• TABLE OF CONTENTS
HIDE
 Copyright
 Introduction
 Symptoms
 Seeds and seed treatment
 Planting the treated seeds - Seedling...
 Planting in the field
 Botrytis control in the field






Group Title: Research report - Bradenton Agricultural Research & Education Center - GC1979-10
Title: Botrytis disease of statice
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00067723/00001
 Material Information
Title: Botrytis disease of statice symptoms and control
Series Title: Bradenton AREC research report
Physical Description: 4 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: 1979
 Subjects
Subject: Limonium -- Diseases and pests -- Control -- Florida   ( lcsh )
Botrytis cinerea -- 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: "June 1979."
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00067723
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 - 73172695

Table of Contents
    Copyright
        Copyright
    Introduction
        Page 1
    Symptoms
        Page 1
    Seeds and seed treatment
        Page 2
    Planting the treated seeds - Seedling production - Seedling selection
        Page 2
    Planting in the field
        Page 3
    Botrytis control in the field
        Page 3
        Page 4
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




100 Agricultural Research & Education Center
Fr"! IFAS, University of Florida
Bradenton, Florida
Bradenton AREC Research Report GC1979-10 -i q i9--

BOTRYTIS DISEASE OF STATICE: SYMPTOMS AND CON OL OCT 91979
Arthur W. Engelhard Jmo *
rthur W. Engelhard Ii.F.A.S. Univ. of Florida
Introduction
Botrytis blight, caused by Botrytis cinerea Pers. ex Fr., on statice (Limonium
sinuatum Mill.) can be so destructive that it can be a limiting factor in crop pro-
duction. Botrytis cinerea attacks seeds, seedlings, flowers, flower stalks, foliage,
crowns, and stubs left after harvesting flowers. The disease can originate from con-
taminated seed and be transferred from seedlings to the field on infected plants.
It spreads by air-borne spores in the field. After the disease becomes well estab-
lished in the field it is extremely difficult, or impossible, to control when clima-
tic conditions are favorable for spread and development of the pathogen.
Botrytis blight was studied extensively in Florida and Colombia, South America.
The climate in Florida is favorable for Botrytis blight development during winter
months, especially December, January, February, and March, but in Colombia it is
ideal year-around. Entire plantings are lost to this disease in Colombia.
The objective of this report is to summarize information and experiences about
the destructive nature of Botrytis blight on statice, a commercially important flower
crop in Florida, California, and several eastern and midwestern states, as well as
several Latin American countries, but primarily Colombia.
Symptoms
Young leaves on seedlings in propagation are frequently infected. Individual
leaves may be completely covered with sporangiophores and spores. Such infections
may emanate from diseased seeds and obviously represent a source of disease that may
be transferred to the field. These infections presumably also may lead to crown rot
on older plants. Mature leaves generally have few lesions unless injured.
Early stages of flower infection are not readily apparent but result in the
shattering of flower heads after harvest. As infections advance, portions or entire
inflorescences become necrotic (blight). Frequently, the terminal 10-15 cm (4-6")
portion of a flower stalk becomes necrotic. The fungus sporulates sparsely between
the individual flowers. On the flower stalk, infection frequently occurs at a node.
The lesion develops up and down the stem. Sporulation, if present, occurs in the
center of the lesion. Spores apparently lodge in the protected nodal areas and then
grow, causing such a lesion. Lesions also develop on the leafy "wings" on the stems.
The entire flower stalk, including the "wings," may become chlorotic when stem les-
ions are present.
Stubs left after flower stalks are harvested are particularly susceptible to
Botrytis infection. The pathogen sporulates abundantly on and in the hollow stubs.
The disease progresses down the stub, eventually reaching the crown-root area where
a dry rot may develop. As multiple infections of dead stubs develop, the entire
plant is weakened and eventually killed if environmental conditions favor the path-
ogen more than the host. The decay in the crown resembles the dry rot incited by
Rhizoctonia solani Kuehn in the field. When the crown is split or broken apart,
Botrytis frequently is seen sporulating and sclerotia are present in cavities in
the crown tissue. The crown rot phase is particularly severe in Colombia.




