Group Title: ARC-A research report - Agricultural Researcn Center-Apopka ; RH-81-4
Title: Common fungal stem rot diseases of foliage plants
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Permanent Link: http://ufdc.ufl.edu/UF00065933/00001
 Material Information
Title: Common fungal stem rot diseases of foliage plants
Series Title: ARC-A research report
Physical Description: 7 p. : ; 28 cm.
Language: English
Creator: Chase, A. R ( Ann Renee )
Agricultural Research Center (Apopka, Fla.)
Publisher: IFAS, University of Florida, Agricultural Research Center-Apopka
Place of Publication: Apopka Fla
Publication Date: 1981
 Subjects
Subject: Foliage plants -- Diseases and pests -- Florida   ( lcsh )
Fungal diseases of plants -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 7).
Statement of Responsibility: A.R. Chase.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00065933
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 70912880

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-i \COMMON FUNGAL STEM ROT DISEASES OF FOLIAGE PLANTS

A. R. Chase I' 4. '5
IFAS, University of Florida
Agricultural Research Center-Apopka
ARC-A Research Report RH-81-4 -
7" p17
.... iv o .
Diseases which occur primarily on plant stems are s m mes-less '

conspicuous than those occurring on the leaves. Since they can escape
notice longer and attack plant stems, they can cause more serious losses
than leafspot diseases and the key to control is prevention of infection.

Most stem rot organisms are soil-borne pathogens and should be controlled

in the soil. Avoid infecting plants by using sterile potting media, new

or clean pots and by growing plants on raised benches away from native
soil which harbors stem rot pathogens. Use pathogen-free stock when
possible since many of these diseases are spread through use of infected

stock plants. In-depth discussions of such control measures can be found

in previous Foliage Digest articles [2(3):16 and 3(10):13].

ASPERGILLUS (7)

Stem rot of Dracaena sanderana is caused by Aspergillus niger.
Infection occurs on cutting bases before or during rooting and is typified

by wilting and yellowing of lower leaves. Stem bases become blackened and
watersoaked and the dark brown sooty fungal spores form there. Since this
organism lives in soil for long periods of time, use fresh potting media
for each crop. Using pathogen-free plants is recommended since spores can

be carried on the cuttings themselves. This disease also has been reported

on Sansevieria spp. showing similar symptoms. It is not common in Florida

since relatively cool temperatures restrict its development, but can be
seen on rooted cuttings shipped from the tropics where the temperature is





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warmer on a year-round basis.


CERATOCYSTIS (3,9)

Ceratocystis blight of Syngonium podophyllum (black cane rot) is

caused by C. fimbriata. Symptoms include chlorosis of plants as well as

leafspots with chlorotic halos, dark brown stem lesions, and root rot

which can result in general plant chlorosis, Stem symptoms are most

noticeable and important in propagation beds where stems become brown to

black, watersoaked, and girdled. Avoidance of both overhead watering and

wounding plants can aid in control of this disease. This organism also

can be introduced through infected stock plants and care should be taken

to use pathogen-free plants at all times. Infected plants should be

removed to eliminate the source of disease spread.


FUSARIUM (5,6)

The most important fungal disease of Thanksgiving cactus, also

called Christmas cactus (Schlumbergera truncata) is stem cladophylll) and

root rot caused by Fusarium oxysporum. Stem lesions are watersoaked and

have a reddish border. They may start at the soil line or above and are

orange colored if they begin on cladophylls well above the soil. Under

dry conditions the lesions appear dry. Orange to beige spores usually can

be seen in the midst of lesions and are readily carried from plant to

plant by numerous vectors including splashing water, human handling, and

insects, Keeping the soil moisture low is highly recommended. The most

important control method is use of pathogen-free plants and careful

handling of infected plants. Healthy plants should not be handled after

infected ones until hands are cleaned or clean gloves are worn,


.4*,





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Another stem disease caused by F. oxysporum and F. solani occurs on

Dieffenbachia maculata cultivars, especially 'Perfection' types. This

disease can cause losses in numerous ways including stem lesions formed

near the soil line or around aerial roots. Lesions are wet, mushy and

sunken and appear similar to those caused by Erwinia spp. However, in

Fusarium stem rot lesions usually are surrounded by a purplish margin.

Lesions also occur on cut ends of stock plants and may result in stem loss

by a rot extending from the cut surface into the plant base. Generally

the rot ceases to progress when it reaches the base of the stem. Reddish

petiole lesions forming in the tissue closest to the stem also are seen

when plants are watered from overhead. In severe lesions small bright red

fruiting bodies of the fungus appear. Control of this disease is based on

use of pathogen-free plants and sanitation. Since symptom similarities

between Fusarium stem rot and Erwinia blight are so great, diagnosis of

the disease prior to treatment is required.

GLIOCLADIUM (8)

Gliocladium stem rot of Chamaedorea spp. is the most important

disease of these plants. G. vermoeseni attacks leaf sheaths and stems and

is typified by dark brown spots (lesions). In severe infections, lesions

girdle the stem and kill plants. A gummy black secretion exudes from stem

lesions and pinkish-orange spore masses form in lesions. Spores are

transferred easily to healthy plants by the wind and splashing water.

