fiff arket Diseases

Tomatoes

Peppers

and Eggplants

lluiidhook No. 2ii

^^sssssss*^

Agricultural Research Service

UNITED STATES DEPARTMENT OF AGRICULTURE
PREFACE

This handbook is a revision of Agriculture Handbook No. 28,

"Market Diseases of Tomatoes, Peppers, and Eggplants," by

Glen B. Ramsey, the late James S. Wiant, and Lacy P. McColloch.

This is one of a group pertaining to market diseases of fruits

and vegetables. The publications are designed to aid in the

recognition and identification of pathological conditions of economic importance affecting fruits and vegetables in the channels

of marketing, to facilitate the market inspection of these food

products, and to prevent losses from such conditions. Other publications in this group are—

MISCELLANEOUS PUBLICATIONS

98. Potatoes. Revised January 1949.

168. Apples, Pears, Quinces. Revised November 1951. [Out of

print.]

228. Peaches, Plums, Cherries, and Other Stone Fruits. Revised

February 1959. [Out of print.]

498. Citrus and Other Subtropical Fruits. June 1943. [Out of

print.]

AGRICULTURE HANDBOOKS

155. Market Diseases of Beets, Chicory, Endive, Escarole, Globe

Artichokes, Lettuce, Rhubarb, Spinach, and Sw^eetpotatoes. April 1959. [Out of print.]

184. Market Diseases of Cabbage, Cauliflov/er, Turnips, Cucumbers, Melons, and Related Crops. September 1961.

189. Market Diseases of Grapes and Other Small Fruits. November 1960. (Reprinted April 1966.)

303. Market Diseases of Asparagus, Onions, Beans, Peas, Carrots, Celery, and Related Vegetables. September 1966.
Market Diseases

of

Tomatoes,

Peppers,

and Eggplants

By LACY P. McCOLLOCH, senior plant pathologitt,

HAROLD T. COOK, director,

and WILLIAM R. WRIGHT, plant pathologitt.

Market Quality Research Division

USDA, National Agricultural Librarv

MAL BIdg '

10301 Baltimore Blvd

Beltsville, MD 20705-2351 jit

Agriculture Handbook No. 28

Agricultural Research Service

UNITED STATES DEPARTMENT OF AGRICULTURE

Wasliington, D.C. Revised February, 1968

For sale by the Superintendent of Documents, U.S. Government Printins Office,

Washington, D.C. 20402 — Price 46 cents
CONTENTS

Fase

Introduction 1

Tomatoes :

Altemaria rot 2

Anthracnose 4

Bacterial canker 5

Bacterial necrosis 6

Bacterial soft rot 7

Bacterial speck 9

Bacterial spot 9

Blossom-end rot 10

Buckeye rot 11

Chemical injuries 13

Sulphur dioxide 13

Nitrogen trichloride 14

Chilling injury 14

Cladosporium rot 17

Cloudy spot 18

Early blight rot 19

Freezing injury 20

Fruit tumor 21

Fusarium rot 21

Ghost spot 22

Gray mold rot 23

Gray wall

(See internal browning.)

Growth cracks 24

Helminthosporium rot 25

Internal browning complex 26

Late blight rot 30

Mechanical injuries 32

Nailhead spot 33

Phoma rot 34

Phomopsis rot 36

Phytophthora rot 37

Pleospora rot 37

Puffiness 39

Pythium rot 40

Rhizopus rot 40

Pase

Ring rot 42

Sclerotium rot 42

Skin checks 43

Soil rot 44

Sour rot 45

Sunscald 46

Virus mottling 47

Tomato mosaic . ; 47

Double-virus streak 49

Spotted wilt 50

Watery soft rot (See sour rot.)

Peppers:

Alternaría rot 51

Anthracnose 52

Bacterial soft rot 53

Bacterial spot 54

Blossom-end rot 54

Charcoal rot 55

Chilling injury 55

Cladosporium rot 56

Cloudy spot 57

Gray mold rot 67

Phytophthora rot 58

Rhizopus rot 59

Ripe rot 60

Sunscald 60

Virus mottling 61

Eggplants:

Alternarla rot 61

Bacterial soft rot 62

Chilling injury 62

Cottony leak 62

Fruit rot (See Phomopsis rot.)

Gray mold rot 63

Phomopsis rot 63

Phytophthora rot 64

Rhizopus rot 65

Literature cited 66

11
MARKET DISEASES OF TOMATOES,

PEPPERS, AND EGGPLANTS

By LACY P. MCCOLLOCH,' senior plant pathologist, HAROU) T. COOK,

director, and WILLIAM R. WRIGHT, plant pathologist. Market Quality Research Division, Agricultural Research Service

INTRODUCTION

NOTE: Illustrations of the market diseases have been inserted in the

back. Insofar as practicable each plate presents diseases similar in appearance, so that differences may be discerned more easily.

The diseases of tomatoes, peppers, and eggplants on the market are definitely associated with the vigor of the plants and the

extent of diseases present in the field, with weather conditions

during the time the fruits were maturing and at the time they

were harvested, and with handling conditions. Very few fungi

or bacteria are able to penetrate the uninjured skin of the fruit,

and yet there are serious losses each year resulting from infections by a number of these organisms. Minute injuries such as

broken glandular hairs, skin checks, and sand scarring are common avenues for infection on apparently sound fruits. In addition, visible blemishes and injuries such as growth cracks, faulty

blossom scars, shoulder scars, and mechanical injuries frequently

permit infection and decay. The majority of rots, however, are

the result of infection by fungi and bacteria present on the fruits

when harvested.

In general, it is advisable to cool tomatoes by ventilation or

refrigeration to remove the field heat soon after loading the cars

or trucks. Prompt cooling is effective in preventing soft rots and

other decays caused by the rapid development of certain pathogens, and it prevents excessive ripening during transit in some

seasons. Tomatoes should not be chilled, however, because chilled

fruits as well as those delayed in ripening are subject to extensive decay by the slow action of weak pathogens.

Nonparasitic, or physiological, diseases are disorders brought

on by abnormal conditions of the plants or fruits and are not

caused by pathogenic organisms. The symptoms of nonparasitic

disorders and virus diseases of the fruit are usually apparent

when they are packed. Although certain of these diseases may become more pronounced after shipping, in general the presence of

these diseases on the market is the result of affected fruits not

being culled at time of packing. Fruits with physiological disorders and those with virus diseases may be worthless because

' Retired December 30, 1966.
2 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OP AGRICULTURE

of the blemished appearance, but these diseases do not directly

result in decay.

Provided the fruits were originally sound and of good quality,

diseases of tomatoes, peppers, and eggplants on the market can

be greatly reduced by proper handling to avoid mechanical injury, by prompt cooling to the desired temperature in transit,

and by proper handling and ripening at the market.

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ALTERNARIA ROT

Alternaria tenui», auct.

Occurrence and Importance

Alternaria rot is a fungus disease of tomato fruits that may

occur wherever tomatoes are grown. The fungus causing this rot

is a weak pathogen that is usually unable to cause an active rot

on sound, uninjured, green tomatoes. Its occurrence, therefore,

depends upon the condition of the fruits.

On vine-ripened tomatoes the rot nearly always follows such

injuries as growth cracks, blossom-end rot, or sunscald. Because

vine-ripened tomatoes are subject to extensive cracking, alternaría rot may be a serious problem in the processing industry

(pl. 1. A).

On tomatoes harvested mature green, a small percentage of

fruits develop alternarla rot at faulty blossom scars (pl. 1, B),

but generally tomatoes do not develop serious alternarla rot in

the ripening room unless they have been weakened by chilling

injury.

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" ' Symptoms

Alternarla rot varies considerably in appearance, depending

upon the conditions under which it develops. In general, the decayed area is brown to black in outward appearance; it may or

may not have a definite margin; it has a ñattened or slightly

sunken surface (pl. 10, E). The lesions are firm; and the rot extends into the flesh of the fruit, producing a dark-brown to black,

dry, corelike mass of decayed tissues (pl. 1, C). Dark-gray mold

is often found in the cavities of the decayed tissues. Dense, velvety olive-green or black spore masses of the pathogen frequently

grow over affected surfaces. Under humid conditions a dark-gray

surface mold may develop. Alternarla rot frequently develops

from the stem scar in V-shaped lesions. At that early stage it is

impossible to distinguish the disease from similar stages of phoma

rot and pleospora rot. Later, however, as the lesions enlarge and

extend toward the shoulders of the tomato, the absence of pimplelike fungus fruiting bodies on the decayed surface helps distinguish alternarla from the other two rote.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 3

After injuries such as sunscald and blossom-end rot, alternaría

rot develops rapidly in the dead tissues and the lesions are soon

covered by velvety spore masses of the fungus. The decay spreads

along the edges of growth cracks without forming definite margins and is usually accompanied by a scanty development of

dark mold. When infection occurs through faulty blossom scars,

the decay generally develops internally more than on the surface

(pi. 1, C). The outward appearance of the spot is often pale

brown instead of black.

Tomatoes that have been chilled too long are extremely subject

to alternaría rot. (See Chilling Injury.) Typical symptoms of aiternaria rot on chill-injured fruits are a ring of decay around

the stem scars (pi. 10, F) and numerous lesions at skin breaks

over the surface of the fruits (pi. 10, G). On green fruits, either

at the time the tomatoes reach the market or shortly after they

are placed in the ripening room, the spots are not so dark as is

usually typical of alternaría rot. Lesions around the stem scars

of chilled fruits are shallow, sunken, and grayish black. Lesions

over the surface of the fruits usually have definite margins, may

be slightly sunken, and are tannish brown. Both types of lesions

gradually become darker.

Another phase of the Alternaría disease is a kind of superficial

scarring that disfigures the fruits, but usually does not develop

into active decay (pi. 10, H). Separate grayish-brown to black

scars may occur over the surface of mature-green tomatoes, during transit or in the ripening room, if harvested from the fall

crop when the pulp temperature is below 60° F.^

Fruits subjected to a week or more of fluctuating moisture and

temperatures in the field may also develop extensive scars around

the shoulder area, especially if the fruits are held for a week or

more at 40° F. or lower after harvest.

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Causal Factors

The causal fungus Alternaría tennis is ever present in nature,

living on weakened plants and on plant debris. It does not affect

tomato plants, and it attacks the fruits only when they have been

weakened by other agents. It can grow and produce spores on

the stem-scar tissue without causing decay of the fruits. Many

tomato fruits show incipient infections at the margin of the stem

scar that usually remain quiescent unless the fruits are subjected

to adverse and weakening conditions. This no doubt is why

Alternaría is the prevailing cause of rot on chilled tomatoes. As

mentioned above, alternarla rot frequently affects tomatoes showing sunscald, blossom-end rot, growth cracks, and faulty blossom

scars.