100 Agricultural Research & Education Center
Fr"! IFAS, University of Florida
Bradenton, Florida
Bradenton AREC Research Report GC1979-10 -i q i9--

BOTRYTIS DISEASE OF STATICE: SYMPTOMS AND CON OL OCT 91979
Arthur W. Engelhard Jmo *
rthur W. Engelhard Ii.F.A.S. Univ. of Florida
Introduction
Botrytis blight, caused by Botrytis cinerea Pers. ex Fr., on statice (Limonium
sinuatum Mill.) can be so destructive that it can be a limiting factor in crop pro-
duction. Botrytis cinerea attacks seeds, seedlings, flowers, flower stalks, foliage,
crowns, and stubs left after harvesting flowers. The disease can originate from con-
taminated seed and be transferred from seedlings to the field on infected plants.
It spreads by air-borne spores in the field. After the disease becomes well estab-
lished in the field it is extremely difficult, or impossible, to control when clima-
tic conditions are favorable for spread and development of the pathogen.
Botrytis blight was studied extensively in Florida and Colombia, South America.
The climate in Florida is favorable for Botrytis blight development during winter
months, especially December, January, February, and March, but in Colombia it is
ideal year-around. Entire plantings are lost to this disease in Colombia.
The objective of this report is to summarize information and experiences about
the destructive nature of Botrytis blight on statice, a commercially important flower
crop in Florida, California, and several eastern and midwestern states, as well as
several Latin American countries, but primarily Colombia.
Symptoms
Young leaves on seedlings in propagation are frequently infected. Individual
leaves may be completely covered with sporangiophores and spores. Such infections
may emanate from diseased seeds and obviously represent a source of disease that may
be transferred to the field. These infections presumably also may lead to crown rot
on older plants. Mature leaves generally have few lesions unless injured.
Early stages of flower infection are not readily apparent but result in the
shattering of flower heads after harvest. As infections advance, portions or entire
inflorescences become necrotic (blight). Frequently, the terminal 10-15 cm (4-6")
portion of a flower stalk becomes necrotic. The fungus sporulates sparsely between
the individual flowers. On the flower stalk, infection frequently occurs at a node.
The lesion develops up and down the stem. Sporulation, if present, occurs in the
center of the lesion. Spores apparently lodge in the protected nodal areas and then
grow, causing such a lesion. Lesions also develop on the leafy "wings" on the stems.
The entire flower stalk, including the "wings," may become chlorotic when stem les-
ions are present.
Stubs left after flower stalks are harvested are particularly susceptible to
Botrytis infection. The pathogen sporulates abundantly on and in the hollow stubs.
The disease progresses down the stub, eventually reaching the crown-root area where
a dry rot may develop. As multiple infections of dead stubs develop, the entire
plant is weakened and eventually killed if environmental conditions favor the path-
ogen more than the host. The decay in the crown resembles the dry rot incited by
Rhizoctonia solani Kuehn in the field. When the crown is split or broken apart,
Botrytis frequently is seen sporulating and sclerotia are present in cavities in
the crown tissue. The crown rot phase is particularly severe in Colombia.




-2-


Seeds and Seed Treatment

Botrytis cinerea is seedborne. The fungus was detected on two percent of the
seeds in some of our experiments, therefore seed treatment is mandatory. Seeds may
be infested (spores are on the seeds or under the integuments) or infected (the fun-
gus has grown into the seed). Deep-seated infections may escape even the best seed
treatments resulting in diseased seedlings. Poor technique in seed treatment may
result in a larger number of diseased seedlings.
Experimentally, a mixture of 0.6 gm benomyl 50W plus 1.2 gm captain 50W/liter
(0.5 lb plus 1 lb/100 gal) water, respectively, was an effective seed treatment for
the fungi on the lots tested. Seeds should be soaked for 15 minutes with the fungi-
cide suspension at a temperature at least 380C (1000F). The seeds should be stirred
constantly to insure that all seeds are thoroughly wetted and treated. If the seeds
are placed in a mesh bag to facilitate dipping, care should be taken that small
enough quantities are placed in the bag to allow the fungicide to flow freely to '
all the seeds. The seeds should be spread out on clean paper after treatment to
dry as rapidly as possible at room temperature and then stored in a dry place for
future use. Individuals should wash their hands before and after handling seeds.
Failure to properly treat the seeds can result in the production of diseased seed-
lings.

