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AGRICULTURAL RESE _CF- TER
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 the office building
greenhouse, and storage building were appropriated by the 1965 State Legis-
lature. 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 designed to closely
duplicate grower conditions with plants grown under shade cloth, slats,
fiberglass and glass.
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, caladiums and certain woody ornamentals such as azaleas,
gardenias 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. Entomologist Insect and Nematode
Pests of Ornamentals.
3. Dr. Richard W. Henley Assoc. Ornamentals Extension Specialist,
Ornamental Horticulture Extension Foliage.
4. Dr. James F. Knauss Assoc. Plant Pathologist Ornamental Plant
5. Dr. Richard T. Poole Professor, Plant Physiologist Horticul-
ture and Physiology of Ornamentals.
6. Open Position Asst. Plant Geneticist Foliage Plant Breeder.
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-75-9, C. A. Conover, R. A. Hamlen,
R. W. Henley, 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 ca-
ladiums. 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 caladiums. Future plans will include de-
velopment of new crops and methods of changing the appearance of crops
Research Project RH-01069
Title: Effects of Photoperiod and Temperature on Growth and Flowering of
Certain Florists Crops.
Determination of optimum light and temperature levels for maximum
growth of high quality plants.
Regulation of light intensity during production of potted foliage has
been shown to be of significant importance in acclimatization. Research
has shown that light acclimatized plants perform better under indoor con-
ditions and provide higher consumer satisfaction. Specific light inten-
sities for various foliage plants are provided in the September, 1975
Florida Foliage Grower. These recommended intensities are considerably
below levels previously suggested, but do not result in reduced production
of potted plants.
Leatherleaf fern grown under 73% lath shade produced 6% more fronds
than fern grown under 73% uniform shade. Fern grown under 47% shade during
the winter and 73% uniform shade during the summer produced 17% more fern
than that grown under 73% uniform shade throughout the year.
Caladiums grown under 40-60% shade were of better quality and more
intense color than caladiums grown under more extreme shade levels. Soil
temperatures of 80 and 900F improved quality of foliage, but 900 restricted
Color of caladium leaves is influenced by light intensity. High light
intensity generally produced the least desirable leaf.
Research Project RH-01555
Title: Weed Control for Ornamental Plants.
Evaluation of weed control techniques for reduction or elimination of
weed populations in commercial production of ornamental plants and deter-
miniation of the effect of these weed control techniques on yield of orn-
Several herbicides have been tested on foliage plants and leatherleaf
fern. Princep, 2 pounds active ingredient/acre, Treflan, 4 pounds and
Planavin, 3 pounds, AAtrex, 2 pounds and Amiben, 2 pounds gave good weed
control; however, yield was sometimes reduced by the application of herbi-
cides. Herbicides for use in non-crop areas were also studied. Tandex, 10
pounds active ingredient/acre and Pramitol, 44 pounds were found to be
Lasso 10G, Treflan 4EC, Eptam 25G and Tok 50 WP applied at rates of
2 pounds active ingredient per acre and Planavin and Princep, one pound ai/
A applied at 3 month intervals did not reduce yield of Philodendron oxycar-
dium vines. However, Tok did cause some leaf necrosis immediately after
Pramitol 20 pounds, Karmex 10 pounds, Phytar 560 5 pounds, Casaron 10
pounds and Banvel 4 pounds ai/A applied to aisles between leatherleaf fern
beds eliminated weed growth without adversely affecting fern growth.
CAUTION improper use and placement of these materials can seriously damage
Research Project RH-01683
Title: Effect of Growth Regulators on Ornamental Plants
Determination of the action of various growth regulators on ornamental
plants for control of growth and development for production of high quality
Several growth regulators have been tested on foliage plants and cal-
adium tubers. Ancymidol (A-Rest), 50 parts per million (ppm) sprayed on
leaves appears to have the widest spectrum of activity. B-Nine (Alar) at
5,000-10,000 ppm is also effective on some plants. Plants sprayed with
these chemicals grew much slower than non-sprayed plants.
Foliar sprays of 4 growth regulators were applied to 11 tropical
foliage plant species to determine their morphological influence, a-cy-
clopropyl-a-(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol), 50 ppm, was
effective in reducing internode elongation on 5 plants tested while elonga-
tion of 2 species was reduced by 10,000 ppm succinic acid 2,2-dimethyl-
hydrazide (SADH) or 200 ppm 6- (benzylamino)-9- (tetrahydropyranyl)-9H-
purine (PBA). Most plants treated with 3,000 ppm (2-chloroethyl) tri-
methylammonium chloride (chlormequat) developed chlorosis or necrosis of
recently expanded leaves. PBA applications markedly inhibited flower de-
velopment in Pilea involucrata and induced branching on several species.
Accel (PBA) applied at rates of 10, 20 and 30 ppm caused bud break of
Theobroma cacao and Carica papaya.
Research Project RH-01615
Title: Properties of Natural and Synthetic Media and Resulting Effects on
Production of Ornamental Plants.
Research on potting media has as major objectives the development of
low cost potting mixtures with physical and chemical properties conducive
to production of high quality plants, as well as desirable properties for
continued growth in the home.
