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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
COMMON VIRUS DISEASES OF FOLIAGE PLANTS
A. R. Chase i jiUiLjE
IFAS, University of Florida L
Agricultural Research Center Apopka | :
ARC-A Research Report RH-81-11
.F.A.S. Univ of Florida
The least commonly recognized diseases of foliage plat-s-a os.e0cCau.l .
by viruses. With the exception of two or three specific diseases a grower
may never notice the symptoms of a virus disease. In general, virus infec-
tions are introduced through the use of infected stock plants which often do
not show symptoms of the infection. Another avenue of introduction is through
insect transmission, especially by aphids feeding on an infected plant and then
on a healthy plant. In some cases the virus source is not a foliage plant but
a weed growing near the greenhouse. The method of transmission or transfer
from an infected plant to a noninfected plant will be discussed for each of the
viruses included below, since it varies according to the disease.
Viruses are among the smallest infectious agents known. They have very
few of the characteristics of the more complex bacteria and fungi and they rely
totally upon a plant host for growth. Viruses cannot be inactivated in the
same ways that bacteria and fungi are killed. Viruses will not grow on the
culture media used to identify bacteria and fungi and positive identification
depends upon very sophisticated techniques including the use of an electron
microscope. Most diseases caused by viruses can be identified with a degree
of accuracy through characteristic symptoms they incite. One of the most
common symptoms of virus diseases is mosaic or a disturbance in the normal
color pattern of the leaf. Others include distortion of leaves, and ringspots
which appear as either light or dark spots. Probably the most difficult
symptom to recognize is stunting of infected plants since many times the entire
planting is infected. If all of the plants grow more slowly than normal the
grower may determine that the cause is environmental, nutritional, disease
caused by root rotting fungi, or any number of other factors which could lead
to poor plant growth. Even experienced virologists cannot easily identify
a new virus disease if the only symptom is reduced plant growth. Symptoms
are not always expressed and they may grow in virus infected plants for a
large portion of their existence without showing them. This makes accurate
diagnosis and subsequent control measures more difficult.
All of these factors contribute toward making control of virus diseases
more difficult than control of most bacterial and fungal diseases. Control
must first be based upon use of pathogen-free plants especially those
propagated from seed or produced through tissue culture techniques and tested
for freedom from viruses. Once a plant is infected there is nothing which
can be done to.the plant either through manipulation of the environment or
application of chemicals which will cure that plant or even diminish the
effects of the virus on the plant. Any plants which show virus symptoms
should be discarded. Even healthy appearing shoots from infected plants
can carry the virus. Maintain a high level of insect control, especially
of aphids, and keep weeds out of pots, walkways and from under benches.
As in the previous four articles of this series, each virus disease
is discussed and references to additional information are given at the
beginning of the section as numbers following the title. A table is included
at the end of the article listing the virus diseases and their known hosts
according to host as well as the mode of transmission. Since viruses and
the diseases they cause are usually referred to by a single name, there is
only one column for this information.
BIDENS' MOTTLE VIRUS (11, 12)
Bidens' mottle virus (BMV) causes a distortion disease of Fittonia
verschaffeltii argyroneura (silver nerve plant and red nerve plant). This
virus was discovered in plantings of nerve plant showing severe leaf distor-
tion resulting in loss of leaf symmetry. Plants are stunted and appear as
though they have been sprayed with a pesticide and suffered a phytotoxic re-
action. The source of the initial BMV infection can be infected Spanish
needles (Bidens bipinnata) growing near the greenhouse. Control of this
disease is based primarily upon control of the weed and insect populations
to eliminate the chance that an aphid will transmit the virus from an in-
fected Spanish needles to a nerve plant. At this time the golden vein plant
(Xantheranthemum igneum)is the only other foliage plant known to be susceptible
to this virus..
CACTUS VIRUS X and others
There are several viruses which infect cacti including Schlumbergera sp.
