Title: Florida plant disease management guide
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00053871/00017
 Material Information
Title: Florida plant disease management guide
Alternate Title: Ornamentals and turf
Fruit and vegetables
General plant pathology, field crops and pasture grasses, fungicides, adjuvants and application techniques
Physical Description: v. : ; 28 cm.
Language: English
Creator: University of Florida -- Dept. of Plant Pathology
Florida Cooperative Extension Service
Publisher: The Extension
Place of Publication: Gainesville Fla
Frequency: annual
Subject: Plant diseases -- Periodicals -- Florida   ( lcsh )
Pesticides -- Periodicals   ( lcsh )
Statement of Responsibility: Plant Pathology Dept., University of Florida and Institute of Food and Agricultural Sciences, Florida Cooperative Extension, University of Florida.
Numbering Peculiarities: Issued in three volumes: v. 1, General plant pathology, field crops and pasture grasses, fungicides, adjuvants and application techniques; v. 2, Ornamentals and turf; v. 3, Fruit and vegetables.
General Note: Description based on: 1999-2000.
General Note: "SP-52"
 Record Information
Bibliographic ID: UF00053871
Volume ID: VID00017
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 44549741
lccn - 00229071
 Related Items
Preceded by: Florida plant disease control guide


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PDM G-V3-45
IFAS Extension

2006 Florida Plant Disease Management Guide:


Ken Pernezny and Tim Momol2

Specific Common Diseases

Anthracnose (Colletotrichum acutatum, C.
gloeosporiodes, Colletotrichum spp.)

Symptoms: Anthracnose or ripe rot is an
increasingly important disease of pepper. Damage
appears primarily on fruit. Fruit may be infected by
spores of the fungus at any time of development, by
symptoms usually expressed on mature fruit.
Symptoms first appear as small, water-soaked lesions
on fruit. These can rapidly develop into larger sunken
areas. A dark growth of the fungus may be visible in
these lesions, with tan to pink concentric circles of
spores evident in some cases. Occasionally, leaf spots
and stem dieback may occur.

Cultural Controls: Use pathogen-free seed.
Avoid overhead irrigation whenever possible. Avoid
injury to fruit. Crop rotation may be important in
reducing primary inoculum.

Chemical Controls: See PPP-6.

Bacterial Spot (Xanthomonas axonopodis
pv. vesicatoria)

Symptoms: Symptoms begin on leaves as small,
water-soaked spots. These become up to 1/4 inch in
diameter, turn dark brown and appear greasy. Scabby
lesions may appear on the fruit. During periods of
high rainfall or humidity, spots on leaves may
coalesce causing "blight" symptoms and abscission.
Bacterial spot can be a seedborne disease and can
spread rapidly in the transplant bed.

Cultural Controls: Transplant production should
be carefully monitored for disease occurrence. Do not
use infected plants for field planting and do not work
transplants when they are wet. Maintain a
preventative bactericide schedule in the transplant
bed as well as the field. Use cultivars with resistance
to specific races ofXanthomonas axonopodis pv.
vesicatoria known to occur in the production area.
Avoid unnecessary foliar or soil applications of
magnesium. See Plant Pathology Fact Sheet No. 3.

Chemical Controls: Maintain a preventative
bactericide schedule in transplant production as well
as the field. See PPP-6.

1. This document is PDMG-V3-45, one of a series of the Department of Plant Pathology, 2006 Florida Plant Disease Management Guide, Florida Cooperative
Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Revised December 2005. Please visit the EDIS Web site at
2. Ken Pernezny, professor, Plant Pathology Department, Everglades Research and Education Center, Belle Glade, FL; Tim Momol, associate professor,
Plant Pathology Department, North Florida Research and Education Center, Quincy, FL; Florida Cooperative Extension Service, Insitute of Food and
Agricultural Sciences, University of Florida, Gainesville, FL 32611.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and
other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex,
sexual orientation, marital status, national origin, political opinions or affiliations. U.S. Department of Agriculture, Cooperative Extension Service,
University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Larry
Arrington, Dean

2006 Florida Plant Disease Management Guide: Pepper 2

Damping-Off (Pythium spp. and Rhizoctonia

Symptoms: Pre-emergence damping-off or
seedling death may occur as a result of soilbome
fungal pathogens. Seedling plants will exhibit a
necrotic collapse of the hypocotyl and root system
when infected. Irregular areas of seedlings may be
affected in the transplant bed corresponding to
inadequate soil fumigation or subsequent
contamination of fumigated soil by run-off water or
soil. In our experience, damping-off problems
commonly occurring in early fall crops in southern
Florida are almost exclusively caused by Pythium spp.

