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
site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University
C. A. Conover, L. S. Osborne and A. R. Chase1
University of Florida, IFAS
Agricultural Research Center Apopka
ARC-A Foliage Plant Research Note RH-1984-B
Heart-leaf philodendron is still one of the best foliage plants
available and is utilized for potted plants, totem poles and hanging
baskets. Although the proper botanical name is now Philodendron
scandens oxycardium, this plant has also been known as Philodendron
oxycardium and Philodendron cordatum.
Latest available data (1975) indicated it represented 14 percent
of sales, but recent market reports (1983) indicate it may now be as
low as 7 percent. This production level is considerably short of the
34 percent of the market heart-leaf philodendron commanded in 1956.
Declining popularity is not due to problems with production of heart-
leaf philodendron, but rather to changing consumer attitudes.
Heart-leaf philodendron stock plants require slightly higher
light levels (2500-3000 ft-c) than potted plants (1500-3000 ft-c).
Best quality stock is produced at about 3000 ft-c and most attractive
potted plants at 2000 ft-c. Excellent growth can be obtained with a
3-1-2 (N-P205-K20) ratio liquid or slow release fertilizer when applied
at a rate of about 1500 lb N/A-yr (equivalent to 34.5 lb N/1000 ft /yr).
Potting media utilized for heart-leaf philodendron should have high
water holding capacity and excellent aeration. Amendments should
include micronutrients and dolomite to supply calcium and magnesium.
Good plant growth will be obtained when soil temperatures are at least
65'F and air temperatures 70F or above. Air temperatures as high as
1050F are not damaging to heart-leaf philodendron, as long as soil
moisture is adequate and proper light levels provided.
1) Cripple leaf
Symptoms Leaves have a wrinkled line beginning at the top of
the hear-shaped lobes extending to the lower margin on the
same side. The wrinkled area may be green, slightly chlorotic
or sometimes have some necrotic spots.
Control The problem is induced by a phytotoxic reaction to
pesticides or liquid fertilizer allowed to dry within the
partially folded leaf. Liquid fertilizers applied overhead
should be washed from leaves after application or applied at
Professor, Ornamental Horticulture and Center Director; Assistant
Professor, Entomology; and Associate Professor, Plant Pathology, Agri-
cultural Research Center, 2807 Binion Road, Apopka, FL 32703, respectively.
rates equivalent to 2 Ib 20-20-20/100 gallons or less at each
application. Phytotoxic pesticide reactions are not common
if proper rates are utilized.
2) Leaf chlorosis
Symptoms Two types of chlorosis are somewhat common on heart-
leaf philodendron. Type I appears near the petiole attachment
on the outer lobe margins. Type II appears on the lower margins
opposite the petiole with some streaks extending upward;
sometimes some marginal chlorosis is associated with this type.
Control Type I chlorosis is due to magnesium deficiency and can
be prevented by incorporation of dolomite into the potting
media at 7 Ib/yd Once Type I chlorosis appears on foliage,
it cannot be fully corrected, but further damage can be
prevented by use of magnesium sulphate (MgSo ) at 3 to 5 lb/100
gallons. Type II chlorosis is suspected to Be due to micro-
nutrient imbalance, but the specific cause is unknown at present.
3) Excess vigor
Symptoms Stock plants growing under proper light levels and
receiving high levels of fertilizer may produce leaves that
are too large to utilize easily in propagation.
Control Reduce fertilizer levels to reduce leaf size, but do not
lower level so much it reduces leaf color. If large leaves
are still a problem after reducing fertilizer level, slightly
reduce the light level.
4) Poor vigor
Symptoms Leaves and stem caliper small and weak. Cuttings root
poorly and do not grow off rapidly.
Control Increase light level and fertilizer level if leaf color
is light green after increasing light level. This will increase
leaf and stem caliper and carbohydrate level within the plant
which will improve rooting and initial growth.