(Christmas cactus). The major symptom of virus infection is stunting of
infected plants, although some viruses cause ringspots. If possible obtain
cacti from pathogen-free sources and discard any plants known to be infected.
COMMELINA MOSAIC VIRUS (6)
Commelina mosaic virus (CoMV) infects many species of the Commelinaceae
some of which occur as common weeds in Florida. These plants may conceivably
serve as a source of infection for the closely related Tradescantia and Zebrina
spp. grown commercially. Infected Commelina sp. show a mosaic of light and
dark areas on leaves. Although the virus has not been reported to cause a
disease of a commercially grown foliage plant, symptoms of the disease in
either of the plants mentioned above should be watched for and if found, weeds
harboring the virus should be removed.
CUCUMBER MOSAIC VIRUS (2,6)
Cucumber mosaic virus (CMV) causes a mosaic disease of both Commelina
and Maranta spp. Symptoms in Commelina sp. can be distinguished from those
caused by Commelina mosaic virus and frequently both viruses are present in
the same plant. Cucumber mosaic virus has a very wide host range occurring
in bean, beet, cucumber, pepper and tomato as well as foliage plants other
than maranta. Symptoms in maranta include a bright yellow ringspot or mosaic
pattern on infected leaves. Plants can also show a reduction in growth.
This virus does not always express itself and stock plants without symptoms
can yield CMV infected cuttings. Other foliage plants which may be susceptible
to CMV are aphelandra, calathea, dieffenbachia, peperomia and philodendron.
Control should involve the use of virus-free stock and avoidance of trans-
mission through use of nonsterile cutting tools.
DASHEEN MOSAIC VIRUS (8,9,10)
The single most important virus disease of foliage plants in Florida is
dasheen mosaic virus (DMV) which infects aglaonema, caladium, dieffenbachia,
philodendrons and other aroids. Dieffenbachias infected with DMV are not
always symptomatic and detection of the virus in plants without symptoms is
not possible. Symptoms include mosaic, distortion, ringspots and necrosis
of large areas of the leaf depending upon the host. 'Perfection' dieffen-
bachias suffer the greatest losses due to this virus since cutting production
can be reduced as much as 80%. Until recently there was no source of
pathogen-free dieffenbachias but through tissue culture the first step towards
controlling losses due to this disease is now possible. Several species of
philodendron also are susceptible to DMV and show severe mosaic symptoms
of bright yellow and dark green, distortion of new leaves, and stunting. DMV
is transmitted both mechanically and through aphid feeding and care should
be taken to avoid movement of disease from infected plants by either of these
pathways. Use new or sterile cutting instruments when removing cuttings and
always destroy infected plants.
FIG MOSAIC VIRUS (1)
Fig mosaic virus causes a disease of many Ficus spp. including Ficus
carica, the commercially produced fig. A study of the host range of this
virus revealed that several Ficus spp. grown for their foliage also are
susceptible, the most important of these being weeping fig (F. nitida).
Symptoms on this plant include a mosaic and slight reduction in leaf size.
Use pathogen-free plants, remove infected plants and use sterile cutting
instruments to control this virus.
TOBACCO MOSAIC VIRUS (3,5,7)
Tobacco mosaic virus (TMV) is the cause of a serious disease of
tobacco but also has been found to infect many other agricultural crops. In
addition, Rhoeo discolor (oyster plant) Columnea and Achimenesalso have been
found to host the virus. Symptoms of the disease of the oyster plant are
severe mosaic and stunting. The mosaic may be severe enough to cause some
leaf distortion as well, and frequently, infected plants will produce many
more side shoots than uninfected plants. This virus is transmitted by
handling infected plants and then handling a healthy plant; thus, sterile
cutting instruments should be used when trimming plants or removing cuttings.
Workers who smoke cigarettes and handle the plants can transmit the disease
to the plants if the tobacco in the cigarette was infected with TMV.
TRADESCANTIA MOSAIC VIRUS-(4)
Tradescantia mosaic virus infects both Tradescantia and Zebrina spp.
