• TABLE OF CONTENTS
HIDE
 Title Page
 Credits
 Table of Contents
 Fig. 2
 Introduction
 Bacterial spot
 Southern blight
 Cercospora leaf spot
 Anthracnose
 Early blight
 Phytophthora blight
 Pink-joint
 Bacterial soft rot
 Mosaic
 Damping-off
 Sunscald
 Blossom-end rot
 Blossom blight
 Phoma rot
 Soil rot
 Helminthosporium pod rot
 Cercospora Pod Rot
 Skin cracks
 Cloudy spot
 Seed treatment
 Spraying and dusting














Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; no. 244
Title: Diseases of peppers in Florida
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027365/00001
 Material Information
Title: Diseases of peppers in Florida
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 46 p. : ill. ; 23 cm.
Language: English
Creator: Weber, George F ( George Frederick ), b. 1894
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1932
 Subjects
Subject: Peppers -- Diseases and pests -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by George F. Weber.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station)
 Record Information
Bibliographic ID: UF00027365
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000924098
oclc - 18204571
notis - AEN4702

Table of Contents
    Title Page
        Page 1
    Credits
        Page 2
    Table of Contents
        Page 3
    Fig. 2
        Page 4
    Introduction
        Page 5
    Bacterial spot
        Page 6
        Page 7
        Page 8
    Southern blight
        Page 9
        Page 10
        Page 11
        Page 12
    Cercospora leaf spot
        Page 13
        Page 14
        Page 15
    Anthracnose
        Page 16
        Page 17
        Page 18
    Early blight
        Page 19
        Page 20
    Phytophthora blight
        Page 21
        Page 22
        Page 23
    Pink-joint
        Page 24
        Page 25
    Bacterial soft rot
        Page 26
        Page 27
    Mosaic
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
    Damping-off
        Page 33
        Page 34
    Sunscald
        Page 35
        Page 36
    Blossom-end rot
        Page 37
        Page 38
    Blossom blight
        Page 39
    Phoma rot
        Page 40
    Soil rot
        Page 41
    Helminthosporium pod rot
        Page 42
    Cercospora Pod Rot
        Page 43
    Skin cracks
        Page 43
    Cloudy spot
        Page 44
    Seed treatment
        Page 45
    Spraying and dusting
        Page 46
Full Text


Bulletin 244


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
Wilmon Newell, Director






DISEASES OF PEPPERS

IN FLORIDA

By GEORGE F. WEBER


Fig. 1.-Pepper pods affected with Phytophthora capsici Leon, showing
three stages of the disease on the pods.



Bulletins will be sent free upon application to the Experiment Station,
GAINESVILLE, FLORIDA


March, 1932












BOARD OF CONTROL

P. K. Yonge, Chairman, Pensacola
A. H. Blanding, Bartow
Raymer F. Maguire, Orlando
Frank J. Wideman. West Palm Beach
Geo. H. Baldwin, Jacksonville
J. T. Diamond, Secretary, Tallahassee


EXECUTIVE STAFF

John J. Tigert, M.A., LL.D., President of the
University
Wilmon Newell, D.Sc., Director
H. Harold Hume, M.S., Asst. Dir., Research
Sam T. Fleming, A.B., Asst.Dir., Administration
J. Francis Cooper, M.S.A., Editor
R. M. Fulghum, B.S.A., Assistant Editor
Ida Keeling Cresap, Librarian
Ruby Newhall, S.eretary
K. H. Graham, Business Manager
Rachel McQuarrie, Accountant


MAIN STATION, GAINESVILLE
AGRONOMY
W. E. Stokes, M.S., Agronomist
W. A. Leukel, Ph.D., Associate
G. E. Ritchey, M.S.A., Assistant*
Fred H. Hull, M.S., Assistant
J. D. Warner, M.S., Assistant
John P. Camp, M.S., Assistant
ANIMAL HUSBANDRY
A. L. Shealy, D.V.M., Veterinarian in Charge
E. F. Thomas, D.V.M., Assistant Veterinarian
R. B. Becker, Ph.D., Associate in Dairy In-
vestigations
W. M. Neal, Ph.D., Asst. in Animal Nutrition
P. T. Dix Arnold, B.S., Assistant in Dairy In-
vestigations
CHEMISTRY
R. W. Ruprecht, Ph.D., Chemist
R. M. Barnette, Ph.D., Associate
C. E. Bell, M.S.. Assistant
J. M. Coleman, B.S., Assistant
H. W. Winsor, B.S.A., Assistant
H. W. Jones, M.S., Assistant
ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agricultural Economist
Bruce McKinley, A.B., B.S.A., Associate
M. A. Brooker, Ph.D., Associate
Zach Savage, M.S.A., Assistant
ECONOMICS, HOME
Ou'da Davis Abbott, Ph.D., Head
L. W. Gaddum, Ph.D., Biochemist
C. F. Ahmann, Ph.D., Physiologist
ENTOMOLOGY
J. R. Watson, A.M., Entomologist
A. N. Tissot, Ph D., Assistant
H. E. Bratley, M.S.A., Assistant
E. F. Grossman, M.A., Asso., Cotton Insects
P. W. Calhoun, Assistant
HORTICULTURE
A. F. Camp, Ph.D., Horticulturist
Harold Mowry, B.S.A., Associate
M. R. Ensign, M.S., Associate
A. L. Stahl, Ph.D., Assistant
G. H. Blackmon, M.S.A., Pecan Culturist
C. B. Van Cleef, M.S.A., Greenhouse Foreman

*In cooperation with U.S.D.A.


PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist
George F. Weber, Ph.D., Associate
R. K. Voorhees, M.S., Assistant
Erdman West, M.S., Mycologist


BRANCH STATIONS

NORTH FLORIDA STATION, QUINCY
L. O. Gratz, Ph.D., Associate Plant Pathologist
in Charge
R. R. Kincaid, M.S., Asst. Plant Pathologist
W. A. Carver, Ph.D., Asso. Cotton Specialist
R. M. Crown, B.S.A., Asst. Agronomist, Cotton
Jesse Reeves, Farm Superintendent

CITRUS STATION. LAKE ALFRED
John H. Jefferies, Superintendent
Geo. D. Ruehle, Ph.D., Asst. Plant Pathologist
W. A. Kuntz, A.M., Asst. Plant Pathologist
B. R. Fudge, Ph.D., Assistant Chemist
W. L. Thompson, B.S., Assistant Entomologist

EVERGLADES STATION, BELLE GLADE
R. V. Allison, Ph.D., Soils Specialist in Charge
R. W. Kidder, B S., Farm Foreman
R. N. Lobdell, M.S., Associate Entomologist
F. D. Stevens, B.S., Sugarcane Agronomist
H. H. Wedgeworth, M.S., Asso. Plant Path.
B. A. Bourne, B.S., Asso. Plant Physiologist
J. R. Neller, Ph.D., Assoc:ate Biochemist
A. Daane, Ph.D., Associate Agronomist
M. R. Bedsole, M.S.A., Assistant Chemist
Fred Yount, Office Assistant

SUB-TROPICAL STATION, HOMESTEAD
H. S. Wolfe.Ph.D.,Asso. Horticulturist in Chg.
Stacy O. Hawkins, M.A., Assistant Plant
Pathologist


FIELD STATIONS

Leesburg
M. N. Walker, Ph.D., Asso. Plant Pathologist
W. B. Shippy, Ph.D., Asst. Plant Pathologist
K. W. Loucks, M.S., Asst. Plant Pathologist
C. C. Goff, M.S., Assistant Entomologist
J. W. Wilson, Ph.D., Assistant Entomologist

Plant City
A. N. Brooks, Ph.D., Asso. Plant Pathologist
R. E. Nolen, M.S.A., Field Asst. in Plant Path.

