• TABLE OF CONTENTS
HIDE
 Copyright
 Symptoms on cuttings
 Symptoms of flowering plants
 Symptoms on stock plants
 Comparison of fusarium stem not...
 Control of fusarium stem rot






Group Title: Research report - Bradenton Agricultural Research & Education Center - GC1976-15
Title: Fusarium stem rot of chrysanthemums, a newly discovered disease in Florida, caused by Fusarium Solani
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00067705/00001
 Material Information
Title: Fusarium stem rot of chrysanthemums, a newly discovered disease in Florida, caused by Fusarium Solani
Series Title: Bradenton AREC research report
Physical Description: 2 leaves : ; 28 cm.
Language: English
Creator: Engelhard, Arthur W
Agricultural Research & Education Center (Bradenton, Fla.)
Publisher: Agricultural Research & Education Center, IFAS, University of Florida
Place of Publication: Bradenton Fla
Publication Date: 1976
 Subjects
Subject: Chrysanthemums -- Diseases and pests -- Florida   ( lcsh )
Fusarium solani -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: Arthur W. Engelhard.
General Note: Caption title.
General Note: "November 1976."
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00067705
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: oclc - 72468980

Table of Contents
    Copyright
        Copyright
    Symptoms on cuttings
        Page 1
    Symptoms of flowering plants
        Page 1
    Symptoms on stock plants
        Page 2
    Comparison of fusarium stem not with other diseases of chrysanthemums
        Page 2
    Control of fusarium stem rot
        Page 2
Full Text





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





AGRICULTURAL RESEARCH & EDUCATION CENTER
) 0IFAS, University of Florida
Bradenton
-Id 7.,Z
Bradenton AREC Research Report GC1976-15 November 1976

FUSARIUM STEM ROT OF CHRYSANTHEMUMS, A NEWLY DISCOVERED DISEASE IN FLORIDA,
CAUSED BY FUSARIUM SOLANI

Arthur W. Engelhard


Fusarium stem rot, a recently discovered disease on chrysanthemums in Florida,
affects flowering plants, stock plants, and cuttings in propagation. There is much
variation among plants in the development of symptoms of the disease. The incidence
of the disease is generally moderate in flowering plants. In stock plantings, even
though a high percentage of the plants may be infected, the transmission rate is
low as determined by tissue isolations from cuttings. Chrysanthemum plants with
symptoms like those of Fusarium stem rot have been observed not only in Florida,
but also in certain chrysanthemum-producing areas in Latin America.

SYMPTOMS ON CUTTINGS .; ..

A brownish-black, wet, soft decay of the base of the cutting occurs with severe
decay. Cuttings less severely affected have red to brown discoloration-inithe7~as-
cular tissue and/or pith, yet have no external visible symptoms. They may still0
develop good roots and subsequently grow into healthy-appearing plants. An infected
cutting may be decayed on one side of the stem but still develop good roots on the
other side. Unrooted cuttings dipped in conidial suspensions of the Fusarium solani.
fungus and placed under intermittent mist developed white, healthy-appearing roots
even though parts of the stems decayed and the pith became discolored. The dark
discoloration and breakdown in the pith and adjacent tissues may extend from a part
to the entire length of the cutting. Roots that develop on infected cuttings are
not visibly decayed.

SYMPTOMS ON FLOWERING PLANTS

Symptoms may appear anytime from planting to flowering. The factors that cause
the continued development or the apparent retardation of the disease symptoms after
infection are not known at the present time. Rooted plants may die soon after they
are planted. On surviving diseased plants, wilting may occur, especially during
the h-tter period of the day. Plants that wilt during the day may recover and grow
to maturity, but they usually are somewhat smaller than adjacent healthy plants and
have small flowers. Symptoms vary on diseased growing plants and include leaf
chlorosis, followed by necrosis, usually beginning on one side of a leaf. The leaf
chlorosis and necrosis accompany an internal discoloration and decay of pith and/or
adjacent vascular tissues, or occur when dark streaks develop externally on the
stems. The dark streaks may appear first in the upper part of a plant or may start
at the soil line (the crown area). These dark streaks appear frequently as plant
development approaches the time when buds begin to show color. When the stem above
the crown dies, adventitious sprouts or shoots develop which may or may not develop
symptoms. On a "pinch crop", one or more of the axillary stems may develop symptoms
and eventually die, whereas other axillary stems on the same plant develop and flower
normally. In experiments with plants growing in ground beds, the plants were pinched
and inoculated at the pinch wound. Some of the inoculated stems died back to the
soil line but new shoots free of symptoms developed from adventitious buds on a
root system that had no apparent decay. The root system does not appear to be
affected until the final stages of the disease when the plant dies.





