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 Copyright
 Introduction
 Physiological problems
 Diseases of dracaena marginata...
 Fungal pathogen
 Major insect and mite pests
 Reference






Group Title: AREC-A foliage plant research note - Agricultural Research and Education Center - RH-84-D
Title: Dracaena Marginata
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00066543/00001
 Material Information
Title: Dracaena Marginata
Series Title: AREC-A foliage plant research note
Physical Description: 7 p. : ; 28 cm.
Language: English
Creator: Osborne, L. S
Chase, A. R ( Ann Renee )
Henley, Richard W
Agricultural Research and Education Center (Apopka, Fla.)
Publisher: University of Florida, IFAS, Agricultural Research and Education Center-Apopka
Place of Publication: Apopka FL
Publication Date: 1984
 Subjects
Subject: Dracaena -- Diseases and pests -- Florida   ( lcsh )
Shrubs -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 6-7).
Statement of Responsibility: L.S. Osborne, A.R. Chase, and R.W. Henley.
General Note: Caption title.
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00066543
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: oclc - 71314037

Table of Contents
    Copyright
        Copyright
    Introduction
        Page 1
    Physiological problems
        Page 2
    Diseases of dracaena marginata and bacterial pathogens
        Page 3
    Fungal pathogen
        Page 4
    Major insect and mite pests
        Page 5
    Reference
        Page 6
        Page 7
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida







HUME LIBRARY

DRACAENA MA GINATA.Ig 3 i


L. S. Osborne, A. R. Cha, &A SR. JiWfJi tojd orida

University of Florida, IFAS
Agricultural Research and Education Center Apopka
AREC-A Foliage Plant Research Note RH-1984-D


Dracaena marginata Lam. is known as the Madagascar Dragontree, also
called red-edge dracaena, and, as the common name implies, is indigenous to
the island of Madagascar. The plant is used as a medium to large size
shrub in southern Florida and is reliably hardy in Zone 10B, where the
average minimal temperature range is 35 to 40 F. Dracaena marginata
is a member of the Agave family, Agavaceae.

The Madagascar Dragontree has been a popular foliage plant for many
years because of its distinctive appearance. The stems are woody, erect
and the long, narrow, sword-like leaves clasp the stem in a closely stacked
fashion. The dark green glossy leaves are trimmed with a narrow, dark red
margin. Leaves on large plants may exceed 18 inches in length, and old
plants may be 10 feet high or more from soil level. Dracaena marginata
is available from Florida nurseries in containers ranging from 3-inch
square pots up to specimens in containers 52 inches across.

The dark green cultivar accounts for most of the plants sold, however,
there are two cultivars worth mentioning. Tricolor has longitudinal ivory
stripes through the cental green area and red margins. Colorama is similar
to Tricolor except there are red and ivory bands in the central sector of
the leaf. Because the variegated cultivars have less chlorophyll than the
species, they are less vigorous during production and less likely to
succeed indoors, except in very bright locations.

Dracaena marginata and its cultivars are propagated from cuttings or,
in a few instances, air layers are used on relatively large stems. Most
small plants are started from terminal cuttings with foliage to the base.
Very large cuttings and layers generally have exposed stems at the base.
Plants can be propagated from cane sections, but are rarely done so because
of the undesirable branching angle of shoots from the upper portion of
cane. Most propagation material used by Florida growers comes from the
Caribbean Basin and Central America, although a few nurseries in South
Florida maintain stock plants of D. marginata in full sun.



Assistant Professor, Entanology; Associate Professor, Plant Pathology; and
Professor, Foliage Extension Specialist, respectively, Agricultural
Research and Education Center, 2807 Binion Road, Apopka, FL 32703








Potting media used for growing D. marginata should be relatively free
from pests, well drained and moisture retentive. Small plants grow well in
a mix composed predominately of organic components. Larger plants growing
in shadehouses should have a heavier mix, often composed of 15 to 25%
coarse sand, to prevent wind toppling. The potting medium should be
adjusted to pH range of 5.5 to 6.0 prior to sticking or potting plants.
Cuttings placed in small pots are usually plunged to the bottom to insure
support. Cuttings and layers used in larger containers are set slightly
above the base to provide a better environment for root development. Use
of rooting substances is considered desirable by most nurserymen using
unrooted cuttings.

Acclimatized D. marginata are produced under 4000 to 6q00 foot candles
with fertilizer applied at the rate of 3.5 lbs of N/1000 ft /month.
Fertilizer analysis ratios of 3-1-2 and 2-1-2 are preferred to 1-1-1,
especially for large plants which require long-term fertilization. Avoid
use of micronutrient blends which contain excessive boron and super-
phosphate which contains fluoride. During periods of heavy rainfall, the
monthly fertilization rates should be increased to compensate for excessive
leaching.