Planting the Treated Seeds Seedling Production Seedling Selection
Treated seeds should be sown in a properly sterilized medium by an individual
who first has washed his hands. The medium should always be sterilized before each
crop. Ideally, seeds should be planted in trays with individual cells to keep a
chance infected seedling isolated, or they may be sown on open benches. Whatever
the method used, plants should be spaced so individual seedlings can develop with-
out crowding. This is important later in selecting the most vigorous plants to set
in the field. The seedlings should be drenched with the benomyl 50W plus captain 50W
at 0.6 gm plus 1.2 gnfliter (0.5 plus 1.0 lb/100 gal) water, respectively, using
sufficient liquid to wet the medium in the root zone. This should be done after
most of the seeds have germinated.
When seeds are sown in open benches the best practice is to transplant the
seedlings to containers with individual cells for each plant. A good transplant
container (also one to plant seeds into directly) has cells with a diameter of
2.5 cm (1 inch) that taper toward the base and have a hole in the bottom to allow
drainage of water and permit air pruning of roots. These trays are available com-
mercially. They should allow pulling or removing the seedlings without disturbing
the root systems. This is extremely important, because when plants are pulled from
a seedbed or a container and the roots are severely disturbed, they require a week
or more to become re-established in the field. During the re-establishment period,
the plants wilt and some of the leaves die. The Botrytis fungus is a good saprophyte,
i.e. it grows well on dead tissue. Therefore, on seedlings the presence of dead
or dying leaves, a weak or injured root system that results in the dying of leaves
before the plant becomes re-established in the field, a genetically weak plant with
chlorotic or necrotic tissue, or a nutritionally starved seedling on which leaves
die prematurely, all encourage blight development and the early demise of the plant.
Another important aspect of seedling production, whether transplanting into
trays or to the field, is the selection of disease-free, vigorous, normal appearing
seedlings. This is an important step in disease control and improved flower pro-
duction. Since seed treatment is not perfect (especially with deep-seated infec-
tions which may escape treatment), a small plant may be weakened from disease, yet
be without obvious symptoms. Also, statice is a seed crop and the plants display




-2-


Seeds and Seed Treatment

Botrytis cinerea is seedborne. The fungus was detected on two percent of the
seeds in some of our experiments, therefore seed treatment is mandatory. Seeds may
be infested (spores are on the seeds or under the integuments) or infected (the fun-
gus has grown into the seed). Deep-seated infections may escape even the best seed
treatments resulting in diseased seedlings. Poor technique in seed treatment may
result in a larger number of diseased seedlings.
Experimentally, a mixture of 0.6 gm benomyl 50W plus 1.2 gm captain 50W/liter
(0.5 lb plus 1 lb/100 gal) water, respectively, was an effective seed treatment for
the fungi on the lots tested. Seeds should be soaked for 15 minutes with the fungi-
cide suspension at a temperature at least 380C (1000F). The seeds should be stirred
constantly to insure that all seeds are thoroughly wetted and treated. If the seeds
are placed in a mesh bag to facilitate dipping, care should be taken that small
enough quantities are placed in the bag to allow the fungicide to flow freely to '
all the seeds. The seeds should be spread out on clean paper after treatment to
dry as rapidly as possible at room temperature and then stored in a dry place for
future use. Individuals should wash their hands before and after handling seeds.
Failure to properly treat the seeds can result in the production of diseased seed-
lings.

Planting the Treated Seeds Seedling Production Seedling Selection
Treated seeds should be sown in a properly sterilized medium by an individual
who first has washed his hands. The medium should always be sterilized before each
crop. Ideally, seeds should be planted in trays with individual cells to keep a
chance infected seedling isolated, or they may be sown on open benches. Whatever
the method used, plants should be spaced so individual seedlings can develop with-
out crowding. This is important later in selecting the most vigorous plants to set
in the field. The seedlings should be drenched with the benomyl 50W plus captain 50W
at 0.6 gm plus 1.2 gnfliter (0.5 plus 1.0 lb/100 gal) water, respectively, using
sufficient liquid to wet the medium in the root zone. This should be done after
most of the seeds have germinated.
When seeds are sown in open benches the best practice is to transplant the
seedlings to containers with individual cells for each plant. A good transplant
container (also one to plant seeds into directly) has cells with a diameter of
2.5 cm (1 inch) that taper toward the base and have a hole in the bottom to allow
drainage of water and permit air pruning of roots. These trays are available com-
mercially. They should allow pulling or removing the seedlings without disturbing
the root systems. This is extremely important, because when plants are pulled from
a seedbed or a container and the roots are severely disturbed, they require a week
or more to become re-established in the field. During the re-establishment period,
the plants wilt and some of the leaves die. The Botrytis fungus is a good saprophyte,
i.e. it grows well on dead tissue. Therefore, on seedlings the presence of dead
or dying leaves, a weak or injured root system that results in the dying of leaves
before the plant becomes re-established in the field, a genetically weak plant with
chlorotic or necrotic tissue, or a nutritionally starved seedling on which leaves
die prematurely, all encourage blight development and the early demise of the plant.
Another important aspect of seedling production, whether transplanting into
trays or to the field, is the selection of disease-free, vigorous, normal appearing
seedlings. This is an important step in disease control and improved flower pro-
duction. Since seed treatment is not perfect (especially with deep-seated infec-
tions which may escape treatment), a small plant may be weakened from disease, yet
be without obvious symptoms. Also, statice is a seed crop and the plants display