(wandering jews). The disease is characterized by a severe mosaic and
distortion of infected leaves as well as stunting. This virus is transmitted
by aphids as many viruses are,and control should include a good program for
insect control as well as use of pathogen-free plants.
-6-
Virus diseases of foliage plants and their hosts.
Virus disease
Achimenes sp.
Aglaonema spp.
Aphelandra sp.
cacti
Caladium sp.
Calathea spp.
Columnea sp.
Commelina spp.
Dieffenbachia spp.
Ficus spp.
Fittonia spp.
Maranta spp.
Peperomia spp.
Philodendron spp.
Rhoeo discolor
Schlumbergera sp.
Tradescantia spp.
Xantheranthemum sp.
Zebrina spp.
Tobacco mosaic virus
Dasheen mosaic virus
Cucumber mosaic virus
Cactus virus X
Dasheen mosaic virus
Cucumber mosaic virus
Tobacco mosaic virus
Commelina mosaic virus
Cucumber mosaic virus
Cucumber mosaic virus
Dasheen mosaic virus
Fig mosaic virus
Bidens' mottle virus
Cucumber mosaic virus
Cucumber mosaic virus
Cucumber mosaic virus
Dasheen mosaic virus
Tobacco mosaic virus
Cactus virus X
Tradescantia mosaic virus
Bidens' mottle virus
Tradescantia mosaic virus
Host plant
Literature Cited
1. Burnett, Harry C. 1960. Species of Ficus susceptible to the fig mosaic
virus. Proc. Fla. State Hort. Soc. 73:316-320.
2. Hearon, S. S. 1979. A ringspot of prayer plant caused by a strain of
cucumber mosaic virus. Plant Disease Reporter 63(1):32-36.
3. Koenig, R. and D. Lesemann. 1973. Tabakmosaikvirus in Achimenes.
Phytopathol. Z. 76:87-89.
4. Lockhart, B. E., Jean Ann Betzold, and F. L. Pfleger. 1981. Character-
ization of a potyvirus causing leaf distortion disease of Tradescantia
and Zebrina species. Phytopathology 71:602-604.
5. Lockhart, B. E. and F. L. Pfleger. 1977. Properties of a strain of
tobacco mosaic virus occurring in Rhoeo discolor in commercial green-
houses. Proc. Amer. Phytopath. Soc. 4:126.
6. Morales, F. J. and F. W. Zettler. 1977. Characterization and electron
microscopy of a potyvirus infecting Commelina diffusa. Phytopathology
67(7):839-843.
7. Thompson, Susan M. and M. K. Corbett. 1970. A mosaic disease of Rhoeo
discolor caused by a strain of tobacco mosaic virus. Phytopathology
60:1018-1019.
8. Wisler, G. C., F. W. Zettler, R. D. Hartman and J. J. McRitchie. 1978.
Dasheen mosaic virus infections of philodendrons in Florida. Proc. Fla.
State Hort. Soc. 91:237-240.
9. Zettler, F. W., M. J. Foxe, R. D. Hartman, J. R. Edwardson and R. G.
Christie. 1970. Filamentous viruses infecting dasheen and other araceous
plants. Phytopathology 60(6):983-987.
10. Zettler, F. W., R. D. Hartman, J. F. Knauss, M. E. Taylor-Knauss and A. R.
Chase. 1980. Evaluation of Dieffenbachia maculata 'Perfection' plants
free of dasheen mosaic virus. Acta Horticulturae 110:259-263.
11. Zettler, F. W., J. A. A. Lima and D. B. Zurawski. 1977. Bidens' mottle
virus infecting Fittonia sp. in Florida. Proc. Amer. Phytopath. Soc.
4:121.
12. Zurawski, D. B., D. E. Purcifull and J. J. McRitchie. 1980. Bidens'
mottle virus of Fittonia verschaffeltii. Fla. Dept. Agr. and Cons. Serv.,
Plant Path. Circ. No. 215.
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