|UFDC Home||myUFDC Home | Help ||
ALL VOLUMES CITATION SEARCH THUMBNAILS PAGE IMAGE ZOOMABLE
STANDARD VIEW MARC VIEW
|Table of Contents|
The Agricultural Research Center at Apopka was established primarily
through the efforts of local nurserymen and agricultural leaders who recog-
nized the need for research on problems associated with commercial foliage
Orange County purchased 18 acres of land and donated it to the Univer-
sity of Florida for the site. Building funds for an office building, green-
house, and storage building were appropriated by the 1965 State Legislature.
Operating funds were appropriated by a special session of the Legislature
in 1968 as part of the special appropriation for the Institute of Food and
Agricultural Sciences. The center officially opened September 1, 1968 with
only the office building completed.
Research facilities at this center have been expanded since 1968 and
have been designed to closely duplicate grower conditions with plants grown
under shade cloth, fiberglass and glass. Presently there are over 40,000
sq ft of research area for plant production. The center also has over 2,000
sq ft of controlled environment rooms to test indoor growth of foliage plants
under consumer conditions.
The primary objective of this research center is to conduct research
and assist in State Extension activities on commercial ornamental horti-
cultural crops of Florida. The major industries involved are foliage
plants, cut ferns and woody plants used for cut foliage.
Six faculty positions presently located at the Agricultural Research
Center Apopka and their area of specialization are:
1. Dr. Charles A. Conover Professor, Ornamental Horticulturist and
Center Director Administration, Soils and Nutrition.
2. Dr. Ronald A. Hamlen Asst. Professor, Entomologist Insect and
Nematode Pests of Ornamentals.
3. Dr. Richard W. Henley Assoc. Professor, Ornamentals Extension
Specialist, Ornamental Horticulture Extension Foliage.
4. Dr. Richard J. Henny Asst. Professor, Plant Geneticist Foliage
5. Dr. James F. Knauss Assoc. Professor, Plant Pathologist Orna-
mental Plant Diseases.
6. Dr. Richard T. Poole Professor, Plant Physiologist Horticulture
and Physiology of Ornamentals.
This report summarizes active research projects. Correspondence with
research or extension faculty regarding completed projects or extension
publications should be addressed to: Agricultural Research Center Apopka,
Rt. 3 Box 580, Apopka, FL 32703.
Telephone Number (305)-889-4161.
ARC-Apopka Research Report RH-77-5, C. A. Conover, R. A. Hamlen, R. W. Henley,
R. J. Henny, J. F. Knauss and R. T. Poole.
HORTICULTURAL RESEARCH PROGRAMS
C. A. Conover and R. T. Poole
Research in this area has as its objective the development of new or
improved methods of increasing yield and quality of foliage, fern and cut
woody foliage. Major research areas include nutrition, media, photoperiod,
light intensity, temperature, growth regulators, herbicides and certain
cultural changes such as irrigation methods and frequency.
Immediate plans are to develop optimum cultural recommendations for
the major foliage crops, fern and cut woody foliage. Future plans will
include development of new crops and methods of changing the appearance
of crops presently grown.
Purpose: -Although most foliage plants are easily propagated, the proper
selection of soil medium, temperature, light intensity, irrigation
method, type and condition of cutting, growth regulators and main-
tenance of pest free materials is important and necessary in order
to produce a quality plant economically.
Approach: Stock plants are being grown in varying light intensities which
receive different quantities of fertilizer. Growth regulators are
betngcapplied to determineitheir influence on.rooting and subsequent
Program Achievements: Improvement in percentage of plants which root and
reduction in time required for development of roots has been shown to
be influenced and greatly improved by many factors. The importance of
vigorous, healthy stock plants has been demonstrated. Cuttings from
stock grown in low light and supplied with inadequate nutrition produce
small cuttings which require long periods to root. Growth regulators
have been shown to be beneficial for a few cuttings such as Aphelandra,
Ficus and Polyscias. Age is particularly important when germinating
tropical foliage seeds. Seeds should be obtained fresh and planted as
soon as possible. Propagation time of tropical plants can be reduced
greatly when medium temperatures are maintained between 75-800F.
