The effect of increasing temperatures on the duration of postharvest flower development was determined for three specialty crop species: marguerite (Argyranthemum frutescens Webb ex Schultz-Bip.) `Butterfly' and `Sugar Baby'; swan river daisy (Brachycome hybrid Cass.) `Ultra'; and bacopa (Sutera cordata Roth.) `Snowflake'. Plants were grown in a greenhouse at 18 °C (65 °F) until flowering, and then transferred into a phytotron to determine heat tolerance. Plants were stored for 8 weeks at constant temperatures of 18, 23, 28, and 33 °C (65, 73, 82, and 91 °F) for 2-week intervals. Flower bud and flower number were recorded weekly. Sutera cordata `Snowflake' and B. hybrid `Ultra' had the greatest flower number at the 23 °C temperature, decreasing in the 28 °C environment. Argyranthemum frutescens `Butterfly' and `Sugar Baby' had greatest flower number at 28 °C, but flowers were of lower quality thanat 23 °C. Flower development of all cultivars ceased at 33 °C, at the end of 8 weeks at increasing temperatures, but when plants were returned to the 18 °C production greenhouse, flower development resumed. High temperatures (28 °C) reduce the postharvest performance of S. cordata, B. hybrid, and A. frutescens plants grown in hanging baskets; therefore, these species should be marketed as spring-flowering products since summer performance may be unsatisfactory in warm climates.
Millie S. Williams, Terri W. Starman and James E. Faust
Henrique Mayer, Adrian Hunsberger and Marguerite Beckford
Miami-Dade County Extension, with the participation of University of Florida faculty and other speakers, created a Certified Course in Horticulture in 2005. The intended audience is landscape maintenance and installation personnel, tree trimming employees, home gardeners, city and parks employees, and others who want horticultural knowledge. The goal of the program was to educate the participants in basic horticultural practices such as: plant selection and installation—including palms and turf; plant propagation; landscape design; pruning; irrigation; fertilization; pest control, and related topics. The class was limited to 60 participants due to space constraints. The response surpassed all expectations with 58 people completing the course and 40 passing the final exam. Eight months after the end of the program, a follow-up telephone survey was conducted with 24 participants. The results reflect that a high percentage of the participants are still using the correct landscape techniques. In order to reach as many people as possible a video or CD with the entire course is going to be prepared.
Jean-Pierre Goffart, Marguerite Olivier and Marc Frankinet
A decision support system (DSS) was based on the splitting of total nitrogen (N) fertilizer application combined with in-season assessments of crop N requirements aimed to matching, at field scale, potato (Solanum tuberosum) total crop N requirements and mineral N supply from soil and fertilizers. After the preplanting establishment of the total N recommendation based on the predictive balance-sheet method at a specific field scale, 70% of the recommended amount was applied to the crop at planting. Subsequently, at 20–50 days after emergence (DAE) the need for supplemental N was assessed through noninvasive measurements of leaf chlorophyll concentration directly in the field. A simple conditional relationship was established to support potato growers’ decisions on the usefulness of applying the remaining 30% N. This required a crop N status (CNS) assessment in the fertilized field and within a small, untreated area (zero-N for reference). The strategy developed is economically feasible, easy to operate, and validated for several potato varieties. It also gives the grower the possibility of improving N use efficiency (NUE). Several tools to assess CNS have been investigated, or are currently being investigated, at the Walloon Agricultural Research Center in Gembloux, Belgium (CRA-W) for integration into this strategy. All the tools are evaluated for four main characteristics: measurement accuracy and precision, sensitivity to N, specificity to N, and feasibility. There are invasive or noninvasive tools. The use of a chlorophyll meter (CM) has been currently developed in the DSS. Current CRA-W research is investigating the potential of crop light reflectance as an indicator of CNS (ground-based radiometers for near remote sensing and satellite multispectral imagery for spatial remote sensing).