Cultural Controls: In the transplant bed, avoid
planting in low, poorly drained areas or into land
previously in peppers. Employ multi-purpose soil
fumigation for vigorous transplant production. In the
field, avoid setting into land with residual,
undecomposed plant debris. Do not set unthrifty
plants. See Plant Pathology Fact Sheet No. 1.

Chemical Controls: See PPP-6.

Bacterial Soft Rot (Erwinia carotovora pv.

Symptoms: This disease is characterized by soft,
often "mushy" rot of the pepper fruit that occurs
primarily after harvest and during shipment. The rot
often occurs on the stem of the fruit, and advances
from that point into the stem end of the fruit. This
decay can progress quickly in transit. Field symptoms
are quite obvious as fruit soften and sag from the
pedicel like a balloon filled with water. Softened
areas usually are gray in color. The invasion by
numerous organisms will confer a characteristically
foul odor to infected fruit.

Cultural Controls: In the field, maintain
adequate insect and disease control. Insects can move
the soft rot bacteria fruit to fruit during feeding.
Severe outbreaks of foliar diseases can expose fruit to
sunscald injury and to subsequent soft rot. Avoid
harvesting while plants are wet. Do not let harvested
fruit set in the sun. Avoid fruit bruising and

In the packinghouse, avoid washing fruit
whenever possible. When fruit must be washed, use
chlorinated water. All fruit should be dried (forced
air) prior to packing to lessen likelihood of soft rot.
Maintain good quality control in the culling lines. See
Plant Pathology Fact Sheet No. 12.

Chemical Controls: See PPP-6.

Frogeye Spot (Cercospora capsici)

Symptoms: Lesions are roughly circular leaf
spots (approximately 1/4 inch in diameter) with light
tan to white centers and narrow dark borders. Leaf
lesions may often appear zonate. Heavy infection
may cause abscission of leaves and subsequently
reduce yield. See Plant Pathology Circular No. 946.

Chemical Controls: Apply fungicide in the
transplant bed at first disease appearance and in the
field as disease severity warrants. This disease is
more important in northern Florida. See PPP-6.

Gray Leaf Spot (Stemphylium solani)

Symptoms: More or less circular spots on leaves,
the spots are at first brown, later turning light tan to
white with sunken centers, and reddish-brown
margins. Spots can also appear on stems, petioles and
fruit pedicels, but have not been observed on fruit or
flower petals. This disease is a rare occurrence in

Chemical Controls: See PPP-6.

Phytophthora Blight (Phytophthora capsici)

Symptoms: This is one of the most common and
serious diseases of pepper in Florida. This disease
can affect all parts of the pepper plant. It causes a
seedling death as well as a root rot, stem canker, leaf
blight, and fruit rot in older plants. Stem infection at
the soil line is common. Affected plants exhibit
sudden wilting and death. The initial canker is dark
green and water-soaked but turns brown as the plant

When mature plants are affected, individual
branches become infected at forks killing whole
branches. Individually infected leaves exhibit small
circular to irregular leaf spots that appear scalded.

2006 Florida Plant Disease Management Guide: Pepper 3

The affected areas are dry and bleached to a light tan
color with a papery consistency.

Fruit are usually infected from the stem end first.
A progressive margin of water-soaked tissue proceeds
from the pedicel into the fruit. The fruit surface will
shrivel and during moist conditions may exhibit the
white fungal growth of the causal fungus.

Cultural Controls: Avoid low, wet fields for
pepper planting. Pump down fields rapidly after
heavy rains. Practice crop rotation.

Chemical Controls: See PPP-6.

Sclerotinia Stem Rot (Sclerotinia

Symptoms: This disease can be damaging some
years, especially in cool, damp winters in fields near
or following susceptible crops. The causal fungus
infects the stem at the soil line, individual petioles of
leaves, and occasionally fruit close to the soil surface.
Stem infections frequently girdle the stem causing
plant wilt and death. When weather is moist, the
white mycelium will often grow up the stem surface
several inches above ground.

Petiole or bud infections proceed rapidly
downward in the plant. Entire branches may be
girdled in this manner. Fruit infected directly from
the soil surface or downward through the pedicel, rot
quickly into a watery mass. The fungus survives as
sclerotia formed in stems and lesions associated with
diseased fruit. These sclerotia are black, irregular in
size (1/8"-3/4"), and highly resistant to environmental
conditions when in plant debris or soil.