Purpose: Determine ingredients for the potting medium and proper maintenance
in the medium to produce quality foliage plants, also, determine the
chemical and physical properties of the medium.
Approach: Since soil medium or substrate can greatly influence growth and
quality of foliage plants, and the combinations of medium ingredients
that will produce satisfactory foliage plants are numerous, medium 4
studies in combination with watering and fertilizing practices are
being conducted to determine if a specific medium can produce good
plants under one or several watering and fertilizing schedules.
Program Achievements: Previous studies have shown that many combinations of
ingredients will produce good quality plants in a relatively short time
but the well aerated mixes frequently require more frequent irrigation
than a less porous mix. An excellent mix for many foliage plants in
pots six inches or smaller is 2 peat:l bark:l shavings. For larger
pots a mix of 3 peat:l sand will grow quality plants.
Purpose: Selection of the proper light level for production is very important,
since it controls appearance, growth rate and longevity indoors. Light
levels supplied plants indoors are also extremely important and the
influence of production light levels on longevity under interior conditions
needs to be known.
Approach: Several experiments on light (shade levels) are being conducted on
Cordyline, Brassaia, Spathiphyllum and Ficus to determine those levels that
provide best appearance and acclimatized plants. Shade variables range
between 30, 47, 63 and 80 percent shade, and most are also combined with
Program Achievements: Publication of light intensity research has resulted
in adoption of recommended light intensities by a majority of the foliage
industry. Foliage plants produced under reduced light have larger leaves,
with increased chlorophyll levels, more open plant appearance, longer
internodes and reduced stem caliper. Such plants are better adapted to
utilization indoors and sell more readily.
Purpose: Many tropical indoor plants, besides having attractive foliage, produce
showy flowers which enhance salability of the plants. There is a need to
determine methods of manipulating the environment so that these plants can
be forced into bloom throughout the year. The capability of forcing plants
into bloom whenever desired is helpful in a plant breeding program to enable
fertilization of plants by other plants that bloom at different seasons of
the year and also to reduce time between different generations of plants.
Approach: Plants are grown under various combinations of light conditions, of
intensity and duration. While subjected to these varying light conditions,
plants are maintained with proper nutrition, irrigation and temperature.
Program Achievements: Aphelandra have been shown to be responsive to light
intensity, not photoperiod. Five hundred foot candles and below will
maintain Aphelandra in a vegetative state. Aphelandra grown in an
environment of one thousand foot candles or above will produce flowers.
Christmas cactus will bloom anytime of year if given the proper photoperiod.
The plants do not need to be subjected to drought, low temperatures or
inadequate fertilization to produce a plant with many blooms. Three weeks
of short days, light from 8 a.m. to 5 p.m. will produce some flowers, five
weeks of short days will produce a Christmas cactus with many blooms any-
time of the year.
Purpose: Need for information on fertilizer sources, levels, ratios and
frequency of application for the hundreds of foliage cultivars grown
commercially has created a need for fertilization research.
Approach: Experiments being conducted in this area include best ratios and
levels of liquid fertilizer for production of Asplenium (Birdnest Fern),
best fertilizer source and level on two Calathea species to yield best
growth and color, influence of fertilizer level on Brassaia (Schefflera)
growth and root system quality and production of Spathiphyllum on slow
release fertilizer sources versus liquid fertilizers.
Program Achievements: Utilization of research results by growers, from many
experiments conducted over the last seven years has allowed production
of higher quality crops. At present suggested fertilizer levels for
over thirty species are listed in a research report, and suggested tissue
levels for these plants have also been published. A major effect of
fertilization research has been a reduction in amount of fertilizer
used, and therefore, a better quality product being sold to consumers.
The reason this has occurred, is that reductions in soluble salts
present in potting media at time of sale for placement indoors results
in increased longevity.
Purpose: Relate soluble salts data to fertilizer recommendations for foliage
crops which vary from a low of 600 to a high of 2400 pounds of nitrogen
per acre per year.
Approach: Plants are watered constantly with varying rates of fertilizer,
750 ppm nitrogen is the maximum rate applied. Known quantities of water
are applied so that the exact amount of fertilizer applied can be
calculated. Bi-weekly collection of the leachate are analyzed for
soluble salts and pH. The volume of the leachate is determined as well
as the color.