AGRICULTURAL RESEARCH & EDUCATION CENTER
) 0IFAS, University of Florida
Bradenton
-Id 7.,Z
Bradenton AREC Research Report GC1976-15 November 1976

FUSARIUM STEM ROT OF CHRYSANTHEMUMS, A NEWLY DISCOVERED DISEASE IN FLORIDA,
CAUSED BY FUSARIUM SOLANI

Arthur W. Engelhard


Fusarium stem rot, a recently discovered disease on chrysanthemums in Florida,
affects flowering plants, stock plants, and cuttings in propagation. There is much
variation among plants in the development of symptoms of the disease. The incidence
of the disease is generally moderate in flowering plants. In stock plantings, even
though a high percentage of the plants may be infected, the transmission rate is
low as determined by tissue isolations from cuttings. Chrysanthemum plants with
symptoms like those of Fusarium stem rot have been observed not only in Florida,
but also in certain chrysanthemum-producing areas in Latin America.

SYMPTOMS ON CUTTINGS .; ..

A brownish-black, wet, soft decay of the base of the cutting occurs with severe
decay. Cuttings less severely affected have red to brown discoloration-inithe7~as-
cular tissue and/or pith, yet have no external visible symptoms. They may still0
develop good roots and subsequently grow into healthy-appearing plants. An infected
cutting may be decayed on one side of the stem but still develop good roots on the
other side. Unrooted cuttings dipped in conidial suspensions of the Fusarium solani.
fungus and placed under intermittent mist developed white, healthy-appearing roots
even though parts of the stems decayed and the pith became discolored. The dark
discoloration and breakdown in the pith and adjacent tissues may extend from a part
to the entire length of the cutting. Roots that develop on infected cuttings are
not visibly decayed.

SYMPTOMS ON FLOWERING PLANTS

Symptoms may appear anytime from planting to flowering. The factors that cause
the continued development or the apparent retardation of the disease symptoms after
infection are not known at the present time. Rooted plants may die soon after they
are planted. On surviving diseased plants, wilting may occur, especially during
the h-tter period of the day. Plants that wilt during the day may recover and grow
to maturity, but they usually are somewhat smaller than adjacent healthy plants and
have small flowers. Symptoms vary on diseased growing plants and include leaf
chlorosis, followed by necrosis, usually beginning on one side of a leaf. The leaf
chlorosis and necrosis accompany an internal discoloration and decay of pith and/or
adjacent vascular tissues, or occur when dark streaks develop externally on the
stems. The dark streaks may appear first in the upper part of a plant or may start
at the soil line (the crown area). These dark streaks appear frequently as plant
development approaches the time when buds begin to show color. When the stem above
the crown dies, adventitious sprouts or shoots develop which may or may not develop
symptoms. On a "pinch crop", one or more of the axillary stems may develop symptoms
and eventually die, whereas other axillary stems on the same plant develop and flower
normally. In experiments with plants growing in ground beds, the plants were pinched
and inoculated at the pinch wound. Some of the inoculated stems died back to the
soil line but new shoots free of symptoms developed from adventitious buds on a
root system that had no apparent decay. The root system does not appear to be
affected until the final stages of the disease when the plant dies.





-2-


SYMPTOMS ON STOCK PLAiNTS

Generally symptoms on stock plants are similar to those on flowering plants.
In addition, dieback of harvest wounds (stubs) occurs, with the stubs becoming
necrotic and blackened. Red to brown discoloration of pith and vascular tissues
extends down from the infected stubs. The new stem(s) which develops from the
axillary bud(s) below the necrotic stub also may have red to brown discoloration
of the pith and/or vascular tissues. Cuttings harvested from stems with discolored
tissues are infected and the new stubs which remain after harvest die back. As the
severity of the disease increases, entire sections of the plant wilt and die.

