Front Cover

Group Title: Bulletin University of Florida. Agricultural Experiment Station
Title: Experiments for the control of phoma rot of tomatoes
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00026880/00001
 Material Information
Title: Experiments for the control of phoma rot of tomatoes
Alternate Title: Bulletin 308 ; University of Florida. Agricultural Experiment Station
Physical Description: 28 p. : ; 23 cm.
Language: English
Creator: Tisdale, W. B. ( William Burleigh ), 1890-
Hawkins, Stacy O.
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville, Fla.
Publication Date: 1937
Copyright Date: 1937
Subject: Tomatoes -- Diseases and pests -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: by W.B. Tisdale and Stacy O. Hawkins.
Bibliography: Includes bibliographical references (p. 28).
General Note: Cover title.
 Record Information
Bibliographic ID: UF00026880
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltuf - AEN5008
oclc - 18212984
alephbibnum - 000924388

Table of Contents
    Front Cover
        Page 1
        Page 2
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Full Text

Bulletin 308 March, 1937







John J. Tigert, M.A., LL.D., President of Geo. H. Baldwin, Chairman, Jacksonville
the University Oliver J. Semmes, Pensacola
Wilmon Newell, D.Sc., Director Harry C. Duncan, Tavares
H. Harold Hume, M.S., Asst. Dir., Research Thomas W. Bryant, Lakeland
Harold Mowry, M.S.A., Asst. Dir., Adm. R. P. Terry, Miami
J. Francis Cooper, M.S.A., Editor J. T. Diamond, Secretary, Tallahassee
Jefferson Thomas, Assistant Editor
Clyde Beale, A.B.J., Assistant Editor BRANCH STATIONS
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Manager NORTH FLORIDA STATION, QUINCY
K. H. Graham, Business Manager
Rachel McQuarrie, Accountant L. 0. Gratz, Ph.D., Plant Pathologist in
R. R. Kincaid, Ph.D., Asso. Plant Pathologist
MAIN STATION, GAINESVILLE J. D. Warner, M.S., Agronomist
Jesse Reeves, Farm Superintendent
W. E. Stokes, M.S., Agronomist**
W. A. Leukel, Ph. D., Agronomist A. F. Camp, Ph.D., Horticulturist in Charge
G. E. Ritchey, M.S.A., Associate* John H. Jefferies, Superintendent
Fred H. Hull, Ph.D., Associate W. A. Kuntz, A.M., Assoc. Plant Pathologist
W. A. Carver, Ph.D., Associate Michael Peech, Ph.D., Soils Chemist
John P. Camp, M.S., Assistant B. R. Fudge, Ph.D., Associate Chemist
W. L. Thompson, B.S., Asst. Entomologist
ANIMAL HUSBANDRY Walter Reuther, B. S., Asst. Horticulturist
A. L. Shealy, D.V.M., Animal Husbandman** EVERGLADES STATION, BELLE GLADE
R. B. Becker, Ph. D., Dairy Husbandman
L. M. Thurston, Ph.D., Dairy Technician A. Daane, Ph.D., Agronomist in Charge
W. M. Neal, Ph.D., Asso. in An. Nutrition R. N. Lobdell, M.S., Entomologist
D. A. Sanders, D.V.M., Veterinarian F. D. Stevens, B.S., Sugarcane Agronomist
M. W. Emmel, D.V.M., Veterinarian Thomas Bregger, Ph.D., Sugarcane Physiologist
N. R. Mehrhof, M.Agr., Poultry Husbandman G. R. Townsend, Ph.D., Assistant Plant
W. W. Henley, B.S.A., Asst. An. Husb.* Pathologist
W. G. Kirk, Ph.D., Asst. An. Husbandman J. R. Neller, Ph.D., Biochemist
R. M. Crown, M.S.A., Asst. An. Husbandman R.W. Kidder, BS., Assistant Animal
P. T. Dix Arnold, B.S.A., Assistant Dairy Husbandman
Husbandman Ross E. Robertson, B.S., Assistant Chemist
L. L. Rusoff, M.S., Laboratory Assistant B. S. Clayton, B.S.C.E., Drainage Engineer*
Jeanette Shaw, M.S., Laboratory Technician SUB-TROPICAL STATION, HOMESTEAD
CHEMISTRY AND SOILS H. S. Wolfe, Ph. D., Horticulturist in Charge
R. W. Ruprecht, Ph.D., Chemist** W. M. Fifield, M.S., Asst. Horticulturist
R. M. Barnette, Ph.D., Chemist Geo. D. Ruehle, Ph.D., Associate Plant
C. E. Bell, Ph.D., Associate Pathologist
R. B. French, Ph.D., Associate W. CENTRAL FLA. STA., BROOKSVILLE
H. W. Winsor, B.S.A., Assistant
W. F. Ward, M.S.A., Asst. An. Husbandman
C. V. Noble, Ph.D., Agricultural Economist**
Bruce McKinley, A.B., B.S.A., Associate FIELD STATIONS
Zach Savage, M.S.A., Associate
A. H. Spurlock, M.S.A., Assistant Leesburg
ECONOMICS, HOME M. N. Walker, Ph.D., Plant Pathologist in
Ouida Davis Abbott, Ph. D., Specialist** W. B. Shippy, Ph.D., Asso. Plant Pathologist
C. F. Ahmann, Ph.D., Physiologist K. W. Loucks, M. S., Asst. Plant Pathologist
J. W. Wilson, Ph.D., Associate Entomologist
ENTOMOLOGY C. C. Goff, M.S., Assistant Entomologist
J. R. Watson, A.M., Entomologist** Plant City
A. N. Tissot, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant A. N. Brooks, Ph.D., Plant Pathologist
A. S. Rhoads, Ph.D., Plant Pathologist
G. H. Blackmon, M.S.A., Horticulturist and A. S. Roads, Ph.D., Plant Pathologist
Acting Head of Department Hastings
A. L. Stahl, Ph.D.; Associate A. H. Eddins, Ph.D., Plant Pathologist
F. S. Jamison, Ph.D., Truck Horticulturist
R. J. Wilmot, M.S.A., Specialist, Fumigation Monticello
Research Sam D. Hill, B.S., Asst. Entomologist
R. D. Dickey, B.S.A., Assistant Horticulturist
David G. Kelbert, Asst. Plant Pathologist
W. B. Tisdale, Ph.D., Plant Pathologist**
George F. Weber, Ph.D., Plant Pathologist Sanford
R. K. Vorhees, M.S., Assistant E. R. Purvis, Ph.D., Assistant Chemist,
Erdman West, M. S., Mycologist Celery Investigations
Lillian E. Arnold, M.S., Assistant Botanist
Stacy O. Hawkins, M.A., Assistant Plant Lakeland
Pathologist E. S. Ellison, Ph.D., Meteorologist*
SPECTROGRAPHIC LABORATORY B. H. Moore, A.B., Asst. Meteorologist*
L. W. Gaddum, Ph.D., Biochemist In cooperation with U.S.D.A.
L. H. Rogers, M.A., Spectroscopic Analyst ** Head of Department.