In many instances, the smaller sizes of D. marginata, usually 6-inch
diameter pots and less, are grown in greenhouses along with a mixture of
other plants which grow best at light intensities in the 2000 to 3500 foot
candle range. Under such conditions, the plants will be somewhat less
vigorous and the leaves will be more pendulous.

Plants root and grow best when temperatures range between 75 and 900F.
To maintain growth through cool periods, temperature in the production
structure should be held above 65 F. To simply protect the plants from
cold damage, a minimum of 500F should be held and plants should be
sheltered from wind. The optimal shipping temperature range is 60 to 650F.

PHYSIOLOGICAL PROBLEMS

1) Chilling injury

Symptoms Chilling for several hours at 30 to 350F without air
turbulence will result in chlorotic or necrotic bands across several
leaves. Slight constriction or irregularity of the leaf surface is
usually associated with the banding. These symptoms are not evident
for 2 weeks or more because damage occurs inside the terminal sheath
of leaves and foliage must elongate first.

Control Avoid chilling plants during production, handling, and
shipping.

2) Phytotoxicity from excesses of soluble salts, fluorides, or boron.

Symptoms Chlorosis and usually necrosis of terminal portion of
leaves. Symptoms are similar for the 3 types of injury and are a
complex of 2 or more types of toxicity.








Control Excess soluble salts can be prevented by following
recommended fertilizer rates. Solubridge meter readings of potting
media periodically are suggested to monitor fertility levels.
Fluoride phytotoxicity usually arises when superphosphate or other
phosphorous sources containing fluorides are used in the fertilizer
program. Avoid use of these products as well as water supplies high
in fluoride. Adjust potting media to pH 6.0-6.5 and avoid other
factors which contribute to rapid fluoride accumulation in the
foliage such as high temperatures, bright light, low humidity, and
wind. If fluoride phytotoxicity is from fluoride particles
suspended in the air (one type of air pollution), little can be
done except grow plants with more resistance to fluoride injury.

Boron also accumulates in the terminal and marginal areas of the
leaf where "burn" is observed. Avoid using fertilizer products
with high levels of born. Remember, boron is an essential element
for plant growth and therefore should be present in the plant in
very small amounts. If the potting medium and water supply are
essentially boron free, a small amount should be added as part of
the fertilizer program.

3) Tip distortion

Symptoms Disfigured new growth of D. marginata has been observed
for several seasons in several South Florida nurseries. The problem
is often severe when present and does not appear to be pathogenic or
nutritional in origin, although same plants have responded to
applications of copper.

Control Not known yet.

4) Flecking

Symptoms Newest leaves have scattered white to yellow spots that are
most cnommn near the apex. Usually these spots eventually turn
green, but marketability is reduced when plants are severely
spotted. No plant pathogens have been isolated from the spots.

Control The problem is most severe in full sun and decreases as
percent shade is increased. Plants grown under 2000 ft-c or less
often have no spotting while full sun grown plants often have
spotting.

DISEASES OF DRACAENA MARGINATA

Very few diseases cause losses during production of this plant,
although those which do occur can be quite serious. Bacterial soft rot of
cuttings and Fusarium leaf spot are the most common diseases encountered.
BACTERIAL PATHOGENS

1) Soft rot (Erwinia carotovora pv. carotovora and E. chrysanthemi)

Symptoms Stem ends of unrooted and sometimes rooted cuttings are








mushy, brown and frequently smell like rotted fish. The ends are
wet and disintegrate rapidly under the warm, moist conditions of
rooting beds. A bacterial slime is sometimes present. Infection
cacmonly extends into the lower leaves and causes their discolora-
tion and collapse. If the ends of infected stems are cut, the
darkened vascular system is a good clue that the rot is due to a
pathogen.

Control The practice of recutting infected plants to remove rotted
portions does little to diminish losses to this serious pathogen.
Sometimes these cuttings will root only to become symptomatic and
rotted. Dipping asymptomatic cuttings appears to decrease losses
when copper or streptomycin products are employed. The only way to
eliminate this disease is to reject all cuttings with these
symptoms..

FUNGAL PATHOGEN

1) Fusarium leaf spot (Fusarium moniliforme)

Symptoms Fusarium leaf spot symptans occur initially on the newest
leaves of the plant which are within the central whorl. Infection
only occurs when this whorl is very wet and spores are present.
Lesions are irregularly shaped, tan to reddish brown and many times
have a chlorotic border. Under conditions of high disease pressure
and continually wet foliage, the lesions coalesce and infection
spreads into the meristem of the plants itself. At this stage, the
meristem may die and growth of the plant is halted. If plants are
treated with fungicides and the foliage kept dry, growth in the
center may resume, frequently from several buds. The creamy orange
spores of the pathogen are commonly produced in the lesions under
wet conditions and splashing water spreads them onto other plants.

Control Keeping the foliage of this plant dry can eliminate this
disease. If this is not possible, then use of one of several
fungicides can greatly diminish symptom expression. Bencnyl,
Daconil and maneb compounds all provide excellent control of
Fusarium leaf spot of dracaenas. Many other dracaenas, such as
'Warneckii', 'Janet Craig' and 'Massangeana' are also hosts of
F. moniliforme.