Brian K. Hogendorp and Raymond A. Cloyd
Sanitation, which includes removing plant and growing medium debris, is an important component of any greenhouse or nursery pest management program. However, there is minimal quantitative information on how sanitation practices can reduce pest problems. In this study, conducted from May through Nov. 2005, we evaluated plant and growing medium debris as a source of insect pests from four greenhouses located in central Illinois. Two 32-gal refuse containers were placed in each greenhouse with a 3 × 5-inch yellow sticky card attached to the underside of each refuse container lid. Each week, yellow sticky cards and plastic refuse bags were collected from the containers and insects captured on the yellow sticky cards were identified. Insects captured on the yellow sticky cards were consistent across the four greenhouses with western flower thrips (Frankliniella occidentalis), fungus gnats (Bradysia spp.), and whiteflies (Bemisia spp.) the primary insects present each week. Insect numbers, in order of prevalence on the yellow sticky cards, varied across the four locations, which may be related to the type of plant debris discarded. For example, extremely high numbers of adult whiteflies (range = 702 to 1930) were captured on yellow sticky cards in one greenhouse each month from August through November. This was due to the presence of yellow sage (Lantana camera), bee balm (Monarda didyma), garden verbena (Verbena × hybrida), common zinnia (Zinnia elegans), sage (Salvia spp.) and fuchsia (Fuschia spp.) debris that was heavily-infested with the egg, nymph, pupa, and adult stages of whiteflies. High western flower thrips adult numbers in the greenhouses were generally associated with plant types such as marguerite daisy (Dendranthema frutescens) and pot marigold (Calendula officinalis) disposed while in bloom with opened yellow flowers, which contained adult western flower thrips. Based on the results of this study, it is important that greenhouse producers timely remove plant and growing medium debris from greenhouses or place debris into refuse containers with tight-sealing lids to prevent insect pests from escaping.
marguerite daisy ( Argyranthemum frutescens ) varieties `Butterfly' and `Sugar Baby' flowered best when the average daily temperature was below 82 °F. Bacopa ( Sutera cordata ) `Snowflake' and swan river daisy ( Brachycome hybrid ) `Ultra' flowered best when
included a frame (10 cm × 20 cm), tweezers, marguerite daisy ( Argyranthemum frutescens ), leatherleaf fern ( Rumohra adianriformis ), fritsch spiraea ( Spiraea prunifolia var. simpliciflora ), rose ( Rosa hybrids), and baby's breath ( Gypsophila
Terri W. Starman, Shannon E. Beach and Kristen L. Eixmann
FloraPlant; Ball Horticulture, Chicago) were received on 14 Jan. and planted on 15 and 16 Jan. Plant cultivars included ‘Comet White’ and ‘Sunlight’ argyranthemum or marguerite daisy ( Argyranthemum frutescens ); ‘Liricashowers Deep Blue Imp’, ‘Starlette
Shannon E. Beach, Terri W. Starman, Kristen L. Eixmann, H. Brent Pemberton and Kevin M. Heinz
(Ball FloraPlant, Ball Horticulture, Chicago) were received on 14 Jan. and were planted on 15 and 16 Jan. Plant cultivars included Comet White and Sunlight argyranthemum or marguerite daisy; Liricashowers Deep Blue Imp., Starlette Trailing Purple, and
Marc W. van Iersel, Geoffrey Weaver, Michael T. Martin, Rhuanito S. Ferrarezi, Erico Mattos and Mark Haidekker
their leaf morphology makes it easy to use the fluorometer leaf clip. Pothos and sweetpotato ‘Marguerite’ were propagated from stem cuttings and grown in 15-cm containers. Experiments were conducted 6 to 8 weeks after rooting. Greenhouse temperature
James E. Faust and Joanne Logan
−1 , then transferred to DLI treatments ranging from 1.2 to 12.3 mol·m −2 ·d −1 . The total dry mass and root:shoot ratio of marguerite daisy ( Argyranthemum frutescens ), twinspur ( Diascia barbarae ), nemesia ( Nemesia fruticans ), cape daisy