Cocoa
A. S. Rhoads, Ph.D., Asso. Plant Pathologist
Hastings
A. H. Eddins, Ph.D., Asso. Plant Pathologist

West Palm Beach
D. A. Sanders, D.V.M., Associate Veterinarian

Monticello
Fred W. Walker, Assistant Entomologist

Bradenton
David G. Kelbert, Asst. Plant Pathologist












TABLE OF CONTENTS
PAGE
INTRODUCTION ..................................---------------------------- ............ 5
BACTERIAL SPOT .................................................................................. ....... 6
Sym ptom s ....................................................................................................... 7
Control ........................................................................................ ...... ............... 8
SOUTHERN BLIGHT ....................... ........................... ...................................... 9
Sym ptom s .... ........... ............... ............................................ ................... 11
Control ...................................................-..... .................................. 12
CERCOSPORA LEAF SPOT ....................................................................... ...... 13
Sym ptom s ................................................................................................ ..... 14
Control ....................................... .....-----.....................--............ ............ 16
A NTHRACNOSE ................................... .............................. .................... .. 16
Sym ptom s ............................................ .. ....... ......... ...... .............. 18
Control ........................... ........ ...... .... ......... ......... ......... 19
EARLY BLIGHT .................... ................... ...................------........ ... 19
Sym ptom s ................................................................... ................................. 20
Control ...................................... ............... .............. .... ............................... 21
PHYTOPHTHORA BLIGHT ..................................................................................... 21
Symptoms ...--....- ..-----.........--- .....---- ---------..-.---.................... 23
Control .........................................------ -------.....---.----... -........ 24
PIN K-JOINT ..................... .......... ................. ............................... .............. 24
Sym ptom s ................ .................................................................................. 25
C control .......................................................................... .......... ........... 26
BACTERIAL SOFT ROT .... ---.................---------------- .....-..-....- -....--..----......-. 26
Symptoms ......................................... ... .... ---------- 27
C control ................................................................................................ 28
M OSAIC .................................-- .. .... ..... .....------------------... ...... 28
Symptoms ..........--.....- ..... .-----.. ................................-- ------- ........ 31
Control ...................---- .....--- ......--- ........-- -- ... --.....--... ....-------....--- 33
DAMPING-OFF ........-- ....-----------.....-..-- ..---- ....- ----............................ .... 33
Symptoms .................................--........-------....... .....---- .........------- 34
C control .......................................................................... .................................. 34
SUN SCALD ........................................................................................................... 35
Symptoms .................................-- -..----.-.. ....-...-...--...................... ...... 36
C control ....................................................................................................... 36
BLOSSOM-END ROT ................................... .............................-----...----.----. 37
Sym ptom s ........................................... ...... ............. .................... ........ 38
Control ..... .... .. ....... ................... ... ....... ..... .. ..................... 39
BLOSSOM BLIGHT ...........-.......... ... ... ----------------- -----......... 39
Sym ptom s ....................................................................................................... 40
C control .......................................................................... .............................. 40
PHOMA ROT ............................................-.----- ---------------- 40
SOIL ROT ................................ .. ... ------------------------ 41
HELMINTHOSPORIUM POD ROT ................------------... ............................ 42
CERCOSPORA POD ROT.................................... ......................................... 43
OTHER DISEASES ...................... ............ .................. ..... 43
SKIN CRACKS ...................................... ....... ......... 43
CLOUDY SPOT ........... -----.......--.................... .......... 44
SEED TREATMENT ................ ----........................ 45
SPRAYING AND DUSTING ...................... .... ........... ............. 46

















































Fig. 2.-Pepper leaves infected with bacterial spot.









DISEASES OF PEPPERS IN FLORIDA

By GEORGE F. WEBER'

INTRODUCTION

The production and farm value of green peppers in Florida
has gradually increased during the past 10 years. During this
period they have returned to the grower from two to two and a
half million dollars annually. The farm value' of green peppers
grown in Florida in the past three years is as follows: 1928,
$2,508,000; 1929, $2,917,000; 1930, $2,748,000. Peppers are
hardy, easily grown, packed and shipped, and produce well in
this climate during the entire year when frost protection is
provided. As a result they are widely grown as a cash crop.
Chile or hot peppers are not cultivated extensively and only in
the past few years have pimientos been grown extensively in
the north central sections of the state for canning purposes.
Two or three decades ago, diseases of peppers were almost
negligible factors in the production of this crop. However, dur-
ing recent years, parasitic organisms and physiological troubles
have caused 15% losses annually. This loss may be partly ac-
counted for by concentrated and state-wide production, short
rotation periods in which peppers follow peppers or other close-
ly related crop plants, and the demand for seed in large quanti-
ties at planting time probably resulting in the use of much in-
ferior, mixed and diseased seed in this State.
Seeds that are not potentially strong often produce constitu-
tionally weak plants that are more susceptible to infection by
parasites. Infected seed are often dead or so weak they often
die and reduce the stand of a good grade of transplanting plants
in seedbeds. They are also considered carriers of some of the
parasitic organisms that are very destructive to young seed-
lings in the seedbed. When infected plants are transplanted to
the field, the disease may spread rapidly and cause more or less
loss during the season. Closer observations and concentrated
study during recent years on the diseases of truck crop plants
may also account for the increasing number of recognized dis-
eases. The purpose of this bulletin is to place before pepper
growers known information concerning the important diseases
'Photos by D. G. A. Kelbert.
'Crops and Markets, United States Dept. of Agr. Vol. 7, No. 12, p. 494.
1930.






Florida Agricultural Experiment Station


of peppers, so that they may be recognized in the field sufficient-
ly to enable the intelligent application of control methods.

BACTERIAL SPOT

Bacterial spot of peppers caused by Phytomonas vesicatorium
(Doidge) S. A. B. is common and often destructive in Florida
wherever peppers are grown. The disease has been found in
several foreign countries and in a large number of the states in
the United States east of the Rocky Mountain region. It was
first recorded in Texas in 1912 and in Florida in 1916.
Since the time it was first found in this State it has been col-
lected in all pepper-growing regions and during certain years
has been exceedingly destructive. It is severe on tomatoes and
certain other solanaceous plants. Peppers should not follow
tomatoes that have shown the disease during the same season.
Certain fields have been abandoned because of the severity of
the disease. The foliage is most severely attacked and is often
badly spotted and shed. The disease is also found on the leaf
petioles, fruit peduncles and on the fruit.
It is seed-borne and undoubtedly lives in the soil or on old
plant material in the field from one season to the next. It is
spread from primary infections to other parts of the plant and
to adjoining plants principally by dew and rain, but more often
by wind and blowing sand. Mechanical injury aids in the in-
fection process but it is not necessary. Infections appear more
numerous on the windward side of growing plants in fields
where sand has been blown, although scattered infections may
be found on plants grown on muck soils. The disease may ap-
pear unobserved on the young seedlings in the seedbed and
transferred to the field when these seedlings are transplanted.
By this means the disease may be spread over an entire neigh-
borhood from the same seedbeds.
Plants are susceptible to infection during their entire exist-
ence. Seedlings are often killed in the seedbed and bearing
plants often become entirely defoliated and die. The fruits are
susceptible to spotting at any time, although the most damage
is done when they are fully grown. Natural infections through
wounds or normal tissue cause lesions on all aerial parts of the
plant.
A large number of peppers have been tested in experimental
plots and the "hot" varieties show considerably less of the dis-






Bulletin 244, Diseases of Peppers in Florida


ease than the more popular, mild or sweet varieties. Among
these mild types there appears to be very little difference in
susceptibility. Those tried out include Ruby King, Ruby Giant,
California Wonder, World Beater, Pimiento, Royal King, Gold
Queen, Bullnose, Chinese Giant and Early Giant.
As peppers are grown throughout the year in Florida, there
are no typical seasonal developments particularly applicable.
SYMPTOMS OF BACTERIAL SPOT
The early infections of plants in seedbeds often consist of
small, irregular blackish spots usually along the margins on the
cotyledonary leaves. As the new leaves develop they become in-
fected and the lesions are
often I a r g e, irregular in
shape, sometimes more or
less circular but generally
more linear and irregular.
(Fig. 2.) In this stage the
leaves are rapidly shed. Se-
verely infected plants often
show only two or four small
rapidly developing leaves at
the growing tips of the
stem.
On the older plants in the
field the disease is first no-
ticeable as s m a 11, slightly
raised, water-soaked, blis-
ter-like spots, green to yel-
lowish in color, and scat-
tered over the blade. When
these spots are numerous
they usually remain small,
whereas if they are few and
whereas ifte they e few and Fig. 3. Pepper pod showing the
well-scattered, they may be- brown, irregular, blisterlike lesions
c o m e several millimeters of bacterial spot.
in diameter. The leaves thickly covered with diseased spots
change rapidly in color from green to yellow and when about
half of the total area is yellowish, the leaves are shed. The larger
scattered spots are surrounded by a lighter colored band or halo
and the time of shedding of an infected leaf depends almost
wholly on the number of lesions present. Often complete shed-






