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- Author or Editor: John M. Dole x
Six defoliants were applied in fall and tested for their efficacy in preharvest defoliation of field grown curly willow (Salix matsudana `Tortuosa'), american bittersweet (Celastrus scandens), and american beautyberry (Callicarpa americana). Defoliants included acetic acid, chelated copper, crop oil concentrate (COC), ethephon, dimethipin plus COC, pelargonic acid, and a tap water control. For chelated copper, a concentration of 800 mg·L–1 was most effective at promoting defoliation, providing 100% defoliation of american bittersweet and 76% defoliation of american beautyberry. For curly willow and american beautyberry, all concentrations of dimethipin produced good or excellent defoliation. Increasing concentrations of ethephon from 200 to 2500 mg·L–1 increased defoliation from 0% to 67%. Pelargonic acid was not effective at promoting defoliation of woody plants at the concentrations used. In an experiment conducted during spring using containerized curly willow, irrigation was stopped for 0, 3, or 6 days before defoliants were applied, but none of the irrigation treatments promoted defoliation. In a postharvest study using cut curly willow, stems were held in distilled water at 5, 20, or 35 °C for 1, 3, 5, or 7 days. Holding cut stems of curly willow at 20 °C promoted 68% defoliation, compared to 53% or 28% for 5 or 35 °C, respectively.
The purple velvet plant (Gynura aurantiaca) has commercial potential as a potted plant due to its attractive purple foliage, if the malodorous flowers can be avoided. Plants were treated with seven concentrations of ethephon, three photoperiodic durations, three light intensities, and combinations of photoperiod and light intensity to inhibit flowering. Although foliar application of ethephon at 1200 to 4800 ppm (μL·L-1) completely inhibited flowering of purple velvet plants, plants were stunted and cutting harvest was impossible. Flowering was promoted at lower application rates of 150 to 300 ppm (μL·L-1). An 8-hour photoperiod increased plant quality and plants had the largest vegetative shoot number and the brightest purple color, compared to 12 or 16-hour photoperiods. All of the shoots were reproductive under the 16-hour photoperiod. Increasing the shade level from 0 to 60% (790 μmol·m-2·s-1 to 230 μmol·m-2·s-1) increased the number of vegetative shoots at 74 and 108 days after treatment commenced but reduced the total number of shoots by 28% at day 108. Plants grown under60% shade and short days had 94% vegetative shoots 102 days after placement in treatment. Growing plants under 8-hour photoperiod and 60% shade from fall to spring is recommended to maintain vegetative stock plants and produce high quality marketable plants. Chemical names used: (2-chloroethyl) phosphonic acid (ethephon).
Oklahoma floriculture producers, ornamental-horticulture retailers, mass-market retailers, and cut-flower wholesalers were surveyed to compare and contrast the industry in terms of attitudes towards their products and problems. Overall, attitudes of all four segments of the industry were neutral to negative on potted flowering plants, but were positive to neutral on bedding and foliage plants. However, producers were slightly negative concerning the postharvest life of bedding plants. While cut-flower wholesalers had a positive attitude concerning cut flowers, ornamental-horticulture retailers and mass-marketers tended to be neutral to negative. In particular, retailers and mass-marketers believed that cut flowers were too expensive and too short-lived. Floral preservatives were used by 82% of ornamental-horticulture retailers, while only 19% of mass-market retailers used preservatives. All cut-flower wholesalers used preservatives. Capital availability and market demand were the factors most limiting expansion for producers and ornamental-horticulture retailers; whereas mass-market firms listed competition as their most limiting factor.
For decades, vegetable growers have used black polyethylene mulch to warm the soil in early spring, reduce weeds, and conserve soil moisture. Use of plastic mulch can increase crop yields and improve fruit quality. This article reviews research performed with plastic, aluminum foil, aluminum-painted, and degradable mulches. Most research focused on the effects of plastic mulches on insects and viruses they vector, and on yields. Aluminum foil and aluminum-painted mulches are effective at repelling insect pests, especially aphids (Aphididae) and thrips (Thripidae). Yields are often higher with black plastic compared to bare ground. Clear plastic is rarely used in the U.S. because it can encourage weed growth, unless a herbicide or fumigant is used underneath. Colored mulches can increase yields and control pests, but color may be less important than brightness of the mulch or contrast with bare soil. New forms of photodegradable mulches eliminate the need to remove and dispose of plastic at the end of the growing season, but have not been widely adapted because they tend to degrade prematurely.