PHYTOTOXICITY OF BACTERICIDES AND FUNGICIDES ON DRACAENA MARGINATA

SAFE UNSAFE

Agri-Strep Daconil 4.17 Ornalin 50 WP
Banrot 40 WP Fungo 50 WP (causes chlorosis of
Benlate 50 WP Maneb compounds new leaves)
Captan 50 WP Subdue 2E
Chipco 26019 50 WP Truban 5 G
Copper compound Zineb 75 WP
Daconil 75 WP Zyban 75 WP

Pesticides were tested at recommended rates and intervals.








MAJOR INSECT AND MITE PESTS

The major arthropod pests of Dracaena marginata include fungus
gnats, mealybugs, mites, scales, and thrips. Mealybug, mite, and scale
infestations are typically the result of bringing infested plant material
into the greenhouse. This is important to note because most of the
dracaena tips are imported. Fungus gnats and thrips have the ability to
fly and thus invade the greenhouse from weeds and other infested plants
outside. In the control section for each pest, a few of the many
registered and effective pesticides will be listed. For a complete
listing, please consult the references at the end of this report.

1) Fungus Gnats

Symptoms Small black flies are observed running around the soil
surface or on leaves. The larvae are small legless "worms" that
inhabit the soil. Larvae spin webs on the soil surface which
resemble spider webs. Damage is caused by larvae feeding on
roots, root hairs, and lower stem tissues. Feeding damage may
predispose plants to disease and dense populations of this
insect are often found in association with diseased plants.

Control Reduce the amount of water applied to each pot where
possible. Soil drenches, soil-surface sprays or application
of granules are effective at controlling the larvae.

2) Mealybugs

Symptoms Mealybugs appear as white,cottony masses in leaf axils,
on the lower surfaces of leaves and on the roots. Honeydew and
sooty mold are often present and infested plants become stunted,
and with severe infestations, plant parts die.

Control Systemic materials are preferred. Examples of chemicals
which have systemic activity are Metasystox-R and Orthene.
Bendiocarb, Dursban and Enstar 5E appear to be as effective as
some of the systemic materials.

3) Mites

Symptoms Two-spotted spider mites are very small and go unnoticed
until plants turn yellow or become speckled due to the feeding of
this pest. Webbing, loss of leaves and plant death can occur when
mite populations reach high levels.

Control Mites can be controlled with Kelthane, Mavrik, Pentac, or
Vendex. The critical point in any control program is thorough
coverage with the pesticide. The best control program is to mini-
mize the possibility of introducing mites into the growing area on
infested plant material.

4) Scales (Florida red scale)

Symptoms Infested plants become weakened or stunted and then die.




-6-


Scales can be found feeding on leaves, petioles, or stems. Their
shape, size, and color are variable and many are hard to distinguish
from the plant material on which they are feeding. The Florida red
scale is the major scale pest of this plant. It is an armored scale
that is reddish-brown to black in color. Feeding by this insect
causes a characteristic yellow or chlorotic streak that radiates
from the point of attachment.

Control See Mealybugs

5) Thrips

Symptoms Infested leaves have silver-gray scars or calloused areas
where feeding has occurred.

Control Many materials, such as Mavrik and Orthene, are registered
and effective at controlling thrips.

PHYIOIDXICITY OF INSECTICIDES AND MITICIDES TO DRACAENA


SAFE UNSAFE

Diazinon EC Qnite WP
Di-Syston EC
Dursban EC
Dylox LS
FC-435 Oil
Kelthane EC
Malathion EC
Malathion + Oil
Morestan WP
Orthene SP
Pentac WP
Plictran WP
Sevin WP
Temik 10G
Vendex WP
Vydate L

Pesticides were tested at recommended rates and intervals.

References

1. Chase, A. R. 1983. Phytotoxicity of same fungicides used on tropical
foliage plants. ARC-Apopka Research Report, RH-83-2.

2. Short, D. E. 1978. Phytotoxicity of insecticides and miticides to
foliage and woody ornamental plants in Florida. Extension Entomology
Report #57.

3. Short, D. E., L. S. Osborne, and R. W. Henley. 1982. 1982-83 Insect
and related arthropod management guide for commercial foliage and woody
plants in Florida. Extension Entomology Report #52.








4. Simone, G. W. and A. R. Chase. 1984. Disease control pesticides for
foliage production. Extension Plant Pathology Report #30.

Mention of a commercial or proprietary product or of a pesticide in this
paper does not constitute a recommendation by the authors, nor does it
imply registration under FIFRA as amended. Pesticides should be applied
according to label directions. Those pesticides listed in the control
sections for each disorder but not listed in the phytotoxicity charts HAVE
NOT been tested for plant safety at the University of Florida.




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