Once alternarla infection has become established the rot T^^'Ogresses faster at 70° to 80° F. than at lower temperatures. The

infection is not entirely prevented, however, by reducing the temperature in transit. Temperatures below 60° delay ripening but

•Unpublished data of R. F. Kasmire, Division of Agricultural Sciences,

University of California, Davis, Calif.
4 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OF AGRICULTURE

permit the continued, slow development of alternaría rot at skin

injuries and blemishes and on weakened tomatoes. The fungus is

able to grow and cause decay even at 32° if the fruits have been

held for a prolonged period at that temperature. Tomatoes harvested from weakened vines near the end of the season, especially

during rainy weather, usually have more blemishes and are weaker

than the average of harvested tomatoes. Therefore, they are

more subject to alternarla rot.

Control

The control of alternaría rot is ordinarily not a problem for

good quality tomatoes that have been properly handled and

promptly ripened at 60° to 70° F. Fruits showing blemishes such

as sunscald, blossom-end rot, and growth cracks should be sorted

out at packing time. At the end of the season fruits from weakened vines should not be shipped long distances to market. Avoid

harvesting the late-fall crop if the pulp temperature is below 60°

or if the crop has been' exposed to chilling temperatures in the

field (see p. 14). It is particularly important that chilling injury

and delay in ripening be avoided. (See p. 17 for discussion of

recommended temperatures.)

(See 13, 81, 82, 88, 89.)^

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ANTHRACNOSE

,:, i ' CoUetotrichum coccodes (Wallr.) Hughes i-'i':-;

Occurrence and importance

Anthracnose occurs in most of the tomato-growing regions of

the United States. It is primarily a disease of ripe tomatoes;

therefore, it is most serious in regions growing fruit for canning

and for the local market. The fungus filaments in the ñesh are

often responsible for the high mold count in canning tomatoes.

It is seldom important in mature-green tomatoes, although occasionally the disease is found affecting fruits as they ripen during

transit and in the ripening rooms at the receiving markets.

,f^> i-'«rt,fP. i.,,,i ^ Symptoms '''' '---^'^^ ' ^

In the early stage, anthracnose lesions are small, circular,

slightly sunken, water-soaked spots (pi. 1, G). Later they become darker and more depressed (pi. 1, H) or develop concentric

ring markings. Numerous dark pustules, which are fruiting

structures, develop through the surface of the lesions. Under

moist conditions, they become covered with cream to salmonpink masses of fungus spores. The older spots are about one-half

inch in diameter. During transit and marketing, the lesions ordinarily do not penetrate the flesh of mature-green tomatoes

very far unless secondary organisms also are present. On vineripened fruit the spots become large and decay penetrates deeply

into the flesh.

' Italic numbers in parentheses refer to Literature Cited, p. 66.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 5

Causal Factors 'i.iy-; 'v-j;,t ;-.,•:.v^-x, :^;.:*

Anthracnose is caused by Colletotrichum coccodes (C. phomoides). The perfect stage of Colletotrichum coccodes is Glomerella cingulata (Ston.) Spauld. & Schrenk. These fungi live from

season to season on plant debris in the soil and in and on the tomato seed. Warm, wet weather favors spread of the fungus and

development of decay in the fruits. Most rapid decay occurs near

80° F., but fairly rapid development of the fungus takes place at

a temperature as low as 65°. Inoculation tests indicate that infection even through wounds will not occur at temperatures below

45°. Both green and ripe tomatoes may become infected without

evident wounds. The susceptibility to decay greatly increases as

the fruits ripen. Inconspicuous anthracnose spots on green tomatoes often increase greatly in size as the fruits turn pink and

then almost double in size overnight when full-red color is attained. This rapid development of anthracnose may occur in canning tomatoes and in shipments of "pinks" without refrigeration,

but it is not usual in shipments of mature-green tomatoes. Chilling of green fruits stimulates development of anthracnose.

i. <■■• /

Infected tomato-plant debris in the field is one of the chief

sources of infection of newly planted crops. Crop rotation should

reduce this source of infection. Recommendations of the State

agricultural extension service or experiment station should be

followed.

(See 36, 60, 66, 76, 91, 105, 132, 139.) . , ^^ ,

BACTERIAL CANKER

Corynebacterium michiganense (E. F. Sm.) Jensen

Occurrence and Importance

Bacterial canker is occasionally very destructive in many tomato-growing regions. It causes wilt and death of seedlings and

cankers on larger plants. It also causes a very definite fruit spot

that often greatly injures the market quality of green tomatoes

and reduces the value of ripe fruits for canning. The spots on

mature-green tomatoes ready for shipment are usually so conspicuous that most of the blemished fruits are graded out at the

packing sheds. Occasionally, however, some fruits escape notice

and reach the market.

Symptoms

Affected fruits on the market show symptoms that are so characteristic that diagnosis is easy. The spots on mature-green fruits

are usually y,e to Yg inch in diameter and are definitely superficial (pi. 5, E). In the early stages the spots appear as white to

light-brown slightly raised areas ; as they enlarge the brown cen-
6 AGRICULTURE HANDBOOK 28, U.S. DEPT. OP AGRICULTURE

ter becomes more prominent and is surrounded by a characteristic white halo that does not show water soaking (pi. 6, E). The

center becomes dark brown as it ages and may show a rift or

slight opening; but the smooth, circular outline of the spot is

maintained and the white halo usually remains visible. Although

the individual spots seldom reach a greater diameter than % inch

on green fruit or % inch on ripening fruit, several spots often

coalesce to form large, rough areas. A soft rot never develops.

The fruits are sometimes infected internally by the passage of

the causal bacteria from the vascular system of the diseased plant

into the vascular system of the fruit; in such instances there are

no external signs of disease in tomatoes of marketable size.

Causal Factors

Bacterial canker is caused by Corynebacterium michiganense.

Contaminated seedbed soil is the principal source of infection;

seed infection plays a relatively minor role. In many instances,

cankerlike lesions develop on the stems of infected plants during

wet weather. Bacteria from these cankers may be spread to the

young fruits and other parts of the plant. There is no evidence to

show that bacterial canker spots change or that new ones develop during transit or on the market.

Control

Recommendations of the State agricultural extension service or

experiment station should be followed to prevent bacterial canker

in the growing crop.

(See 2, 10, 11, 43, US.)

BACTERIAL NECROSIS

'•»•i'-.'"A f Various species of bacteria vó ») ; >'

Occurrence and Importance

A dry, firm, tissue breakdown around the shoulder area of

mature-green tomatoes has been noted in shipments from Texas,

California, and Florida. Losses observed on the market varied.

Some were not extensive, but others amounted to 20 percent of

the load. The disease is probably related to weather and growing

conditions and may therefore be expected to be sporadic in

occurrence.

- ^.-.t.-xT^ r.~.. Symptoms rc^tii'>^'<.* .^t-ü:' '^ii-á-.V^K.

Externally, the aifected tissues are confined to the shoulder

area. They are sharply sunken, firm, and a brownish-gray color

(pi. 5, F). The affected surface may change from green to brown,

but the development of red pigment in the necrotic area is

suppressed.

Internally, the diseased tissues are dry and brown. The discolored tissues are confined to the pericarp and septa, but masses

of bacteria collect in the seed cavities.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 7

.^i'i . ■■.-', -.-.v/n . ;.- Causal Factors :J!. ';,fi vh^^f ',.,

Nothing is known about the conditions that may permit bacterial necrosis to develop in the field.

No single species of bacteria can be considered to be the cause

of necrosis. Twenty-one isolates were obtained from affected tissues, eight of which caused tissue darkening and collapse. Most

of the isolates causing necrosis were placed in the genus Aerobacter; one isolate was identified as a species of Xanthomonas.

The symptoms are similar to certain extreme phases of internal browning, and the possibility exists that the bacteria may be

secondary to the internal browning disorder.

Control measures have not been developed.

(See .4.)

BACTERIAL SOFT ROT

Erujinia carotovora (L. R. Jones) Holland, and other bacteria

,,, Occurrence and Importance

t-,'.i;- _: ... ^ i:.. :■■ Bacterial soft rot occurs wherever tomatoes are grown. Although at times it may be responsible for fruit losses in the field,

it is primarily a decay of tomatoes during transit and ripening.

Terminal inspection records taken on the New York City market

have shown it to be the most prevalent decay in rail shipments.

Green fruits are more susceptible to decay from bacterial soft rot

than ripe fruits.

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The first symptom of bacterial soft rot is the appearance of a

slightly depressed, water-soaked spot on the fruit. The spot enlarges rapidly to affect much of the tomato, and the affected

tissues soon become very soft and watery (pi. 3, G and H).

Watersoaking is particularly prominent at the borders of the

lesion. The causal bacteria dissolves the material that holds together the cells of the tomato tissues. This action accounts for the

extreme softness of decayed tissues. The skin is easily broken

in the more advanced lesions. Sound tomatoes frequently are

infected by contact with decayed adjacent tomatoes. The decay

penetrates deeply into the tomato fruit. Diseased tissues are

sharply delimited from healthy tissues inside the fruit by their

softness and water-soaked appearance. Decayed tissues usually

have a foul odor caused by secondary saprophytic bacteria.

Bacterial soft rot may at times resemble rhizopus rot and sour

rot. If, however, the tissues affected with rhizopus rot are gently

pulled apart, a few coarse threads of the Rhizopiis mold can usually be seen, and the decayed tissues tend to hold together, becoming "mushy" rather than "soupy" as in bacterial soft rot. The

foul odor characteristic of bacterial soft rot is not associated

with rhizopus rot.

Tomatoes affected with sour rot resemble those with bacterial
8 AGRICULTURE HANDBOOK 28, U.S. DEPT. OP AGRICULTURE

soft rot chiefly because of the water-soaked appearance of the

spots. In sour rot, however, the affected tissues of mature-green

tomatoes remain firm until the tomatoes are almost completely

decayed. As the name indicates, fruits decayed by this organism

have a sour, lactic acid odor. Frequently, sour rot is followed by

bacterial soft rot.

■■^^r:',. t;i.,::;¡:;. -.¡'fi :ïi ::'yj Causal Factors 'C,¿^^':.' ">

Massey, in 1924, identified the bacterial pathogen that causes

soft rot of tomatoes as Erwinia aroideae (Townsend) Holland.

This organism is considered by some workers to be identical with

the common soft rot bacterium Erwinia carotovora (L. R. Jones)

Holland, which causes a soft rot of a wide variety of leafy and

root-crop vegetables. The latter usage is here followed. There is

a strong possibility that such organisms as Bdcillus subtilis and

B. polymyxa, commonly found in the soil and reported to be associated with potato soft rots, may also be responsible for tomato

soft rots, particularly at high temperatures.