Page Page
Experimental Methods ................................. 5 Experimental Results ...................................... 10
Spraying ............. .............................. 10
Management of Seedbeds ............ .... 5 Effect of Fruit Wraps ...................... ..... 20
Management of Field Plots ................. 6 Picking Fruit While Wet ....................... 21
Storage Room ........................ ............. 7 Comparative Resistance of Varieties ...... 22
Effect of Fungicidal Washes .................... 22
Chem ical W ashes .......................................... 8 Sum m ary ......................................... 27
Fruit W raps ....... ............... ................ 10 Literature Cited ................................... ......... 28

Phoma rot (Phoma destructive Plowr.) of tomatoes (Lyco-
persicon esculentum) was first reported from Florida in 1915
by Jamieson (2)1. In that report it was stated that this fruit-
spotting caused great loss to tomato growers in Dade County,
Florida, in 1912, but no information was given concerning its
occurrence and destructiveness on the plants in the field. How-
ever, Jamieson determined through inoculation experiments that
the fungus would attack leaves and stems of the tomato plant.
The experiments also showed that the parasite could attack
tomato fruits only through wounds, growth cracks and stem
scars and that the spots developed more rapidly on ripe fruits
than on green fruits. These points have since been verified by
Rosenbaum (6) and Nightingale and Ramsey (3). Nightingale
and Ramsey (4) have reported more recently that the fungus
grows best at 70 F. and causes most rapid decay of ripe fruit
at this temperature. At 450 F. decay developed very slowly,
even in ripe fruits. They also stated that slower decay in gieen
fruits was due to a more acid condition than exists in ripe ones.
Since Phoma rot was first reported in Florida, it has been
observed in all of the important tomato-growing states (3) and
is said to be most destructive on the winter crop in the Southern
states (1). Stevens and Nance (8) reported that it is second
in importance as a single cause of decay of tomatoes in transit
from Mexico and those tomato-shipping states (California, Flor-
ida, Mississippi, Tennessee and Texas) having the largest num-
ber of market inspection certificates for the nine-year period,

IItalic figures in parentheses refer to "Literature Cited" in the back
of this bulletin.

4 Florida Agricultural Experiment Station

1922-1930. These investigators also reported that during this
period the losses from Phoma rot were decidedly higher in
tomatoes shipped from Florida than from any other state and
that it was the most important single cause of spoilage in toma-
toes shipped from Florida.
In his study of the origin and spread of tomato fruit rots in
transit, Rosenbaum (6) found that bruises or injuries to the
skin and the presence of the disease in the field were important
factors favoring the development of Phoma rot in transit. He
also reported that Phoma rot does not penetrate the wrappers
and infect adjacent healthy fruits. Even with this information,
plant pathologists could not appraise the losses caused by Phoma
rot in transit and in storage until after the inauguration of the
food-products inspection service of the Bureau of Agricultural
Economics and that of the work in market pathology by the
Bureau of Plant Industry in 1917 (7). Also, prior to this time
the grower and shipper did not realize the condition in which
their tomatoes reached the market and why they sometimes got
little or no returns for them. Since fruits free from mechanical
injuries do not develop Phoma rot in the field and since Florida
tomatoes are shipped in the mature-green stage, growers and
shippers believed that the disease originated in transit. Further-
more, since plant pathologists had difficulty in distinguishing
Phoma spot on the foliage from certain other common diseases
in the field, they were unable to evaluate properly the amount
of damage it caused.
After the inspectors had obtained information on condition
of tomatoes at destination of car-lot shipments, shippers were
informed of the cause of spoilage or depreciation. Reports of
inspection also informed the shipper of the time of year and
the locality in which Phoma rot was most severe. After obtain-
ing this information for a few years the Florida shippers recog-
nized that greatest losses were occurring in the fruit shipped
during the winter and early spring months from the southern
part of the state. This conclusion has been verified by examina-
tion of copies of inspection certificates covering 590 car-lot ship-
ments of tomatoes from Florida during the seven-year period
1922-1928. Certificates covering shipments made during Decem-
ber, January, and February showed a higher percentage of
Phoma rot than did those covering shipments made during other
months. Having learned the cause of this spoilage, shippers
requested that a study of the disease be made in an effort to

Experiments for Control of Phoma Rot of Tomatoes 5

develop some means of control. Although comparatively little
was known about the occurrence and destructiveness of Phoma
rot in the field, there would seem to be no necessity of argument
to show the need of preventing, so far as possible, the enormous
loss of tomatoes in transit, especially after all the expenses of
harvesting, packing and shipping had been incurred.
Consequently, experiments were inaugurated in September,
1931, at the Sub-Tropical Experiment Station, Homestead, to
develop some means of control. Preliminary information was pub-
lished on results of this work in 1934 (9). About the same
time Porte (5) published "Notes on the control of transit and
storage decays of tomatoes by the use of chemical washes".
Porte's work consisted of inoculating mature-green tomato fruits
obtained from packing houses and then treating them with vari-
ous chemicals to determine their effectiveness in preventing
infection. His results showed little increase in percentage of
Phoma rot as a result of inoculation, which was according to
expectation after Jamieson had previously determined that the
fungus attacks fruit only through growth cracks, stem scars
and other injuries to the skin. Although most chemicals tested
by Porte produced significant reductions in percentage of decay,
none of them reduced decay below an average of 11 percent.
Upon the inauguration of experiments reported herein, it ap-
peared desirable to attack the disease both in the field and on
the picked fruits. Spraying was the principal means of attack
in the field and antiseptic washes or fungicides were used on
the fruits immediately after picking. The purpose of this bulle-
tin is to describe the methods used for the treatments and give
the results obtained.

Management of Seedbeds:-Experimental work for the control
of Phoma rot was initiated in the seedbeds in all tests conducted
at the Sub-Tropical Experiment Station and, with one exception,
the cooperative experiments were begun in the field. Seedbeds
were never sown two years in succession in the same plots and
each season an effort was made to sow the seedbeds as far as
practicable from the field in which tomatoes were grown during
the previous season. When two or more seedbeds were sown
during the season they were located as far as feasible from each
other. Methods of preparing the seedbed and dates of sowing
seed were the same as those employed by growers. Seeds for the