much variation which in part may be genetic in origin. Some plants may have a
genetic basis for being small, low in vigor, poor flower producers, or disease
susceptible. Therefore, this is the ideal time to eliminate weak plants that are
or may be non-productive, inferior, or diseased and constitute a source of infec-
tion for other plants.

Planting in the Field

Strong, vigorous seedlings should be carefully removed from containers (see
under "Planting the Treated Seeds") and planted in the field without significantly
disturbing the root system. Ah occasional chlorotic, necrotic or blemished leaf
should be removed at this time. Plants that wilt for several days before becoming
established usually have leaves that become chlorotic and die. This situation
predisposes the p!.nt to Botrytis blight.

The soil in which the seedlings are to be planted should be of seedbed tilth
to encourage early root growth. It should have had prior treatment with steam or
an acceptable soil fumigant to control diseases, nematodes, insects and weeds.
The day after the plants are set and watered-in in the field, they should be drenched
for disease control with up to 473 ml (1 pt) per plant of a suspension containing
benomyl 50W plus captain 50W at 0.6 gm plus 1.2 gm/liter water (0.5 lb plus 1.0 lb/
100 gal), respectively. Transplanting large plants to the field or from one loca-
tion to another usually is not successful.

Botrytis Control in the Field

Botrytis control is best accomplished through an integration of methods in-
volving culture, sanitation and chemicals:

Cultural Control Wet plants, high humidity, dew, rainfall, and cool temper-
ature (below 250C (770F)) are factors that encourage the growth, development and
sporulation of B. cinerea. Therefore, any practice that helps keep the plants dry
or shortens the duration of wetness, such as growing under cover, aids in disease
control. Watering should be done in a manner to keep the foliage and flowers dry.
Overhead watering is discouraged, as is watering late in the day which keeps the
plants wet and the humidity high during the night. Standing water in the rows and
adjacent work areas should be drained to reduce humidity. Where practical, such as
when growing under cover, any practices such as polyethylene barricades that pre-
vent the flow of cool, moisture-laden air at night or the use of fans and poly-
ethylene tubing to force air through the area to reduce the humidity and keep the
plants dry, are helpful. Other beneficial practices include increasing the dis-
tance between plants (reduces plant density) and keeping out weeds to allow improved
air circulation to facilitate drying.

Sanitation Old flowers, plants, and, in general, dead vegetation in and
around the statice fields are excellent inoculum sources. They should be raked,
hauled away and buried or burned daily. Severely diseased flowers and/or plants
should be removed from the field. Old plantings should be removed immediately
after harvest is completed, especially if other susceptible crops are nearby.
Severely diseased plantings should be removed if other plants are in the area. The
Botrytis fungus produces spores so prolifically that once the inoculum (air-borne
spores) builds up, no amount of spraying will protect a highly susceptible crop
such as statice.

Chemical Control Chemical control is a supplement to the partial control
provided through proper cultural procedures and sanitation practices. Experience
indicates that chemicals alone will not provide adequate control when other prac-
tices allow a massive buildup of air-borne spores in the crop area.






much variation which in part may be genetic in origin. Some plants may have a
genetic basis for being small, low in vigor, poor flower producers, or disease
susceptible. Therefore, this is the ideal time to eliminate weak plants that are
or may be non-productive, inferior, or diseased and constitute a source of infec-
tion for other plants.

Planting in the Field

Strong, vigorous seedlings should be carefully removed from containers (see
under "Planting the Treated Seeds") and planted in the field without significantly
disturbing the root system. Ah occasional chlorotic, necrotic or blemished leaf
should be removed at this time. Plants that wilt for several days before becoming
established usually have leaves that become chlorotic and die. This situation
predisposes the p!.nt to Botrytis blight.

The soil in which the seedlings are to be planted should be of seedbed tilth
to encourage early root growth. It should have had prior treatment with steam or
an acceptable soil fumigant to control diseases, nematodes, insects and weeds.
The day after the plants are set and watered-in in the field, they should be drenched
for disease control with up to 473 ml (1 pt) per plant of a suspension containing
benomyl 50W plus captain 50W at 0.6 gm plus 1.2 gm/liter water (0.5 lb plus 1.0 lb/
100 gal), respectively. Transplanting large plants to the field or from one loca-
tion to another usually is not successful.