Florida Agricultural Experiment Station


ding of leaves takes place as described above during a period
of two or three weeks. This results in stunted plants early in
their development and badly sunburned pods during the fruit-
ing period.
On the fruit the lesions are at first yellowish brown, irregular
and blister-like (Fig. 3). With age they gradually enlarge, often
becoming a centimeter in diameter. During this development
the surface of the blister usual-
ly cracks and the lesion be-
comes irregularly ridged, rough
and cankerous (Fig. 4). They
penetrate deep into the flesh
and make the pods unfit for
market. They also open the way
for the development of decay by
secondary organisms incapable
of causing primary infections.
The bacterial spot organism
very seldom causes the pods to
shed.
CONTROL OF BACTERIAL SPOT
Satisfactory control can be
Fig. 4.-Raised rough and canker- obtained except under most ad-
ous spots on pepper pods caused verse conditions. During rainy,
by the bacterial spot organism. warm weather the d i s e a s e
spreads very rapidly and control measures known and applied at
the present time are not adequate to hold it in check.
The sedbeds should be made on soil not previously used for
this purpose. If new land is not available, the soil should be
disinfected with steam or formaldehyde. The seed should be
treated in 1:1,000 corrosive sublimate for eight minutes, washed
and dried. When the seedlings have developed four or 6 leaves
they should be thoroughly sprayed with 2-4-50 bordeaux mix-
ture to which has been added a small amount of calcium case-
inate which acts as a spreader. This spray should be repeated
weekly or at such intervals as are necessary to keep all parts of
the plants covered and protected.
Peppers should not follow peppers and the longer the rota-
tion period the better the chances are for disease-free products.
Peppers should not be planted in fields following tomatoes, at
least during the same year; several years rotation would be





Bulletin 244, Diseases of Peppers in Florida


safer. Infected fruits should be removed from the plants and
field at picking time and buried at least six inches deep. Badly
infected plants and fallen leaves in fields should be plowed under
as deep as possible.
SOUTHERN BLIGHT

Southern blight, one of the most common and destructive dis-
eases of peppers and other truck crop plants in the South, is
caused by the fungus Sclerotium rolfsii Sacc. It is annually a
serious disease of peppers, usually attacking and eventually
killing them after they have begun to bear fruit. (Fig. 5.) The
fungus causing the disease is widespread throughout the south-

















Fig. 5.-Portion of a pepper field showing certain plants killed by
southern blight.

ern part of the United States, from Maryland throughout Texas
and north to the Ohio river. The fungus has been collected in
several states bordering on this area and a few others but has
not been reported plentiful except in the South Atlantic and
Gulf states. In Florida it is state-wide in its distribution, occur-
ring on practically all types of soils. In addition to peppers it
has been found causing a blight disease on all of the commer-
cial truck crops, numerous flowering annuals, field crops and
even on some of the woody perennials. It has been found dur-
ing all months of the year affecting living pepper plants on the
wide range of Florida conditions. The fungus remains viable in
the soil for indefinite periods and under favorable environmental






Florida Agricultural Experiment Station


conditions attacks almost any plant with which it may come in
contact. In the northern part of the state it is most common on
peppers from the beginning of the rainy season in the later
part of June and continues active until November. In the
central and southern portions of the state it may occur at any
time of the year when peppers are growing.
The fungus produces seed-like bodies known as sclerotia, in
which form the fungus survives unfavorable conditions in the
soil. The fungus is spread by these sclerotia and diseased plant
parts being strewn by cultivation and by winds and rain that

-

















Fig. 6.-Pepper plants killed by southern blight (left) and a healthy plant.

blow and wash the sclerotia considerable distances. The scle-
rotia, which are usually round, hard, brown and about the size
of mustard seed, are formed in quantities in the soil close to
diseased plants as well as on the affected parts of these plants.
They become dry when the plant parts disintegrate and may
remain in this condition for an indefinite time. When favor-
able conditions appear, these sclerotia germinate and produce
abundant mycelium of the fungus which grows through the soil
until it comes in contact with plant stems which it parasitizes
and eventually kills. Under conditions where there is very little
surface moisture the fungus develops deeper in the soil. Pepper
plants were found killed by this fungus on soil that was dry for
more than three inches below the surface. In such instances the







Bulletin 244, Diseases of Peppers in Florida


fungus developed below this depth,
infected the main roots and girdled
them. Continued dry weather aids
in hastening the death of the af-
fected plants.
Plants that are attacked by this
fungus do not survive; the rapidity
with which they succumb depends
almost entirely upon moisture and
temperature relations. Fruits occa-
sionally have been found infected
where they were in contact with the
soil, but this is not common. How-
ever, fruits picked and discarded
between the rows in fields have
been found over-grown by the fun-
gus which produced numerous scle-
rotia. No peppers have been found
that show any resistance to attacks
of this fungus.
SYMPTOMS OF
SOUTHERN BLIGHT
Diseased plants in a field can be
detected by their wilted condition,
the drooping of all foliage, some
yellowing and shedding of leaves,
and browning and drying of the
stems and branches. Under aver-
age growing conditions the plants
are attacked at or slightly below the
soil line where the fungus comes in
contact with the main stem. The
fungus penetrates the cortex and
grows into the living parts of the
stems. When these tissues just be-
neath the bark are penetrated all
around the stem, the plant soon
dies (Fig. 6). When girdled plants
are pulled a fungus-infested clump
of soil often clings to them or the
bark may slough off entirely, leav-


Fig. 7.- Stem of a pepper
plant showing advancing
margin and sclerotia of
the southern blight fun-
gus.







Florida Agricultural Experiment Station


ing only a smooth woody stem. While this development takes
place underground, the leaves show a slight wilting in the mid-
dle of the day. Gradually the wilting becomes more pronounced
until the plant fails to revive during the night. Thus, a wilted
plant results from the girdled stem. These girdled plants dry
out slowly, because only small amounts of moisture are supplied
to the aerial portions of the plant through the woody portions
of the stem. The leaves are shed gradually, often requiring a
week or two for complete defoliation. In the meantime the
branches and stem dry out and remain erect. The fungus grows
very rapidly just before and following the time when the stem
is girdled. Under moist conditions it may grow several inches
up the stem above ground (Fig. 7). It produces sclerotia in great
profusion over the involved parts of the plant.

CONTROL OF SOUTHERN BLIGHT
Numerous experiments have been conducted in an attempt to
find satisfactory methods for the control of this disease but none
worthy of recommendation have been found. Sanitation should be
practiced to protect following crops. Plants that show the con-
stitutional wilt should be removed from the field before the


Fig. 8.-Branch of a pepper plant showing effects of Cercospora leafspot.







Bulletin 244, Diseases of Peppers in Florida


sclerotia are formed, thus preventing a more or less "seeding
down" of the soil for the following crop.
Fungicides applied for the control of this disease are not bene-
ficial.
CERCOSPORA LEAF SPOT

Cercospora leaf spot of pepper, often referred to as "frogeye",
is caused by the fungus Cercospora capsici Heald and Wolf.
This disease is more or less common on peppers wherever they
are grown in the United States. It is less destructive in northern
sections than in the south-
ern states. In Florida it is
common and destructive an-
nually and can usually be
found in fields at any time of
the year. It is more preva-
lent, however, in the sum-
mer months during the
rainy season and continues
to be important until late
fall. The losses resulting
from this disease may be
considered secondary be -
cause the fruits are not at-
tacked directly. The loss re-
sults, however, from partial
or complete defoliation of
the plants and from stem or
peduncle infections which
often result in stunted and
irregular shaped pods. (Fig.
8.) This fungus attacks all
varieties of peppers both hot
and sweet with about the
same severity. The destruc-
tiveness of the disease de-
Fig. 9.-Cercospora leafspot of pep-
pends largely on environ- per leaf showing detailed charac-
mental factors such as tem- teristics of the disease.
perature and moisture. The fungus is disseminated by wind
and water. It may be found on seed but does not cause infec-
tion from that source; neither does it remain alive in the
soil from one season to the next. Plants do not usually show