The soft rot bacteria are found in soil and plant debris wherever tomatoes are grown. They are spread by insects, by field

operations, and by the blowing, washing, or splashing of contaminated soil. Tomatoes may be inoculated with the bacteria

while on the vines or, more likely, during picking and packing

operations. In initial infection the bacteria enter the fruit only

through weakened tissues and breaks in the skin ; so high-quality,

unwounded fruits are the best preventive.

Undoubtedly most of the bacterial soft rot found on tomatoes

upon arrival at the market and much of that which develops in

the ripening room started in field or packinghouse injuries that

were not visibly infected at the time of shipment. However, there

may be some spread from badly decayed fruits to adjacent fruits

during transit and in the ripening room.

Warm and humid or wet weather favors the growth and multiplication of the causal bacteria. The most favorable temperature

range for development of this decay is between 75° and 85° F.;

at these temperatures the entire fruit may rot in 3 to 10 days.

Decay may be fairly rapid at somewhat lower temperatures. Below about 65°, however, development of decay is slowed perceptibly. There is practically no development at 45° or lower, but

this is too low a temperature at which to hold mature-green

tomatoes.

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Careful handling of tomatoes during picking and packing is

essential to avoid skin cuts and punctures. Picking containers

should be cleaned and disinfected at frequent intervals. Good

sanitation practices around packinghouses are advisable. In general, tomatoes should be picked while dry and kept as dry as

possible before shipment. If tomatoes are washed, running water

should be used and they should be dried before being packed.

Decay is retarded by cooling the fruits rapidly to a temperature
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 9

between 55° and 65° F., and maintaining that range during

transit.

(See 12, 28, i8, 93, 95, 161, 163.)

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■■;'-;^-:;^ ' BACTERIAL SPECK -'"-•^'" ^ '''if'Ú

' ' ^'J , Pseudoïïnonas tomato (Okabe) AltsUatt

Bacterial speck is so named because of the very small lesions

produced on the fruit and elsewhere on growing tomato plants.

This disease is most often found on tomatoes in the Middle Atlantic and Gulf Coast States. It is seldom of great importance,

but occasionally the mature-green fruits are so badly speckled

that their market quality is reduced.

The bacterium causing this disease affects the leaves, stems,

and petioles of the growing plants as well as the fruit. Specks on

the fruit are superficial and V^^ to Vie inch in diameter; the

larger ones result from infections of the fruit when very young.

Most of the spots are no larger than 1/32 inch in diameter. They

are dark brown, slightly raised, and have definite margins (pi.

6, F). There is no white halo about these spots, as in bacterial

canker, or feathered edges, as in bacterial spot. The very early

stages of bacterial spot, however, are very similar to the mediumsized spots caused by the bacterial speck organism. None of these

three types of bacterial spot on tomatoes cause decay of the fruit.

They do not develop or change in transit, but are merely blemishes that were present at the time of shipment. They affect only

the appearance of the fruit.

Wet weather with temperatures between 73° and 77° F. favors

the spread of infection and development of bacterial specks on

tomatoes in the field.

Recommendations of the State agricultural extension service

or experiment station should be followed.

(See 11, 27.)

BACTERIAL SPOT

Xanthomonas vesicatoria (Doidge) Dowson

Occurrence and Importance

Bacterial spot of tomatoes is found in the market on fruit from

many of the Atlantic Coast, Gulf Coast, and Central States and

sometimes on tomatoes shipped from Mexico. In some seasons

this disease causes considerable damage to tomato plants in the

field and blemishes the fruits so badly that they are unmarketable. Some fruits are affected by bacterial spot each year.

Symptoms

On young fruits the lesions appear as small, dark, slightly

raised dots, sometimes with a narrow water-soaked border. The
10 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OP AGRICULTURE

smallest lesions of bacterial spot are very similar to the larger

lesions of bacterial speck. The small bacterial spot lesions can

usually be distinguished from bacterial speck by their slightly

water-soaked border and irregular margin. On mature-green

fruits received on the market the spots appear as brownish-black,

elevated scablike areas (pi. 5, A and B) % to % inch in diameter

(pi. 6, C), with feathered or irregular margins. Spots initiated

early in the season often reach a diameter of % inch by harvesttime. They are sunken and appear gray or bleached, owing to the

dry paperlike condition of the affected skin, which is usually torn

and ragged (pi. 6, D). Fruits showing this stage of bacterial spot

may be confused with nailhead spot (see Nailhead Spot) ; nailhead spot fruits seldom reach the market, however. Regardless

of size, these scablike spots remain superficial and never develop into a soft rot. «irî;î S^'îUSS >f* S

'5=.-; . i-i^>:\.:f;i. ill á'-fí' Causal Factors bniüCrw»' *3fi îi/-a ir:

The causal bacterium' Xanthomonas vesicatoria is carried on

contaminated seed harvested from diseased fruit, and it is believed that the organism may also remain alive in the soil from

one season to the next. Moderately warm weather (74° to

77° F.) with frequent rain favors the spread of the bacteria in

the field and the production of spots on the fruit. Young green

fruits are readily infected, but ripe fruits resist infection. Although wounds apparently are not necessary for infection, it is

believed that sometimes insect injuries play a part in causing

infections. Most infections occur while the fruits are quite young ;

and by the time the fruits are large enough to market, the spots

are conspicuous and are easily graded out in the packing shed.

There is no measurable increase in the size of the spots during

transit. Those found on the market were present at time of

shipment. M-?yvluÄ :^i biyofff. íU.íúM h ;:>

Control V

Recommendations of the State agricultural extension service

or experiment station should be followed.

(See 11, 27, 38.) -..ái^^saí

n BLOSSOM-END ROT

Occurrence and Importance

Blossom-end rot is a physiological disease of tomato fruits that

is found wherever tomatoes are grown. It may cause serious

losses during certain seasons. The disease is of considerable importance annually in the Southeastern and Gulf Coast States.

Blossom-end rot commonly is found on market tomatoes from

many different producing areas, although usually in small
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 11

îîN; ,í.,{i ícf'iVí;;;«: s'ii-: Sí«? Symptoms K^QH lia '{lùi^-MmA .o-^i"'

. The first symptom of blossom-end rot is usually the appearance of a small, water-soaked spot at or near the blossom scar of

green fruits. As the spot enlarges the affected tissues dry out and

become light brown to dark brown (pis. 9, E, and 8, D). The lesion thus develops into a well-defined sunken spot, with the

affected tissues collapsed and leachery. The skin remains unbroken, because it is the tissues beneath that have dried out and

collapsed ; and the darker colored strands of the vascular system

can be seen radiating from the blossom scar. Blossom-end rot is

not actually a decay, although it frequently is followed by alternaria rot, bacterial soft rot, or other rots.

Although fruits of any age may become affected, blossom-end

rot usually appears on fruit when it is a third to half grown. The

spots vary considerably in size and may affect as much as onehalf of the fruit. On slightly affected fruit the only evidence of

blossom-end rot may be a slight drying out and browning of a

small, superficial, irregularly shaped area near or at the blossom

scar. This type of symptom is frequently seen on the market.

.. - ., -i.'-r ... !-..,, ß.- Causal Factors T.-í....,,-,:. ¡, --r'

There has been considerable experimentation and speculation

about the cause of blossom-end rot. It appears that blossom-end

rot may be caused by calcium deficiency since it can be greatly

reduced by applying heavy dosages of gypsum and calcium nitrate to the soil and by spraying the plants with calcium chloride

solution.

Because of the physiological nature of the disorder, there is no

spread from fruit to fruit during transit. Under certain conditions, however, blossom-end rot may become apparent during

transit and on the market in tomatoes that showed no sign of the

disorder at the time of shipment. Blossom-end rot lesions already

present on fruits at time of shipment change little, if any, in

size unless secondary organisms are present.

Control

Blossom-end rot must be controlled by cultural practices. Recommendations of the State agricultural extension service or

experiment station should be followed.

(See 31, 39, 40, 80, 117, 135, 136.)

; -:.i-'JJ''!,fï 10 ÍTiil ß TO 3'>ÍSJ -I

iCi 'ío íteíj^yxi Un. BUCKEYE ROT oo

-'í^'íú ,'-'"ro!ä3i ,íoi lío? Phytophthora spp. " ^ > ï'^J

Occurrence and Importance

>

Buckeye rot, a fungus disease of tomato fruits, has been reported from most of the important tomato-growing regions of

the United States. The disease also occurs in Cuba and Puerto
12 AGRICULTURE HANDBOOK 28, U.S. DEPT. OF AGRICULTURE

Rico. Apparently all species of tomatoes are susceptible, but

certain varieties and breeding lines are more resistant than others. Although buckeye rot may cause extensive losses, generally

it occurs sporadically.

The occurrence and seriousness of the disease depends upon

weather conditions. Prolonged periods of warm, wet weather encourage its development, regardless of geographical location.

Such conditions, however, are more prevalent in the Southeastern and South Central States than elsewhere in the United

States.

Buckeye rot is generally confined to fruits that are near or in

contact with the soil. It attacks green fruits at any stage of maturity as well as ripe fruits. When conditions are favorable for

the development of the disease, it may cause serious losses both in

the field and in tomatoes shipped to market.

Symptoms

On green fruits the rot is hard and at first brown to grayish

green (pi. 2, C). As the rot enlarges it remains moderately firm.

The margin of the advancing rot is irregular and indefinite and

has a characteristic water-soaked appearance and grayish-green

color. Occasionally the entire lesion appears watersoaked, but

more often it is marked by one or more fairly broad, irregular

zones of alternating shades of brown and grayish brown (pi. 2,

D). The surface of the well-developed rot is usually smooth, and

the skin is unbroken. The typical color is chocolate brown.

The rot on ripe fruits is usually watersoaked and lacks the

dark-brown color and the zoning.

Ordinarily little or no surface mold is evident, but if decaying

tomatoes are held in a humid atmosphere a white, fluffy mold

that becomes matted and tough when wet appears on the surface

of the rot. This condition occurs in the field during rainy weather

on fruits in advanced stages of decay.

Under certain conditions it is diflScult to distinguish buckeye

rot from late blight. (See Late Blight Rot.) In early stages of

buckeye rot, when the surface of the lesion is rough, lacks the

zoning, and has a paler brown color than is typical, it resembles

late blight. On the other hand, when late blight spots are smooth,

watersoaked, and darker brown than typical, they resemble buckeye rot. Generally, however, the surface of late blight spots is

rough, or when it is smooth the margin of the spots shows a

slightly roughened surface of a tan or rusty-brown color typical

of late blight. Zoning is very rare in late blight.