Program Achievements: Experiments have been conducted which show that most
foliage plants will grow satisfactorily even though fertilizer quantity
varies greatly. Experiments have also shown that excess fertilizer
reduces growth of plants even though visible symptoms generally associ-
ated with excess soluble salts, such as necrotic edges, are lacking.
Research results have also shown that heavily fertilized plants are much
more susceptible to mite injury.
Purpose: Extensive research has and is being conducted in acclimatization
because of problems associated with the transition of plants from
production areas to building interiors.
Approach: Experiments underway include establishment of specific light and
fertilizer levels during production that will allow plants to adjust
rapidly to reduced light levels indoors. Plants produced in these
experiments are moved to an interior environment for 8 to 26 weeks where
light, temperature and humidity is controlled to simulate office conditions.
Genera presently being tested include: Brassaia, Chamaedorea and Spathi-
Program Achievements: Results of many experiments have indicated that acclimat-
ization may be accomplished by growing plants under high light and nutrition,
and then holding them under reduced light and nutritional levels for 3 to
9 months prior to interior use, or growing them under reduced light on
lower fertilizer regimes. The best system is to grow the plants under
proper light and nutritional levels for acclimatization, as a higher
quailty product is produced in less total time.
Purpose: Industry requests for information on growth and maintenance of foliage
plants indoors continues to increase. For this reason, the level of
research effort has been increased in an attempt to solve some of the most
pressing problems facing the interior plant industry.
Approach: Two experiments are underway at present on interior maintenance. One
includes levels and light duration and the other light levels and fertilizer.
Light durations include 12, 18 and 24 hours per day at 75 or 150 foot-candles,
on 5 genera for the purpose of determining light effects on growth and
maintenance. The other experiment is on 3 genera and has 3 light levels,
50, 100 and 200 foot-candles with several fertilizer sources and levels.
This experiment will have run for 1 year in January 1978.
Program Achievements: Results of the light duration work are not available.
However, preliminary results of the light intensity research and fertilizer
source and level experiment indicate that our previous recommendation of an
interior fertilizer rate of 10% of the production rate is adequate when the
light intensity is near 100 foot-candles or below. At levels of 200 foot-
candles or more the rate should be raised to 20 to 25% of the production
PLANT PATHOLOGY RESEARCH PROGRAMS
J. F. Knauss
Foliage Plant Indexing Tissue Culture Program
Purpose: Develop known pathogen-free stocks of tropical foliage plants.
Identify culture contaminants and their sources.
Approach: Plantlets developed in tissue culture thru shoot tip, shoot
meristem and meristem culture are indexed for known fungal, bacterial
and viral plant pathogens. Once a clean line has been obtained methods
for its rapid increase for industry release are evaluated and/or
developed. Contaminants commonly found in Tissue Culture Stages II
and III (the multiplication and pre-planting stages) are isolated and
identified. Their significance as plant pathogens is determined.
Methods for elimination or reduction of contaminants are under
Program Achievements: Several lines of Dieffenbachia x 'Exotica Perfection',
and D. amoena have successfully been indexed for fungal and bacterial
pathogens. These lines are currently under investigation for their
freedom from Dasheen Mosaic Virus. The virus determinations will be
concluded in late summer of 1978. Release of plantlets to industry is
planned as soon after final virus evaluation, as is possible. In
addition to the proceeding, other dieffenbachias in the indexing
program are D. picta, D. x 'Exotica', D. maculata 'Rudolph Roehrs',
D. maculata, D. amoena 'Tropic Snow', and additional dieffenbachia
selections. Initial studies with several aglaonemas and dracaenas
have produced lines free of fungal and bacterial microorganisms.
Tissue culture contaminants were found to be reduced when explant
source plants were pre-conditioned in a lighted air-conditioned room
for 2-3 weeks. Erwinia carotovora, a common bacterial pathogen, was
found to be a contaminant of fern cultures growing in commercial
facilities. The role and overall significance of E. carotovora in
the tissue culture procedure is still undetermined.
Foliage Plant Disease Identification and Control
Purpose: Identify important pathogens of foliage plants and develop
effective and safe methods for their control.