Florida Agricultural Experiment Station


primary infection until about blossoming time and they may
be entirely defoliated within two or three weeks.
SYMPTOMS OF LEAF SPOT
The earliest indication of the disease on the foliage is a small,
circular, water-soaked spot. This spot becomes surrounded with
a dark band even when less than a millimeter in diameter and
the center fades gradually to a lighter color as the spot becomes
dry. (Fig. 9.) These spots enlarge rapidly until they attain
about a centimeter in diameter, after which time the rate of en-
largement is much slower; they continue to enlarge, however,
and may eventually involve a large portion of the blade. As the
spot enlarges the dark, bordering band becomes wider and the
center fades until it is almost white. These developments pro-
duce a very contrasting spot that should be easily identified by
the most casual observer.
As the spots become old-
er, larger and drier they
often crack across and
portions of dead leaf tis-
sue may fall out. The
spores of the fungus are
produced in abundance
on the killed area within
the borders of the spots,
and are easily detached
and scattered by air cur-
rents and meteoric wa-
ter. They germinate
quickly and when condi-
tions are favorable sec-
ondary infections almost
Fig. 10-Pepper pod and portion of leaf keep pace with the
showing lesions caused by the leafspot growth of the plant. The
fungus on peduncle and petiole. leaf spots often coalesce
when numerous, and the leaves are rapidly killed and become
dry and brown. They are eventually shed. All stages of the dis-
ease can usually be found on a single plant.
Infection spots also occur on the leaf stems petioless), the
fruit stems peduncless) and the main branches of the plant.
(Fig. 10.) Serious damage results particularly from the first
two. The spots, at first small, enlarge rapidly, become some-






Bulletin 244, Diseases of Peppers in Florida


what elongated or linear, and eventually girdle the stems. Gird-
ling deprives leaf petioles and fruit peduncles of adequate
moisture and food supply and consequently these parts wilt, be-
come stunted or die and are shed. The spots on the branches


Fig. 11.-Stems and pod peduncles (left) showing lesions caused by
Cercospora Leafspot fungus.






Florida Agricultural Experiment Station


do not enlarge as rapidly nor do they attain the size as those on
the stems; they are characteristically whitish in the center and
surrounded by a narrow, dark band. (Fig. 11.) The spores of
the fungus are produced over the lighter colored area of all of
the spots.
CONTROL OF LEAF SPOT
The best control of leaf spot is accomplished by the applica-
tion of 4-4-50 bordeaux mixture containing a spreader such as
calcium caseinate applied weekly or often enough to keep all
parts of the plants covered and protected.
Copper-lime dust, 20-80 formula, containing 8 to 10% metallic
copper also may be used. If possible, the dust should be applied
to the plants when they are wet with dew. Do not dust when the
wind is blowing because large quantities of it will be wasted.

ANTHRACNOSE

Anthracnose, a disease of the pods of pepper plants, is caused
by the fungus organisms Gloeosporium piperatum E. & Stonem.


Fig. 12.-Pepper pods showing anthracnose lesions.







Bulletin 244, Diseases of Peppers in Florida


and Colletotrichum nigrum E. & H.* The disease caused by these
organisms is of wide distribution, occurring almost everywhere
peppers are grown commercially. A fruit rot is produced on a
number of different plants by these fungi. All varieties of pep-
pers are susceptible, including both hot and sweet, and there
appears to be little or no
variation i n suscepti-
bility or resistance to
the disease. (Figs. 12
and 13.) Green fruits -
are probably more re-
sistant to t h e disease
than ripe fruits but they
often s h o w infections,
probably resulting from
invasion of the fungi
through wounds of vari-
ous kinds including insect
punctures. T h e losses
resulting from this dis-
ease occur in the field, in
transportation a n d in
storage. The disease is
usually found in pepper
fields, especially in the
south where it is more
severe than in other
pepper producing sec-
tions of t h is country.
When conditions favor
the development of the
f ung i, considerable
losses may result. Ripe
fruits are most severely
fruits are most severely Fig. 13.-Pepper pods of a "hot" variety
affected. showing anthracnose lesions.
The lesions formed on
the fruit, although varying in size, usually become speckled
with the black, speck-like acervuli, the spore-bearing struc-
tures of the fungus (Fig. 12). The spores escape from the
acervulus in the presence of moisture and may be scattered by
various carriers considerable distances. The disease appears
*Perfect stage of both is apparently Glomerella cingulata (St.) Spaul
& Von Sch.







Florida Agricultural Experiment Station


when the first pods become ripe, which is usually in the early
summer, and continues in importance until the end of the sea-
son in late fall. In Florida the disease is most severe at about
the end of the rainy season or during August and September.

SYMPTOMS OF ANTHRACNOSE
On ripe fruit, early infection is indicated by a slight sunken
surface area. This sunken area enlarges and the center darkens
to a smoky-gray. (Fig.
14.) The spots enlarge
but remain sunken until
they are one-half to one
centimeter in diameter,
S when they become black
and specked. These
specks are scattered
more or less over the
surface of the lesion or
they may often be ar-
ranged in more or less
concentric circles or

S blackish specks are cov-
.' ered with fine black
hairs which give the
spot a black appearance.
The specks may be pink
instead of blackish at
First and appear to be
wet and glistening. These
pink masses are exuded
spores which ma y be
either washed away by
moisture or dried down
Fig. 14.-Anthracnose lesions of various during the day and be-
sizes on ripe pepper pod. come dark colored.
come dark colored.
Green fruits are attacked usually in areas that are weakened
by sunburn or some other outside agency. In such instances the
lesion enlarges rapidly and eventually may involve the entire
pod. During dry periods the diseased pods shrivel and wrinkle
as they are killed by the parasites and persist on the plants in






Bulletin 244, Diseases of Peppers in Florida


more or less mummied form. In wet, rainy weather the infected
pods become invaded by soft rotting bacteria which cause rapid
disintegration and an eventual sloughing off or shedding of the
pod from the pe-
duncle.

CONTROL OF
ANTHRACNOSE
No control can be
recommended. Rota-
tion, sanitation and
a spray schedule are
suggested.

EARLY BLIGHT

Early blight of
peppers is caused by
the fungus Alter-
naria solani (E. &
M.) J. & G. and is
not common in the
state. It has been
found only on seed-
lings under crowded
conditions in seed-
beds where they
were subjected to
long periods of high
humidity and very
little aeration. The
fungus, although
widespread and de-
structive on a number Fig. 15. Pepper seedlings showing early
of t h e solanaceous blight lesions. The lower leaves have shed
because of the disease.
relatives of pepper,
has not been found doing damage on pepper plants in the field.
The fungus causes a serious disease of eggplants under similar
conditions. It is favored in its development by high tempera-
ture, high humidity and lack of ventilation. The fungus forms
spots on the leaves which cause them to be shed (Fig. 15).
This infection and shedding progresses up the plant, attacking
the leaves as they develop. The spores borne on the killed areas






Florida Agricultural Experiment Station


in the lesions are easily detached and carried by wind and wa-
ter. The disease may occur at any time of the year when condi-
tions are favorable for its development. Affected plants often
recover by growing away from the parasite when set in the
field but growers interested in a profitable crop do not often
take such chances.
SYMPTOMS OF EARLY BLIGHT
The infections are at first revealed as dark specks of pin-point
size, few or many, well scattered over the leaf blades. As the
spots increase in size a definite yellowish halo appears around
them. The spots enlarge; the killed tissue within its circumfer-
ence becomes a smoky-black color, with a white center, zonate
markings appear and the larger spots crack across or cause
irregularities in the normally smooth, flat leaves (Fig. 16). The


Fig 16.-Pepper leaves showing spots caused by Alternaria solani (E. &
M.) J. & G., the Early blight fungus.






Bulletin 244, Diseases of Peppers in Florida


spots usually include a very small portion of the leaf tissue but
they may enlarge to include half its area. Numerous spots on
a single leaf cause it to become yellow and eventually shed. The
lower leaves of seedlings in seedbeds are quickly shed, resulting
in "long-legged", spindling plants which are not satisfactory
for transplanting in the field. Lesions are formed also on the
main stem but they have not been observed often or found to be
of any importance. Spores are produced abundantly on the sur-
faces of the spots on the leaves after they are two or three milli-
meters in diameter.
CONTROL OF
EARLY BLIGHT
Control measures
for early blight con-
sist of adequate
spacing in the seed-
bed to prevent
crowding. Good ven-
tilation and the ap-
plication of a good
fungicide at inter-
vals often enough to
keep all new growth
covered and protect-
ed are also suggested.