Cultural Controls: Avoid rotations involving
susceptible crops such as cabbage, celery, lettuce,
potatoes or tomatoes. Deep plow fields with a
previous history of this fungus to bury fallen
sclerotia. Fields may be flooded with several inches
of water for six weeks in the off-season in order to
kill sclerotia. An emergency exemption for use of
thiophanate methyl on pepper is currently in effect.
See Plant Pathology Fact Sheet No. 22.

Chemical Controls: See PPP-6.

Southern Blight (Sclerotium rolfsii)

Symptoms: This is a warm, humid-weather
disease. Infected plants exhibit a progressive wilt due
to root and stem invasion prior to death. During moist
weather, a white collar of coarse white fungal
mycelium can be observed on the stem at the soil
line. Numerous white nodules form on this
mycelium. These structures (sclerotia) mature to a
tan color, and are the size of mustard seed. They
provide an overseasoning mechanism for this fungus
as they are incorporated into the soil.

Cultural Controls: Rotate to a grass crop in
fields with a high infestation of this fungus. Deep
plow infested crop debris to place the sclerotia below
the root zone of the next crop. Wind, water, or
equipment that can move soil can spread this fungus
in the field. See Plant Pathology Fact Sheet No. 4.

Chemical Controls: See PPP-6.

Viruses (Cucumber mosaic, Pepper mottle,
Potato Y, Tobacco etch, Tobacco mosaic,
Tomato Spotted Wilt)

Symptoms: It is difficult to distinguish single or
multiple virus infections in the field. Most of these
viruses induce degrees of mosaic, mottle, vein
banding, and plant stunting. Malformation, leaf
cupping, and fruit distortion may also be encountered.
Accurate diagnosis is dependent on laboratory tests
involving serology or viral inclusion examination.

Tobacco mosaic virus is commonly mechanically
transmitted during transplant production, harvesting,
and setting. Pepper mottle, potato Y, and tobacco etch
are primarily transmitted by aphids during feeding.

Tomato spotted wilt virus (TSWV) is transmitted
by thrips. Western flower thrips is the important
vector in north Florida for TSWV. Minute pirate bug
(Orius insidiosus) is an effective predator that
suppressed populations of western flower thrips in
north Florida.

These viruses are known to survive in numerous
weed hosts such as ground cherries (l'Piy,,i, spp.),
nightshades (Solanum spp.) common groundsel
(Senecio sp.), wild tobacco (Nicotiuan sp.), toadflax
(Linaria sp.), sicklepod (Cassia sp.), and jimson weed

2006 Florida Plant Disease Management Guide: Pepper 4

(Datura sp.).

Cultural Controls For:

Tobacco Mosaic Virus

Use resistant varieties. Workers handling
pepper plants should wash hands with strong soap and
water or 70% alcohol before handling plants. This is
most important for workers who use tobacco. This
will assist in controlling tobacco mosaic virus.

Pepper Mottle, Potato Y, Tobacco Etch

To reduce insect transmission of viruses
(tobacco etch virus, potato Y virus, and cucumber
mosaic virus from wild host plants (nightshade,
ground cherry and others) several practices are

1. Eradicate wild host plants in fence rows and on
ditch banks during seasons when crops are not

2. Destroy old infected crops well before planting
subsequent crops along side them.

3. Plant barrier crops around pepper fields. A
50-foot strip of a non-susceptible crop (corn,
sugarcane, etc.) tends to trap insects flying in
until they become non-infective.

4. Spray barrier crop with suitable insecticide at
least weekly to reduce population of insect

5. JMS Stylet Oil has received a Florida state label
for control of tobacco etch, potato Y, and
cucumber mosaic viruses on pepper. This product
interferes with the acquisition and/or
transmission of a virus by the aphid in the field.
Application requirements are highly specific and
must be followed precisely to achieve control.
See section on chemical control.

Tomato spotted wilt

1. Monitor crops for thrips, especially vector thrips
to time insecticide applications.

2. Locate fields as far away as possible from very
susceptible crops such as tomato, peanut and

Chemical Controls: See PPP-6. For TSW
management, use insecticides specific to vector thrips
and not effective on the thrips predator Orius sp.

Wet Rot (Choanephora cucurbitarum)

Symptoms: This disease produces a blossom
blight as well as a fruit rot stage and occasionally a
leaf blight. Blossoms exhibit a lack of turgidity as
petals begin to wilt. Stiff whisker-like strands of the
causal fungus, topped with black heads (sporangia)
grow off the infected blossoms causing a blossom
drop. Young fruit may become infected, soften and
abort with the same fungal growth apparent on the

Cultural Controls: Plant crop to the proper
spacing to maintain adequate air circulation. Use of
fungicides to control other disease will aid in control
of wet rot.

Chemical Controls: There are no materials
labeled for this disease on this crop at this time.

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