6 Florida Agricultural Experiment Station

early or pineland crop were sown during the first 10 days of Au-
gust on seedbeds built up slightly above the surface of the soil as
an insurance against drowning during the period of heavy rains,
which usually occur at this season of the year. Seedbeds for the
late crop on the marl glades soil were sown from the latter part
of October to the middle of November on flat beds or in shallow
trenches. By that time, as a rule, the rainy season had passed
and to prevent drying out, in so far as possible, it was necessary
to keep the beds low. Even with flat beds or trenches, usually
it was necessary to sprinkle them once a day to insure an ade-
quate supply of moisture for maximum germination of seed and
normal growth of plants. At times it was necessary to water
the seedbeds for the early or pineland crop, as the water-holding
capacity of the soil is very limited.
During the first two seasons experiments were conducted to
ascertain the amount of Phoma infection that might develop on
seedlings in the seedbed. During the 1931-32 season portions
of the seedbeds on the Station Farm and on that of a cooperative
grower were sprayed with 2-2-50 bordeaux and the remainder
left unsprayed as checks. Applications of the spray were made
at weekly intervals, the first being applied about the time the
majority of the plants were showing their first true leaves. The
plants were sprayed three time before they were ready for trans-
planting. At the time of setting no spotting of leaves or stems
was observed on the plants of the sprayed portions of the seed-
beds and only a small amount in the unsprayed portions. The
spotting in every case examined, however, was due to early blight
(Alternaria solani (E. & M.) (J. & G.) or gray spot (Stemphy-
lium solani Weber). Results of tests the second season were
similar to those for the first. After this season no portions of
the seedbeds were left unsprayed. Subsequent observations made
during the remaining seasons on seedbeds both at the Station
and in the fields of growers showed that Phoma spotting is not
a serious factor on seedlings in the seedbeds. This is due, very
probably, to the fact that the seedbeds are sown at the time of
year when environmental conditions are unfavorable for growth
of the fungus.
Management of Field Plots:-The plants were removed from
the seedbeds and set in the experimental field plots about 30
days after the seeds were sown, when the plants were six to
eight inches high. Only the stockier, disease-free plants were
pulled for use in the field. Plants were set 18 inches apart in

Experiments for Control of Phoma Rot of Tomatoes 7

four-foot rows on the pineland and 30 inches apart in six-foot
rows on the glades. In the experiments of the first two seasons,
two-, three-, or four-row plots were used, depending upon the
length of the row, so that there was about one-ninth or one-
sixth of an acre in each plot. The plots were replicated from
four to nine times. In the later experiments the plots on the
Station farm were reduced to 1/200 acre with a greater number
of replications than was used in earlier tests. The plots to be
compared in any one season were always the same size.
At the outset it was decided to use only bordeaux in these
experiments, as it proved most satisfactory in earlier spraying
experiments for the control of nailhead rust and early blight.
However, during the last two years certain other materials that
recently had come on the market were tested in comparison with
bordeaux. This was done primarily because it was found that
bordeaux reduced the yield of marketable fruits during dry sea-
sons. When only one fungicide was used, sprayed plots were
alternated with non-sprayed check plots. In those experiments
in which more than one fungicide was used, the non-sprayed
check plots were replicated the same number of times as the
sprayed plots. The time the first application of fungicides was
made and the frequency of subsequent applications were de-
termined to some extent by prevailing weather conditions. Us-
ually, if the weather was rainy or warm and accompanied by fogs
and dew, the plants were sprayed within 10 days after being
set. In periods of dry or cool weather the time before the first
application was lengthened to two weeks or longer, and the inter-
val between subsequent applications was lengthened. As a rule,
however, eight applications were made during the season, the
last being made shortly after the first picking.
In all experiments, spray solutions were applied with a knap-
sack sprayer and an effort was made to see that thorough spray-
ing was done at each application. All portions of the vines were
covered with the fungicides.- Calcium caseinate was used as a
sticker and spreader with bordeaux, except when otherwise speci-
fied, to insure better coverage and longer duration of the sprays.
This was considered essential because of the heavy and frequent
rains in some seasons.
Storage Room:-The building in which the fruits were stored
until they ripened consisted of one room with inside dimensions
about 8'x8'x8'. It was insulated with a double wall of celotex
with a 2-inch dead air space between the walls. The building

8 Florida Agricultural Experiment Station

was also equipped with an inside and outside door with a four-
inch space between. On the north side of the building were two
small windows, one on either side of the door. The windows
were fitted with celotex shutters on the inside so they could be
removed whenever necessary to admit light. The building was
also equipped with a ventilator system just large enough to
effect circulation of air in the room. There were three tiers of
shelves on three sides of the room. These were made by fasten-
ing six-inch boards to brackets nailed to the wall in such manner
that each board was set out about three inches from the wall
to permit circulation of air around the fruits on the shelves.
The lowest tier of shelves was three feet from the floor, and the
space between tiers was 18 inches. The floor of the ripening
room was sawdust.
No equipment, other than the construction described above,
was used to maintain a constant humidity and temperature in
the ripening room. Continuous relative humidity and tempera-
ture records were made in the ripening room each season while
tomatoes were in storage. These records showed an appreciable
fluctuation of temperature and relative humidity from day to
night and from one part of the season to another, but the changes
inside the room were always smaller than those outside. During
warm weather the room temperature was generally 8' to 100 F.
cooler than outside, and in cool weather about the same number
of degrees warmer. However, in all cases, the temperature and
relative humidity were sufficiently high to permit development
of Phoma rot while tomatoes were in storage.
Chemical Washes:-It was recognized at the beginning of
these investigations that if any chemical was to have practical
application it must possess fungicidal properties, and be com-
paratively cheap and non-toxic to human beings. Furthermore,
it must not stain or injure the skin of the fruits. The number
of chemicals meeting these requirements was limited. Several
chemicals used in preliminary tests were later discarded because
of one or more undesirable qualities. Preliminary tests also
showed the necessity for using a wetting agent in the washes.
Investigations with wetting agents also showed limitations in
the field for selection. In addition to being non-toxic and caus-
ing no stain or injury to the fruit, they must be compatible with
the chemical in solution. Certain wetting agents were found
which fulfilled these requirements and these are listed in con-
nection with experimental results.

Experiments for Control of Phoma Rot of Tomatoes 9

The procedure followed in all tests was essentially the same.
For each treatment mature-green tomatoes were picked from
the experimental plots, both sprayed and non-sprayed, and dipped
in the chemical washes soon after delivery to the packing shed
or in the field immediately after picking. During the first sea-
son some of the fruits were immersed in the solutions for various
lengths of time up to five minutes to determine whether the
period of immersion improved the effectiveness of the chemicals.
Tests were also conducted to determine the effect of temperature
of the wash upon its effectiveness. Although it was found that
both of these factors influenced the effectiveness of the washes,
it was recognized that the time the fruits could remain sub-
merged in the wash must be short for commercial use because
large quantities of fruit must be handled rapidly, and that there
are practical difficulties involved in keeping the temperature of
the washing bath much above that of the fruit. Consequently,
it was considered advisable to use a wetting agent in combination
with a stainless fungicide to insure immediate wetting of all
parts of the fruit and retention of a film of the wash on the
surface of the fruits. Accordingly, after the first season all
treatments were applied by dipping the fruits into the washes
at natural or prevailing temperature.
All fruits used for the various treatments and holding tests
were carefully sorted and all showing breaks in the skins or any
indication of infection were discarded. By thus selecting the
fruits, as is done in commercial practice, it was found that the
number of fruits available from each picking for holding tests
and after-picking treatments was rather small. Consequently,
all fruits from plots receiving like treatments in the field were
placed in one lot and composite samples taken for subsequent
treatments. When the total number was small, a correspond-
ingly small number was used in the treating and holding tests.
After the fruits were removed from the solutions they were
allowed to drip and were then placed in four-quart baskets and
stored in the ripening room until ripe or fairly evenly colored.
This required a period of 10 to 14 days, when they were inspected
for the presence of rots. All of the minute necrotic specks that
could not be identified by inspection were ignored. Furthermore,
all fruits bearing spots that could be identified were placed in
the proper category regardless of the number and size of the
spots and marketable condition of the fruits.