Soil rot may be confused with buckeye rot because of the

zoned appearance of the decayed spots. The soil rot lesions, however, are usually smaller and have a fairly definite margin and

flat surface. The zone bands are narrow and nearly symmetrii-al

in form. The surface of the affected skin is often cracked. (See

Soil Rot.) ^
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 13

'Or.Oj Causal Factors c.f-ift.a

Buckeye rot is caused by several species of Phytophthora. In

California it is attributed to P. capsici Leonian and P. drechsleri

Tucker; in Colorado only P. capsici has been reported as the

cause. Elsewhere the cause of buckeye rot has been attributed to

P. parasitica Dast.

These species of Phytophthora are soil-inhabiting fungi that

do not cause disease except in warm, wet weather. Two kinds of

spores are formed. The primary spores, or sporangia, develop

first and these in turn give rise to swarm, or swimming, spores.

The sporangia are not formed unless the soil is wet and the

temperature is above 65° F. At 70° they may be formed within

24 hours. The sporangia may remain alive for days. When they

become wet they burst open and discharge large numbers of

swimming spores that must have free water to remain alive. It

is the swimming spores that infect the tomato fruits. Infection

can occur through the unbroken skin. A temperature of 80° or

above is ideal for infection and development of the rot. Visible

signs of the disease may appear within 20 hours, and the rot

develops rapidly.

Fruits showing small spots overlooked in packing or contaminated fruits that appear sound may develop extensive decay

during transit or after reaching the market. The rot enlarges at

any of the temperatures desirable for handling tomatoes, but development is much slower at 55° F. than at higher temperatures.

The disease may spread from decayed fruits to other fruits in

contact with them, in transit or in the ripening room, especially

at temperatures of 70° or somewhat higher.

Control

Tomatoes should be carefully sorted at packing to eliminate

those that show buckeye rot. Buckeye rot is primarily a field

disease. Most of the tomatoes that develop the disease after harvest were infected in the field, but did not show signs of the

disease at time of packing. No method has been developed to

prevent decay of infected fruits. A 24-hour delay in packing tomatoes suspected of having incipient infection may permit the

disease to become evident so the fruits can be discarded at

packing.

(See 32, 70, 107, 131, 133, 1Í6.) ,,,,^

CHEMICAL INJURIES

:,i: Sulphur Dioxide j ^i;,.-: -. -^^

Injury to tomato fruits caused by exposure to sulfur dioxide

gas has been observed on the markets in stock shipped from

California and Florida. Although this type of injury has not been

observed in recent years its possible recurrence warrants mention.
14 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OF AGRICULTURE

The tomatoes affected show a very pronounced sinking and

drying out of the tissues at the stem scar. The gas enters the

fruits through the stem scar or through wounds elsewhere on the

surface. The cells immediately surrounding the openings are

killed and lose their water rapidly by evaporation, which causes

collapse of the affected area. In some tomatoes the stem scar is

sunken 14 ¡"c^ and the tissues immediately around the scar are

bleached to a light greenish tan, while the rest of the tomato remains normal except where mechanical injury is evident. Wherever the cuticle and epidermis of the fruit show a wound, the

surrounding tissues are sunken and bleached greenish tan like

those around the stem end. The sunken stem scars dry rapidly

and crack, thus opening the way for various decay-producing

organisms such as Altemaria and Rhizopus. This injury is somewhat similar to that caused by nitrogen trichloride ; however, the

strong bleaching action of sulfur dioxide causing extensive grayish-green to light-tan discoloration of the affected areas is usually sufficiently characteristic to distinguish this injury from

nitrogen trichloride injury.

The injury results from using sulfur dioxide gas, as with

grapes in California, to reduce the amount of decay during transit and marketing. No experimental data are available, however,

to show that sulfur dioxide is of value in reducing decay in

tomatoes. ' ' :'

(SeellÄ.) =• :

Nitrogen Trichloride

Nitrogen trichloride has been used in a limited way for fumigating tomatoes to reduce decay during transit and marketing

and has occasionally caused some injury to the fruit. When this

chemical is used improperly, sunken tan to brown areas are evident on the fruits where there are injuries or scars that allow

the gas to penetrate into the inner tissues. Gas that penetrates

the stem end of the fruit causes a sinking of the tissues and a

band of light-brown tissue at the edges of the stem scar. This

injury is similar to that caused by sulfur dioxide; however, the

affected tissues are usually darker brown, less extensive in area,

and not so deeply sunken.

CHILLING INJURY '

Occurrence and Importance

Chilling injury may occur in the field while the fruits are on

the vine, while they are in transit, or after they reach the market

if held at low, but nonfreezing, temperatures for too long a time.

Tomatoes from all localities are subject to chilling injury, but

susceptibility of fruits differs within a variety as well as between

varieties. Mature-green tomatoes are more sensitive to chilling

injury than fruits that were partially ripened on the vine and

classed as "pink" tomatoes.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 15

In general, the conditions during the normal transit period

from shipping point to market are not conducive to chilling injury. Yet, until less than a decade ago chilling injury caused

serious losses in tomatoes reaching the market, especially during

the late fall and winter months. Although some chilling injury

continues to occur, the application of research findings has

brought this serious problem under control.

T

Symptoms / ' ,^-^'

Ordinarily, chilling injury cannot be detected at the time tomatoes are removed from cars or trucks with low temperatures.

The injury usually does not become apparent until the tomatoes

have been in the ripening room for 2 or 3 days or longer. Tomatoes show a range of symptoms and indications of chilling

injury depending on the severity of the damage. Unfortunately,

the most positive physiological symptoms do not develop until

tomatoes have been chilled to death. Mature-green tomatoes that

have been held near 32° F. for 30 days or longer develop a dull,

lifeless, pickled appearance (pi. 10, D) and feel rubbery to the

touch. The internal symptoms are a watery, but not mushy, appearance of the tissues and a slightly fermented odor.

Tomatoes that are seriously injured, yet not chilled to death,

may show such symptoms in the ripening room as irregular ripening or brown seeds. These symptoms are not entirely reliable

if considered independently, but are useful when used as an adjunct to other indications. For example, irregular ripening may be

caused by other agents than low temperature. Seeds of tomatoes

tend to turn brown if the fruits are held at 32° to 40° F. for 9

days or longer. Seeds that are uniformly dark or brown seem to

be a reliable symptom of chilling injury, but nonchilled tomatoes

often have speckled seeds.

Alternarla rot in a pattern around the stem scar (pi. 10, E

and F) and in the form of numerous small lesions (pi. 10, G)

over the surface of a high percentage of tomatoes in the ripening

room usually follows chilling injury and indicates that the fruits

have been chilled. (See Alternarla Rot.)

Tomatoes harvested from the fall crop when the pulp temperature is below 60° may develop dark scars over their surface (pi.

10, H), during transit or ripening, owing to the Alternaría

fungus. -' ;

^:c; . >íí,íí¡'?;i I Causal Factors .)!;;•::•::> ,;, ; ■■'"-'

The effects of low, but nonfreezing, temperatures on the physiological processes of mature-green tomatoes are not well understood. It appears, however, that the fruits are unable to carry on

normal metabolism at temperatures below 50° F., and as a result

of prolonged holding at low temperatures their tissues gradually

become injured. Tomatoes may therefore be considered as having

been chilled when their physiological processes have been so impaired that ripening does not take place when the fruits are
16 AGRICULTURE HANDBOOK 28, U.S. DEPT. OF AGRICULTURE

returned to temperatures that are ordinarily favorable for ripening. Chilling injury is distinct from freezing injury and occurs

when tomatoes are held for prolonged periods at 32° to 45°.

Fruits that have been chilled are weakened and are more subject

to decay by Altemaria tennis, and to a lesser extent by Cladosporium herbarum and Pénicillium sp. When fruits have been

seriously chilled, a high percentage show alternarla rot.

Tests with freshly harvested mature-green tomatoes have

shown that tomatoes may be held at temperatures of 32° to 40° F.

for 3 to 5 days and still ripen satisfactorily with little or no

increase in decay. Tomatoes held for 6 to 8 days will color satisfactorily but will show an increase in decay in proportion to the

length of exposure. Tomatoes are definitely weakened by holding

at these low temperatures for 9 to 12 days. Ripening is unsatisfactory and decay is extensive. Tomatoes are so weakened by

holding at 32° to 40° for 17 to 21 days that the entire lot usually

rots without ripening. Chilling injury develops more slowly at

45° than at 32° to 40°. Definite symptoms of chilling injury do

not develop, however, in tomatoes held at 45° for as much as 15

days. The nature and extent of decay that develops while the

tomatoes are in the ripening room indicate that they were weakened or injured. Holding tomatoes at 45° for more than 3 to 5

days should be avoided.

Tomatoes harvested after exposure to a week or longer in the

field at temperatures below 50° F., and predominantly below 40°,

will likely develop serious chilling injury {82).

Ordinarily, the field heat in mature-green tomatoes when

loaded is sufficient to require several days to cool the shipment

to desirable temperatures, even by refrigeration. If the car is

moved under bunker icing, however, fruits in the bottom bunker

position will cool rapidly and may arrive on the market with a

pulp temperature of 36° to 40° F. Under normal conditions, if

the transit period does not exceed 6 days, the tomatoes would be

at such temperatures for only 2 to 4 days, and these temperatures

alone are not sufficient to cause chilling injury. If, however, the

transit period exceeds 10 days and the load moves under refrigeration, there is danger of chilling injury in tomatoes near

the bottom bunker. If the tomatoes have been exposed to temperatures of 50° or below in the field for a week or more before

harvesting or stored at 40° to 45° for a week before shipping,

and if they are refrigerated in transit or if the car is iced and

left on the track at the market, the fruits may be at low temperatures for a sufficient time to become chilled. Tomatoes in cars

with bunker icing for prolonged transit periods, because of diversion from one prospective market to another, are likely to

become chilled. Chilling injury is likely to occur in cars during

periods of low outdoor temperatures, and it is obvious that under these temperatures heavy icing would be undesirable. Tomatoes moving to northern markets during the winter months

may need heater service to protect them against chilling injury

as well as freezing injury.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 17

f^n'i'f •''' •' :>'n'(-'ii "--.h,^'' -vii Control i-lá'iúíi -v/rrnnü n övsfi bau

. The recommended transit temperature for mature-green tomatoes is 55° to 65° F. Although tomatoes can withstand low

temperatures for 3 to 5 days without being injured, it is not advisable for the fruit temperature to be lower than 55° during

transit. This recommendation is made because of the uncertainty

of the previous treatment of the tomatoes and also the uncertainty of how the load may be handled before the tomatoes are

ripened.

Avoid long delays at temperatures below 55° F. Use heater

service during periods of low outside temperatures to protect the

tomatoes against chilling injury.

To avoid dark scars over the surface of the fruits that are

associated with low temperatures, avoid harvesting mature-green

tomatoes until the pulp temperature is 60° F. or above.