PHYTOPHTHORA
BLIGHT

Phytophthora
blight is caused by
the fungus Phytoph-
thora capsici Leon.
It has only recently
been found in Flor-
ida, consequently its
present distribution
and future import-
ance cannot be defi-
nitely defined. The
Fig. 17.-Pepper leaf showing spots caused by
disease was first re- Phytophthora capsici Leon.






Florida Agricultural Experiment Station


ported from New Mexico and later from Porto Rico. The only
other report in the United States is this report from this state.
The disease in Florida affected stems, branches, fruit and


Fig. 18.-Pepper plant killed by Phytophthora blight in contrast to
healthy plant.






Bulletin 244, Diseases of Peppers in Florida


leaves. (Figs. 1 and 17.) Only sweet varieties of peppers were
found showing the disease in nature. The fungus was evidently
brought into the state on infected seed as the planted fields that
showed it were supplied with plants from the same seedbed.
This fungus is closely related to other parasites that attack sola-
naceous plants such as potatoes and tomatoes.
SYMPTOMS OF PHYTOPHTHORA BLIGHT
The stems of the plants are often infected at the soil line
where they are girdled, resulting in a sudden wilting and death
of the entire plant. At the time the plant wilts, the affected part
of the stem consists of a dark-green, water-soaked band, which
later dries brown, beginning at or slightly below the soil line
and extending an inch or slightly more up the stem. The upper
line of demarcation between the killed and living tissue is dis-
tinct. When the stems are infected above the soil line the width
of the girdling band increases in proportion to the distance the
infection is from the soil line. If infection takes place at the
first fork of the branches or above on young plants the entire
top is invaded and killed (Fig. 18). If the plants are older the
woodiness apparently retards the rapid spread of the fungus
and the wilting of the tops occurs before they are invaded by
the fungus. When one branch is invaded the fungus almost
without exception grows down to the primary stem and eventu-
ally kills the entire top.
On the leaves, the spots are at first small, circular or irregular
in shape and appear scalded. Later, they enlarge, become dry
and bleach to a light-tan color and are of a papery consistency.
These areas eventually crack and in some instances fall away
from the unaffected tissue. No sign of the fungus has been ob-
served on the surface of affected leaf tissue. Entire leaves
killed by this disease have not been observed, although extensive
dead areas are common.
The fruits are infected at the stem by the fungus growing
through the pedicel from diseased stems and branches. Diseased
spots on the fruits proper have not been observed. The fruit
pedicels or stems are always killed before there is any evidence
of pod infection. The progress of the fungus in the invasion of
the pods is easily determined by the dark-green, water-soaked
appearance of the invaded cells in contrast to the light green
color of the healthy ones (Figs. 1 and 19). The development of
the fungous threads and the production of spores on the sur-







Florida Agricultural Experiment Station


face of the pods lags behind the advance of the fungus through
the tissue from a few millimeters to one and a half centimeters.
After several days the entire pepper pod is invaded and cov-
ered with a more or
less surface growth
of the fungus. Fol-
lowing this the pod
dries o ut rapidly,
shrinks and becomes
a wrinkled lifeless
mummy hanging on
the defoliated plant.
CONTROL OF
PHYTOPHTHORA
BLIGHT
None recommend-
ed; seed treatment
suggested.

PINK-JOINT

The pink-joint dis-
ease and stem-canker
are caused by the
fungus Sclerotinia
sclerotiorum (Lib.)
Mass. The former is
Fig. 19.-Pepper pod showing Phytophthora much more prevalent
blight disease.
and destructive than
the stem canker. These diseases have not been reported from
other parts of the United States and are not common except in
scattered fields in Florida. Pink-joint does not occur in epidemic
form every year but occasionally causes extensive damage in
individual fields. The disease on peppers develops rapidly, espe-
cially during wet weather and certain fields have been aban-
doned because of it. The fungus is statewide in its distribution
and is very important on several other truck crops plants such
as lettuce, celery and cabbage. It causes considerable damage in
transit, especially to beans. It is most serious in peppers early
in summer in fields previously planted to a susceptible crop. The
fungus develops large, irregular, black sclerotia which keep it
alive from one season to the next. They are formed in the pith







Bulletin 244, Diseases of Peppers in Florida


in the branches of affected pepper plants and are held there
until the plants die and disintegrate. They are often widely
scattered with the plant debris left in the fields. The host tissue
protects the sclerotia and aids in supplying conditions favorable
for their germination. The sclerotia germinate by forming very
small mushrooms on the surface of the soil which produce quan-
tities of spores that are scattered by the wind. The spores germi-
nate and develop fine, white fungous threads that cause infec-
tion on pepper plants. The fungus is favored in its growth by
heavy dews, foggy weather and rains.


Fig. 20.-Tips of pepper branches killed back by the pink-joint fungus.

SYMPTOMS OF PINK-JOINT
The first indications of pink-joint are drooping leaves, result-
ing from petiole infections. These infections vary in size and are
usually located at the base of the leaf petiole or in the growing
bud. Following these early infections the tips of the branches
are rapidly killed and become blackened. The infection extends
down the branch various distances up to six inches and usually
stops at a swollen, woody node.






Florida Agricultural Experiment Station


The portion of the branch which is killed dries out rapidly,
the leaves shrivel and a large percent of them usually shed. The
dead portions bleach unevenly and often become pink or rose
colored, especially at the nodes (Fig. 20). This is a very char-
acteristic symptom from which the disease obtains its common
name. Often during extremely wet weather the white fungous
mycelium will develop in clumps or entirely overgrow the in-
fected portions, although these areas usually remain bare. The
disease can be positively identified by the black irregular scle-
rotia which can be found occasionally on the inside (pith) of
the infected stems. They are black and shiny on the surface and
when cut across reveal a thin black layer covering a white,
tough interior.
Stem cankers result from this fungus infecting plants at the
soil line. The fungous threads grow into the bark and invade it
to the woody interior parts. The plant will show wilting symp-
toms when about one-third of the stem is girdled and death of
the plant results shortly afterward because the stem has been
completely girdled. Often when conditions are favorable the
fungus will grow up the stem a few inches, forming a white fur-
like collar. Sometimes the sclerotia are formed on the outside
of the plant but usually they are scarce, probably because of the
woody nature of the lower stem and the resulting lack of ade-
quate moisture.
When the pods on the plant are attacked, which is very sel-
dom, they drop to the ground and become a soft, watery mass,
disintegrating entirely in a short time. Pods touching the ground
or left on the ground following picking are often overgrown by
this fungus, resulting in the formation of numerous sclerotia
which aid in the dissemination of the fungus.
CONTROL OF PINK-JOINT
Rotation; peppers should be followed by plants seldom severe-
ly attacked by the fungus, such as potatoes, white or sweet, pea-
nuts, or corn.
Spray schedule of 4-4-50 bordeaux mixture, keeping all parts
covered.
BACTERIAL SOFT ROT

Bacterial rot of pepper pods attached to the plants and not
contacting the soil is usually caused by Bacillus aroideae Town.
and Bacillus carotovorus Jones. Both of these organisms may be






Bulletin 244, Diseases of Peppers in Florida


present or either of them may cause the trouble. There is very
little opportunity for secondary organisms to develop because
the infected pepper pods become entirely involved very rapidly
and are shed. This disease although widely scattered is not
usually considered serious except in limited local areas during
certain seasons. The losses are most important during the sum-
mer rainy season. These organisms are also responsible for a
similar disease of tomato fruits, either green or ripe, while still
attached to the plant. Bacillus carotovorus Jones has also been
designated as the cause of a
soft rot of carrots and a
large number of other plants
and plant parts, especially in
storage. The trouble is prob-
ably brought on in most in-
stances through mechanical
wounds. The organisms in-
vade the interior of the pods .
and break down the plant
tissue almost to the consis-
tency of a sack of slimy
fluid. Eventually the sack
breaks and its contents es-
cape to the soil covering
plant leaves, fruits and
stems which may be in its
path. The organisms are
probably spread by insects,
wind and rain. They sur-
vive from season to season
in plant debris and on other
hosts.
SYMPTOMS OF
BACTERIAL ROT Fig. 21.-Pepper pod showing soft rot
The early indications of symptoms.
the disease are the appearance of a depression or sunken area
usually around a skin puncture. This area is very soft and
semi-liquid. It enlarges rapidly and in a day or two involves
the entire pod (Fig. 21). The fluid contents collect at the bot-
tom of the pod, being retained by the skin, and the pod has the
appearance of a sack of fluid. Eventually the skin breaks,
freeing the contents, and the skin dries, bleaches and is shed.





