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  • Author or Editor: B. K. Harbaugh x
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Abstract

A wide response was found in flower and foliage characteristics in 53 cultivars encompassing 21 genera of flowering potted plants under simulated home conditions. One or more cultivars performing as well or better than Chrysanthemum ‘Puritan’ or a Sinningia mixture were found in Episcia, Exacum, Capsicum, Ceiosia, Achimenes, Begonia, Catharanthus and Tagetes.

Open Access

Abstract

Chrysanthemums (Chrysanthemum morifolium Ramat. cv. Manatee Iceberg) were grown in plots in the open or under polypropylene 25% shade cloth covered structures and were either treated with pesticides or untreated. The number of stems damaged by lepidopterous larvae before harvest was reduced and chemical control efficiency increased by pest exclusion. Shade cloth improved flower quality ratings 41% and 26%, respectively. In a second experiment, plots grown as before were treated either weekly or on demand (when larval densities were >1/1.5 m2) for Lepidoptera control. Significantly fewer stems were damaged in enclosed plots with 2 insecticidal applications than with 11 applications in unenclosed plots. Shading improved flower quality ratings 29% and 22%, respectively, for plots treated weekly or on demand.

Open Access

Abstract

Twenty eight cultivars of Chrysanthemum morifolium Ramat. varied widely in foliar damage by the vegetable leafminer, Liriomyza sativae Blanchard. The total number of leafmines per 5 stems range from 1.3 for ‘Nob Hill’ to 15.5 for ‘Deep Valiant.’ In general, the standardtype cultivars had less leafminer damage than the spray-types. ‘Iceberg,’ a spray-type cultivar commonly grown in Florida, was more damaged than 11 spray and 9 standard cultivars. Foliage of ‘Bright Yellow Tuneful,’ ‘Divinity,’ ‘Pink Marble,’ ‘Nob Hill,’ ‘Albatross,’ ‘Sea Foam,’ and ‘Colonel Comfort’ had less damage in 2 experiments than foliage of ‘Iceberg.’

Open Access

Abstract

When cultivars of chrysanthemums, Chrysanthemum morifolium Ramat. were evaluated for resistance to the vegetable leafminer, Liriomyza sativae Blanchard, more differences among mean leafmines occured as each flowered than when biweekly evaluations were made before harvest. Pinched plants at this time also had more leafmines than unpinched plants, probably because of the increased maturation time and, hence, increased exposure to the leafminer population. When cultivars were evaluated simultaneously after they all had flowered, pinched plants had fewer complete leafmines on 2 of 10 cultivars.

Open Access

Abstract

Flowering Kalanchoe blossfeldiana Poelln, exposed to various concentrations of ethylene (0-1 μl/liter of air) at 23.5°C for 2 and 3 days were injured at levels of ethylene greater than 0.5 μl/liter of air for 2 or more days. Ethylene induced leaf abscission and chlorosis, and closed open florets (sleepiness). Sleepy florets failed to re-open. Bud florets were not as severely injured by ethylene as open florets. Bud florets opened when removed from an ethylene environment but their opening was delayed. Florets on plants exposed to 2.5 μ1 ethylene/liter air for 3 days at 6°C were slightly injured. At 2.5 μl ethylene/liter air, severity of injury increased as temperature increased.

Open Access

Abstract

Stored ‘Candidum,’ ‘Carolyn Whorton,’ and ‘Frieda Hemple’ caladium tubers were soaked for 0, 4, 8, 16, 32, or 64 hours in 0, 250, 500, or 1000 mg/liter gibberellic acid (GA3) solutions to determine if flowering could be enhanced during the subsequent forcing period. Mean number of inflorescences produced per plant with no soaking was 0.2, 0.7, and 0.0 for ‘Frieda Hemple,’ ‘Candidum,’ and ‘Carolyn Whorton’ respectively, while tubers soaked in 250 mg/liter GA3 for 16 hours at 23°C averaged 2.4, 3.7, and 4.0 inflorescences per plant, respectively. There was no significant difference in number of inflorescences per plant from tubers treated with 250, 500, and 1000 mg/liter GA3. Optimum soaking time was 8 hours for ‘Frieda Hemple’ and ‘Carolyn Whorton,’ and 16 hours for ‘Candidum.’

Open Access

Abstract

Daily water use for potted Chrysanthemum ×morifolium Ramat. ‘Spirit’ was estimated from pan evaporation and plant height data collected over 2 seasons using 3 different growing environments (glass greenhouse, saranhouse, and outside—no structure). Regression equations derived using pan evaporation and plant height were not significantly improved with the inclusion of plant width as an additional variable to estimate water use.

Open Access

Abstract

A hypothesis was tested that the cause of a damaging marginal bract necrosis common to ‘Gutbier V-14 Glory’ poinsettia is a deficiency of Ca that is expressed when the rapidly growing bract outdistances the current supply of Ca. Plants were grown in the greenhouse in a sedge peat-EauGallie sand mix with fertility adjustments designed to moderately enhance Ca deficiency. Twice-weekly foliar applications of Ca (432 ppm) were begun at the stage of first bract coloration to attempt to prevent necrosis. In addition to bract necrosis, puckering of bracts occurred on controls but not in Ca-treated plants. In another experiment, induced Ca deficiency symptomology included bract necrosis. Calcium chloride spray essentially prevented the necrosis. Necrotic bract marginal tissue had 0.07% Ca, whereas sprayed tissue contained more than three times this Ca concentration.

Open Access

Abstract

Plants of Philodendron scandens subsp. oxycardium (Schott) Bunt. were exposed to ethylene-air mixtures at various temperatures and levels of light and CO2. Plants held in ethylene (2.5 to 10μl/liter air) abscised leaves and stipules, developed chlorotic foliage, and grew poorly. As the levels and duration of exposure to ethylene increased, the rate of leaf abscission increased. Plants exposed to 5μl ethylene/liter air at 23.5°C for 3 days in light abscised more than 50% of their leaves, whereas plants similarly handled but held in darkness lost 20%. At a given level of ethylene, the lower the temperature the fewer the number of leaves abscised. Plants held at 27° at 10 μl/liter air had total leaf abscission. Plants held in ethylene with 5% CO2 or with lanolin-coated leaves abscised fewer leaves than plants without added CO2 or non-coated leaves.

Open Access

Abstract

Geranium seedlings were exposed to various levels of ethylene (0–10 µl/liter air) at 23°C for 2 and 5 days in light. Seedlings held in ethylene for 2 days developed more chlorotic leaves and did not grow as well as seedlings held in air. Seedlings exposed to ethylene for 5 days abscised leaves, whereas those exposed for 2 days did not. Seedlings exposed to ethylene (1 µl/liter air) at 23° for 3 days in dark had more chlorotic leaves and did not grow as well as seedlings exposed to ethylene in light. Seedlings held in air in darkness had more chlorotic leaves than seedlings held in air in light. Seedlings held in air in the laboratory grew as well as seedlings held in the greenhouse. Seedlings exposed to ethylene (1 µl/liter air) for 3 days in dark retained more chlorophyll and had better growth at low temperatures (4.5°, 10°) than those exposed at higher temperatures (15.5°, 23°). Seedlings held in air at all temperatures for 3 days had similar chlorophyll levels and growth patterns. Temperature was negatively correlated with loss of chlorophyll and plant dry weight and positively correlated with number of chlorotic leaves of seedling held in darkness for 7 days.

Open Access