Although more resistant than mature-green tomatoes, pink tomatoes are subject to chilling injury and should not be held at

40° F. or below. Holding and transit temperatures depend on

stage of ripeness. If fruits need to ripen they can be held at 60°.

If ripening is to be retarded they should be precooled to 50° and

held at 45° to 50°.

{See 82, 88, 89, 111, 130.)

nf:iiKi>;E',.„iJv'.í .'Í "ir- jij-.'dk, ¡ •À ''tygu

CLADOSPORIUM ROT ¿Si^n;l;?^ î-'

Cladosporium herbarum Fr. -íL^Tí íUUU'/, ¡í:

Occurrence and Importance

Cladosporium rot has occasionally caused heavy losses during

transit and marketing of California tomatoes during November

and December and of tomatoes imported from Mexico during

January. The most serious losses have occurred during long

transit periods and in the ripening rooms at the receiving markets if the tomatoes were very slow in ripening. Although the

causal fungus is widely distributed and of common occurrence,

the decay of tomatoes is ordinarily not commercially important.

Cladosporium does not cause decay of tomatoes in the field, except on discarded fruits or when associated with other types of

decay.

' " Symptoms ' ' ' ' '"""' ''"' *

On green tomatoes the first visible signs of cladosporium rot

are small light-tan spots in the skin without visible surface mold.

As the spots enlarge they become slightly sunken and have darkbrown to black centers with margins of tan or light brown (pi.

4, E). Most cladosporium rot lesions on fruits arriving at eastern

markets range from % to % inch in diameter. In delayed shipments and in ripening rooms the spots may reach a diameter of

% inch or more; they are shiny black and smooth at the center

(iß
18 AGRICULTURE HANDBOOK 28, U.S. DEPT. OP AGRICULTURE

and have a narrow, light-brown border. Under humid conditions

spots of this size often develop á fine, granular, dark-green, sporebearing mold on their surface. The decayed tissues are usually

limited to the outer wall of the fruit, but occasionally they may

extend to the seed cavity. The. affected tissues are moderately

firm to slightly spongy, and moderate-sized lesions can be readily

lifted out of the fruit with the point of a knife.

Causal Factors

Cladosporlum rot of tomatoes is caused by Cladosporium herbarum. This fungus commonly occurs on plant debris and in the

surface soil, but it is considered to be a weak pathogen. During

foggy or rainy weather when the temperature is moderately low

some incipient infection of the fruits may occur before harvest.

In general, however, infection and decay develop after harvest

during abnormally long transit or holding periods at temperatures near 40° F. Under such conditions tomatoes become weakened by chilling injury and are susceptible to cladosporium rot.

The fungus appears to penetrate the weakened tissues without

the aid of a skin break. Several lesions usually occur over the

surface of a fruit, but they develop very slowly. Although the

optimum temperature for the growth of the fungus on nutrient

agar is about 70° F., cladosporium rot is not a problem on tomatoes except at low temperatures. Cladosporium is quite tolerant of temperatures of 32° to 40°, and in time it can induce decay

in mature-green tomatoes held at those temperatures.

_ , Control

The use of fans in conjunction with bunker icing, mechanically refrigerated cars and trucks, and accelerated transit schedules have done much to prevent over-refrigeration and resultant

cladosporium rot. General precautions against cladosporium rot

are to ship high-quality tomatoes free of field chilling injury under protective services that will provide temperatures ranging

from 55° to 65° F.

(SeeJ.^^.)

''^''" '" "' " -'^-'CLOUDY SPOT '''"'^ ^'*'-'"-'^^-:^

Cloudy spot is a blemish of tomato fruits. It is often found in

small amounts on the market on fruits shipped from many tomato-growing regions, but serious loss seldom occurs because of

this trouble.

On green fruits this blemish is characterized by cream-colored

spots, which change to yellowish spots on ripening fruits. The

spots are without definite margins and are found just underneath

the skin of affected fruits (pi. 5, G and H). These light areas are

made up of silvery-white cells that have a spongy texture. No

decay or further discoloration of the tissues takes place after

harvest. Most spots range from % to % inch in diameter, but
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 19

sometimes several spots coalesce and form large, irregular

blotches that reduce the market value of the tomatoes.

It is believed that cloudy spot is caused by the feeding punctures of certain species of Pentatomids known as stinkbugs. Only

certain plants in a field may show fruits affected by cloudy spot.

Usually this disease is not serious' enough to warrant spraying

to control the stinkbugs. Tomatoes blemished enough to affect

their market value should not be packed for shipment.

(See 27, 156.)

aoiù * .-;Uß3iL..>ii9'J

EARLY BLIGHT ROT

«^iJSiuu Alternaría solani (Ell. & G. Martin) Sor.

Occurrence and Importance ¡%

Early blight occurs to some extent in most tomato-growing

regions. It is most serious on tomatoes grown in the New England, Atlantic, and Central States, and it is usually of minor

importance in the Pacific Coast States.

The early blight fungus causes a spotting of the fruits that is

seen more often in the field than on the market, but it is sometimes found on vine-ripened tomatoes harvested for canning, especially late in the season.

Even though this blight is not important on mature-green tomatoes, it is included here so that it can be clearly distinguished

from the more important alternarla rot that is caused by Alternaria tenuis (see Alternaría Rot).

• ' • ' Symptoms

Typical early blight spots are dark brown, leathery, and somewhat sunken. They are usually less than an inch in diameter and

show concentric markings (pi. 4, D). The dark, dry decay usually does not extend more than % inch deep.

Early blight spots nearly always occur at the stem end of the

fruit. Very often the stem becomes infected and the disease

spreads to the fruit. In other fruits the lesion develops from the

stem scar, but some soots develon on the shoulder aoart from the

stem attachment. Early blight spots have been observed on fruits

of all stages of maturity on weakened plants.

Causal Factors

Early blight fruit spotting is worse in seasons of prolonged or

heavy rainfall. Under such conditions the plants are weakened

through the destruction of the foliage by leaf-spotting fungi and

through poor aeration of the roots in waterlogged soil. The early

blight spots are found on the smaller, weaker tomatoes in the

cluster, but if the entire plant has been weakened, spotting may

occur on many green fruits on the plant.

It is not uncommon to find Alternaría tenuis invading the early

blight spots and causing a secondary rot in the field.
20 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OF AGRICULTURE

Control

Recommendations of the State agricultural extension service or

experiment station should be followed.

(See ^7, 81.)

FREEZING INJURY r

Periodically, tomatoes of the late-fall crop and those grown

during the winter months are injured before harvest by subfreezing temperatures. Commercial loads of tomatoes moving or

standing without heater service during periods of low outside

temperatures may also develop freezing injury.

Freezing ordinarily occurs when tomatoes are cooled sufficiently for their tissues to reach a temperature of 30° to 31° F. The

average freezing point of ripe and green fruits has been found to

be about 30.5°. The lowest point determined at which freezing

first occurs was 29.7°, and the highest temperature was 31.1°.

Freezing injury does not occur unless ice is formed in the tissues.

It is possible to undercool tomatoes (as well as other vegetables

and fruits) for short periods at temperatures several degrees

below their actual freezing point without producing ice crystals

or causing freezing injury if they are not disturbed. Such conditions seldom occur under commercial practice.

The chief symptom of severe freezing injury is a glassy or

water-soaked appearance of the fruits. The border between uninjured tissue and frozen tissue may be quite distinct, particularly on green fruits (pi. 10, A).

Fruits frozen throughout collapse when held at ripening-room

temperatures, and those with serious localized freezing injury

retain the water-soaked appearance of the spots (pi. 10, B).

Fruits showing either type of injury decay rapidly.

Tomatoes subjected to freezing temperatures in the field develop a wide range of symptoms. The extent of injury depends

upon the vine cover and duration of subfreezing temperatures.

Watersoaked areas are readily recognized as freezing injury, but

many fruits less damaged may show no evidence of injury immediately after the freeze. In such fruits the frozen and normal

tissues are intermingled; and when the ice crystals melt, the injured tissues tend to recover because of the presence of normal

tissues. If the damage is fairly extensive the affected tissues become dry, bleached, and sunken. Sunlight hastens moisture loss

and collapse. If bright sunlight follows the freeze, some damage

is evident within 24 hours. If damage is less extensive, fruits

gradually develop a pebbly surface over the affected area (pi.

10, C). This symptom may develop in 1 to 4 days. A slight to

moderate yellowish color over the affected area is the best indication of freezing injury too slight to be accompanied by tissue

collapse. „ ,'r T ,,

(See 8S, 128, 159.) . .
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 21

FRUIT TUMOR

Fruit tumor, also known as waxy blister, is the cause of a

serious blemish that has been observed periodically on the market

for the last 25 years. This physiological disorder is characterized

by waxlike tumors on the surface of mature-green tomatoes. The

most serious blemishes of this type occur in California tomatoes

shipped during the fall and winter months. These white to creamcolored irregular blisters (pi. 8, A and B) usually range from

% to ^4 inch in diameter and frequently are more than % inch

high (pi. 9, A). While the tomatoes are still green these blemishes remain smooth and turgid; as they ripen, the affected tissues change from light brown to dark brown and eventually

become depressed and cracked. The tissues of the tumors are

made up of elongated cells in and underneath the epidermis.

Some tumors occur on tomatoes in the field, but most develop

after the fruit is packed and while it is in transit. The disorder

appears to be worse on fruits lacking maturity.

Rubbing the fruits while they are still green will cause tumors

to develop. The slight mechanical damage apparently liberates

growth hormones that incite increased cell activity and tumors.

The minimum and maximum temperatures for tumors to develop

are 70° and 96° F., respectively. At 91.4° the first signs of tumors may be seen within 21 hours. Ordinarily, fruit tumor does

not cause consistent losses, but if it becomes a problem, fruit

tumor may be controlled by careful picking and packing, and

ripening at 65° F.

(See 12J!t, U8.)

FUSARIUM ROT ' VrV^ V

Fusarium spp. , v.^'.-

Occurrence c»nd Importance

Fusarium rot occurs on tomatoes from all producing areas of

the country. It is most destructive on ripe tomatoes in the field,

and it may cause serious losses in the canning crop. The Fusarium

fungus is a weak pathogen and ordinarily does not cause much

loss in tomatoes harvested mature green. Only occasionally is the

rot found on tomatoes in the ripening room (pi. 4, A). During

1965, however, several shipments of tomatoes developed extensive

fusarium rot a few days after they were unloaded (pi. 4, B).

Losses up to 40 percent were recorded. It is believed that the

tomatoes were handled in some way that weakened them, but the

predisposing factors are unknown.

Symptoms

On vine-ripened fruits fusarium rot causes a slight water soaking, sinking, softening, and wrinkling of the affected tissues.