Florida Agricultural Experiment Station


There is also considerable loss resulting from washing pepper
pods after they are picked. The skin punctures and stem ends
usually become infected following washing and soft rot develops.
It is much better to pack them dry as they are usually clean ex-
cept for the adhering sand which eventually dries and drops off.
CONTROL OF BACTERIAL ROT
Follow spray schedule, remove infected pods before they break
open and do not wash pods after they are picked preparatory to
packing.
MOSAIC
Mosaic is the name applied to a disease of peppers character-
ized by more or less mottled or malformed leaves and stunted


Fig. 22.-Healthy (left) and mosaic pepper plants showing general stunt-
ing of diseased plant.

growth (Fig. 22). The exact cause of this disease is not known,
although abundant information is available concerning it. At
the present time it is classified as a "virus" disease in which the
infective agent is contained in the sap of diseased plants and
the disease may develop in a healthy plant as a result of the
transfer of sap or plant juice from a mosaic plant.


X


qk. I





Bulletin 244, Diseases of Peppers in Florida


This disease is very common in Florida and has been col-
lected on many different plants in all parts of the state. It sur-
vives in growing plants in the areas of the state where no frost
appears and elsewhere when the plants are not killed to the
ground. Wild plants such as pokeweed and wormseed may be
frozen to the ground but the fleshy root remains alive and the
new shoots that grow the following season are diseased. There
are some instances where the disease has been carried in the


















Fig. 23.-Pepper field showing 100% mosaic plants.

seed, especially in beans. The disease has been found on almost
all of the cultivated truck crop plants such as lettuce, celery,
spinach, beets, cucumbers, squash, and sweet potato, that are
not closely related to the peppers and on potato, tomato, egg-
plant, tobacco, ground cherry, nightshade, and Jimson weed,
that belong to the same family as pepper. In addition to these
truck crop plants the disease is found on a wide variety of other
plants such as sugarcane, crotalaria, sweet peas, pokeweed, and
hibiscus, all of which grow in Florida.
The disease often becomes of considerable importance, espe-
cially when whole fields become infected as shown in Fig. 23. In
such cases the field is a total loss. This is also true with other
cultivated plants, especially tomatoes and cucumbers. The dis-
ease is most definitely diagnosed by the mottling of light and
dark green or yellowish and green areas on leaves of diseased






Florida Agricultural Experiment Station


plants. The young leaves at the growing tip often show the
greatest contrast in this respect. There is often a mal-formation
and stunting of aerial parts. Plants may show the disease at
any time during their development but seldom in the seedling
stage.
Mosaic is spread to healthy plants by the transmission of sap
or plant juices from a diseased plant to a healthy plant. This
transfer of sap may be accounted for by a number of ways, all
of which have been found to be possibilities. The rubbing to-


Fig. 24.-Growing tip of a pepper plant showing mosaic symptoms.

gether of a diseased and a healthy leaf may result in the develop-
ment of the disease on the healthy plant after a week or 10
days. The picking operation has been shown to be very import-
ant in spreading the disease. The infective sap may be carried
on pickers' hands from mosaic plants to healthy ones. Even
brushing against plants injures them enough to cause sap to
exude and it is carried on clothing to other plants. Probably
the most important means of transfer, however, is by certain
insects such as aphids, jassids, thrips, whiteflies, and red spi-
ders. These insects puncture the pepper plants to obtain their






Bulletin 244, Diseases of Peppers in Florida


food, the sap. As long as these insects feed on either healthy or
mosaic plants alone, no development of the disease takes place.
However, if an insect feeds on a mosaic plant and then feeds
on a healthy plant the latter usually develops the disease in
about a week or 10 days. If infection takes place after the
plant is well grown the new leaves show the malformation or
mottling, while the older leaves already on the plant will show
no perceptible change.
SYMPTOMS OF MOSAIC
The most characteristic, easily recognized, indication of the
disease is the mottling of yellow and green color of the leaves
as shown in Fig. 24. Often accompanying the mottling there
appear depressions or pockets and raised areas in the leaf
blade, the margin may be wavy, buckled or curled instead of


Fig. 25.-A pod from a healthy pepper plant (left) as compared with pods
of the same age from mosaic plants.

being flat and smooth. There is also a definite stunting of the
plant in general, caused from shorter stems. The fruits of mo-
saic plants are always small and stunted and usually irregular
in shape and otherwise malformed (Fig. 25). .When the dis-
ease appears early in the growth of the plant or when it is un-
usually severe the fruits may show a distinct mottling as is
characteristic of the leaves. The blotches on the fruits, how-






Florida Agricultural Experiment Station


F


L


Fig. 26.-Growing tips of pepper plants showing: (B) healthy, and vari-
ous mosaic symptoms, (A) mottling, (C) Rosette, (D) long stems, (E)
Stunt, (F) Blotch, and (G) Chlorosis.






Bulletin 244, Diseases of Peppers in Florida 33

ever, are usually more linear in outline and not so distinct as on
the leaves. These are only general characters of the disease as
it usually appears on peppers. However, there are considerable
variations of symptoms between plants and varieties. Fig. 26 (b)
shows a portion of a healthy growing branch tip which may be
compared with other growing tips that show the mosaic dis-
ease in some of its varying forms.
Fig. 26 (a) shows the growing tip from a pepper plant af-
fected with the most common type of mosaic already described;
(b) shows a portion of an apparently healthy pepper plant of
the same age; (c) represents the rosette type caused by short
petioles and an abundant development of leaves. The affected
leaves have a yellowish-green color somewhat reticulated with
a very fine grained mosaic pattern; (d) is very similar to the
preceding except that the leaves are long-stemmed and few in
number in contrast to the rosette of the preceding type; (e)
shows a very characteristic blotching effect of the shades of
green, namely, dark, light and yellowish green. It is also pecu-
liar in that the pattern is not the same on both surfaces of the
leaf. Otherwise it is quite similar to specimen (a). One of the
common types of the disease is shown in (f) and, with the ex-
ception of (a) the mottled type, is probably the most common.
The affected parts are yellowish-green, reticulate veined, and
considerably stunted. This form may be easily confused with
effects of deficient fertilizer on plants in which they show con-
siderable yellowing. A type that is thick and fleshy is repre-
sented in (g). The stems are stout and brittle while the leaves
are fleshy, decidedly stunted and the margins rolled inward.
The whole plant is of a very dark green color and produces
few leaves and no fruit.
CONTROL OF MOSAIC
Control sucking insects as much as possible. Remove plants
from the field that show symptoms, they will seldom produce
marketable fruit. Destroy for a distance of at least 100 feet
bordering the pepper field all wild plants that show the mot-
tling symptoms.
DAMPING-OFF

The damping-off disease of pepper seedlings may be caused
by one or more of several different parasites but principally by






Florida Agricultural Experiment Station


the fungus Rhizoctonia solani Kiihn and the bacterial organism
Bacterium vesicatorium Doidge. The former is a very common
fungus in Florida and is present in soils throughout the entire
state, while the bacterial parasite is usually carried on the seed
and causes epidemics in seedbeds in the early seedling stage only
when environmental conditions especially favor its growth. This
damp-off stage seldom occurs, although the bacterial spot dis-
ease previously discussed is often of considerable importance
on seedlings.
Rhizoctonia solani has been found causing damage to a large
number of cultivated plants in the seedling stage. Unless it at-
tacks pepper seedlings early, the chances of causing any damage
is remarkably lessened. The fungus develops rapidly under con-
ditions that favor the germination of pepper seed and the subse-
quent growth of the seedlings. Consequently, when the fungus
is present more or less damage to the seedlings can be expected.

SYMPTOMS OF DAMPING-OFF
The seedlings are attacked at the soil line by the parasite
which penetrates the epidermis and kills the cells of the plant;
the seedling shows wilted and drooping cotyledons. As the fungus
develops a watersoaked lesion appears at the soil line and the
seedling becomes so weakened that it collapses. The fungus
overgrows it rapidly and with the increased food supply derived
from it grows luxuriantly and attacks other nearby seedlings
which results in more or less circular areas appearing in the
seedbeds where the seedlings are killed. The seedlings wither and
dry leaving bare places in the bed. Seedbeds have often been
entirely destroyed in this way. At the present time growers
plant excessive amounts of seed so as to be sure they have enough
plants at transplanting time to insure planting a certain acreage.