Approach: Studies are continuing to determine the identity of pathogens
affecting foliage plants in production. Isolation into pure culture
and the later reinoculation into healthy plants are steps used to
determine pathogenicity. Undescribed diseases are numerous because
of the many plants grown, the abundance of pathogens, and the very
favorable environment for disease development. Wherever possible
cultural methods for control are investigated. Chemical control
compounds, where needed, are evaluated.
Program Achievements: Many new or previously undescribed diseases have
been identified. Major foliar fungal pathogens are species of
Alternaria, Botrytis, Cercospora, Fusarium, Helminthosporium and
others. Bacterial pathogens belong to the genera Erwinia, Pseudomonas,
and Xanthomonas. Erwinia chrysanthemi is without doubt the most
important single bacterial pathogen. Soil-borne fungal pathogens of
importance are species of Pythium and Phytophthora, Rhizoctonia solani,
and Sclerotium rolfsii. Specific disease descriptions and control
recommendations can be found in the following issues of The Florida
Foliage Grower, Vol. 12(10), Vol. 12(11), and Vol. 13(3).
Disease Control Chemicals Registration and Re-registration
Purpose: Provide data necessary to ensure the continued availability of
disease control compounds that are effective in control and non-
phytotoxic to tropical foliage plants.
Approach: Tests on efficacy of control and the potential phytotoxicity of
chemical disease control compounds are performed under greenhouse,
slat shed, and commercial conditions. New experimental compounds that
exhibit exceptional promise are included whenever possible. At
present, particular attention is being paid to develop data required
for the re-registration and label expansion of compounds found in the
past to be essential in tropical foliage plant production.
Program Achievements: Past work has assisted in obtaining label clearance
for several disease control compounds employed in the foliage plant
industry. Among these are Benlate, Daconil, FORE, Kocide 101, Manzate
200 and Truban. Specific concentrations and rates of application
have been worked out for many compounds for use on tropical foliage
ENTOMOLOGY AND NEMATOLOGY RESEARCH PROGRAMS
R. A. Hamlen
Foliage Plant Production Pests Identification and Control
Purpose: Identify important insect, mite, nematode and other pests in
foliage production and develop effective and safe methods for their
Approach: Visual and microscopic observations are continually made of
infested plant material and that suspected to be infested to deter-
mine the identity of pests affecting foliage plants in production.
Pest problems are numerous in production due to the enormous number
of foliage plant species grown, the intensive plant culture and the
highly favorable environment for rapid pest population development.
Cultural methods of control, whenever possible, are investigated.
Chemical methods of control including pesticides, microbial insecti-
cides and insect growth regulators are evaluated if necessary.
Program Achievements: As the tropical foliage plant industry is still a
relatively new area of ornamental horticulture, many previously
undetected pest problems have been identified. Major foliar pests
include several species of aphids (Myzus, Aphis), mealybugs
(Phenacoccus, Pseudococcus, Planococcus), scales and thrips
(Hercinothrips, Heliothrips), while lepidopterous larvae (Spodoptera)
and whiteflies (Trialeurodes), are potentially serious pests. Soil
inhabiting pests include fungus gnats (Bradysia), root mealybugs
(Geococcus,Rhizoecus) and several types of root-feeding nematodes
(Heterodera, Meloidogyne, Pratylenchus, Radopholus). Mites are
without doubt the most destructive pest group with the tetranychid
(spider mites), tarsonemid (broad and cyclamen) and tenuipalpid
(false spider) mites being the most important pests in foliage
production. Specific information on foliage pest identification
and control can be found in Florist 9(3), The Florida Nurseryman
21(3) and The Florida Foliage Grower 14(1) and 14(2).
Control of Foliage Pests Under Interior Environments
Purpose: Identify important insect and mite pests of indoor plants and
evaluate and develop effective and environmentally acceptable methods
Approach: The increasing use of foliage plants indoors by the American
public has increased demands for better quality plants. Insects
(aphids, mealybugs and scales) and tetranychid mites often gain
entry to indoor plants by escaping detection during production and
by surviving the most rigorously applied chemical control program.