There may be one or more lesions per fruit. The early appear-
22 AGRICULTURE HANDBOOK 28, U.S. DEPT. OF AGRICULTURE

ance in the center of the lesion of a slightly raised, whitish or

pinkish mold mass is the most important diagnostic characteristic of this decay. Rapid progression of the decay results in complete destruction of the fruit within a few days.

The symptoms usually found in the ripening room on tomatoes

harvested at the mature-green stage differ somewhat from those

on vine-ripened fruits. The decayed area appears somewhat

water soaked. It gradually becomes slightly sunken, but it is quite

firm unless invaded by bacteria. A tuft of cottony-white mold is

usually present on the surface (PI. 4, A). Internally the decay

is a pale-brown, corelike mass that frequently can be lifted out

in a single piece. White mold may be present in the cavities of

the decayed tissues. The decay progresses at a moderate rate, and

the lesions are usually from % to 1^/^ inches in diameter.

Causal Factors . , ......

A number of different species of Fvsarium can cause the decay.

They are widely distributed in the soil and plant debris. Entrance to the fruit is through wounds, insect injuries, and lesions

caused by other diseases. Although most of the decay seen on the

market probably develops from incipient infections present at

the time of shipment, tomatoes may become infected in the ripening room. Spread from diseased to healthy tomatoes is unlikely

during transit. The causal fungi grow rapidly at temperatures

optimum for tomato ripening and cause maximum decay at

75° F.

Specific control measures are lacking. Careful handling of

fruits at all times and the culling out of tomatoes showing cracks,

injuries, or disease lesions are recommended.

(See Í 05.)

GHOST SPOT

.•*",:- <->'::j,;'-. Botrytis cinérea Fr. ,,. n'uvr- n'-\

Occurrence and Importance

The blemish known as ghost spot is found occasionally on tomatoes on the market, but it is seldom serious enough to be of

any consequence. This type of spot is found on tomatoes from

many regions and on greenhouse fruits as well as field-grovsm

fruits. .,.,., .., ., ,, .,,,.,. ^^^,, ,-,,....,.,.,, .V

Sympfoms

Ghost spot may occur anywhere on the surface of the fruit but

is most commonly seen near the calyx end. It is characterized by

a white circle, or ring, surrounding a green center (pi. 4, H).

These rings of light-colored tissue are only skin deep and usually

range from % to ^ inch in diameter. The inner part of the circle

is normal in color except there is often a very small brovoi speck

in the center, which resembles an insect sting. As the fruits ripen.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 23

the circles gradually become yellow. There are no silvery-white

pockets of spongy tissue underneath these spots as in cloudy

spot. Decay has never been observed to develop in spots of this

type. Affected fruits develop to normal size, shape, and background color, although the ghost spot lesion remains prominent.

Causal Factors

Ghost spot has been variously attributed to insect injury, lens

action of sunlight on water droplets, and Botrytis cinérea. Investigations in this country and abroad have established the latter

as the causal agent. Young, immature and mature-green fruits

are the most susceptible. Botrytis spores germinating on the surface of the fruits under cool, humid conditions penetrate the

epidermis creating a small brown necrotic speck. If the fruits are

then exposed to warm, sunny weather the sporeling dies. Toxic

materials released before its death, however, damage the surrounding cells sufficiently to create the halo characteristic of

ghost spot.

Control

Recommendations of the State agricultural extension service or

experiment station should be followed to prevent ghost spot in

the growing crop.

(See 1, 2U, 25, 33, 108, 151, 152.)

GRAY MOLD ROT

Botrytis cinérea Fr.

Occurrence and Importance

Gray mold rot is a fungus decay commonly found in market

tomatoes, but it is a problem only during cool, moist weather.

The decay occurs regularly in late-fall shipments from California

and during the winter on tomatoes shipped from Florida.

Symptoms

Lesions of gray mold rot on tomato fruits are conspicuous

spots that occur singly or severally anywhere over the surface

of the fruit, but they are most often found on the shoulder areas

adjacent to the stem scar. The affected areas may have a somewhat water-soaked appearance. The chief symptom of gray mold

rot, however, is the grayish-green (pi. 3, A) to grayish-brown

(pi. 3, B) color of the decayed spots. The advancing edges of

the lesions are regular and sharply defined.

The decay penetrates deeply and advances rapidly both on

green and ripe fruits. Affected tissues are moderately soft and

watery, although not so much so as those affected with rhizopus

rot. They may have an earthy odor.

A grayish mold may develop where the lesions have cracked or
24 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OP AGRICULTURE

it may develop sparingly over the surface at the center of the

more advanced spots. Under humid conditions the mold develops

a grayish or brownish-gray granular, velvety layer consisting of

innumerable tiny clusters of spores borne on short, upraised

filaments. . .. ,- .-,...-, ,, ,._ , ,,

Causal Factors

Gray mold rot is caused by Botrytis cinérea, a fungus that is

widely distributed and that attacks many kinds of fruits and

vegetables. As indicated by the name of the rot, the causal fungus

grows over the decayed areas in the form of a prominent gray

mold. The fungus can enter the tomato fruit through the unbroken skin or through cuts and cracks. Frequently it infects the

fruit at the edge of the stem scar. Growth of the pathogen and

development of the decay are most rapid at about 75° to 80° F.

Although development is less rapid at lower temperatures, the

fungus continues to develop even at 32°. Tomatoes that have

been exposed to moderately low temperatures for extended periods, either in the field or in transit, appear to be more susceptible to gray mold rot than those at normal temperatures. The

disease may therefore be more prevalent at or following moderately low temperatures than at temperatures of 75° to 80°,

which are optimum for the growth of the fungus.

Although the rot can spread from decayed to sound tomatoes

in the package, it is probable that most of the decay seen on the

market originated from infections occurring in the field or at the

time of harvesting and packing.

j

Control

During the season when gray mold rot is a problem, special

attention should be given to certain handling practices, including

proper temperature and humidity.

Mature-green tomatoes should be shipped at 55° to 65° F. On

arrival they should be unloaded and sorted promptly. Fruits

showing color should be held at somewhat lower (85 percent)

relative humidity than usual and all fruits should be ripened

promptly at about 70°. These handling practices will aid in reducing gray mold rot which might otherwise develop from spores

fji iiicipieiii/ line

(See 162.)

CLlUll.

bloru y,Ê-!"î 'c file

0 '.H:<'!:¿, b'-i;:í4líii -»ílT Tíí^^ír; ÍTt'í;'-

GROWTH CRACKS ^

Occurrence and importance

Growth cracks affect tomatoes wherever grown. Losses are

greater when tomatoes are ripened on the vine. On the market,

growth cracks detract from the appearance of the fruit and predispose it to decay.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 25

,;-a-T*i„ Ul ^if-i H-,-i t'î-A'jj' (-lö.-fAi-- « Symptoms nfni^.- "!*^t^JTÍ:;,íí'f T':. r-'r-:,''-!

As indicated by the name, the chief symptom of this injury is

rupture, or cracking, of the fruit about the stem end. Usually the

cracks radiate from the stem scar and extend well down over the

shoulders of the fruit (pi. 8, E) ; or they may develop in more or

less circular fashion around the shoulder area, frequently with

two or more cracks arranged concentrically (pi. 8, F). The cracks

may be shallow or may extend deep into the flesh. Concentric

cracks are usually shallower than radial cracks and are often

healed over by corky tissue. Slight to moderate radial cracks often

dry out and appear healed, but larger cracks are subject to decay.

Alternarla rot commonly develops in growth cracks.

The causes of growth cracks are not well understood. The injury is usually considered to occur most often where tomato

fruits have developed rapidly, particularly as they approached

maturity. Periods of abundant rainfall and high temperatures

favor rapid growth and seem to increase the damage from

growth cracks. Fruit that has reached the ripening stage during

dry weather may show considerable cracking if such conditions

are followed by heavy rains and high temperatures.

Although the handling incident to picking and packing niay

reopen old cracks, new growth cracks do not develop during

transit or on the market. Consequently, growth cracks found on

fruit in the market were present at the time of shipment, but decays that develop in the cracks may not have been evident at the

shipping point.

Control

During periods when cracking is serious tomatoes should not

be allowed to remain on the vine longer than necessary. Tomatoes showing grovrth cracks should be sorted out during packing.

Crack-resistant varieties may eventually replace susceptible

varieties. i KB í5snuj«:i3q«i»j m f '. a;.iiuj

(See 27, 35, 115, 165.)

^^ , ,,^^ HELM!NTHOSPORIUM ROT . . ,

Helnunthosponum carposaprum foliack

Occurrence ond Importance

Helminthosporium rot, a fungus disease of tomato fruits, has

not been found on tomatoes grown in the United States, but occasionally it is found by inspectors at ports of entry on tomatoes

imported from Mexico, Haiti, and British Guiana. The disease is

included in this publication not because of its importance but as

an aid to plant-quarantine inspectors in recognizing it.

M"* '•"• ^

Symptoms

Specimens of the rot intercepted at ports of entry are characterized by circular to irregular areas on the fruits, an inch or
26 AGRICULTURE HANDBOOK 2 8, U.S. DEFT. OF AGRICULTURE

less in diameter, sometimes covered by a dense weft of dark-gray

to almost black mycelium that completely obscures other characteristics of the rot spot.

Lesions produced on tomatoes by inoculation are flattened to

slightly sunken and circular at first but becoming irregular in

shape as the decay advances. Considerable variation is found in

the surface coloring of the lesions, but in general it is distinct

from other tomato rots. The tissue about the point of infection

is usually dark or black. The most variable character is the extent of the cream-colored area surrounding the dark center. The

cream color is nearly always present on infected fruits at temperatures of 60° to 80° F. This serves as a striking diagnostic

character when present (pi. 4, F). An area of dark reddish

brown often surrounds the cream-colored area. Occasionally

there are lesions that advance slowly at 70° in which the creamcolored area never develops. Such lesions resemble those caused

by Altemaria tennis (see Alternaria Rot). At lower temperatures,

especially at 50°, the spot is poorly defined; the fungus penetrates the tomato slowly, and at the end of a week the tissues

are not completely killed but have a bronzy appearance. When

this fruit is transferred to higher temperatures, the lesions gradually become like those developed at higher temperatures.

The rot consists of a firm, spongy mass of decayed tissues that

extend deeply into the fruit but cause no offensive odor. When

fruits with advanced decay are cut, dark-gray mycelium is evident through the necrotic tissue.

Causal Factors

The rot is caused by Helminthosporium carposaprum. This

fungus is able to penetrate only through wounds. Once infection

has occurred, the rot develops most rapidly at 70° to 80° F. Its

development is greatly retarded at temperatures below 60°, but

infection occurs at temperatures as low as 40°. ^nJfJíT.í '

s. 9í^8)

Control

The disease apparently does not occur extensively enough to

warrant special control measures.

