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Copyright 2005, Board of Trustees, University
CORN PLANT E RA
C. A. Conover, A. R. Chase and L. S. OsA&AeA io
University of Florida, I AS
Agricultural Research and Educat .fk teUniv of Florida
AREC-A Foliage Plant Research Not"
Dracaena fragrans (Corn Plant) and its cultivars are one of the most
popular dracaena groups and considered among the best of interior plants.
Most potted corn plants are sold as standards (plants with multiple heads on
cane with length varying from 6 inches to 5 feet). Often three or more
canes of differing height are planted in a single pot. Corn plant is also
very attractive when potted as a single cutting in a 5 to 8 inch pot. Corn
plant gets its common name from its upright growth and graceful leaves which
look like corn foliage.
Dracaena fragrans, the species, is entirely green and although it is an
excellent plant, most consumers prefer the more colorful cultivars.
Dracaena fragrans 'Massangeana' is the most popular cultivar and has leaves
with a broad yellow central stripe. This cultivar accounts for nearly 90%
of the corn plants sold. Two other attractive cultivars that are found in
the marketplace are Dracaena fragrans 'Lindenii' with white marginal stripes
and Dracaena fragrant 'Victoria' with golden marginal stripes.
Light levels can strongly affect appearance of corn plants, especially
the variegated cultivars. Suggested shade level is 63 to 73% (about 3000 to
3500 ft-c), which produce 'Massangeana' with good contrast between the
yellow and green portions of leaves. Best growth can be obtained with a
fertilization regime that provides 1500 lb N/A/yr from a 3-1-2 ratio
fertilizer source; liquid or slow-rglease (equivalent to approximately 34 lb
N, 12 lb P 0 and 23 lb K 0/1000 ft /yr). Where plants are subjected to
heavy rainafil or frequent irrigations, the fertilizer level may need to be
increased by 10 to 20%.
Potting media utilized for corn plants must be supportive of the canes,
yet provide good aeration. Such mixtures usually contain some sand, such as
a 3:1 peat:sand mixture, which helps hold canes straight, yet provides good
water and fertilizer retention. Media should be amended to include a
moderate level of micronutrients such as 1 lb Micromax/yd and sufficient
dolomite to adjust medium pH to 5.5 to 6.5. Elevating pH levels above 6.5
have been shown to cause iron deficiencies. Suggested air temperatures for
best growth range between 65 and 950F. Temperatures below 50 F, but above
freezing, have been observed to cause chilling damage when plants are
exposed to wind.
.Professor, Ornamental Horticulture and Center Director; Associate
Professor, Plant Pathology and Assistant Professor, Entomology,
respectively. Agricultural Research and Education Center, 2807 Binion
Road, Apopka, FL 32703
1) Leaning canes
Symptoms Canes become loose in pots causing plants to be unsalable and
sometimes damaged. This often occurs during shipping.
Control Growers have approached the problem of loose or leaning canes
in several ways: 1) Utilize a potting medium that packs around canes;
2) Ship with a spacer between multi-cane plants to prevent movement;
and 3) Induce rooting further up the cane as well as at the base to
provide additional support.
2) Fluoride toxicity
Symptoms On 'Massangeana', the first indication is a mottled loss of
pigmentation within the green area, most easily observed from
undersides of leaves. With time, these areas -become chlorotic and
then necrotic, often progressing to the point that the leaf margin is
damaged. On 'Lindenii' and 'Victoria', the problem appears mainly in
the white or golden margins and is first observed as necrosis. The
severity of this problem on these two cultivars often limits their
Control Potting media should have a pH of 5.5 to 6.5 to control
fluoride availability. Care must also be taken to use water and
fertilizer sources that do not contain fluoride.
Symptoms Plants produce sprays of light lilac flowers. As the sprays
are terminal, they result in loss of the terminal meristem and cause a
cessation of growth until side nodes break. This usually ruins the
Control Flowering appears related to cool temperatures in the fall or
early winter, especially where minimum night temperatures are near
45F or below for several weeks. Observation indicates that 7 to 14
cool nights in a row will probably initiate flowering. We suggest
maintenance of 55 F or higher to prevent flower formation.
4) Small heads
Symptoms Canes break poorly and only produce 1 to 2 heads per cane.
Control Use only fresh cane or presprouted cane of good quality.
Generally, small thin canes and thick old canes produce the lowest
number of sprouts. Poor sprouting also occurs when canes have been in
storage or transit too long.