10 Florida Agricultural Experiment Station

Fruit Wraps:-During the first two years of the investiga-
tional period several kinds of chemically treated wraps were
tested for preventing decay in picked fruits. Fruits for these
tests were picked in the mature-green stage from non-sprayed
plots and wrapped separately as soon as possible after picking.
Tomatoes used in these tests were carefully selected for freedom
from injuries to the skin and signs of infection. Approximately
the same number of fruits were wrapped in standard plain wraps
as in treated ones, the former serving as checks. After being
wrapped the fruits were placed in standard four-quart baskets
and stored in the ripening room until ripe. The different chemi-
cals used in this test were copper sulfate, wettable sulfur, and
an organic mercury compound. The copper sulfate wraps were
a commercial product manufactured principally for wrapping
pears to prevent the spread of Botrytis rot in shipment. The
wettable sulfur and organic mercury wraps were made at the
Station laboratory by thoroughly soaking standard fruit wraps
in a suspension of the sulfur (8 lbs. to 100 gal. water) and a
.25 percent solution of the organic mercury compound, respec-
tively. In addition to these, tests were made also with plain
transparent cellophane wraps and oiled wraps.

Since early blight (Alternaria solani) and gray spot (Stem-
phylium solani) usually were prevalent in tomato fields in the
area, it was impossible to determine separately the increase in
yield of marketable fruit resulting from the control of Phoma
spot. Furthermore, the prevalence and seriousness of all three
of these diseases varied from year to year. During seasons of
ample rainfall and moderately low mean temperature all were
abundant, and significant increases in yield were obtained
through spraying. Consequently, the increases in yield shown
in the tables are the results of controlling all of these diseases.
On the other hand, when the season was characterized by scant
rainfall and a high mean temperature, the diseases were con-
spicuous by their absence, and spraying not only failed to in-
crease yields but sometimes reduced them. Since bordeaux was
the fungicide used most extensively, the reductions in yield may
be explained by increase in transpiration as a result of applying
bordeaux during dry weather (10). Because of these complica-
tions encountered in the field the principal criterion used as a

Experiments for Control of Phoma Rot of Tomatoes 11

basis for measuring effectiveness in the control of Phoma rot,
through spraying, was the amount of this disease that developed
on the fruit after they were picked and placed in storage. Since
the amount of Phoma rot developing on the fruit after picking
varied from year to year, it seems advisable to present the re-
sults by years.
1931-32:-Three separate spraying experiments were con-
ducted during the 1931-32 season. Two of these were coopera-
tive with growers and one was on the Sub-Tropical Experiment
Station pineland farm. One of the cooperative experiments was
on pineland and the other was on the marl "glades" soil. The
Break O'Day variety was used in the cooperative pineland ex-
periment and the plants were set on September 23. Eight ap-
plications of 4-4-50 rock-lime bordeaux were made to the plots
during the season, the first on October 2 and the last on Novem-
ber 30.
No comparative yield data were recorded from the various
plots, as the object of this test was to determine the effectiveness
of spraying in the field in controlling Phoma rot in the fruits
in storage. The data thus obtained (Table 1) show that con-
siderably less rot developed in fruit from sprayed plots than in
that from check plots.

Plot Condition of Fruit after Storage
Treatment Picking I Total Number Phoma Rot Other Diseases
of Fruits Percent Percent
Pinelands Soil

Sprayed-....... First 119 23 4
Check ............ First 119 55 2
Sprayed ........- Third 135 14 5
Check....--..-- Third 140 58 19

Glades Soil

Sprayed. ........ Second 124 8 1
Check..-.. Second 128 13 2
Sprayed ..-...I Fifth 162 22 5
Check-...... Fifth 195 19 8

The cooperative experiment on glades soil was started later
in the season. Livingston's Globe was used in this experiment

12 Florida Agricultural Experiment Station

and the plants were set on December 1. Nine applications of
4-4-50 rock-lime bordeaux were made during the season, the
first on December 8 and the last on February 12. Fruits of the
second picking were packed and shipped to Gainesville for read-
ings on development of diseases, and samples of fruits of the
fifth picking were stored in the ripening room at Homestead.
Data obtained from these lots of fruit are also given in Table 1.
It may be seen that the fruits of the fifth picking showed very
little difference in percentage decay between sprayed and check
plots. This is possibly due to the fact that all plants became
infected with mosaic about the time of the first picking and
they were almost dead at the time of the fifth picking.


Avg. Yield
Plot Marketable Observation DS
Treatment Picking Fruit at *g 0 I
Pounds 1
per Plot

Sprayed...... First 135 Homestead, Fla. 214 10 .5
Check....... First 117 Homestead, Fla. 125 27 3
Sprayed-..... First I Champaign, Ill.* 1,320 11 0
Check.....-- First Champaign, Ill. 816 20 1
Sprayed...... Second 125 Homestead, Fla. 261 12 0
Check........- Second 100 Homestead, Fla. 294 22 0
Sprayed..... Second Gainesville, Fla. 293 7 0
Check.......... Second Gainesville, Fla. 310 20 6
Sprayed...... Third 112 Homestead, Fla. 313 28 5
Check-........ Third 83 Homestead, Fla. 271 40 14
Sprayed...... Third Gainesville, Fla. 350 32 1
Check.......... Third Gainesville, Fla. 351 63 3
Sprayed...... Fourth 283 Homestead, Fla. 667 16 6
Check.......... Fourth 150 Homestead, Fla. 624 33 25
Sprayed ... Fourth Gainesville, Fla. 352 25 0
Check.......... Fourth Gainesville, Fla. 180 41 13
Sprayed ...... Fifth 163 Homestead, Fla. 1,034 34 4
Check......... Fifth 33 Homestead, Fla. 150 36 5
Sprayed .... Sixth 38 Homestead, Fla .....
Check.......... Sixth 8 Homestead, Fla .- ... .

*Made by a representative of the Goulds Growers, Inc.

