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- Author or Editor: A. Green x
The University of Georgia trial garden has been in existence since 1982, and the method of evaluation and distribution of taxa has evolved over the years. Annual and perennial taxa are evaluated systematically, over the entire season, providing season-long summaries for each one. Annuals are evaluated every 2 weeks, and scores are based on plant performance, including foliar health, flower numbers and the appearance of disease and insect damage. Perennials are evaluated similarly, however flowering time, flowering persistence and height in the landscape are also noted. Summaries for each taxon are presented in tabular and graphic form. Many new crops have been evaluated and introduced to the floriculture industry. New crops are placed in the horticulture gardens and evaluated by garden personnel and by commercial growers and landscapers. Plants have been distributed free of charge to propagators and growers, resulting in rapid market acceptance of successful taxa.
A series of four experiments were undertaken to evaluate the effects of individual and combined applications of prohexadione-Ca (P-Ca) and GA4+7 primarily on fruit russet, but also on fruit set, fruit weight, early season shoot growth, and fruit maturity of ‘Golden Delicious’ apples (Malus × domestica Borkh.). A single application of P-Ca (138 to 167 mg·L−1) at petal fall (PF) reduced the severity of russet in three of the four experiments; however, multiple applications of 20 ppm GA4+7 at 10-day intervals beginning at PF generally reduced russet more effectively than P-Ca. P-Ca did not reduce the efficacy of GA4+7 sprays for russet reduction. However, GA4+7 sprays reduced the inhibitory effects of P-Ca on shoot growth measured 30 days after PF. A single application of P-Ca at PF had no effect on mean fruit weight at harvest. Fruit size was lowest for the combined P-Ca and GA4+7 treatment in every experiment, although there was a significant interaction between P-Ca and GA4+7 sprays on mean fruit weight in only one experiment. There were no consistent effects of P-Ca and GA4+7 sprays, alone or in combination, on fruit maturity parameters at harvest. These data show that a single application of P-Ca at PF reduced russet severity, and the effects of P-Ca and GA4+7 sprays on russet can be additive. The economic benefits resulting from a reduction in russet severity after combined P-Ca and GA4+7 sprays will need to be balanced against their occasional negative effect on fruit size. Chemical names used: prohexadione-calcium [3-oxido-4-propionyl-5-oxo-3 cyclohexenecarboxylate formulated as Apogee (27.5% a.i.)].
A closed, insulated, pallet production system (CIPPS) has been designed to meet current challenges: 1) Elimination of production related pollution. 2) Reduction and conservation of resources. 3) Improvement of working conditions. 4) Alternatives to pesticides. 5) Prevention of temperature extremes and rapid temperature fluctuations in the plant environment. Biological feasibility of CIPPS was established in research on pathogen epidemiology, water and fertilize efficiency, plant growth and development in CIPPS. Water and fertilizer ion movement-removal in the closed system was plant-driven in response to growth and transpiration; water and fertilizer use in CIPS was 10% of that applied to open containers. Growth of 28 plant species ranging from herbaceous annuals to woody perennials was greater in CIPPS than in control, individual containers. Phytophthora cinnamomi did not spread from inoculated to noninoculated plants within CIPPS. Inoculation with nonpathogenic bacteria increased plant growth (gfw) in CIPPS but not in open plant containers.
Harvest date, bulb weight, and the number of scale and leaf primordia of the daughter axis of July-to-October-harvested bulbs of Lilium longiflorum Thunb. cvs. Croft, Ace and Nellie White were harvest maturity indices (HMI) evaluated as predictors of subsequent bulb responses to dormancy-removing and flower-forcing treatments. Higher HMI ratings associated with late harvest, e.g., increased bulb size and increased numbers of daughter leaf primordia, favored early shoot emergence and flowering with standard forcing programs. However, early-harvested bulbs with lower HMI ratings could be forced with equal or superior quality when given modified forcing regimes. Early-harvested bulbs without cold treatment were more responsive to long day (LD) flower induction than late-harvested bulbs. The optimum dormancy-removing temperature was always 15°C, but the flower-inducing optimum tended to shift from 10° to 5° with progressively later harvest. However, 10° storage favored earlier emergence, greater leaf and flower numbers, while total days to flower from potting remained the same at the 2 inductive temperatures. The interaction of bulb maturity at harvest and forcing regime emphasize the necessity of tailoring the forcing regime to the HMI of the bulb.