Many standard and experimental insecticide, miticide and insect
growth regulator aerosol formulations have been evaluated for
indoor use. Also testing of several formulations of dichlorvos
impregnated polyvinyl chloride has been carried out under controlled
Program Achievements: Past evaluations of aerosol formulations has
demonstrated their effectiveness and safety to specific foliage
plant species. These tests have made available to plant retailers
and consumers needed information for selection of effective and safe
chemicals for control of pests on indoor foliage plants. Specific
information can be found in Florists' Review 159(4128) and the
Florida Foliage Grower 14(5). Evaluations of dichlorvos has
demonstrated a potential for use in pest control on indoor plantings.
Insect, Mite, Nematode and other Pest Control Chemicals Registration and
Purpose: Provide effectiveness and plant safety data to ensure the
continued availability of pest control chemicals for use in the
foliage plant industry.
Approach: Tests on effectiveness of pest control and potential phytotoxicity
of chemical pest control compounds are carried out under greenhouse and
shade house conditions. New experimental compounds that show potential
usage are included whenever possible. Emphasis, also, is being given to
compounds of low mammalian toxicity. Presently, efforts are to obtain
data required for the re-registration and label expansion of pesticides
found previously to be essential in production of quality foliage plants.
Program Achievements: Specific concentrations, application times and
techniques have been developed for various compounds and the respective
chemical producers have petitioned for registration of these compounds
for use on tropical foliage plants.
GENETIC RESEARCH PROGRAMS
R. J. Henny
Determining Breeding Potential of Selected Foliage Plants
Purpose: To help fill the need for genetic improvement of ornamental
tropical foliage plants.
Approach: Development of new or improved cultivars of ornamental foliage
plants acceptable to both the producer and consumer is a major objective
of this program. Intraspecific and interspecific crosses within genera
will be the main means of transferring genetic variability. The col-
lection of basic information relevant to breeding foliage plants is also
an important goal. Factors such as floral morphology, pollination
methods, pollen structure, pollen-tube growth, chromosome numbers and
the presence of genetic incompatibilities or sterilities will be
studied. Tissue culture is being studied as a method to increase sel-
ected plant types. Present and future plans include screening indexed
lines of Syngonium and Dieffenbachia developed in the plant pathology
Program Achievements: Five genera of foliage plants (Dieffenbachia, Aglaonema,
Maranta, Calathea and Aphelandra) are being screened for their breeding
potential and several species of each are being collected and grown.
Seeds have been obtained from self-pollination of Maranta and from sev-
eral self and one interspecific cross-pollination of Dieffenbachia.
Peperomia obtusifolia and Peperomia rufescens 'Red Ripple' have been
induced to form new shoots from leaf discs in tissue culture. Ten lines
of indexed Syngonium have been selected for final evaluations.
HORTICULTURAL EXTENSION PROGRAMS
R. W. Henley
The State Extension Foliage Specialist was located at the Agricultural
Research Center Apopka due to the high concentration of commercial foliage
producers in Central Florida and the close proximity to University of Florida
faculty involved with tropical foliage research.
Extension Foliage Program Areas:
1. Edit the Foliage Digest a monthly magazine for the foliage industry
published by the Foliage Education and Research Foundation, Inc.
2. Co-edit Foliage News a monthly newsletter for County Extension Agents
3. Co-coordinate the National Tropical Foliage Short Course.
4. Coordinate regional short courses for foliage plant producers and
foliage plant retailers.
5. Help County Extension Horticulturists with aspects of their programs
pertaining to foliage production or utilization.
6. Assist tropical foliage plant growers with production problems.
7. Photograph plants listed in Florida Foliage Buyer's Guide.
8. Prepare visual aids on foliage plant production and utilization for
County Extension Agents and horticultural teachers.
9. Develop miscellaneous publications pertaining to both the commercial
foliage plant industry and amateur interests.
This public document was promulgated at an annual cost
of $120.60 or $.048 cents per copy to inform county and
state extension personnel, foliage growers, marketers,
and allied trades of research results and improved
practices in ornamental horticulture.
State Road 437
To Plymouth (4 mi)
Office-conference building and pathology-[
Entomology and breeding greenhouse
Pathogen-free plant production greenhouse
Plant tissue and breeding laboratories
Space frame shadehouse
To Apopka (5 mi)
To Ocoee (5 mi)