COMPARISON OF FUSARIUM STEM ROT WITH OTHER DISEASES OF CHRYSANTHEMUMS

Stem rot, caused by F. solani, is difficult to distinguish in the field from
Fusarium wilt caused by Fusarium oxysporum f. sp. chrysanthemi, or F. oxysporum f. sp.
tracheiphilum tace 1. Wilting may occur with either disease. Early symptoms may
aid in identification, as F. solani causes a red to brown pith discoioratioh at some
location in the stem, whereas the dark discoloration caused by the Fusarium wilt
fungus is limited to the vascular strands. Also, the stem and leaf curvature typical
of Fusarium wilt is not present with stem rot. Development of adventitious shoots
from the crown or basal stem area after the stem dies occurs frequently with stem
rot, but not with Fusarium wilt. Dark streaks on the stem extending upward from the
base of a plant or developing in the upper parts of a plant are common to both dis-
eases. The dark streaks extend to the vascular tissues in Fusarium wilt, but with
stem rot they may be present, but not always, only in the epidermal and/or outer
cortical tissues. The cultivars affected by these two organisms are distinctive.
The Iceberg family is susceptible to stem rot but tolerant to Fusarium wilt. The
Torches are susceptible to both diseases. Knowing the reactions of the cultivars also
provides a clue to the organism involved. Field diagnosis is difficult and for accu-
rate diagnosis, tissue isolations must be made from diseased plant parts.

Symptoms of bacterial blight caused by Erwinia chrysanthemi may resemble those
of stem rot on young plants and rooted cuttings. Reddish discoloration of the pith,
dark decay of the base of the cutting and young plants, and vascular discoloration
are common to both diseases. As disease develops, however, the stems become hollow
with bacterial blight, but not with Fusarium stem rot. Also, with bacterial blight,
the leaves may wilt, become chlorotic and wither on one side of a plant whereas wilt-
ing is more general in the plant with stem rot. Pythium root rot, with its charac-
teristic stem rot, root rot and dark streak up the stem during wet, warm weather also
has overlapping symptoms with Fusarium stem rot.

CONTROL OF FUSARIUT STEM ROT

Known control measures are limited at the present time. Since the disease spreads
in cuttings, growers should use disease-free cuttings. Removing diseased plants as
they appear in stock beds appears to be a good practice, because diseased plants can
appear to recover. Keeping the "people traffic" to an absolute minimum in stock
Plant areas is also a good practice. The fungus F. solani on other crops is known
to survive in the soil for long periods so good soil fumigation practices should be
used, as well as rotation of stock production areas.

REFERENCE
Engelhard, Arthur U., G. L. Crane, and H. C. Mellinger. 1976. Stem rot, a new
disease on chrysanthemum incited by Fusarium solani. Plant Disease Reporter
60:437-441.





-2-


SYMPTOMS ON STOCK PLAiNTS

Generally symptoms on stock plants are similar to those on flowering plants.
In addition, dieback of harvest wounds (stubs) occurs, with the stubs becoming
necrotic and blackened. Red to brown discoloration of pith and vascular tissues
extends down from the infected stubs. The new stem(s) which develops from the
axillary bud(s) below the necrotic stub also may have red to brown discoloration
of the pith and/or vascular tissues. Cuttings harvested from stems with discolored
tissues are infected and the new stubs which remain after harvest die back. As the
severity of the disease increases, entire sections of the plant wilt and die.

COMPARISON OF FUSARIUM STEM ROT WITH OTHER DISEASES OF CHRYSANTHEMUMS

Stem rot, caused by F. solani, is difficult to distinguish in the field from
Fusarium wilt caused by Fusarium oxysporum f. sp. chrysanthemi, or F. oxysporum f. sp.
tracheiphilum tace 1. Wilting may occur with either disease. Early symptoms may
aid in identification, as F. solani causes a red to brown pith discoioratioh at some
location in the stem, whereas the dark discoloration caused by the Fusarium wilt
fungus is limited to the vascular strands. Also, the stem and leaf curvature typical
of Fusarium wilt is not present with stem rot. Development of adventitious shoots
from the crown or basal stem area after the stem dies occurs frequently with stem
rot, but not with Fusarium wilt. Dark streaks on the stem extending upward from the
base of a plant or developing in the upper parts of a plant are common to both dis-
eases. The dark streaks extend to the vascular tissues in Fusarium wilt, but with
stem rot they may be present, but not always, only in the epidermal and/or outer
cortical tissues. The cultivars affected by these two organisms are distinctive.
The Iceberg family is susceptible to stem rot but tolerant to Fusarium wilt. The
Torches are susceptible to both diseases. Knowing the reactions of the cultivars also
provides a clue to the organism involved. Field diagnosis is difficult and for accu-
rate diagnosis, tissue isolations must be made from diseased plant parts.