5) Wind burn
Symptoms Leaves develop a water-soaked or grayish area along leaf
margins which turns brown or black after several days. Leaves most
likely to be damaged are the last 4 to 6 leaves that have developed.
Control Keep plants away from wind whenever temperatures are lower than
50 F. Temperatures as low as 350F are usually safe, provided plants
are protected from all wind, as in a closed greenhouse. In windy
areas, plants can be partially protected by wind breaks or heating.
6) Shipping leaf breakdown
Symptoms Although plants appear normal at time of shipping, leaves may
be severely chlorotic or even necrotic several days later when they
are unpacked. The pattern of damage is primarily a wide marginal
band, but can also occur within the leaf blade.
Control The cause is still not fully known, but the following
suggestions should reduce severity of this problem: 1) Grow plants
under suggested light and fertility regimes (plants from high light
and receiving heavy fertilization are usually most severely injured);
2) Water plants several days before shipping, but not within the last
day or two before packing. Recent research has shown that plants not
watered for up to a week before shipping may be damaged least,
provided the potting medium does not become dry.
DISEASES OF CORN PLANT
Corn plants (Dracaena fragrans) are among the most disease resistant
foliage plants produced. The few diseases which do occur on these plants
can generally be avoided if high quality, healthy cane pieces are used and
overhead watering is avoided.
1) Erwinia cane and cutting rot (Erwinia spp.)
Symptoms Cane bases become blackened and rotten. Sometimes this area
smells very putrid. Tip cuttings which are rooting can rot from the
base and turn black.
Control The best and probably only controls are use of cane pieces
which are healthy appearing and rooting canes with a minimum of both
soil and air moisture. Preventive dips of cane pieces with
bactericides are not usually effective. Removing all tip cuttings
with Erwinia from the propagation area is essential to stop spread to
1) Fusarium leaf spot (Fusarium moniliforme)
Symptoms Lesions form on leaves which are immature. The lesions are
generally reddish to tan with a wide chlorotic halo (yellow border).
This disease is not usually severe on this species of dracaena,
although the same pathogen causes a severe leaf spot and bud rot of
Control Keeping the foliage dry can eliminate this disease. Fungicide
applications which can provide control of Fusarium leaf spot include
Benlate, Chipco 26019, Daconil, Manzate 200, and Zyban.
2) Fusarium cane and cutting rot (Fusarium moniliforme and F. oxysporum)
Symptoms The bottom and sometimes the top end of the cane piece turn
purplish to brown. Tip cuttings rot from the base and turn black
appearing the same as cuttings infected with Erwinia spp.
Control Preventive drenches with Benlate at the time of rooting can
help control losses due to species of Fusarium. Sometimes both
Erwinia and Fusarium are involved in a stem rot disease. Since
symptoms are so similar, diagnosis of the cause is essential in choice
of the optimum control method.
Little information is published as to the safety of fungicides and
bactericides on corn plant and its close relatives. Since more information
is available for 0. marginata, some growers may choose fungicides for corn
plant from the list of safe chemicals for Dracaena marginata (see Foliage
Plant Research Note RH-1984-D).
MAJOR INSECT PESTS
The major arthropod pests of Dracaena fragrans include ambrosia
beetles, mealybugs, scales, and thrips. Ambrosia beetle, mealybug, and
scale infestations are typically the result of bringing infested plant
material into the production area. This is important to note because most
ambrosia beetle infestations on Dracaena cane are the result of importing
the beetles along with the cane. Ambrosia beetles and 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.
1) Ambrosia beetles (Xyleborus spp.)
Symptoms Sawdust-like material may be noticed at the base of cane
sections. These deposits actually are a combination of fecal material
and wood borings. Occasionally, tendrils of this material can be seen
extending from the sides of infested cane. This pest forms many
tunnels within infested cane which will eventually die. Cane contain-
ing an initial infestation can cause rapid spread to uninfested cane
Control Two controls are available: 1) A 30-minute immersion of
infested, unsprouted cane sections in water at 460C (115 F); and 2) An
application of Lindane. Bendiocarb may also aid in the control of
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
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*
Diazinon EC Omite WP
Malathion + Oil
Pesticides were tested at recommended rates and intervals.
*There is no data available on the sensitivity of this plant to
insecticides or miticides. This table is based on information obtained
from treating D. marginata.
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. 1982-83 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.