Experiments for Control of Phoma Rot of Tomatoes 13

The Marglobe variety was used in the experiment on the Sub-
Tropical Station farm and the plants were set on October 15.
Because of the cool, dry weather which prevailed at this time
the plants grew slowly and as a result were not sprayed for about
three weeks after setting. Nine applications of 4-4-50 rock-lime
bordeaux were made, the first on November 6 and the last on
January 14.
Six pickings were made in these plots, the first on December
28 and the last February 18. Complete records of yields of
marketable fruit per plot were made of each picking, and fruits
were selected from each picking from the sprayed and check plots
and stored in the ripening room at the Station for readings on
disease development. Also samples of the fruit of certain pick-
ings were packed and shipped to Champaign, Illinois, and Gaines-
ville, Florida, to compare data obtained at these points with those
obtained with fruits placed in storage at Homestead. Data ob-
tained from this experiment with fruit placed in transit and held
in storage are given in Table 2. The results obtained by these
two methods of handling the fruit appeared sufficiently similar
to justify the use of the storage room at Homestead for further
use in these tests.
1932-33:-Two spraying experiments were conducted during
the 1932-33 season, both on pineland soil. One was a cooperative
experiment and the other was on the Sub-Tropical Station farm.
The Marglobe variety was used in the cooperative experiment,
and the plants were set on September 16. Two fungicides, 4-4-50
bordeaux and 20-80 copper-lime dust, were used to compare their
efficiency. Eight applications of these fungicides were made,
the first on September 27 and the last on December 15.
The plants in this experiment met with many adverse weather
conditions. Shortly after the first applications of fungicides,
a heavy rain drowned one plot and a portion of a second. This
difference was taken into consideration in calculating results.
Furthermore, the roots of all plants in the entire experiment
were damaged to some extent from a concentrated solution of
fertilizer. The fertilizer had been applied just before a rain.
Applications of spray had also been made on the day before the
rain and when the plants were examined it was noted that all
plants receiving 4-4-50 bordeaux were more severely wilted and
burned in the tops than those in the dusted or check plots. The
two latter series of plots showed no appreciable difference in this
respect. This injury was manifest also in the lower yields of

14 Florida Agricultural Experiment Station

marketable fruit from the first five pickings, as shown in Table
3. Later pickings showed heavier yields from the sprayed plots,
which indicated a recovery of the vines.


Avg Yield Condition of Fruit
Marketable After Storage
Plot Picking Fruit Total
Treatment IPounds Fruit Phoma Rot Other
per Plot I Diseases
____ No. % No. %
Sprayed...... First 58 41 0 0 4 10
Dusted....... First 100 42 1 2 6 14
Check.......... First 104 45 0 0 5 11
Sprayed...... Second 38 15 0 0 1 7
Dusted........ Second 54 14 0 0 2 16
Check.......... Second 68 17 0 0 2 12
Sprayed...... Third 108 21 0 0 0 0
Dusted........ Third 122 20 1 5 2 10
Check ........ Third 103 21 1 5 0 0
Sprayed..... Fourth 158 39 0 0 0 0
Dusted........ Fourth 209 21 0 0 0 0
Check.......... Fourth 204 18 2 11 3 17
Sprayed...... Fifth 95 20 0 0 0 0
Dusted........ Fifth 100 20 0 0 0 0
Check.......... Fifth 100 20 0 0 0 0
Sprayed...... Sixth 121 20 0 0 0 0
Dusted........ Sixth 116 20 0 0 0 0
Check---....... Sixth 104 19 1 5 0 0
Sprayed...... Seventh 117 42 0 0 0 0
Dusted........ Seventh 112 40 1 2 0 0
Check.......... Seventh 75 40 0 0 0 0
Sprayed...... Eighth 33 40 4 10 1 2
Dusted........ Eighth 18 40 6 15 0 0
Check ......... Eighth 21 40 10 25 4 10

Summary for Season

Sprayed-..... All Pickings 91 238 4 2 6 3
Dusted........ All Pickings 104 217 9 4 10 5
Check........- All Pickings 97 220 14 6 14 6

Eight pickings were made from these plots from November 11
to January 16. Although Phoma infections among fruits from
the various plots were light in all pickings, the efficiency of bor-

Experiments for Control of Phoma Rot of Tomatoes 15

deaux was evident, as no Phoma rot developed on any fruit from
the sprayed plots, except the last picking. However, there was
a reduction in total yield in the sprayed plots for the season.
The experiment on the Sub-Tropical Station farm was started
on October 17 with Marglobe plants. Because of prevailing dry
weather only six applications of bordeaux were made during
the season, the first on November 1 and the last on December 16.
Five pickings were obtained from the plots between January 2
and February 16, and samples of the fruit from each picking
were stored for observations on the development of Phoma rot.
Results obtained and given in Table 4 show excellent control of
Phoma rot. Furthermore, the last picking from the sprayed
plots was heavy, while the plants in the check plots were dead
and no fruit was obtained from them at that time.


JAvg. Yield Condition of Fruit
IMarketable After Storage
Plot I Picking Fruit Total Ot
Treatment Pounds Fruit Phoma Rot Other
per Plot I Diseases
No. % No. %
Sprayed.... First 33 21 0 0 0 0
Check.........- First 41 20 3 15 0 0
Sprayed.... Second 104 63 1 1 0 0
Check.. ....... Second 140 102 12 12 0 0
Sprayed.....- Third 161 236 7 3 9 3
Check.... .... Third 131 190 48 25 8 4
Sprayed... Fourth 215 547 16 3 18 3
Check .. .; Fourth 79 515 230 45 27 5
Sprayed..... Fifth 75 1142 97 8 86 8
Check ......i Fifth 0

Summary for Season

Sprayed ...All Pickings 117 2009 121 6 113 6
Check...... All Pickings 78 827 293 35 35 4

1933-34:-Three spraying experiments were conducted dur-
ing the 1933-34 season, all on pineland soil. Two of these were
located on the Sub-Tropical Station farm and the other was a
cooperative experiment on the farm of a grower. Two varieties,
Marglobe and Pritchard, were used in the early experiment on