(See «7.)

INTERNAL BROWNING COMPLEX

JO'i 353f(i> Occurrence and importance ¿jni 'leo-rt'Míí

Similar appearing disorders of tomato fruits have been described by research workers under such names as vascular browning, brown wall, internal browning, gray wall, cloud, and blotchy

ripening. Between 1949 and 1957 researchers attempted to show

that such diseases as gray wall, internal browning, and blotchy
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 27

ripening were distinct disorders. Between 1958 and 1965, however, because of the wide variety of causal factors reported and

the inability to distinguish between the various disorders on a

symptom basis, the tendency was to consider them as a group,

with perhaps certain reservations.

It seems logical to place internal browning, brown wall, vascular browning, gray wall (thin wall) of California, gray wall of

Florida, and blotchy ripening, which includes "cloud," in the

same group.

The disorder listed as blotchy ripening appears to be partly

influenced by localized high temperature injury (a kind of sunburn injury), which is not present in internal browning or the

so-called gray wall of tomatoes in Florida. Blotchy ripening accompanied by necrotic internal tissues, however, is difficult to

distinguish from the internal browning group.

Internal browning in some form probably occurs wherever tomatoes are grown and to some extent in most years. The disease

was first observed in Florida in 1927 and has caused very heavy

losses in certain years. Heavy losses have also been reported in

other States along the East Coast, and in greenhouse tomatoes

in Ohio. Internal browning is also a problem in Texas, Colorado,

and California.

Apparently all commercial varieties of tomatoes are susceptible

to the disease, but some varieties and breeding lines are much

more resistant than others. There seems little doubt that internal

browning is the most important physiological disease affecting

tomato fruits.

Fruits become predisposed to the disease while they are on the

vine. Ordinarily, the disease is readily visible at harvest and the

only subsequent change is that affected tissues may become more

sharply sunken. Occasionally, however, fruits may show little

evidence of the disease until they are in the ripening room. During ripening, affected areas may become more discolored and

sharply sunken. Diseased fruits may be either slightly or severely

blemished. Although slightly affected areas on tomatoes harvested

when mature green and ripened for fresh use may not cause rejection of the fruits, the blemishes will detract from their appearance and will cauge wastage in their preparation. Severely

blemished fruits are not marketable. The presence of the disease

in tomatoes grown for canning and processing is much more

serious, because all affected fruits must be discarded. The disease

does not cause a rot, but the dead tissue may be invaded by rotproducing organisms that bring about secondary decay.

\'',hA-^-. i»! UK'. -üíaíY ifii'f •yri'v Symptoms p-S-rrr^ i-.rr,,:,- nl

On green fruits, internal browning (including vascular browning, gray wall of Florida, and certain types of blotchy ripening)

appears externally as a grayish-brown discoloration, because the

brown internal tissues of the wall show through the healthy palegreen tissues and the skin. When the tissues are killed and the

brown color extends to the surface, the external appearance is
28 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OP AGRICULTURE

more brown than gray. On ripened fruits, the affected area

around the lesions may fail to develop a good red color and may

remain greemsn or yellow. The suriace color of the lesions on

ripened fruits is very much like that on green fruits. The inner

tissues of the fruit wall of the affected areas often appear somewhat bleached or whitish, especially on ripe fruits that are only

moderately affected.

Although fruits usually are affected more on the sides and

shoulders than elsewhere, in some severe cases the discolored

tissues extend from the stem scar to the blossom end. Generally,

only the outer wall is affected, but in some fruits the cross walls

and even the basal part of the seed-bearing tissues are affected.

On the surface the discolored areas appear as longitudinal, sunken streaks or as faint circular or irregular sunken areas (pi. 9, F

and H). The margins of the affected areas are indistinct. In mild

cases the surface is only slightly depressed ; in severe cases it is

sharply sunken, producing a lumpy or corrugated condition.

It is necessary to cut the fruits in cross section to examine

thoroughly the internal symptoms of the disease. In milder forms

of the disorder only the tissues around the vascular bundles are

dead and brown, but generally a larger part of the surrounding

tissues are affected and are brown, grayish brown, or somewhat

bleached. If the fruits are cut and the seeds and pulp removed, it

is evident that the vascular areas and the inner surface of the

wall are affected first and that the disease then progresses toward

the surface of the fruits. Severely affected fruits sometimes show

definite ring patterns on the inner surface of the outside wall as

well as irregular blotches and streaks with diffuse margins (pi.

9, G) ; or perhaps where tobacco mosaic virus is involved, the

entire inner surface of the fruit wall may be affected and brown.

The fact that internal browning appears first in the area of the

vascular bundles and on the inner surface of the tomato wall

distinguishes it readily from other tomato diseases. Late blight,

for example, always starts on the surface as a circular lesion and

penetrates into the fruit. (See Late Blight Rot, p. 30.) Doublevirus streak likewise develops on the surface, forming brown or

dark-brown streaks or angular spots that may or may not be

sunken. (See Virus Mottling, Double-Virus Streak, p. 49.)

Fruits may be affected at any size from ^^ inch in diameter up.

The disease may appear in a single fruit or a single cluster on a

plant; or all fruits may be affected. Ordinarily, the first tomatoes

showing internal browning are from the second or third picking.

Affected plants often seem to recover from the disorder and produce normal fruits from later blooms.

In some fruits the symptoms of blotchy ripening can be readily

included with those described above. Other fruits are not affected until they begin to ripen. In general, fruits with blotchy

ripening have hard, green, waxy or glassy areas. These areas

often occur around the stem end, but they may occur anywhere

on the fruits. Affected areas are slow to lose the green color
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 29

when the fruit ripens; they usually turn yellowish. Such areas

may or may not be accompanied by necrotic tissues.

« ."« Causal Factors ' •^ö

Many causal factors have been reported from studies on

vascular browning, blotchy ripening, gray wall, and internal

browning. Among these are rank vine growth, deep shade, high

humidity, high temperature, high transpiration rates and water

deficits, high soil moisture, low temperature, excess fertility, and

nutritional imbalance. In addition, certain more specific causes

have been advanced, such as tobacco mosaic virus, abnormal sugar

metabolism, and low nitrate/chloride ratios.

Perhaps because it is uncertain whether there is one or several disorders, no specific cause has been completely accepted.

The preponderance of evidence, however, indicates that the internal browning complex is basically a physiological disease. Research has clearly shown that tobacco mosaic virus alone does

not produce symptoms, but may increase the percentage of fruits

affected and intensify the symptoms if the virus is present in

plants also affected by other predisposing factors.

Research evidence is also being accumulated that shows that

susceptibility to internal browning may be due to a genetic factor

that allows some varieties to develop the disorder more readily

than others when exposed to predisposing conditions.

Since 1958 the thesis has been gaining acceptance that the internal browning disorder follows an interference in the conversion of starch to sugar in the leaves and the inadequate transport

of reducing sugars to the developing tomato fruits. Conditions

that affect the physiology adversely also interfere with normal

sugar metabolism. For example, it has been shown that the presence of tobacco mosaic virus or a deficiency of boron or potassium or shading the plants alters sugar metabolism. A disturbance

in sugar metabolism is therefore viewed as a result of the same

conditions that cause internal browning rather than its cause.

The disease may be viewed as a complex in which any one condition or a combination of certain conditions can cause the disorder. The loss of water from the fruits during periods of high

transpiration, especially because of an imbalance between tops

and roots, appears to be a basic factor, however, because many

of the predisposing factors reported would be activated by a

temporary water deficit.

. - . .- . , .í; Control . Ví''\::íM •■■-!.,MH-^t!..>-¡ ^íH' ;v:,,r

I,. ..-..-ri -..^-i. ,.,^- ... .,:„- ,«*;.,. .:«..,i,.,,„ /,,.,.-...,,-?

Recommendations of the State agricultural extension service or

experiment station should be followed to reduce internal browning.

(See 5, 6, 8, 9, 20, 21, 22, Al, U, -45, 50, 56, 67, 68, 97, 100,

101, 103, 125, 127, 129, 138, HI, H2, 157, 158.)
30 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OF AGRICULTURE

f 1 <? LATE BLIGHT ROT r

Phytophthora infestons (Mont.) DBy. ut^- ; íí; n

Occurrence and Importance

Late blight may occur in any region where tomatoes are grown

if weather conditions are favorable to the development of the

fungus that causes the disease. In many years the conditions are

favorable for late blight development in the tomato-producing

areas of California, Florida, and the Rio Grande Valley of Texas

during the fall, winter, or early-spring months. Late blight,

which is usually sporadic in occurrence, has been widely distributed and has caused serious losses in many localities in recent

years.

Symptoms

Typical late blight rot appears on the tomatoes as brown to

rusty-tan blotches without definite margins; it usually develops

in a circular pattern. The surface of the spots is pebbly to moderately roughened (pi. 2, A). Late blight rot is firm, but in the

advanced stages other rot-producing organisms may cause it to

become soft.

Although late blight rot often starts at the stem scar (pi. 2,

B), it can occur anywhere on the tomato fruit. In early stages

tissues affected by late blight, especially at the stem scar, appear

water soaked or greasy. Such spots generally involve only one

side of the fruit. In some fruits, however, the edge of the stem

scar is uniformly infected and the decay spreads over the shoulder area. The surface of alfected areas that start as watersoaked spots may remain smooth or may become irregular or

roughened as the decay advances. When the surface of the advanced spot is smooth, the marginal area usually remains greenish and water soaked while the central area becomes brown. It

is this phase of late blight rot that closely resembles buckeye

rot. (See Buckeye Rot.) Late blight spots, however, are rarely

zoned, and the margin of the spots nearly always shows a slightly

roughened or pebbly surface of a rusty-tan color characteristic

of late blight rot.

Other early stages of late blight rot appear as small, brown to

rusty-tan, irregularly shaped spots intermingled with the green

surface. Numerous small, slightly sunken areas soon develop on

the surface of the affected area, producing a mild pebbly or moderately roughened surface. As these spots enlarge they may retain the roughened surface or eventually most of the surface may

become smooth with only the margin remaining pebbly. The advanced spots vary considerably in color. They are usually darker

brown than early-stage spots, and the margin is usually flecked

with tan.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 31

The fungus Phytophthora infestans is the cause of late blight

on tomatoes and potatoes. The amount of damage caused is directly related to the weather conditions during, and a few weeks

before, harvest. Most serious losses occur during wet seasons

when the nights are cool (50° to 60° F.) and the days only moderately warm (60° to 70°). Mean daily temperatures above 75°

for 1 or 2 weeks check the disease. The spores of the fungus are

killed within a few days during dry weather when the temperature reaches 80° or above.