Botrytis Control in the Field

Botrytis control is best accomplished through an integration of methods in-
volving culture, sanitation and chemicals:

Cultural Control Wet plants, high humidity, dew, rainfall, and cool temper-
ature (below 250C (770F)) are factors that encourage the growth, development and
sporulation of B. cinerea. Therefore, any practice that helps keep the plants dry
or shortens the duration of wetness, such as growing under cover, aids in disease
control. Watering should be done in a manner to keep the foliage and flowers dry.
Overhead watering is discouraged, as is watering late in the day which keeps the
plants wet and the humidity high during the night. Standing water in the rows and
adjacent work areas should be drained to reduce humidity. Where practical, such as
when growing under cover, any practices such as polyethylene barricades that pre-
vent the flow of cool, moisture-laden air at night or the use of fans and poly-
ethylene tubing to force air through the area to reduce the humidity and keep the
plants dry, are helpful. Other beneficial practices include increasing the dis-
tance between plants (reduces plant density) and keeping out weeds to allow improved
air circulation to facilitate drying.

Sanitation Old flowers, plants, and, in general, dead vegetation in and
around the statice fields are excellent inoculum sources. They should be raked,
hauled away and buried or burned daily. Severely diseased flowers and/or plants
should be removed from the field. Old plantings should be removed immediately
after harvest is completed, especially if other susceptible crops are nearby.
Severely diseased plantings should be removed if other plants are in the area. The
Botrytis fungus produces spores so prolifically that once the inoculum (air-borne
spores) builds up, no amount of spraying will protect a highly susceptible crop
such as statice.

Chemical Control Chemical control is a supplement to the partial control
provided through proper cultural procedures and sanitation practices. Experience
indicates that chemicals alone will not provide adequate control when other prac-
tices allow a massive buildup of air-borne spores in the crop area.







Thorough spray coverage is extremely important in controlling Botrytis blight
since there are many critical sites of infection on which an air-borne spore may
land. Spray must penetrate the inflorescence to cover the tissue between the indi-
vidual flowers. The stalk, with the ridges and/or highly susceptible wings, must
be thoroughly covered as well as the many axes between the pedicels and stems or
between branches where infections start. Spray must be directed around and into
the hollow flower-stalk stubs which are highly susceptible to Botrytis infections
that may lead to dry rot in the crown. In addition, the difficult-to-spray rosette
of leaves must be covered to control leaf infections and possible disease coming
from seedlings.

Fungicides effective for control of Botrytis blight on selected ornamental
crops include the following, applied as preventive maintenance sprays before blight
becomes established:
Fungicides (including tank-mixes) lb/100 gal water gr./l water

Benomyl** 501 plus Chlorothalonil 75W
(Benlate 50W plus* Daconil 2787 751) 0.25 + 0.75 0.3 + 0.9

Benomyl 50H plus Captan 50W
(Benlate 50W plus Orthocide or Captan 50W) 0.25 + 0.75 0.3 + 0.9
Chlorothalonil 75W
(Daconil 2787 75W) 1.5 1.8
Captan 50W
(Captan 50W or Orthocide 50W) 1.5 1.8

*An equivalent amount of Daconil 2787 Flowable may also be used.
**Benomyl should not be used if resistance to Botrytis is known or even suspected.

After disease becomes established, and especially when the weather is conducive
for blight development (temperature below 25C (77F), and plants are frequently wet
with dew or rain), the rates of the fungicide should be increased. In the tank-mix
combinations, benomyl 50W should be increased to 0.6 gr/l (0.5 lb/100 gal) and
captain 50W or chlorothalonil 2787 75W to 1.2 gm/l (1.0 lb/100 gal) or equivalent in
other formulations. When chlorothalonil 75W or captain 50W are used alone, the rates
should be increased as the label indicates for Botrytis control to 2.4 nm/1 (2.0
lb/100 gal) of water. Benomyl 50W should not be used alone because of the risk of
increasing resistant strains of the pathogen.

Application frequency is dictated by the amount of disease present and climatic
conditions. It is necessary to increase the frequency from a weekly preventive spray
before disease appears to several times per week under severe disease conditions.
Spraying should always be accompanied by cultural methods and sanitation procedures
that aid in disease control.




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