DISEASES OF HEART-LEAF PHILODENDRON
Heart-leaf philodendron has a long list of serious diseases. Many
of these diseases are not as common or serious as they were when
philodendron plantings in ground beds were more common. Nevertheless,
many diseases caused by bacteria, fungi, nematodes and viruses persist
in philodendron grown by the foliage industry.
1) Bacterial leaf spot (Erwinia carotovora and E. chrysanthemi)
Symptoms Lesions initially appear as small water-soaked, irregu-
larly shaped areas which rapidly become necrotic and sometimes
encompass the entire leaf blade. Lesions may also occur on
leaf petioles and stems. Many times the center of a lesion
falls out or becomes mushy. This disease is most severe under
conditions of high moisture and temperature. The bacterium
appears to be dormant during the cool winter months.
Control Preventive sprays of Agri-Strep or Agrimycin (labeled)
may be beneficial if the foliage is kept as dry as possible.
Removal and destruction of infected tissue is most desirable
and infected plants should never be used as a cutting source.
A combination spray of a maneb compound and basic copper
sulfate or cupric hydroxide (Kocide 101 is labeled) may also
2) Pseudomonas leaf spot (Pseudomonas cichorii)
Symptoms This disease appears similar to Erwinia leaf spot
except that lesions rarely become mushy and do not appear
Control Same as for Erwinia leaf spot (above).
3) Red-edge (Xanthomonas campestris pv. dieffenbachiae)
Symptoms Reddish-brown margins on edges of lower leaves is the
most common symptom. Under wet and warm conditions, bacteria
also spread into leaf centers and lesions expand until they
reach a leaf vein. Sometimes lesions are also small, water-
soaked specks which enlarge into irregularly shaped areas.
Control Use of raised benches and minimizing foliage wetting
are two of the most important cultural controls of red-edge
disease. Foliar applications of copper and maneb compounds
as well as use of Agrimycin on a weekly basis provide adequate
1) Dactylaria leaf spot (Dactylaria humicola)
Symptoms Pinpoint water-soaked lesions on young leaves are the
first symptom of this disease. Lesions turn chlorotic and
then tan, have depressed centers, and usually remain quite
small (less than 1/8" wide).
Control Many fungicides control this leaf spot including
benomyl, chlorothalonil and maneb compounds, all of which are
labeled for this crop. This disease is not commonly found
in the industry except in ground beds exposed to overhead
2) Phytophthora leaf spot (Phytophthora parasitica)
Symptoms Lesions are dark brown, water-soaked, irregularly
shaped, and 1/2 to 1" wide. The disease is most severe in
the summer months in ground beds of philodendron.
Control Growing plants in sterilized potting media on raised
benches eliminates much of the source of this disease.
Preventive sprays of maneb compounds or chlorothalonil have
been shown to provide control. In addition, ethazole and
metalaxyl are effective in controlling species of Phytophthora.
3) Pythium root and stem rot (Pythium spp.)
Symptoms One of the first symptoms of Pythium root rot on
this philodendron is yellowing of leaves on rooted cuttings.
Leaves turn brown and usually remain attached to the stems
while leaves farther up on the vine may wilt. Stems are
easily removed from pots to reveal few healthy roots. The
roots themselves are blackened and mushy and the cortex of
an infected root is readily stripped from the inner core.
Control Soil drenches of metalaxyl or ethazole are effective.
Always use sterilized potting media and grow on raised
4) Southern blight (Sclerotium rolfsii)
Symptoms Plants with southern blight may initially appear
similar to those infected with many stem or root infecting
fungi. As the disease advances, however, the white cottony
masses of mycelia and brown seed-like sclerotia set this
disease apart. The sclerotia usually form on the basal
portion of stems of infected plants but may also be found on
infected leaves. Eventually the entire cutting or plant may
be covered with the fungus.
Control Southern blight must be controlled through prevention
since the only effective chemical (PCNB) can only be used
once a year. Use pathogen-free potting medium, pots and
planting materials. PCNB has been shown effective but due
to severe phytotoxicity (stunting) may be used only rarely.