Six defoliants were applied in fall and tested for their efficacy in preharvest defoliation of fieldgrown curly willow (Salix matsudana `Tortuosa'), american bittersweet (Celastrus scandens), and american beautyberry (Callicarpa americana). Defoliants included acetic acid, chelated copper, crop oil concentrate surfactant (COC), ethephon, dimethipin plus COC, pelargonic acid, and a tap water control. For chelated copper, a concentration of 800 mg·L–1 (ppm) was most effective at promoting defoliation, providing 100% defoliation of american bittersweet and 76% defoliation of american beautyberry. For curly willow and american beautyberry, all concentrations of dimethipin produced good or excellent defoliation. Increasing concentrations of ethephon from 200 to 2500 mg·L–1 increased defoliation from 0% to 67%. Pelargonic acid was not effective at promoting defoliation of woody plants at the concentrations used. In an experiment conducted during spring using containerized curly willow, irrigation was stopped for 0, 3, or 6 days before defoliants were applied, but none of the irrigation treatments promoted defoliation. In a postharvest study using cut curly willow, stems were held in distilled water at 5, 20, or 35 °C (41.0, 68.0, or 95.0 °F) for 1, 3, 5, or 7 days. Holding cut stems of curly willow at 20 °C promoted 68% defoliation, compared to 53% or 28% for 5 or 35 °C, respectively.
The effects of various postharvest treatments on cut stems of ‘Coral’ and ‘Sparkling Burgundy’ pineapple lily (Eucomis sp.) were evaluated to determine best postharvest handling practices. The use of a commercial hydrator, holding solution, or both significantly reduced vase life for ‘Coral’; the deionized (DI) water control had the longest vase life. ‘Sparkling Burgundy’ vase life was significantly reduced to 29.9 days when both a commercial hydrator and holding solution were used as compared with 50.3 days when DI water was the hydrator used with the commercial holding solution. The use of a bulb-specific preservative reduced vase life of ‘Coral’ to 43.8 days, while the DI water control had a vase life of 66.4 days, and commercial holding solution was intermediate at 56.8 days. A 10% sucrose pulse reduced vase life to 46.9 days compared with the 0% sucrose control (58.9 days) and the 20% sucrose concentration (62.5 days), which were not significantly different. The use of floral foam and/or 2% or 4% sucrose concentrations plus isothiazolinone reduced vase life significantly to an average of 11.1 days. The vase life of stems cold stored at 2 °C for 1 week (37.7 days) was not significantly different from the unstored stems (43.0 days), while longer storage times up to 3 weeks significantly reduced vase life. The use of hydrating solution pretreatments before and holding solution treatments during 4 days of cold storage had no significant effect on vase life. ‘Sparkling Burgundy’ stems harvested with 100% of the florets open had the longest vase life of 51.2 days compared with 38.4 days when 1% of the florets were open. Vase life was unaffected by exogenous ethylene exposure up to 1 ppm for 16 hours. For best postharvest quality, ‘Coral’ and ‘Sparkling Burgundy’ pineapple lily should be harvested when at least 50% of the florets are open, held in plain water without preservatives, and stored for no more than 1 week (wet or dry) at 2 °C.
Effects of homemade or commercial floral preservatives, applied as 48-hour grower treatment or continuous retailer/consumer application, were studied on cut ‘ABC Blue’ lisianthus (Eustoma grandiflorum), ‘Maryland Plumblossom’ snapdragon (Antirrhinum majus), ‘Mid Cheerful Yellow’ stock (Matthiola incana), and ‘Deep Red’ Benary’s zinnia (Zinnia violacea). Cut stems were placed in solutions containing 500 mL·L−1 lemon/lime soda (soda); 6 mL·L−1 lemon juice plus 20 g·L−1 sugar (lemon juice); 100 mg·L−1 citric acid plus 20 g·L−1 sugar plus 200 mg·L−1 aluminum sulfate (C-AS); 400 mg·L−1 citric acid plus 20 g·L−1 sugar alone (citric acid), or combined with either 0.5 mL·L−1 quaternary ammonium chloride (C-QA), or 0.007 mL·L−1 isothiazolinone (C-IS); 10 mL·L−1 Floralife Clear Professional Flower Food (Floralife); or 10 mL·L−1 Chrysal Clear Professional 2 (Chrysal), dissolved in tap water, which was also used as control without any added compound. Cut stems of lisianthus and stock had longest vase lives (22.1 and 12.7 days, respectively) when placed in C-IS continuously, while snapdragon and zinnia stems had longest vase lives (22.3 and 16.3 days, respectively) when placed in C-QA solution continuously. Continuous use of soda extended vase life of cut lisianthus, snapdragon, and stock stems, but not zinnia, compared with tap water. Citric acid extended the vase life of lisianthus and stock when used continuously and of zinnia when used for 48 hours. Use of C-AS or lemon juice either had no effect or reduced vase life of the tested species, except lemon juice increased zinnia vase life when used as a 48-hour treatment. Stems of lisianthus, stock, and zinnia placed continuously in C-IS, C-QA, or citric acid had high solution uptake. No significant differences were observed for vase life of all tested species with short duration (48 hours) application of solutions, except 48-hour use of citric acid or lemon juice increased zinnia vase life compared with tap water. Overall, continuous vase application of the homemade preservatives resulted in longer vase life extension than 48-hour treatment. Among tested preservative recipes, C-IS, C-QA, soda, or citric acid demonstrated best postharvest performance of tested species. However, recipes containing C-AS or lemon juice had detrimental effects and should not be used for handling cut stems of tested species.