Potting media commonly used in production of potted foliage have been
tested on capillary watering mats. These tests have shown that best growth
on constantly wet mats is obtained from mixtures with excellent aeration
characteristics such as 2-1-1 Peat-Pine Bark-Shavings, but pure peat was
not satisfactory. On mats irrigated intermittently, where the capillarity
was allowed to break between waterings, pure peat was satisfactory, as was
the 2-1-1 ratio of Peat-Pine Bark-Shavings.
Medium has been shown to greatly influence fern spore germination.
Florida (peace River) peat is superior to many other commonly used compon-
ents of soil media.
Several potting media have been developed that utilize low cost com-
ponents, but provide plant growth equal to or better than more expensive
combinations. Some of the more desirable low cost components include
native peat, pine bark and shavings, and one of the most desirable light-
weight media is 50% peat, 25% pine bark and 25% shavings. Compared with
imported peat, perlite and fir bark or vermiculite the low cost mixture
costs 50% less.
Influence of pot size on aeration of various potting mixtures has pro-
vided information that is of value in determining those media best adapted
to use in small, medium or large pots. In small pots, less than 4 inch,
mixtures high in peat must have at least 20% perlite or 15% sand to provide
proper drainage and aeration.
Research Project RH-01107
Title: Macro-Element Nutrition of Certain Floricultural Crops.
Research under this project has as its aim, development of nutritional
programs that will maximize production efficiency and produce plants with
desired properties for continued growth under interior conditions.
Recommendations are now available on fertilizer requirements of es-
sentially all of the commonly grown foliage plants. Recommendations are
also provided for liquid, slow-release or combined nutritional programs.
Research has shown that nutritional level of the soil at time of
transfer of a plant from the production area to utilization area can
strongly influence keeping quality. Therefore, acclimatization (condition-
ing) recommendations are now provided on soil as well as light conditioning.
Research at Apopka showed that tip burning of many foliage plants in
the Liliaceae family, is due to fluorine toxicity. Plants most severely
injured include those in Chlorophytum, Cordyline, Calathea, Dracaena,
Maranta, Pleomele and Spathiphyllum. Methods of reducing injury include
elimination of superphosphate from the growing medium, raising medium pH
to 6.0 to 6.5, using irrigation water with less than 1/2 ppm fluoride, and
reduction of transpiration rate.
PLANT PATHOLOGY RESEARCH PROGRAMS
J. F. Knauss
Research Project RH-01021
Title: Nature, Cause and Control of Diseases of Tropical Foliage Plants.
Identification of major plant pathogens attacking tropical foliage
plants, cut fern and foliage and caladiums is a major objective. Often the
pathogen has been reported previously but is new to the host plant being
grown. In some cases, however, the pathogen was found to be completely new
to the U.S.A. Obtaining effective controls for plant pathogens remains an
important phase of this research project. Control is achieved by both cul-
tural improvements, development of known pathogen free stock plants through
tissue culture and information achieved in the determination of non-phyto-
toxic and effective fungicides and bactericides.
Information on many new and/or previously undescribed diseases has re-
suited from this work. Suggested cultural changes and knowledge resulting
from fungicide and bactericide testing (See: Florida Foliage Grower, Vol.
10(9); Florists' Review, May 17, 1973 and Oct. 11, 1973) have enabled
growers to effectively control most major and minor disease problems. In-
dexed stock production via tissue culture at ARC-A and in cooperation with
Dept. Plant Pathology, Gainesville, has produced indexed stocks of caladium
nephthytis and dieffenbachia. These stocks are presently under test for
suitability to industry use.
Research Project RH-01518
Title: Diseases of Ornamental Plants Caused by Soil-Borne Pathogens.
Soil-borne plant pathogens are the most important and destructive
pathogen group attacking tropical foliage plants. Understanding the dis-
eases they cause, how they arise and determination of effective methods for
their control is the objective of this research project. Continued eval-
uation of soil fungicides has been and will continue to be an important
portion of research carried on under this project. Current emphasis is be-
ing placed on evaluation of granular formulations for preplant incorpora-
tion in soil mixes. Combination drenches and rate (volume) of application
are also under investigation.
The major soil-borne plant pathogens have been identified as Pythium
spp., Phytophthora spp., Rhizoctonia solani and Sclerotium rolfsii. Infor-
mation on cultural and chemical methods for control have been published
(See: Florida Foliage Grower, Vol. 10(9) and Florists' Review, May 2,
1974). Results of soil fungicide testing at ARC-A, have assisted in the
clearance for use in the foliage industry of several soil fungicides in
common use in the industry today. Results achieved at ARC-A have been in-
strumental in helping with proposed clearance of a new systemic compound
"Nurelle" which will be available in 1976 for Phytophthora spp. and Pythium
Research Project RH-01657
Title: Non-Chemical Control of Soil-Borne Fungal Pathogens of Container-
Grown Ornamental Plants.
Many microorganisms which normally inhabit soils or plant growing
media possess the ability to be antagonistic to soil-borne plant pathogens.