Symptoms of bacterial blight caused by Erwinia chrysanthemi may resemble those
of stem rot on young plants and rooted cuttings. Reddish discoloration of the pith,
dark decay of the base of the cutting and young plants, and vascular discoloration
are common to both diseases. As disease develops, however, the stems become hollow
with bacterial blight, but not with Fusarium stem rot. Also, with bacterial blight,
the leaves may wilt, become chlorotic and wither on one side of a plant whereas wilt-
ing is more general in the plant with stem rot. Pythium root rot, with its charac-
teristic stem rot, root rot and dark streak up the stem during wet, warm weather also
has overlapping symptoms with Fusarium stem rot.

CONTROL OF FUSARIUT STEM ROT

Known control measures are limited at the present time. Since the disease spreads
in cuttings, growers should use disease-free cuttings. Removing diseased plants as
they appear in stock beds appears to be a good practice, because diseased plants can
appear to recover. Keeping the "people traffic" to an absolute minimum in stock
Plant areas is also a good practice. The fungus F. solani on other crops is known
to survive in the soil for long periods so good soil fumigation practices should be
used, as well as rotation of stock production areas.

REFERENCE
Engelhard, Arthur U., G. L. Crane, and H. C. Mellinger. 1976. Stem rot, a new
disease on chrysanthemum incited by Fusarium solani. Plant Disease Reporter
60:437-441.





-2-


SYMPTOMS ON STOCK PLAiNTS

Generally symptoms on stock plants are similar to those on flowering plants.
In addition, dieback of harvest wounds (stubs) occurs, with the stubs becoming
necrotic and blackened. Red to brown discoloration of pith and vascular tissues
extends down from the infected stubs. The new stem(s) which develops from the
axillary bud(s) below the necrotic stub also may have red to brown discoloration
of the pith and/or vascular tissues. Cuttings harvested from stems with discolored
tissues are infected and the new stubs which remain after harvest die back. As the
severity of the disease increases, entire sections of the plant wilt and die.

COMPARISON OF FUSARIUM STEM ROT WITH OTHER DISEASES OF CHRYSANTHEMUMS

Stem rot, caused by F. solani, is difficult to distinguish in the field from
Fusarium wilt caused by Fusarium oxysporum f. sp. chrysanthemi, or F. oxysporum f. sp.
tracheiphilum tace 1. Wilting may occur with either disease. Early symptoms may
aid in identification, as F. solani causes a red to brown pith discoioratioh at some
location in the stem, whereas the dark discoloration caused by the Fusarium wilt
fungus is limited to the vascular strands. Also, the stem and leaf curvature typical
of Fusarium wilt is not present with stem rot. Development of adventitious shoots
from the crown or basal stem area after the stem dies occurs frequently with stem
rot, but not with Fusarium wilt. Dark streaks on the stem extending upward from the
base of a plant or developing in the upper parts of a plant are common to both dis-
eases. The dark streaks extend to the vascular tissues in Fusarium wilt, but with
stem rot they may be present, but not always, only in the epidermal and/or outer
cortical tissues. The cultivars affected by these two organisms are distinctive.
The Iceberg family is susceptible to stem rot but tolerant to Fusarium wilt. The
Torches are susceptible to both diseases. Knowing the reactions of the cultivars also
provides a clue to the organism involved. Field diagnosis is difficult and for accu-
rate diagnosis, tissue isolations must be made from diseased plant parts.

Symptoms of bacterial blight caused by Erwinia chrysanthemi may resemble those
of stem rot on young plants and rooted cuttings. Reddish discoloration of the pith,
dark decay of the base of the cutting and young plants, and vascular discoloration
are common to both diseases. As disease develops, however, the stems become hollow
with bacterial blight, but not with Fusarium stem rot. Also, with bacterial blight,
the leaves may wilt, become chlorotic and wither on one side of a plant whereas wilt-
ing is more general in the plant with stem rot. Pythium root rot, with its charac-
teristic stem rot, root rot and dark streak up the stem during wet, warm weather also
has overlapping symptoms with Fusarium stem rot.

CONTROL OF FUSARIUT STEM ROT

Known control measures are limited at the present time. Since the disease spreads
in cuttings, growers should use disease-free cuttings. Removing diseased plants as
they appear in stock beds appears to be a good practice, because diseased plants can
appear to recover. Keeping the "people traffic" to an absolute minimum in stock
Plant areas is also a good practice. The fungus F. solani on other crops is known
to survive in the soil for long periods so good soil fumigation practices should be
used, as well as rotation of stock production areas.

REFERENCE
Engelhard, Arthur U., G. L. Crane, and H. C. Mellinger. 1976. Stem rot, a new
disease on chrysanthemum incited by Fusarium solani. Plant Disease Reporter
60:437-441.




University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs