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Starting in 1999, the University of Arkansas implemented an annual workshop to prepare employees of the landscape and retail sectors for the spring rush. Since the sales and service sectors account for 91% of the annual gross sales for the Arkansas Green Industry it was felt a specialized workshop was justified. The program format consists of three, one-hour sections devoted to the most common disease, insect, and weed problems that these professionals face. The program is presented in the evening so more employees can attend. The format has changed over the years from the typical road-trip, to a compressed video conference format, and finally back to a live performance in the two major population markets in the state. A detailed handout is provided so participants can easily follow the program. These same notes serve as a handy reference when these employees return to their jobs. To further expand the audience, an interactive CD is now available that summarizes the three topic areas. Because the CD program is hyperlinked, viewers can either proceed through the program in a linear fashion or easily search for answers on specific topics of interest. For disease and insect topics, life cycle and host information is provided. Control measures are separated into chemical and biological options. A recent addition to the CD is the inclusion of actual photographs of consumer products to illustrate examples of suitable active ingredient options for the control of specific pests or diseases.
The iron-efficiency of pin oak (Quercus palustris) and red oak (Quercus rubra) grown in a static solution culture system was evaluated. Treatments included nutrient solutions with no iron, an unavailable iron form (Fe2 O3), and an available iron form (FeEDDHA), each adjusted to a starting pH of 5.5 or 7.0. Both oaks grew better when the available form of iron was used than when the solution contained unavailable or no iron. There was no difference in the height or leaf color for plants of either species when grown with unavailable or no iron. Red oak grown with an available iron form significantly lowered the pH of the solution prior to a growth flush. A similar drop in solution pH was not observed for pin oak growing under similar conditions.
The iron-efficiency of pin oak (Quercus palustris) and red oak (Quercus rubra) grown in a static solution culture system was evaluated. Treatments included nutrient solutions with no iron, an unavailable iron form (Fe2 O3), and an available iron form (FeEDDHA), each adjusted to a starting pH of 5.5 or 7.0. Both oaks grew better when the available form of iron was used than when the solution contained unavailable or no iron. There was no difference in the height or leaf color for plants of either species when grown with unavailable or no iron. Red oak grown with an available iron form significantly lowered the pH of the solution prior to a growth flush. A similar drop in solution pH was not observed for pin oak growing under similar conditions.
The decline in the availability of pine (Pinus taeda L.) bark (PB) supplies and increasing prices have caused concerns in the nursery industry. Research was conducted to evaluate the effect of parboiled rice (Oryza sativa L.) hulls (PBH) as a substrate amendment to PB-based container substrates on the growth of Spiraea ×bumalda L. ‘Anthony Waterer’ and to examine the changes in physical properties of the substrates during long-term production cycles under outdoor nursery conditions. Six substrates were formulated by blending PB with 0%, 20%, 40%, 60%, 80%, or 100% PBH (by volume). Substrate composition affected plant growth components evaluated, generally decreasing growth as the amount of PBH increased. However, amending PB with up to 40% PBH did not result in a significant decrease in plant growth or increase the volume or frequency of irrigation for container-grown spirea. Physical properties of substrates amended with PBH improved over time. Based on these results, PB-based substrates amended with up to 40% PBH retained physical properties that were generally within current guidelines for nursery container substrates after one (25 weeks) and two (70 weeks) growing seasons.
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.
Abstract
Rooting of light-grown cuttings of mung bean [Vigna radiata (L.) R. Wilcz.] was stimulated by wounding and by the ethylene-releasing compound (2-chloroethyl)phosphonic acid (ethephon) at 0.1, 1.0, and 10.0 mg/liter with a maximum response at 1 mg/liter. The inhibitor of ethylene synthesis, aminoethoxyvinylglycine (AVG), at 10 µm, significantly decreased root number in wounded cuttings, but ethephon overcame this inhibition. Rooting in wounded cuttings was stimulated by indolebutyric acid (IBA) at a concentration of 5 × 10−6 m but root numbers decreased by 56% with AVG + IBA. Application of ethephon or IBA, and extensive wounding, caused an upward redistribution of roots away from the base of the cuttings.
Abstract
A description for the design and use of a flowing solution culture for the mung bean bioassay is presented. A single module for the system is an assembly of polyvinyl chloride (PVC) pipe, Tygon tubing, and 12 hypodermic syringe barrels to accomodate 60 cuttings of mung bean, Vigna radiata (L.) R. Wilcz, (5 per syringe barrel). Solution is circulated by an electric fluid pump. A comparison of this system with conventional vial culture indicates no difference in mean root numbers and their standard deviation, although a more stable solution pH is maintained in the flowing system. In the vial system, pH drifted by as much as 1.4 units within 12 hours, but only 0.2 units in the flowing system. The system presented is ideal for investigations where a stable rooting environment is required.
The Univ. of Arkansas initiated a statewide plant evaluation program in 1999. This trial will enable us to evaluate plants on a statewide basis, improve statewide marketing programs, and serve as a propagation source for nonpatented or non-trademarked material. Trees and shrubs will be evaluated for 5 years and herbaceous material for 3 years. Three test sites were established across the state, one in Fayetteville, Little Rock, and Hope, Ark. These sites correspond to the three USDA plant hardiness zones found in Arkansas (Zones 6, 7, and 8). A consistent planting protocol (e.g., distance between plants, irrigation system, bed width) is used at all three locations. Data collection consists of annual growth measurements and qualitative evaluations for factors such as time of flowering, length of flowering, and disease or insect problems. A standard protocol has been established for identifying future plants to be evaluated in the program. In the first year, 17 accessions were planted at each of the three different locations. Best plant growth on 15 of the 17 accessions occurred at the Little Rock site. This may be a reflection of the environment present at the sites in Hope and Fayetteville. Both of these sites are exposed, full-sun situations, whereas the Little Rock site receives some afternoon shade. Reception to this trial program has been favorable, with the Little Rock site gaining much attention from the Arkansas nursery industry.
One-year-old paper birch (Betula papyrifera Marsh.) seedlings were exposed to water deficit, ethylene, or inhibitors of ethylene action under greenhouse conditions to investigate ethylene's role in water-deficit stress-induced leaf abscission. Exposing well-watered and water-stressed paper birch to 20 ppm ethylene resulted in more than 50% leaf abscission after 96 h regardless of plant water status. However, application of a physiological level (1 ppm) of ethylene did not cause leaf abscission in either well-watered or water-stressed paper birch. Inhibitors of ethylene action (1ppm 1-methylcyclopropene or 0.1 mm silver thiosulfate) did not affect predawn water potential, gas exchange, or chlorophyll fluorescence. A significant increase in ethylene production was not detected in water-stressed paper birch before the onset of significant leaf abscission. Based on these observations, ethylene would appear to play a minor role in water-deficit stress-induced leaf abscission in paper birch.
Japanese beetle (Popilla japonica Newman) has caused severe damage on a wide range of horticultural crops since its first introduction to the Eastern United States from Japan in 1916. Leaves are skeletonized by adult beetles feeding in masses, which makes this insect damage easy to identify. In Arkansas, Japanese beetle was first trapped in Washington County in 1997 and has reached epidemic proportions in the most recent three years. Leaf skelotonization and feeding preference on eighteen birch accessions by Japanese beetle were recorded in 2003 and 2004. There was a wide range from no feeding (0% leaf skelotonization) to high feeding preference (89% leaf skelotonization). Betula utilis var. jacquemontii and B. papyrifera `Renaissance Upright' had highest preference. Betula pendula `Laciniata' had no feeding damage from Japanese beetle.