1) Burrowing nematode (Radopholus similis)
Symptoms Small root systems, reduced vigor and reduced yields
of cuttings from stock plants are common symptoms of burrowing
nematode infestations. Plants may appear similar to those
infected with root rotting fungi, and diagnosis is very
important for all root problems. The nematode lives inside
the roots and does not form any obvious outward structures
such as galls.
Control A combination of cultural controls is the best way to
avoid nematode infestations. Methods listed for the fungal
root and stem rotting pathogens are effective.
1) Dasheen mosaic virus (DMV)
Symptoms Chlorotic streaking and mosaic patterns as well as
distortion of new leaves are found in philodendron infected
with DMV. Growth of infected plants is reduced compared to
healthy plants even when obvious symptoms are not present.
Control This virus is also a pathogen of Aglaonema, Dieffenbachia
and Spathiphyllum, and control practices should include these
genera as well. Elimination and destruction of infected plants
is the only way to stop spread of the virus. Aphid control
and sterilization of cutting instruments periodically also
are important ways to minimize virus spread since the virus
may be vectored by either method.
PHYTOTOXICITY OF BACTERICIDES AND FUNGICIDES ON HEART-LEAF PHILODENDRON
Agri-Strep Daconil 4.17 F Truban 25 EC
Banrot 40 WP Daconil 75 WP Zineb 75 WP
BenTate 50 WP Maneb compounds Zyban 75 WP
Captan 50 WP Subdue 2E
Chipco 26019 Truban 5 G
Copper compounds Truban 30 WP
Pesticides were tested at recommended rates and intervals.
MAJOR INSECT AND MITE PESTS
The major arthropod pests of this plant include aphids, caterpillars,
mealybugs, scales, and thrips. Mealybug and scale infestations are
typically the result of bringing infested plant material into the green-
house. Aphids, moths and thrips have the ability to fly and thus invade
the greenhouse from 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.
Symptoms Aphids are pear-shaped, soft-bodied insects which vary
in color from yellowish-green to dark brown. Infestations
frequently go undetected until honeydew or sooty mold is observed.
Aphids can cause distortion of new growth or, in extreme cases,
infested plants will be stunted.
Control There are a number of materials that will control aphids;
for example, Orthene 75S, Vydate 2L and Mavrik.
2) Caterpillars (worms)
Symptoms Infestations are easy to detect because worms, their
excrement and the damage they cause, are usually quite visible
to the unaided eye. Damage appears as holes in the center or
along the edges of leaves. Old damage can be distinguished
from new by the calloused appearance of the damaged areas
(worms are usually gone by this time).
Control Lannate, Orthene, Dursban, Sevin, Dycarb or Ficam,
Mavrik, and Bacillus thuringiensis are effective in the control
Symptoms Mealybugs appear as white cottony masses in leaf axiles,
on the lower surfaces of leaves and on roots. Honeydew and
sooty mold are often present, and infested plants become
stunted and, with severe infestations, plant parts begin to die.
Control Systemic materials are preferred. Examples of chemicals
which have systemic activity are: Cygon, Disyston, Metasystox-R,
and Orthene. Dycarb or Ficam appear to be as effective as some
of the systemic materials. Control of root mealybugs is
accomplished with soil drenches. Diazinon and Vydate are the
only insecticides registered for this purpose but both can cause
some phytotoxicity. When pesticides are applied to the soil,
care must be taken to assure that the pots have good drainage
with no saucers attached, or phytotoxicity may result.
Symptoms Infested plants become weakened or stunted and 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
Control See Mealybugs
Symptoms Infested leaves become curled or distorted, with
silver-gray scars or calloused areas where feeding has
Control Many materials are registered and effective at
PHYTOTOXICITY OF INSECTICIDES AND MITICIDES ON HEART-LEAF PHILODENDRON
Pesticides were tested at recommended rates and intervals.
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. 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
4. Simone, G. W. 19S2. Disease control pesticides for foliage
production 1982. 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.