16 Florida Agricultural Experiment Station

the Station farm. The plants were set on September 15, but
due to unusually dry, hot weather almost 90 percent of the plants
died within two days after being set. The plots were reset on
September 21, and the plants were irrigated until it rained.
Heavy rains on October 4 and 5 covered the plants with water
to a depth of six inches, but, because of the dry condition of
the soil previous to the rains, the water disappeared rapidly
and the plants were apparently damaged very little. After a
short time the weather turned dry again, making it necessary
to irrigate the plots for the remainder of the season. This irriga-
tion extended the life of the plants for a longer period than usual,
and a greater number of applications of spray was made during
the season. Ten applications of bordeaux were made, the first
on October 7 and the last on December 22. Seven pickings of
fruit were made from the plots between November 22 and Jan-
uary 25. Since the weather was comparatively warm and dry
during a greater portion of the season, Phoma infection was
light on the vines in the field and also on the fruits placed in
storage. The total yields for the season were also light, even
though the plots were irrigated. Results of the experiment
are given in Table 5.
For the second experiment on the Station farm, plants of
the Glick Globe variety were set on October 19. Because of
prevailing dry weather it was necessary to irrigate the plots
for the greater part of the season. Eleven applications of bor-
deaux were made between November 2 and January 27. Five
pickings of fruit were obtained from the plots between January
10 and February 20, and the data obtained from them are given
in Table 6. It may be seen from these data that the percentage
of Phoma rot was comparatively low for the first two pickings.
The Marglobe variety was used in the cooperative experiment
and the plants were set on September 25. Eight applications of
bordeaux were made between October 7 and December 11. No
facilities were available for irrigating the plots and the plants
suffered from drought. The fruit was picked seven times be-
tween November 27 and January 17, but samples of only three
of the pickings were placed in storage for readings on the de-
velopment of Phoma rot. The yields were low, those from the
sprayed plots being significantly lower than those from the non-
sprayed plots. Since environmental conditions in these plots
were similar to those described by Wilson and Runnels (10)
it appears probable that the reduction in yields in the sprayed

Average Yield F
Variety I Marketable Condition of Fruit After Storage
of I Plot Picking Fruit Total
Tomato Treatment Pounds Fruit Phoma Rot Other Diseases
per Plot No. Percent No. Percent

Marglobe ..........--.-- Sprayed First 3.... ........ ...
Marglobe .................. Check First 1 .... ..... -.

Pritchard -------.......... Sprayed First 1....
Pritchard --.............. Check First 1...-......

Marglobe ................. Sprayed Second 9 21 0 0 0 0
Marglobe .................. Check Second 9 20 0 0 0 0 0
Pritchard ....-............-- Sprayed Second 7 20 0 0 0 0 '-.
Pritchard -...----......... Check Second 7 19 0 0 0 0

Marglobe .-......-....... Sprayed Third 15 16 0 0 0 0
Marglobe ..--...-....-... Check Third 19 16 0 0 0 0

Pritchard ....---.....---. Sprayed Third 22 15 0 0 0 0
Pritchard ....-....-....-... Check Third 24 19 0 0 0 0

Marglobe .................. Sprayed Fourth 21 33 0 0 1 3
Marglobe .........--..... Check Fourth 20 39 1 3 0 0
Pritchard ...-........-..... Sprayed Fourth 21 42 1 2 0 0
Pritchard ........-......... Check Fourth 22 46 1 2 0 0

Marglobe ................. Sprayed Fifth 13 24 0 0 0 0
Marglobe .................. Check Fifth 15 24 5 21 0 0

Average Yield
Variety Marketable Condition of Fruit After Storage
of Plot Picking Fruit Total .
Tomato Treatment Pounds Fruit Phoma Rot Other Diseases o
per Plot No. Percent No. i Percent

Pritchard .............. Sprayed Fifth 15 26 1 4 0 0
Pritchard ............. Check Fifth 14 29 3 10 0 0
Marglobe ............... Sprayed Sixth 20 71 0 0 0 0
Marglobe ........... Check Sixth 17 73 8 11 1 1
Pritchard .................. Sprayed Sixth 11 69 1 1 0 0
Pritchard .................. Check Sixth 11 69 12 17 12 17
Marglobe ........--..... Sprayed Seventh 25 ........
Marglobe ............. Check Seventh 21 .......
Pritchard .................. Sprayed Seventh 25 ...... ... ....
Pritchard .................. Check Seventh 9

Summary for Season

Marglobe .........- Sprayed All Pickings 15 165 0 0 1 .5 0
Marglobe .............. Check All Pickings 14 172 14 8 1 .5
Pritchard .----------- Sprayed All Pickings i 14 172 3 2 0 0
Pritchard ------- Check All Pickings 13 182 16 9 12 7

Experiments for Control of Phoma Rot of Tomatoes 19

plots was due to the combined effects of dry weather and the
bordeaux spray. No Phoma rot developed on any fruit from
these plots, except in that from the last picking. Consequently,
the data are not given.

PLANTING, 1933-1934.

Avg. Yield Condition of Fruit
Marketable After Storage
Plot Picking Fruit Total I
Treatment Pounds Fruits Phoma Rot | Other
per Plot Diseases
____ ___ __ No. | % No. %
Sprayed...... First 16 72 1 1 2 3
Check.......... First 11 70 6 9 2 3
Sprayed...... Second 15 88 2 2 1 1
Check.......... Second 17 89 8 9 1 1
Sprayed..... Third 27 105 2 2 1 1
Check.......... Third 26 50 8 16 6 12
Sprayed...... Fourth 17 161 4 3 4 3
Check......... Fourth 15 146 20 14 8 6
Sprayed ..- Fifth 20 205 32 16 5 2
Check.......... Fifth 10 56 15 27 6 11

Summary for Season

Sprayed...... All Pickings 19 631 41 6 13 2
Check--. All Pickings 16 411 57 14 23 6

1934-35:-Early this season an experiment was started on
the Sub-Tropical Experiment Station farm. Another pineland
experiment was started on October 10. Some data were obtained
from the first picking in the first experiment but no fruits were
picked from the second one before the plants in both experiments
were killed by cold on December 12.
A third experiment (cooperative) was started on glades soil
on December 1 to test the efficiency of different kinds of spray
materials for the control of Phoma rot. All plants were frozen
on December 12 and the plots were reset on January 2. Eight
applications of the various sprays were made in this test from
January 14 to March 29. The fungicides used were 4-4-50 rock-
lime bordeaux, bentonite bordeaux, and basic copper sulfate.

20 Florida Agricultural Experiment Station

Bentonite bordeaux was prepared in the same manner as regular
bordeaux, except that two pounds of bentonite were substituted
for two pounds of lime so that the formula would be 4-2-2-50.
Bentonite was used as a wetting-sticking agent with the basic
copper sulfate. A formula of 2 pounds of bentonite and 2 pounds
of basic copper sulfate to 50 gallons of water was found to be
quite satisfactory.
Four pickings were made in this experiment from March 20
to April 12. Dry weather prevailed during the season and a
significant reduction in yield was again obtained in plots in which
regular bordeaux and bentonite bordeaux were used. Since no
Phoma rot developed in any of the fruits placed in storage from
these plots during the season, the results are not shown in
tabular form.
1935-36:-Weather conditions were so unfavorable during the
1935-36 season that no accurate data could be obtained. The
seedbeds sown on August 22 were drowned during the hurricane
of September 2. Marglobe plants purchased and set in the ex-
perimental plots on September 23 were all badly injured by the
hurricane on November 4. The plants which survived were
killed by frost on the night of November 30.
A cooperative experiment on pineland soil was started on Octo-
ber 10 with Marglobe plants. Five applications of bordeaux were
made from October 28 to January 10, and three pickings of
fruit were obtained from January 4 to January 20. No Phoma
rot or other diseases developed in fruits of the first two pick-
ings, and only a small percentage of Phoma rot developed in
fruits of the third picking. A reduced yield on plots sprayed
with bordeaux during dry weather was apparent again this year.