The effects of production temperature and transplant stage on stem length and caliper of cut stems and postharvest treatments on vase life of ‘Esprit’ penstemon (Penstemon grandiflorus) were examined. Plugs transplanted with eight to nine sets of true leaves had a longer stem length (64.3 cm) at harvest than those transplanted with two to three sets (57.7 cm) or five to six sets (60.8 cm). Time to flowering from transplant shortened as production temperature increased and when transplants had a greater number of true leaves. The addition of 2% or 4% sucrose with 7 ppm isothiazolinone as a vase solution resulted in the longest vase life (9.4 days) of all treatments compared with the control (4.5 days). A holding solution increased vase life to 7.0 days for Floralife holding solution and 5.9 days for Chrysal holding solution from the 4.3 days control, although hydrating solutions and preservative brand had no effect. The use of floral foam or antiethylene agents, ethylene exposure, or sucrose pulses also had no effect on vase life. Extended cold storage lengths either wet or dry for 2 or 3 weeks caused vase life to decrease to 2.0 days when compared with 5.6 days for the unstored control and 7.6 days for 1 week storage. ‘Esprit’ penstemon may be suitable for greenhouse production and has acceptable potential as a locally grown specialty cut flower.
Pineapple lily (Eucomis hybrids) has long, striking inflorescences that work well as a cut flower, but information is needed on proper production methods and postharvest handling protocols. The objective of this study was to determine the effects of bulb storage temperature and duration, production environment, planting density, and forcing temperatures on cut flower production of ‘Coral’, ‘Cream’, ‘Lavender’, and ‘Sparkling Burgundy’ pineapple lily. Stem length was greater in the greenhouse than the field and at the low planting density. Plants in the field at the low planting density had the shortest stem length for ‘Coral’ and ‘Cream’, but still produced marketable lengths of at least 30 cm. Planting density did not affect ‘Lavender’ and ‘Sparkling Burgundy’ stem length or number of marketable stems. The productivity (number of marketable stems per bulb) was affected only by planting density for ‘Coral’ and planting environment for ‘Cream’. Differences in stem quality and productivity differed for each cultivar and planting density over the next two seasons. The productivity of ‘Coral’ increased significantly from year to year, while the productivity of ‘Cream’ only significantly increased between the first and second years. The low planting density resulted in slightly more stems per bulb for ‘Coral’ over the next two seasons. Emergence after bulb storage treatments was highest in treatments where the bulbs were not lifted from the substrate and were subsequently grown at 18 °C. Bulbs grown in the warmest (18 °C) production temperature flowered soonest and had shorter stem lengths. For earliest flowering, bulbs should be stored in substrate in cool temperatures of at least 13 °C and forced at warm temperatures of at least 18 °C.
These studies were conducted to determine the effect of 1) temperature on P leaching from a soilless medium amended with various P fertilizers, 2) water application volume on P leaching, and 3) various fertilizers on P leaching during production and growth of marigolds (Tagetes erecta L. `Hero Flame'). Increasing temperature linearly decreased leaching fraction; however, total P leached from the single (SSP) or triple (TSP) superphosphate-amended medium did not differ regardless of temperature. Despite a smaller leaching fraction at higher temperatures and no change in the total P leached, P was probably leached more readily at higher temperatures. More P was leached from the medium amended with uncoated monoammonium phosphate (UCP) than from the medium containing polymer-coated monoammonium phosphate (CTP) at all temperatures, and more P was leached from UCP-amended medium at lower temperatures than at higher temperatures. More P was leached from TSP- than from SSP-amended medium and from UCP- than from CTP-amended medium regardless of the water volume applied, but leachate P content increased linearly as water application volume increased for all fertilizers tested. Plant dry weights did not differ regardless of P source. Leachate electrical conductivity (EC) was lower with TSP than with SSP. Leachate EC was also lower with CTP than with UCP. A higher percentage of P from controlled release fertilizer was taken up by plants rather than being leached from the medium compared to P from uncoated fertilizers.