (I. hawkeri Bull.) has become one of the most important spring crops for many growers. Rapid and continuous development of new and improved cultivars have lead to tremendous diversity in flower color, leaf color, plant size, and growth rate. Penn State has conducted large-scale garden evaluations of New Guinea Impatiens since the mid-1990s. Each cultivar is evaluated in both the sun and shade for uniformity, flowering, foliage, and overall growth and form. Ratings use a 1 to 5 scale with 1 being unacceptable, 2 = poor, 3 = fair, 4 = good, and 5 = excellent. Height, width, and flower size are measured in August. One hundred fourteen cultivars in 15 commercial series have been in the trials for two or more seasons. There are significant differences in the performance of cultivars and series in the trials. `Celebrette', `Paradise', `Pure Beauty', `Celebration', and `Riviera' were the top-performing series. Within each series there were outstanding cultivars and others that did not perform as well. Plants performed better in the shade than in the sun. The average rating for plants grown in the sun was 3.3 while the rating for shade grown plants was 3.8. New Guinea impatiens were shorter (11 vs. 12.3 cm), spread less (18.9 vs. 22.1 cm), and had smaller flowers (4.8 vs. 5.3 cm wide) in the sun than in the shade, respectively. There were no significant interactions between sun vs. shade, and cultivar or series.

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Michael D. Orzolek, Cathy Thomas, Robert D. Berghage and Paul R. Heller

The dramatic reduction in available greenhouse insecticides and the potential for increased insect resistance has necessitated a change in insect control techniques. Because of the large acreage of greenhouse production in Pennsylvania and the need for a more environmentally effective method of controlling insects in greenhouses, an aggressive Integrated Pest Management research program was initiated and has been on-going since 1989. Our objectives were to develop a bibliography of major insect pests; to determine effectiveness of parasitoids on greenhouse and silverleaf whitefly, western flower thrip, and aphids; to reduce pesticide usage; and to comply with worker protection standards. The program was implemented by a joint venture among the Pennsylvania State Univ. faculty and technical staff, grower cooperators, the Pennsylvania Dept. of Agriculture, and the Pennsylvania Vegetable Growers Association. The IPM program was started with an active scouting and monitoring program in commercial houses to determine threshold levels. Control measures were implemented with biological controls, cultural management, and lastly chemical. In addition, the implementation of the results of this research to commercial growers has resulted in the formation of a Greenhouse Crop Management Association. Results of the 5-year research program are discussed.