The data given in Table 7 show that no control of Phoma
rot or other diseases was obtained from the use of fruit wraps.
As explained under the heading "Experimental Methods",
fruits used in these tests were picked from the non-sprayed
plots and were wrapped within a few hours after picking. These
data confirm results obtained in other experiments which showed
that infection occurs through growth cracks and mechanical in-
juries and that the fungicides must penetrate these injuries to
be effective in preventing decay.

Experiments for Control of Phoma Rot of Tomatoes 21

Season Kind of Wrap Total Phoma Rot Diseases
Fruits Percent Percent
1931-32 Plain paper ............. 153 37 6
1931-32 Copper sulfate
impregnated paper 151 34 4
1931-32 Sulfur covered
paper ..................... 61 39 7
1931-32 Organic mercury
impregnated paper 148 35 6
1932-33 Plain paper .............. 97 16 3
1932-33 Oiled paper .............. 95 19 2
1932-33 P. T. Cellophane ...I 90 17 4

A test was conducted during the 1932-33 season with tomatoes
from sprayed and check plots to determine whether any more
Phoma rot developed on tomato fruits picked when wet than
when picked dry. In February fruits were picked before the
dew and fog of the preceding night had dried from the fruit
and vines. These fruits were stored immediately in the ripening
room. Later in the same day, after the vines and fruits were
thoroughly dry, other fruits were picked from the same plots
and these fruits were likewise stored for future observation.
After a period of 12 days the fruits were examined and the
results of the test are recorded in Table 8.

Condition of Fruit
Plot Condition After Storage
Treatment When Total Other
Picked Fruits Phoma Rot Diseases
Percent Percent
Sprayed...... .......... Wet 88 8 5
Check................... Wet 101 65 1
Sprayed................ Dry 78 8 0
Check-.............. Dry 93 28 4

It is apparent from these data that picking the tomatoes while
they are wet increases the percentage of Phoma infection.

22 Florida Agricultural Experiment Station

During the four seasons 1932-33 to 1935-36, inclusive, dif-
ferent varieties of tomatoes were tested for comparative re-
sistance to Phoma infection and other diseases. Results of
1932-33 and 1933-34 tests are shown in Tables 9 and 10.
As with the spray tests, each variety was divided into an equal
number of plots; half of them were sprayed with 4-4-50 bor-
deaux and the remaining half left unsprayed as checks. At
each picking all uninjured marketable fruits were taken from
both the sprayed and the check plots and stored for readings
on Phoma rot. As a rule, there were more good fruits at each
picking from the sprayed plots than from the check plots, hence
the difference in the number of fruits stored from sprayed and
check plots of the same variety. Since fruits from these vari-
eties were used only for comparative disease readings, only three
replications were the average for sprayed and check plots in
each variety.
Although yield data are shown in the tables, the principal ob-
jective was to obtain information on the amount of infections
developing on the different varieties in the field and in storage.
Certain varieties which proved most susceptible in the first tests
were not included in succeeding tests because of this and other
undesirable characters for local conditions.
The number of fruits examined from each variety for different
seasons was determined to a great extent by weather conditions
while the experiment was in progress. Because of cold and
drought injury during the 1934-35 season and of hurricane and
cold injury in 1935-36, the quantities of fruits were too small
to yield any significant data.
During the 1931-32 season preliminary tests were conducted
with several different fungicides and spreaders. Many commer-
cial products tested were discarded along with spreaders and
fungicides prepared in the laboratory because of ineffectiveness,
objectionable residue or some other objectionable character.
Tests were made also on the effect of time elapsing between
picking and treating and period of immersion upon the degree
of control of Phoma rot. These tests indicated that treatments
applied immediately after the fruits were picked were most ef-
fective. When applied immediately after picking, variations
in the period of immersion seemed to have little effect upon
degree of control. All that appeared to be necessary was to


Average Yield Percent Condition of Fruit
Variety Plot Marketable Gain Total After Storage
of Treatment Fruit Sprayed No. Other
Tomato Pounds Over Fruit Phoma Rot Diseases
Super Plot Check Percent Percent

John Baer ............................. Sprayed 114 128 397 4 7
John Baer .............................. Check 50 174 18 9
Cooper's Special ..--................... Sprayed 93 112 324 3 2
Cooper's Special ...............-...... Check 44 154 9 4
Kilgore's Special --......--...... Sprayed 89 82 312 3 2
Kilgore's Special --.................... Check 49 171 8 2

Marglobe .........--....------.. Sprayed 85 67 297 2 0.5
Marglobe ................................. Check 51 178 8 4
Pritchard ....-----....-..--.......-... Sprayed 55 49 190 0.5 1 1
Pritchard ......................... Check 37 130 3 2


Average Yield Percent
Marketable Gain Other
"Variety Plot Fruit Sprayed Total Phoma Rot Diseases
Treatment Pounds Over Fruits Percent Percent
per Plot Check

Cooper's Special ..................... Sprayed 57 -3 97 2 4
Cooper's Special ..................... Check 59 35 9 0

Livingston's Globe ................. Sprayed 68 +21 149 0 0
Livingston's Globe .................. Check 56 81 1 2

Pritchard .................................. Sprayed 63 +15 151 .5 0
Pritchard .................................. Check 55 116 10 10

Marglobe ............-- ............ .... Sprayed 62 +15 156 0 0
Marglobe ............. .............. Check 55 99 9 2

Experiments for Control of Phoma Rot of Tomatoes 25

thoroughly wet the fruits with the fungicidal wash containing
a wetting and sticking agent. Consequently, after the first sea-
son, all washing was done in the field. It was found that treat-
ing the fruit in the field could be accomplished very easily by
hauling the wash to the field and putting it in barrels or vats
on low sleds or wagons and pulling it about the field. The fruits
were carried to the end of the row, dipped into the fungicidal
solution, and then poured into field crates.
The effect of temperature of the washes upon their effective-
ness was tested during the 1931-32 season. Although higher-
than-air temperatures increased the effectiveness of most of the
solutions, it appeared more feasible to treat the fruits in the
field than to install equipment to maintain a constant high
temperature of the washing bath.
During the 1932-33 season the three most promising fungicides
of the previous season were tested. These were borax, sodium
hypochlorite, and sodium polysulfide. Concentrations of these
found most effective the year before were a 5 percent solution by
weight of borax, 1 percent solution by weight of sodium hypo-
chlorite, and 1 gallon of sodium polysulfide (commercial prepara-
tion) to 150 gallons of water. The most satisfactory spreader
found during the previous season was tar soap, and this was
added to each of the above solutions at the rate of one-half
percent per unit weight of the solution.
Of all the washes tested during the 1931-32 season and used
during the two succeeding seasons, the 5 percent borax solution
gave the most consistent control, as shown in Tables 11 and 12.
Phoma Other
Fruit Treatment Plot Total Rot Diseases
Treatment IFruits Percent Percent
None ...-.... ...... .......................... Sprayed 2,009 6 6
N one ........................................ Check 827 35 5
Borax .................................... Sprayed 1,568 2 13*
Borax ................................... Check 340 21 2
Sodium hypochlorite .......... Sprayed 112 2 0
Sodium hypochlorite ........ Check 167 15 2
Sodium polysulfide ..-- ....--- Sprayed 135 4 0
Sodium polysulfide .............. Check 193 14 4

*High percentage due to incipient infections of early blight developing
on fruit just previous to last picking.

