| Material Information
||Diseases of tissue-cultured foliage plants
||ARC-A research report
||2 p. : ; 28 cm.
||Chase, A. R ( Ann Renee )
Agricultural Research Center (Apopka, Fla.)
||University of Florida, IFAS, Agricultural Research Center-Apopka
||Place of Publication:
||Foliage plants -- Diseases and pests -- Florida ( lcsh )
||government publication (state, provincial, terriorial, dependent) ( marcgt )
non-fiction ( marcgt )
||Statement of Responsibility:
||Florida Historical Agriculture and Rural Life
|Table of Contents
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
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site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University
DISEASES OF TISSUE-CULTURED FOLIAGE PLANTS
A. R. Chase
IFAS, University of Florida
Agricultural Research Center Apopka
ARC-A Research Report, RH-83-26
There are many reasons to produce foliage plants using tissue
culture methods. One of the most important is the elimination of
plant pathogens from the plant. Although tissue culture may produce
pathogen-free plants, the process does not eliminate the possibility
that the plantlets will become infected when transferred to potting
medium. There are several important diseases of foliage plants which
are very severe on tissue-cultured material, including ones caused
by fungi, bacteria and viruses.
One of the most compelling reasons for the production of pathogen-
free Dieffenbachias was control of the disease caused by dasheen
mosaic virus. In vitro methods were developed to produce plants free
of the virus an-to-evauate those plants for 2 or more years under
highly controlled conditions to establish their pathogen-free status.
These plants have been produced in the industry for about 2 years at
present and although the possibility of reinfection with IMV exists,
the disease has not become a problem on pathogen-free stock. This
is probably due to the practice of selling the tissue-cultured plants
themselves instead of establishing longterm stock.
A second serious disease of Dieffenbachia is Erwinia blight caused
by E. carotovora pv. carotovora and E. hrysanthei. It is probably
the~single greatest cause of oliageplant disease losses. Use of
pathogen-free plantlets can aid in control of this disease since the
plants are free of the pathogen during the crucial early period of
establishment and development. The practice of selling most of these
plants before they become infected with Erwinia spp. is the best method
to maintain high quality plants.
One of the most severe diseases of tissue-cultured Dieffenbachia,
Syngonium, and Spathiphyllun is caused by the fungus Myrotheciun roridum.
This pathogen has a very broad host range and may infect any size plant.
Tissue-cultured plantlets are especially susceptible to this pathogen
since they are under stress following transfer to potting medium and the
handling process can create numerous wounds allowing entry of the fungus.
Once infection occurs, the disease progresses rapidly and many plantlets
can be lost. Control of this disease should be based on preventive
treatments of the potting medium (new or steamed medium only) and chemical
applications of benomyl (labelled). Both chlorothalonil and mancozeb
are also effective although they may not be labelled for all hosts of
Associate Professor of Plant Pathology, Agricultural Research Center -
Another serious disease which is controlled through use of tissue-
cultured plants is Cylindrocladium petiole and root rot of Spathiphyllum
spp. caused by C. spathiphylli. This disease is severe on all sizes of
Spathiphyllum and can result in complete crop loss unless measures are
taken to avoid infection. The use of new or sterile pots and potting
media, and growing plants on raised benches separated from native soil
is imperative. Preventive applications of benoryl to the potting medium
and plantlets may be advisable under some conditions. Since even benoryl
does not eradicate the pathogen from infected plants prevention of in-
fection must be stressed.
Although Syngonium have long been known hosts of bacterial plants
pathogens, a new disease has developed during the past 18 months. The
disease is not well understood at this time but appears to be caused by
a Pseudamonad and occurs on Svngonium 'White Butterfly' most commonly.
Infection may occur when plantlets are small but symptoms are most common
on relatively large plants. This plant has not been available until the
last two years and the disease has only been a serious consideration in
the past 18 months. Symptoms appear to develop "overnight" as a water-
soaking of the leaves between veins. Within a few days to a week this
tissue turns tan and dies. The lesions are found first on the older
lower leaves of 'White Butterfly' in 4 to 6" pots and spread rapidly
throughout the plant. Some growers report control by elimination of
overhead water, removal of infected leaves and bactericide applications
but this is not always successful. Research is currently underway to
identify the cause of disease, the way disease occurs, and possible con-
Fusarium solani causes a stem and leaf spot of large Dieffenbachia.
It is also a pathogen of tissue-cultured Dieffenbachia Perfection'.
The disease starts on the newly transferred plantlets and can cause
their immediate death by rotting the new roots and the stem end.
Plantlets which are not infected until they are a month old show symptoms
of stunting and overall chlorosis which appear similar to nutritional
deficiency. Examination of the stems near the soil line reveals the
mushy stem rot found also on older plants as well as the bright red
fruiting bodies of the pathogen. Generally the roots of these plants are
severely rotted. Control of this disease can be accomplished using the
methods described for control of Cylindrocladium root rot. Benomyl is
effective in protecting plants from infection and to a large degree in
controlling existing infections.
Awareness of the potential disease problems of plants produced using
tissue culture methods may allow for better transfer of plantlets to the
greenhouse environment. Tissue culture laboratories can possibly provide
their customers with preventive treatments to insure rapid adjustment of
plantlets with a minimum of losses to pathogens. Since these plantlets
are very small and loss of a single leaf may result in their death, the
prevention of disease is of paramount importance.