Removal of lower leaves before they die creates wounds which admits the

spores and new infections begin. Avoidance of wounds and excessive













splashing during watering are recommended to decrease spread of

Gliocladium blight to healthy plants. Chrysalidocarpus lutescens (areca

palm) also has been reported as susceptible to this organism although it

rarely occurs naturally.

HELMINTHOSPORIUM (4)

Helminthosporium stem rot is caused by H. cactivorum and is known to

occur on numerous species of cacti. The initial symptom is well defined

yellow spots which become brown with age. In advanced infections the stem

becomes black and rotten and may collapse. Under wet conditions the entire

cactus may become a watery mass. This disease can be important in seedling

beds and causes severe losses when plants are transferred to pots.

Infections usually occur through wounds and careful handling of small cacti

is important in minimizing losses. Use of sterile soil in seedling beds is

needed to avoid introduction through the soil.


KUTILAKESA (2)

Stem gall and cankers of Aphelandra squarrosa (zebra plant) and many

varieties of Codiaeum variegatum crotonn) is caused by Kutilakesa pironii.

Stem galls incited by this pathogen can reach 4.8 cm (2") in size on croton

and are roundish and corky. Galls may form where cuttings have been

removed and at leaf axils if the leaf has abscised. Symptoms on

aphelandras are similar. Since this fungus is an obligate wound pathogen

avoidance of wounding stock plants is recommended. Removal of infected

plants and use of pathogen-free stock is also important.













SCLEROTIUM (1)

Sclerotium rolfsii causes a serious stem and leaf rot of Peperomia

obtusifolia and many other foliage plants. Symptoms of rot appear to be

most important in propagation beds where conditions for the spread of the

pathogen are ideal (warm and wet). Watersoaked cutting rot is followed

by a blackened mushy area frequently covered with the white growth of the

fungus and eventually with the brown seedlike fruiting bodies (Sclerotia).

Use of pathogen-free cuttings and the control measures mentioned in the

articles cited in the introduction are necessary to control this disease.

There are many other foliage plants which are susceptible to this organism

including philodendrons, dieffenbachias, palms, pothos, scheffleras and

syngoniums. Care should be taken to avoid infesting stock beds with this

organism since control through chemical applications is difficult in

planted beds and can result in phytotoxic reactions especially stunting.

Sterilization of infected stock beds prior to replanting is highly

desirable since the organism survives long periods of time in the form of

sclerotia.











Diseases of foliage plants occurring on stems.

Host Disease Pathogen
Aphelandra squarrosa Aphelandra stem gall Kutilakesa pironii
Cacti Helminthosporium
stem rot H. cactivorum
Chamaedorea spp. Gliocladium blight G. vermoeseni
Codiaeum spp. stem gall and canker Kutilakesa pironfi
Dieffenbachia spp. Fusarium stem rot F. solani
F. oxysporum
Dracaena sanderana stem rot Aspergillus niger
Peperomia spp. and
many others Southern blight Sclerotium rolfsii
Sansevieria sp. stem rot Aspergillus niger
Schlumbergera truncata Fusarium stem rot F. oxysporum
Syngonium spp. black cane rot or
Ceratocystis blight C. fimbriata











References


1. Alfieri, S. A., Jr., and J. F. Knauss. 1972. Stem and leaf rot of

peperomia incited by Sclerotium rolfsii. Proc. Fla. State Hort. Soc.

85:352-357.

2. Alfieri, S. A., Jr., J. F. Knauss, and C. Wehlburg. 1979. A stem gall-

and canker-inciting'fungus, new to the United States. Pl. Dis. Reptr.

63:1016-1020.

3. Davis, L. H. 1953. Black cane rot of Syngonium auritum, Phytopath.

43:586. (Abstr.)

4. Durbin, R. D., L. H. Davis, and K. F. Baker. 1955. A Helminthosporium

stem rot of cactus. Phytopath. 45:509-512.

5. Miller, J. W. 1975. Blight and leafspot of Christmas cactus caused by

Fusarium oxysporum. Fla. Dept. Agric. & Cons. Ser. Div. Plant Ind,

Proc. Amer. Phytopath. Soc. 2:62.

6. Moorman, G. W. and R. A. Klemmer. 1980. Fusarium oxysporum causes basal

stem rot of Zygocactus truncatus. Pl. Dis. Reptr. 64(12):1118-1119.

7. Natour, R. M. and H. N. Miller. 1960, Stem rot of Dracaena sanderana.

Phytopath. 50:648. (Abstr.)

8. Reynolds, J. E. 1964. Gliocladium disease of palm in Dade County, Florida.

Pl. Dis. Reptr. 48:718-720.

9. Uchida, J. Y. and M. Aragaki. 1979. Ceratocystis blight of Syngonium

podophyllum. Pl. Dis. Reptr. 63:1053-1056.







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