26 Florida Agricultural Experiment Station

Phoma Other
Fruit Plot Total Rot Diseases
Treatment Treatment Fruits Percent Percent

None ...................... ........ Sprayed 780 6 2
None ....... .......--.....----- Check 466 12 5
Borax .............. ..... ......... Sprayed 333 2 3
Borax ................................. Check 189 5 4
Sodium hypochlorite ........ Sprayed 283 1 6
Sodium hypochlorite ....... Check 184 9 5
Sodium polysulfide ........ Sprayed 227 4 0.5
Sodium polysulfide ......... Check 127 9 8


None .............------------ ... Sprayed 287 5 5
Borax ............----.........- Sprayed 212 2 4
Sodium hypochlorite ........ Sprayed 208 8 3
Sodium polysulfide .......... Sprayed 140 3 5


None .......--- .....-.. Sprayed 134 6 4
Borax...-....-- Sprayed 130 0 3
Sodium hypochlorite ........ Sprayed 102 5 5
Sodium polysulfide ......... Sprayed 71 6 4

All three washes reduced the percentage of Phoma rot in
fruits from both sprayed and check plots during the 1932-33
season, but sodium hypochlorite and sodium polysulfide appeared
slightly less effective than borax during the 1933-34 season.
Data in these tables represent summaries of results obtained
from all pickings for the respective seasons. In certain pickings
in which the percentage of Phoma rot developing on non-treated
fruits was high, differences between treated and non-treated
fruits were much greater than shown in the summary. Because
of unfavorable weather conditions there were no fruit available
from the experimental plots for treatment during the 1934-35
season. The borax solution was more difficult to prepare than
the others, since it was necessary to heat the water to dissolve
the borax, and, while using it was necessary to keep the solution
agitated to prevent crystallization. Metaborate was not used

Experiments for Control of Phoma Rot of Tomatoes 27

in any of the tests because it was not available at that time,
but it is probable that it would be as effective as the regular
borax and be less difficult to use.

Phoma rot has been known to occur in tomatoes shipped from
the lower East Coast of Florida since 1915. Since that time
it has been reported to be the most important single cause of
spoilage in tomato fruits shipped from Florida, and second in
importance as a single cause of decay in winter-grown tomatoes
in transit from certain other Southern states.
Previous investigators have found that Phoma rot develops
most rapidly in ripe fruits at about 700 F. It does not spread
from diseased to healthy adjacent fruits in containers. It was
also found that stem scars, growth cracks, or mechanical in-
juries are necessary for the fungus to gain entrance and that
the source of the spores causing infection was the field. Inocula-
tion experiments showed that the fungus would attack the
foliage and stems of tomato plants but little was known about
the extent of its occurrence and resulting damage caused in
the field.
Experiments conducted during five years at Homestead have
shown that Phoma spot occurs extensively on the foliage of the
winter crop of tomatoes in that section during seasons of mod-
erate temperatures and high relative humidities. During warm,
dry seasons the disease is less prevalent and may cause little
or no damage.
Phoma spot of the foliage is not readily distinguished from
early blight, except by microscopic examination. Prevalence of
Phoma rot was determined by placing mature-green fruits from
"experimental plots in storage until they ripened.
Spraying experiments showed that 4-4-50 bordeaux increased
the yields of marketable fruit and prevented a high percentage
of Phoma rot in stored fruits during seasons favorable for de-
velopment of the disease. During warm, dry seasons bordeaux
reduced the yields of marketable fruit.
The percentage of Phoma rot was further reduced by washing
the fruits immediately after picking with 5 percent borax solu-
tion, 1 percent sodium hypochlorite solution, or 1-150 sodium
polysulfide solution, each containing 1 of 1 percent liquid tar
soap as a wetting agent. The borax solution proved slightly
more satisfactory than the other two for all tests. The most

28 Florida Agricultural Experiment Station

satisfactory place found for applying this treatment was in the
field. The solution was placed in tubs or barrels at the ends
of the rows and the fruits were dipped into it before being placed
in field boxes for hauling to the packinghouse.
The fruits should be handled carefully at all times to avoid
all forms of mechanical injury.
Picking the fruit while wet with dew or fog increased the per-
centage of Phoma rot in storage.
The chemically treated wraps tested did not reduce the per-
centage of Phoma rot in stored fruit.
Among the varieties tested, Livingston's Globe, Marglobe and
Pritchard showed most resistance to both leaf and fruit infec-
tion. During the 1935-36 season the Rutgers variety showed
most resistance to leaf infection, but because of the hurricane
no fruits were available for comparative tests.

1. CHUPP, CHARLES. Manual of vegetable-garden diseases. 584-586. The
Macmillan Co. 1925.
2. JAMIESON, CLARA O. Phoma destructive, the cause of a fruit rot of
the tomato. Jour. Agr. Res. 4: 1-20. 1915.
3. NIGHTINGALE, ALICE A., and G. B. RAMSEY. Development of Phoma
rot of tomatoes in transit and in storage. U. S. D. A. Circ. 371. 1935.
4. Temperature studies of some
tomato pathogens. U. S. D. A. Technical Bul. 520. 1936.
5. PORTE, WILLIAM S. Notes on the control of transit and storage decays
of tomatoes by the use of chemical washes. Phytopath. 24: 1304-
1312. 1934.
6. ROSENBAUM, J. The origin and spread of tomato fruit rots in transit.
Phytopath. 8: 572-580. 1918.
7. SHEAR, C. L. Pathological aspects of the Federal fruit and vegetable
inspection service. Phytopath. 8: 155-160. 1918.
8. STEVENS, NEIL E., and NELLIE W. NANCE. Spoilage of tomatoes in
transit, as shown by inspection certificates, 1922 to 1930. U. S. D. A.
Circ. 245. 1932.
9. TISDALE, W. B., and STACY HAWKINS. Control of Phoma rot of toma-
toes. Fla. Agr. Exp. Sta. Press Bul. 467. 1934.
10. WILSON, J. D., and H. A. RUNNELS. Some detrimental effects of spray-
ing tomatoes with bordeaux mixture. Ohio Agr. Exp. Sta. Bimo.
Bul. 18: 1: 4-15. 1933.

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