CONTROL OF DAMPING-OFF
Treat the pepper seed before planting. Plant the treated seed
in sterilized soil if possible.
If damping-off appears, apply a disinfecting solution of an
organic mercury compound dissolved in water. Disinfectant
can be purchased at drug stores or seed dealers with directions
attached. Repeat this treatment in three days if necessary.






Bulletin 244, Diseases of Peppers in Florida


SUNSCALD

Sunscald of peppers is an injury, especially to the fruits in
any stage of their development, caused by exposure to direct
sunlight, resulting in the killing of the plant cells (Fig. 27).
During certain seasons this trouble is more common than others;
however, it occurs every year to a greater or lesser extent, de-
pending on a number of different contributing factors such as
varieties, location of fields and defoliation of the plant by para-
sites. Pepper parasites often cause considerable defoliation of
the plants which naturally results in more or less exposure of
the pods to the sun's rays. There are certain varieties that pro-


















Fig. 27.-Pepper pods showing stages of sunscald.

duce the pods upright rather than pendant. The varieties pro-
ducing upright pods often suffer more from sunscald than the
other varieties. Certain fields or portions of fields have been ob-
served in which the plants were apparently more subject to
burning than usual. Some possible contributing factors in re-
spect to these areas are lighter, more thirsty soils and sections
protected by woods and hillsides. Sunscald is also common on
varieties that show poor, little or no growth. In this instance
the pods are produced on the extreme tips of the branches and
are entirely exposed. In addition to this exposure the lack of
food supply and moisture predispose the pods to injury.







Florida Agricultural Experiment Station


SYMPTOMS OF SUNSCALD
Early symptoms consist of a light colored area, indefinite in
extent, located on the exposed surfaces on fruits of any size or
stage of maturity. This affected area at first displays no other
characteristics. Shortly after, the area may become slightly
sunken or wrinkled and become creamy white in color. Often
there appears to be no definite line of demarcation between the
lig h t colored portions
and the normally green
tissue. The spots on the

tannish brown instead of
light colored. The more
mature the pod the light-
er colored the killed tis-
sue becomes. This killed
tissue dries out rapidly

often becomes thin, pa-
perlike, brittle, s h i n y
and smooth (Fig. 28).
However, these spots be-
come infected eventually
by secondary organisms
in most instances which
grow o ver the entire
killed area. Under such
conditions, a single pod
Fig. 28.-White, dry area on pepper pod may have as many as a
following sunscald. half dozen different fun-
gi growing on it at the same time, as is shown in Fig. 29. Occa-
sionally soft rotting bacteria invade the dead cells and result
in a rapid, soft, mushy decay.
CONTROL OF SUNSCALD

No direct control methods are known. Otherwise, methods of
controlling leaf parasites should be practiced. Proper varieties
should be grown and the field should be carefully located to af-
ford adequate ventilation.







Bulletin 244, Diseases of Peppers in Florida


Fig. 29.-Area of pepper pod killed by sunscald and infected by secondary
organisms of various kinds.

BLOSSOM-END ROT
Blossom-end rot is a disease of pepper pods probably result-
ing from inadequate or varying soil water. The disease has not
been associated with any single parasite nor is there any con-
sistency in its appearance, when environmental factors are
taken into consideration, with the possible exception of moisture
variations. It has been found on all varieties of peppers under
a wide variation of conditions and is much more severe during
certain seasons. The losses occasionally amount to 50% of the
crop. A similar condition of tomatoes in Florida is known to
practically all tomato growers in the state. There may be some
difficulty in certain cases in distinguishing this disease from






Florida Agricultural Experiment Station


sunscald. However, blossom-end rot always occurs at the blos-
som-end of the fruit, whereas sunscald may appear at any place
on the surface of the pod but usually not at the blossom-end.
This disease probably results from an extreme drying out of
the soil following early growth with adequate moisture, result-
ing in wilting of the plant and checking of growth. Spots on the
pod are caused by the drying out of the plant cells which collapse
and die. The cells on the inside of the pod and at the blossom
end are affected first. The spot often enlarges rapidly and be-
comes overgrown with numerous weak parasitic fungi such as
Choanephora cucurbitarum (B. & R.) Thax., Blakeslea trispora



i. -















Fig. 30.-Blossom-end rot of pepper pods showing secondary infection by
Alternaria sp.

Thax. (Fig. 32), Fusarium sp. (Fig. 31), Alternaria sp. (Fig.
30), Penicillium sp. and others. These organisms, after gaining
a foothold by invading the weakened tissue, grow rapidly and
eventually involve the entire pod. A casual observer can easily
mistake one of the above fungi for the causal agent, since they
are so common on affected fruits.

SYMPTOMS OF BLOSSOM-END ROT
The early appearance of the affected tissue of the pods is
very similar to sunscald, except that it appears at the blossom-
end. The spots are light colored and sunken at first. They en-
large rapidly, involving more and more of the end of the pod.






Bulletin 244, Diseases of Peppers in Florida


The pod is eventually overgrown by secondary organisms. These
secondary organisms
grow slowly and the
dead tissue dries out
rapidly so that the
pods become decided-
ly shrunken and
wrinkled.


CONTROL OF
BLOSSOM-END ROT
No control meth-
ods are known. It is
possible that irriga-
tion during dry pe-
riods will reduce or
prevent this trouble.

BLOSSOM BLIGHT

Blossom blight of
pepper flowers is
caused by the fungus
Choanephora cucur-
bitarum (B. & R.)
Thax. This fungus
is very common on
declining flowers of
a number of other
plants, especially the
cucurbits and cer-
tain ornamental gar-
den annuals. It is
well distributed over
the state and occurs
whenever conditions
are favorable for its
development. Exces-
sive rainfall and
heavy dews accoin-
panied by warm tem-
peratures produce


Fig. 31.-Blossom-end rot of pepper pod show-
ing secondary infection by Fusarium sp.


Fig. 32.-Blossom-end rot of pepper pod show-
ing secondary infection by Blakeslea tri-
spora Thax.





Florida Agricultural Experiment Station


ideal conditions for the development and
growth of the fungus. This disease has not
been of considerable importance on peppers
except in a very few instances when a large
percent of the flowers were attacked and
killed, resulting in the loss of a large num-
ber of the first blossoms. The actual im-
portance of the disease is based on the loss
of the early flowers which usually set and
develop into the early, high-priced pods. The
fungus usually involves the entire flower
in less than a day, causing it to shed. When
Fig. 33. Blossom it falls off and dries little or no trace of the
blight sh owing
fruiting structures fungus can be found. Growers are often
of Choanephora cu- perplexed because of blossom shedding for
curbitarum (B. &
R.) Thax. no apparent reason. This disease may ac-
count for more or less of the trouble. The
spores of the fungus are easily detached by the wind after the
flowers dry out in the morning.
SYMPTOMS OF BLOSSOM BLIGHT
The disease appears very quickly, involves the entire flower
and disappears almost as soon. The whole visible process takes
place from early evening to late morning. The invaded flowers
are often more than a day old and declining. The affected petals
often show a lack of turgidity or even a transparency that may
signify infection. The fungus develops stiff thread-like hairs
of a distinctive metallic lustre capped with small black knobs
(Fig. 33). The hairs are often one eighth of an inch long and
the cap resembles a minute black head. This fungus can be most
easily distinguished in the morning when wet with dew at which
time it resembles a dew-covered spider web.
CONTROL OF BLOSSOM BLIGHT
Not considered important enough for advocating control
methods.
PHOMA ROT
This disease of peppers is caused by Phoma destructive Plowr.
It is not common in Florida and has not been a factor in pepper
fields in relation to losses caused by fungous diseases. It is the
same fungus that causes black spot of tomatoes which is common






Bulletin 244, Diseases of Peppers in Florida


and destructive in the state. This disease has been found only on
nearly ripe pods. It causes a semi-soft rot resulting in a sunken,
wrinkled area of a slightly darker color than the normal pod.
Later the diseased area becomes speckled with numerous ex-
tremely small, light-colored or nearly white specks which are
the fungous structures that produce the spores. The entire pod
eventually becomes involved, dries out rapidly, shrivels and
hangs in a mummied form on the plants unless other organ-
isms enter the affected areas and produce soft decays. In such
instances the pod is usually
shed. Since this disease is
not common, no control
methods will be given.