It is conceivable that research into ways to manipulate these antagonists
to the demise of soil-borne pathogens may result in effective control with-
out the employment of soil fungicides.
Several isolates of actinomycetes have been found to exhibit a high
degree of antagonism in petri plate culture to foliage plant pathogens be-
longing to the genera Pythium and Phytophthora. An experimental system for
low temperature pasteurization (aerated steam sterilization) has been con-
structed and is in use to determine the heat sensitivity of selected antag-
onists. Current studies will also determine the antagonistic acceptibility
of various soil mixes.
ENTOMOLOGY AND NEMATOLOGY RESEARCH PROGRAMS
R. A. Hamlen
Research Project RH-01668
Title: Biology and Control of Insects and Related Pests on Ornamental
The objectives of this program are to identify, describe and solve the
insect, mite and related pest problems encountered by the Florida commer-
cial foliage, fern and caladium growers. Presently major emphasis is being
placed on the evaluation and selection of effective means of chemical con-
trol that are safe both to the plant and the environment. Techniques also
are under evaluation for the control of pests under interior environments.
Present and future plans involved additional chemical testing for pest con-
trol along with development of new programs to evaluate non-pesticide means
of pest control.
1. Identification and control of the broad mite, Polyphagotarsonemus
latus (Banks), causing a previously undetermined necrosis of the vegeta-
tive shoot apex of Aphelandra squarrosa. 2. Programs for control of hemi-
spherical scale, Saissetia coffeae (Walker) on A. squarrosa with foliar
sprays and soil surface applications with systemic chemicals. 3. Identi-
fication and control of Phenacoccus solani Ferris on A. squarrosa through
in-pot application of systemic insecticides. 4. Identification and con-
trol of scolytid (ambrosia beetle) infestations, Xyleborus ferrugineus
(Fab.) and X. affinis Eichh., of Dracaena fragrans 'Massangeana' cane and
container grown plants. 5. Control of a new commercially important root
mealybug, Rhizoecus floridanus Hambleton, infesting bromeliads, Aechmea
fasciata and Vriesea rostrum Aquille hybrid. 6. Influence of insecticides
on an Encyrtus parasitoid of S. coffeae. 7. Evaluation of insect growth
regulating chemicals (IGRs) for control of foliar and soil mealybug (Pseu-
dococcus longispinus (T.-T.), P. solani and R. floridanus), scale (S.
coffeae) and spider mite (Tetranychus urticae Koch) populations on green-
house grown tropical foliage crops. IGRs are chemicals that do not poison
the insect as do conventional pesticides, but rather are toxic to the pest
by inhibiting its normal development. IGRs appear as possible alternatives
to the use of hazardous pesticides. 8. Accumulation of effectiveness and
plant safety data to support registration of pesticides for use on foliage
crops grown in the greenhouse.
Research Project RH-01662
Title: Biology and Control of Nematodes Affecting Ornamental Crops. 4
Research is being directed toward the identification and solution of
nematode problems faced by the Florida foliage, fern and caladium growers.
Currently, major activity concerns the evaluation of registered and experi-
mental nematicides for effectiveness and safety. Future objectives call
for further chemical evaluations as well as the establishment of new re-
search areas for the integration of chemical and non-chemical means of con-
1. Determination of effective nematicides for control of the cyst ne-
matode, Heterodera cacti on Christmas cactus. 2. Control of root-knot,
Meloidogyne spp., in field grown caladiums by foliar sprays of systemic ne-
naticides. 3. Effectiveness data on the use of nematicides against Praty-
lenchus penetrans on leatherleaf fern through bare-root dips of propagating
rhizomes. 4. Determination of effective nematicides for control of root-
knot nematode, Meloidogyne javanica on container grown Maranta.
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 plant producers in Central Florida and the close proximity to Uni-
versity of Florida faculty involved with tropical foliage research.
Extension foliage program areas:
1. Edit the Florida Foliage Grower a monthly newsletter for the foliage
2. Coordinate the National Tropical Foliage Short Course.
3. Maintain a type collection of useful commercially produced tropical
foliage cultivars. This collection which is on display at the Agri-
cultural Research Center Apopka is available for viewing by both com-
mercial producers and amateur horticulturists.
4. Help County Extension Horticulturists with aspects of their programs
pertaining to foliage production or utilization.
5. Assist tropical foliage plant growers with production problems.
6. Photograph plants listed in Foliage Plant Buyers Guide.
7. Prepare visual aids on foliage plant production and utilization for
County Extension Agents and horticulture teachers.
8. Develop miscellaneous publications pertaining to both the commercial
foliage plant industry and amateur interests.
AGRICULTURAL RESEARCH CENTER APOPKA
Space frame shadehouse
Plant conditioning and entomology laboratory
Shop and utility building
Supply storage building
Pathogen-free plant production greenhouse
Office-conference building and pathology-physiology
Plant tissue and breeding laboratories
437 To Apopka (5 mi)
To Plymouth (4 ml) To Ocoee (5 ml)
- To Ocoee (5 mi)
i-- To Plymouth (4 mi)