Phytophthora diseases are economically important, requiring the use of chemical fungicides and, more recently, biological controls. Recent research suggests that composted bark products may lessen the impact of the disease, even in the absence of these chemicals. An experiment was conducted to compare chemical and biological fungicides to untreated pine bark compost. Impatiens wallerana plugs were transplanted from 288 trays into 1801 trays. All plants were planted into Berger BM-7, 35% composted bark mix (Berger Horticulture, Quebec, Canada). Media was prepared by premixing one of the five following fungicide treatments: 1) Control, 2) Banrot at 0.6 g/L, 3) Root Shield at 1.6 g/L, 4) Actino-Fe at 5.1 g/Ll, or 5) SoilGard at 1.6 g/L. Plants received no fertilizer. Three strains of Phytophthora were grown in 25 °C on clarified V8 media. Pathogenic inoculum was made by macerating the growth media and fungi in 100 ml H2O. Mixture was pulse-blended for 1 min, and an additional 200 mL dH2O was added. Inoculation was 5 ml per plant. Flats were kept on a misting bench, and misted twice daily for 15 min. The experiment was set up using a RBD repeated six times with three plants per rep. Plants were rated weekly for 5 weeks using a damage scale of 0 to 5, with 0 indicating no sign of disease and 5 being dead. Statistical analysis was conducted using a Chi-Square. Disease incidence between the biological, chemical, and composted bark treatments did not differ, with all treatments providing complete control. At least in this study, the use of composted pine bark media provided Phytophthora control equivalent to current chemical and biological fungicides.
An automatic sampling system for monitoring CO2 evolution and O2 uptake of irradiated fruits under a continuous air flow was used. All fruits showed increased respiratory activities immediately following irradiation. The respiratory activities of irradiated tomatoes and strawberries decreased within 24 hr following irradiation, while those of oranges and grapefruit remained at elevated levels. The respiratory quotients (RQ) of irradiated citrus fruits were higher than those for control fruits, while those of tomatoes and strawberries were not. All RQ values were less than unity.
Urban foresters must be able to accurately assess costs associated with planting trees in the built environment, especially since resources to perform community forest management are limited. Red oak (Quercus rubra) and swamp white oak (Q. bicolor) (n = 48) that were produced using four different nursery production systems—balled and burlapped (BNB), bare root (BR), pot-in-pot container grown (PIP), and in-ground fabric (IGF)—were evaluated to determine costs of planting in the urban environment. Costs associated with digging holes, moving the trees to the holes, and planting the trees were combined to determine the mean cost per tree: BNB trees cost $11.01 to plant, on average, which was significantly greater than PIP ($6.52), IGF ($5.38), and BR ($4.38) trees. Mean costs for BR trees were significantly lower than all other types of trees; IGF trees were less expensive to plant (by $1.14) than PIP trees, but this difference was not statistically significant (P = 0.058). Probabilities that cost per tree are less than specific values also are calculated. For example, the probabilities that IGF and BR can be planted for less than $8.00 per tree are 1.00. The probability that a PIP can be planted for less than $8.00 is 0.86, whereas the probability for a BNB tree is just 0.01. This study demonstrates that the cost of planting urban trees may be affected significantly in accordance with their respective nursery production method.
HortBase, a global electronic information system for classroom, distance education, lifelong learning and Extension, incorporates three innovative concepts: 1) Three-dimensional team-creation of the electronic information files (subject, communications, and information science authors working together from start to finish to create the file). Team-creation respects, uses, and develops the professional strengths of each of the three team members. 2) National peer review by each file creator's professional society (ASHS, ACE, and ASIS, respectively) not only enhances information quality and continued professional development of the authors, but also creates wider acceptance and use of the information. 3) Nationwide, or even worldwide, distribution of the workload and costs of creation, review, revision, and distribution of the electronic information, rather than individual efforts-expenditures within each state, will minimize redundancy and will enable us to do more as a group and to specialize individually. Capabilities of electronic information systems facilitate, indeed require, this new approach to information development and delivery.