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0-C DRACAENA 'WARNECKII' AND 'JANET CRAIG'
R. T. Poole, A. R. Chase and L. S. Osborne1
University of Florida, IFAS
Agricultural Research and Education Center Apopka
AREC-A Foliage Plant Research Note RH-1985-C
The two cultivars, 'Warneckii' and 'Janet Craig', are derived from the
species Dracaena deremensis Engl. 'Warneckii' is a stiff, erect variety with
gray-green leather-Tlke leaves striped with white. 'Janet Craig' has long
shiny dark green leaves more flexible than 'Warneckii'. Both remain
attractive under light levels as low as 50 foot-candles (ft-c), but 100-150
ft-c is preferred. Best production light level is 2000-3500 ft-c, or about
70-80% shade. Plants should receive a fertilization regime of 1500 Ib
nitrogen per acre a year from a 3-1-2 ratio fertilizer. A level teaspoon of a
19-6-12 fertilizer applied to a six inch pot every 3 months, or 200 ppm N from
a 9-3-6 fertilizer applied weekly will supply the required fertilizer. Plants
can tolerate low soil moisture, but best growth is obtained if plants are not
subjected to drought conditions. For maximum production, root zone temperature
should be between 75 and 800F with air temperatures to 900F. At soil or air
temperatures less than 700F, very little growth will occur. Plants will be
damaged at 350F air temperature if exposed for short periods, 1-2 days, or if
exposed to 550F for 1 week.
The potting medium should be free of pests, well drained and capable of
high moisture retention. Combinations of peat and bark (1:1 by volume)
provide the necessary aeration and water-holding capacity. Many commercially
prepared mixes are also satisfactory. The pH of the mix should be 6.0-6.5.
Many tip cuttings are imported from the tropics for propagation. Cut-
tings should be obtained from stock plants that are healthy, fertilized
properly and free of pests. Rooting hormones are not necessary for rooting of
tip cuttings. Mist is not required during propagation, but temperature should
be high and medium moist. Good quality plants have been grown with a tissue
composition of: N, 2.0-3.5%; P, 0.15-0.30%; K, 3.0-4.5%; Ca, 1.0-2.0% and Mg,
0.3-1.0%. Plants ship best at 60-650F.
1) Fluoride toxicity
Symptoms Elongated tan to dark brown areas usually form in the tissue of
'Warneckii'. 'Janet Craig' tips have chlorotic and necrotic areas.
Control Maintain pH between 6.0 and 6.5. Avoid water, medium components,
and fertilizers containing fluoride.
1Professor, Plant Physiology; Associate Professor, Plant Pathology; and
Assistant Professor, Entomology, Agricultural Research and Education Center,
2807 Binion Road, Apopka, FL 32703, respectively.
2) Tip chlorosis
Symptoms New growth a general light green to yellow color.
Control Frequently, this is due to high pH, 7.5-8.0, which results in
iron chlorosis. Use iron spray and reduce pH with sulfur or acid
3) Notching ('Warneckii')
Symptoms Base of leaves appear to be cut by knife. Serrations are per-
pendicular to long axil of leaf, 1/8 to 1/2 inch deep.
Control Exact control unknown, but proper cultural conditions of light,
water, temperature and nutrition appear to lessen or eliminate serrations
on new growth; most common under excessively high light.
DISEASES OF DRACAENA 'WARNECKII' AND 'JANET CRAIG'
Very few diseases cause losses during production of these plants,
although those which do occur can be serious. Bacterial soft rot of cuttings
and Fusarium leaf spot are the most common diseases encountered.
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 (Fig. 1). The ends are wet
and disintegrate rapidly under the warm, moist conditions of rooting
beds. A bacterial slime is sometimes present. Infection commonly
extends into the lower leaves and causes their discoloration and
collapse. If the ends of infected stems are cut, a darkened vascular
system may be present.
Control The practice of recutting infected plants to remove rotted
portions does little to diminish losses of cuttings. Sometimes cuttings
will root only to become symptomatic and rotted at a later date. Dipping
asymptomatic cuttings appears to decrease losses when copper or strepto-
mycin products are employed. The only way to eliminate this disease is
to reject all cuttings with these symptoms.
1) Fusarium leaf spot and stem rot (Fusarium moniliforme)
Symptoms Fusarium leaf spot symptoms 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
(yellow) border. Under conditions of high disease pressure and
continually wet foliage, the lesions coalesce and infection spreads
into the plant meristem. Stem rot often occurs on cuttings during mist
propagation. Symptoms are identical to those caused by Erwinia and
culture of the pathogen is required to differentiate the two diseases.
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 leaf or stem lesions under
wet conditions and splashing water spreads them onto other plants.
Control Keeping the foliage of this plant dry can eliminate the foliar
phase of this disease. If this is not possible, use one of several
fungicides to diminish symptom expression. Benomyl (Benlate),
chlorothalonil (Daconil) and maneb compounds (Manzate 200) all provide
excellent control of Fusarium leaf spot of dracaenas. Soil drenches of
benomyl can decrease the stem rot phase on these plants. Many other
dracaenas, such as D. marginata and 'Massangeana' are also hosts of F.
PHYTOTOXICITY OF BACTERICIDES AND FUNGICIDES ON DRACAENA MARGINATA
Agri-Strep Daconil 4.17 Ornalin 50 WP
Banrot 40 WP Fungo 50 WP (causes chlorosis of
Benlate 50 WP Maneb compounds new leaves may not
Captan 50 WP Subdue 2 E hold true for
Chipco 26019 50 WP Truban 5 G 'Warneckii' and
Copper compounds Zineb 75 WP 'Janet Craig')
Daconil 75 WP Zyban 75 WP
Pesticides were tested at recommended rates and intervals.
Little pesticide testing has occurred on 'Warneckii' or 'Janet Craig'. It
is likely that those found safe on D. marginata will also be safe on these
two cultivars but testing under your conditions is highly recommended.
MAJOR INSECT PESTS
The major arthropod pests of 'Warneckii' and 'Janet Craig' include
mealybugs, scales, and thrips. Mealybugs and scale infestations are typically
the result of bringing infested plant material into the production area.
Thrips have the ability to fly and thus can invade from weeds and other
infested plants. 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.
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
infestation, 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
Symptoms Infested plants become weakened or stunted and then die.
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
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.
PHYTOTOXICITY OF INSECTICIDES AND MITICIDES TO DRACAENA MARGINATA
Diazinon EC Di-Syston EC Omite WP
Dursban EC Dylox LS
FC-435 Oil Kelthane EC
Malathion EC Malathion + Oil
Morestan WP Orthene SP
Pentac WP Plictran WP
Sevin WP Temik 1OG
Vendex WP Vydate L
Pesticides were tested at recommended rates and intervals.
Little pesticide testing has occurred on 'Warneckii' or 'Janet Craig'. It is
likely that those found safe on D. marginata will also be safe on these two
cultivars but testing under your conditions is highly recommended.
1. Chase, A. R. 1983. Phytotoxicity of some 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
3. Short, D. E., L. S. Osborne, and R. W. Henley. 1982. 1982-1983 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.