SOIL ROT

Soil rot is caused by the
fungus Rhizoctonia solani
Kiuhn. The disease first ap-
pears on the portion of the
pepper pods which rests
upon the soil. From this ini-
tial infection t h e fungus
rapidly invades the entire
pod, causing a semi-soft rot
and the eventual shedding of
the pod (Fig. 34). The fun-
gus is very common and
widespread, being present
in practically all of the soils
of the state used for truck
crop production. It attacks
a large number of truck
crop plants and is generally
considered the most destruc-
tive fungus found in the
state. It is also probably the Fig. 34.- Pepper pod invaded by
Rhizoctonia solani Kuhn at point of
m o s t difficult parasite to contact with soil.
control. However, the dis-
ease of peppers caused by it is not of considerable importance,
as it occurs on peppers only under most favorable circumstances;
consequently no further description or control methods appear
to be warranted.






Florida Agricultural Experiment Station


HELMINTHOSPORIUM POD ROT

This disease is caused by Helminthosporium curvulum and is
not of frequent occurrence in the state. The spot at first is cir-
cular, sunken and of a slightly darker color than normal tissue.
As it grows older it enlarges and the pycnidia containing the


Fig. 35.-Pepper pod showing Helminthosporium pod rot.

spores of the fungus are formed upon the killed host tissues in
more or less concentric zones. The spores of the fungus are
produced over these spots in great profusion (Fig. 35). The
tissue dries out rapidly and forms a hard, sunken spot. When
the fungus penetrates the fleshy wall of the pod it develops






Bulletin 244, Diseases of Peppers in Florida


much more rapidly, causing a more or less semi-soft rot. This
disease is not of any economic importance and consequently will
not be discussed further.

CERCOSPORA POD ROT

This disease is caused by a fungus Cercospora sp., which is
distinctly different from the fungus Cercospora capsici H. & W.
that causes leaf spot of peppers. The fungus is a definite para-
site causing a semi-
soft rot of pepper
pods. It produces
spores in abundance
on the surface of the
spot, which is dark
colored, slightly con-
centrically zoned and
more or less sunken
(Fig. 36). Occa-
sionally radial rup-
tures appear, espe-
cially on nearly ma-
ture pods. The dis-
ease is not common
and of no economic
importance at the
present time.

OTHER DISEASES
There are a num-
Fig. 36.-Pepper pod showing Cercospora
ber of other para- pod rot.
sites that cause seri-
ous diseases of peppers in the United States but they have not
been found or collected in Florida.

SKIN CRACKS
Pepper plants occasionally produce pods that show a distinct
skin cracking over their entire surface. There appears to be no
definite pattern except that they are usually perpendicular to
the stem axis of the pod. There is no particular damage caused
to the pod (Fig. 37). It dries out more rapidly and is usually






Bulletin 244, Diseases of Peppers in Florida


much more rapidly, causing a more or less semi-soft rot. This
disease is not of any economic importance and consequently will
not be discussed further.

CERCOSPORA POD ROT

This disease is caused by a fungus Cercospora sp., which is
distinctly different from the fungus Cercospora capsici H. & W.
that causes leaf spot of peppers. The fungus is a definite para-
site causing a semi-
soft rot of pepper
pods. It produces
spores in abundance
on the surface of the
spot, which is dark
colored, slightly con-
centrically zoned and
more or less sunken
(Fig. 36). Occa-
sionally radial rup-
tures appear, espe-
cially on nearly ma-
ture pods. The dis-
ease is not common
and of no economic
importance at the
present time.

OTHER DISEASES
There are a num-
Fig. 36.-Pepper pod showing Cercospora
ber of other para- pod rot.
sites that cause seri-
ous diseases of peppers in the United States but they have not
been found or collected in Florida.

SKIN CRACKS
Pepper plants occasionally produce pods that show a distinct
skin cracking over their entire surface. There appears to be no
definite pattern except that they are usually perpendicular to
the stem axis of the pod. There is no particular damage caused
to the pod (Fig. 37). It dries out more rapidly and is usually






Florida Agricultural Experiment Station


smaller in size when mature than pods that do not show this
trouble. The cause is not known but is considered to be an in-
herited characteristic.


Fig. 37.-Pepper pod showing characteristic skin cracking.
CLOUDY SPOT

This spot, occasionally found on pepper pods, is not caused by
fungi or bacteria. The true cause is not known but it is thought
to be caused by sucking insects. These insects puncture the
skin of the pod and suck juices from it. The cloudy spots are
always located in the flesh of the pod at varying depths from
the skin and varying considerably in size and shape (Fig. 38).
When examined carefully no injury can be found. The cells ap-
pear to be more or less pithy, dry and tough in texture. In
Florida the trouble occurs wherever peppers are grown, but it
has never been important in causing any losses. All varieties
have been found showing these spots at all seasons of the year.






Bulletin 244, Diseases of Peppers in Florida


SEED TREATMENT

Pepper seed should always be disinfected before being planted.
They are more sensitive to treatment with disinfectants than a
number of other seed. Consequently, the time of immersion in
1:1,000 bichloride of mercury has been limited to 8 minutes,
5 to 8 minutes being
sufficient. They can
also be treated very
satisfactorily w i t h
organic mercury
dust in the dry state.
In treating w i t h
bichloride o f mer-
cury, the solution is
prepared in small
quantities by dissolv-
ing one tablet (pur-
chased f r o m local
druggist) in one pint
of water. This gives
the desired strength
of 1:1,000. If larger
quantities of the so-
lution a r e desired
the crystals of the
poison should be pur-
chased and dissolved
in water at the rate
of 1 ounce to seven Fig. 38.-Pepper pod showing cloudy spot.
and one-half gallons
of water. This forms a solution of the same strength. The
seed should be placed in loosely woven cloth bags in quanti-
ties sufficient to fill them about half full. The bags of seed
should then be submerged in the solution and stirred around
with a stick sufficiently to loosen all adhering air bubbles. After
five minutes, remove them from the solution, hold them to drain
a minute or two and then give them a vigorous washing in sev-
eral changes of fresh water or better in running water, if avail-
able. After being washed they should be spread out to dry in
the shade on clean cloth or newspapers. The disinfecting solu-
tion is poison and should be cared for accordingly. It should






Florida Agricultural Experiment Station


not be placed at any time in metal containers; use crock-ware,
glass or wood.
The organic mercury dust can be used either in the powder
form or in the preparation of a disinfecting solution. The pro-
duct can be purchased from most Florida seed dealers and each
package contains full directions for use.

SPRAYING AND DUSTING
The application of fungicides to peppers is to be recommended
in Florida. Whether bordeaux mixture or copper-lime dust is to
be used is optional with the grower. The liquid spray requires
more labor to prepare and apply than the dust but in the end it
is cheaper and more effective and can be applied at any time
during the day, whereas dust which costs more but is easier to
apply should be applied when the plants are wet with dew or
rain and when there is little or no wind. For these reasons
dust applications can be made only at certain times for the best
results. Wet plants aid in the immediate effectiveness of the
dust, while winds cause a wide distribution of it, resulting in
unwarranted waste of the material.
Liquid bordeaux mixture should be applied at the strength of
2-4-50 in the seedbeds and increased to 4-6-50 in the field. These
formulas require 2 pounds of dissolved bluestone, 4 pounds of
hydrated lime and 50 gallons of water, and 4 pounds of blue-
stone, 6 pounds of hydrated lime and 50 gallons of water, respec-
tively. A request for further information concerning the prepa-
ration of bordeaux mixture should be addressed to the Experi-
ment Station.
Copper-lime dust of the 20-80 formula-20 pounds of dehy-
drated copper sulphate and 80 pounds of hydrated lime mixed
dry-has been successfully used. Should the control of chew-
ing insects be desired a 20-20-60 formula should be used, con-
sisting of 20 pounds of dehydrated copper sulphate, 20 pounds
of calcium arsenate and 60 pounds of hydrated lime, mixed dry.
Power machinery gives best results in the application of these
fungicides, either liquid or dust. If, however, the plantings
are limited, hand machinery may be more advantageously used.
The fungicides should be applied in the seedbed when the
seedlings have developed four to six leaves past the cotyledon
stage. Further applications of the fungicide should be made
throughout the season at such intervals as are necessary to keep
all parts of the plants protected.




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