When late blight is present on the plants in the field it causes

a serious problem of unpredictable losses in tomatoes shipped to

market. Tomatoes harvested from fields where late blight is

prevalent may be infected and yet appear sound, because the

lesions have not developed enough to be visible. It is impossible

to sort out all of the infected fruits immediately after harvest, and

fruits with this latent infection may develop late blight after

being packed and shipped. The amount of late blight rot that

develops in tomatoes during transit or after reaching the market

varies with the severity of the leaf infection and the weather

conditions just previous to harvesting the fruits. It has been

found that nearly all infected tomatoes develop visible late blight

spots in 4 to 7 days, and only a small percentage of fruits develop the disease after that time. The size of the late blight rot

lesions found on tomatoes when they reach the market varies

considerably, but lesions measuring 1^/4 to 2 inches in diameter

have been found after 6 days in transit on tomatoes that appeared sound when shipped. Apparently there is very little spread

of late blight rot from one fruit to another either in transit or in

the ripening room.

Control • 1 Í

The prevention of late blight rot of the fruits depends upon the

control of the disease on the plants in the field. Recommendations

of the local agricultural experiment station should be followed.

Variations in weather conditions in the different tomato-growing

areas make it advisable for local investigators to determine the

need for spraying, the kind of spray to be used, and the time of

application.

When late blight is in the field, perhaps the most practical

way to salvage the crop is to hold the tomatoes for 4 to 7 days

after harvest to permit the late blight rot to develop so that the

diseased fruits can be sorted out before being packed.

Late blight rot cannot be controlled by manipulating temperatures in transit. Its development is somewhat delayed by temperatures of 55° F. or lower, but the rot resumes development

when the fruits are placed in the ripening room. Tomatoes show-
32 AGRICULTURE HANDBOOK 28, U.S. DEPT. OF AGRICULTURE

ing the disease on arrival at the market should be sorted out,

and only the fruits that seem sound should be placed in the ripening rooms. It is advisable to ripen the tomatoes at a temperature

of 65° to 70°. Late blight rot develops rapidly at these temperatures, and frequent sorting to eliminate the diseased fruits will

help in keeping out secondary decay such as bacterial soft rot.

(See 23, 27, 98, 122, UO.)

MECHANICAL INJURIES

Market tomatoes may be affected by a wide variety of blemishes, scars, discolorations, and disfigurations resulting from mechanical injuries of various sorts. Dark-brown or black, sunken

areas over the shoulders are one of the most common types of

injury. These are often referred to as shoulder scars. The abra^

sive action produced by rubbing the shoulders of tomatoes

against a rough board or the grading belt in the packing shed

will cause this type of injury (pi. 8, G). A high percentage of

similar shoulder injuries results when tomatoes that are in contact with rough unlined field boxes are hauled for some distance

over unpaved roads. Similar injuries are produced elsewhere on

the fruits. The abrasive action of sand adhering to the tomato

may also be responsible for minute scratches in the skin that

later develop into sunken pits or spots.

Unfortunately, the prevalence of mechanical injuries is usually

not apparent when the tomatoes are packed. After they have been

packed and shipped, however, the injured areas dry out, shrivel,

and discolor, forming conspicuous pits and spots. Alternarla rot,

phoma rot, and other decays frequently develop in such injuries.

Punctures and rim cuts are other forms of mechanical injuries

that are usually followed by decay.

Bruising, in which the skin is not broken, is also a serious kind

of mechanical injury. Bruising injury is cumulative and unless

the fruits are pressed out of shape the damage is mostly obscured. Bruising injury may be caused by fixed pressure and by

strong shocks or repeated impacts.

Green tomatoes under fixed pressure for 5 days or longer are

permanently pressed out of shape and the internal tissues may

be dry or stringy (pi. 9, C). The gelatinous tissues of tomatoes

that are ripening when subjected to strong shocks or repeated

impacts may be seriously damaged. The affected gel either becomes cloudy (pi. 9, D) or in more seriously affected fruits the

gel tissues break down and spill out when the fruits are cut.

Handle tomatoes as carefully as possible at all times. Keep

field boxes and picking containers free of sand and dirt. Avoid

overfilling and careless stacking of all containers. Keep handling

operations to a minimum during ripening. Avoid tossing and

dropping tomatoes during sorting.

(See A6, 78, 79, 8A, 96, 102.)
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 33

NAiLHEAD SPOT ^ -... ,

AÜernaria tomato ( Cke. ) Brinkman

?3t u Occurrence ond Importance

Nailhead spot of tomatoes is a fine example of a disease that

has been almost completely eliminated from domestic commercial

shipments of mature-green tomatoes by the use of resistant varieties. This disease at one time caused serious blemishes on tomatoes grown in Florida and other Gulf Coast States, but in recent

years it has been of no importance at the market, except in a

few shipments of tomatoes received from Mexico.

Symptoms ..,

Nailhead spot acquires its name from the characteristic small,

circular, slightly sunken, tan to brown superficial spots produced

on the fruit (pis. 5, C and 6, A). In the early stages the spots

are tan and fiat and can be identified by the time they reach a

diameter ranging from Ke to % inch. The margins become more

definite and dark brown to black as the spots enlarge, and the

centers change to grayish brown and become definitely sunken

(pis. 5, D, and 6, B). On tomatoes on the market nailhead spots

range in size from Ke to % inch in diameter, the average being

usually less than ^4 inch. In ripe and turning fruit the older

lesions are sometimes surrounded by a halo of green tissue. Typical nailhead spots are shallow blemishes that seldom penetrate

the wall of the fruit, but in some fruits these spots are invaded

by Altemaria tennis and CUtdosporium herbarum and the resulting decay may extend into the seed cavity. This is likely to occur

during long transit periods or in the ripening rooms when the

tomatoes do not ripen promptly.

Nailhead spot can be distinguished from bacterial spot by the

fact that the lesions are fiat or sunken, that they continue to enlarge after packing, and that the enlarged areas are brown and

have definite margins. Bacterial spot is usually raised and scablike, and the margin is narrow, brown, and feathered. Even when

the bacterial spots have become sunken (pi. 6, D), they never

develop the broad band of brown.

Causal Factors

The fungus {Altemaria tomato) that causes nailhead spot

lives from season to season on plant debris, on volunteer plants

in the field, on related crop plants, or on weeds. It produces

spores on the tomato plants in the field that are readily disseminated by winds, water, insects, and field workers. The optimum temperature for spore germination is believed to be near

80° F. The minimum temperature for growth of the fungus on

culture media is about 41° ; the optimum is between 75° and 80° ;

and the maximum is about 93°. Under moderate temperature and

moisture conditions the spores are able to germinate and infect
34 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OP AGRICULTURE

uninjured immature-green fruit. Most infections take place in

the field before the fruit reaches a diameter of 2 inches, but new

infections may take place in fruits of any marketable size. The

rate of development of nailhead spots is most rapid in green

tomatoes; it decreases as the fruits mature. Nailhead spots that

are present on tomatoes at shipping time may enlarge to some

extent during transit. Experimental evidence indicates that spots

He inch in diameter and smaller usually almost double in size

during 6 days in transit. The larger spots up to % inch in

diameter enlarge very little during the usual transit period unless they are invaded by secondary organisms.

Control

The best control of nailhead spot is obtained by planting resistant varieties. Tomatoes with nailhead spots should be discarded at the time of packing to avoid the development of

secondary rots.

(See 110, 120, 15Jt.) :i y ,.

., PHOMA ROT ., ' ,

\_^: Phoma destructiva Plowr.

Occurrence and Importance

Phoma rot is primarily a transit and market decay. Until

about 1950, it was one of the most serious diseases of tomatoes

after harvest. It occurred on tomatoes from many Eastern,

Southern, and Gulf Coast States, but it was particularly widespread on the winter-grown southern crop. Serious losses frequently occurred in tomatoes from Florida and Mississippi and

also in those shipped into the United States from islands of the

West Indies. It was not found on tomatoes shipped from California or Mexico. At present (1966), the disease is rarely seen

on the domestic crop during marketing.

Symptoms

The first symptom of phoma rot on tomato fruit is tjTDically

the appearance of one or several small, slightly sunken brownish

spots at the edge of the stem scar (pi. 1, D). As the spots enlarge they extend somewhat radially over the shoulder of the

tomato and become circular or elliptical. The centers of the spots

turn brownish black and become dotted with tiny, raised brownish-black fruiting bodies, or pycnidia, of the causal fungus (pi. 1,

E).

The lesions may also occur at growth cracks, mechanical injuries, or under certain conditions the fungus may enter through

the unbroken skin. While they occur more often at the stem end,

they may occur anywhere on the tomato. The decay advances

more rapidly on turning and ripe fruits than on green ones. On

riper fruits the spots are somewhat water soaked and are slightly
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 35

sunken. By the time the lesions reach a diameter of y^ inch much

of the sunken area is black, leathery, and firm and dotted with

black pycnidia. The borders of the lesions are light brown and

water soaked. In a humid atmosphere white, slimy spore masses

may ooze out of the pycnidia. At times, the dry, crustlike center

of the lesion cracks, and the grayish-white mycelium develops

in the crevices.

Phoma rot penetrates deep into the pulp of the tomato. The affected internal tissues are brown or black and remain firm until

the spots become very large or are infected with secondary

organisms.

The symptoms of phoma rot are almost identical with those of

pleospora rot. However, tomatoes reaching the market from

California and Mexico, where pleospora rot is found chiefly, seldom if ever have phoma rot. The presence of the fungus fruiting

bodies distinguishes phoma rot from alternarla rot, which it

closely resembles otherwise.

The fungus causing phoma rot also produces a leaf spotting

in the field.

Causal Factors

Phoma rot is caused by the fungus Phoma destructiva. The

disease is most prevalent during seasons of moderate temperatures and high relative humidities. Great quantities of spores are

exuded during wet weather from the fungus fruiting bodies

(pycnidia) that develop on diseased leaves. These spores are

washed onto the surface of the fruit by rain or spread by field

operations when the leaves are wet with dew. Upon germination

of the spores, the fungus enters the fruit through stem scars and

through cracks or other wounds and injuries. The fungus may

become established in the tissues of the stem scar of tomatoes that

have no visible skin blemishes. Since it takes several days after

inoculation before the lesion becomes visible, tomatoes inoculated

in the field shortly before picking appear sound at the time of

shipping. The fruits are also readily inoculated at the stem scar

and elsewhere during picking and packing operations. Ordinarily,

much or most of the phoma rot found in tomato shipments when

they arrive on the market or in the ripening rooms was not visible when the tomatoes were packed and shipped. There is little

or no spread of the rot from diseased to healthy tomatoes during

transit or on the market.

Growth of the fungus and the development of decay can take

place over a wide temperature range. The most favorable temperature for both is around 70° F., and there is little development

of either below about 45°. When tomatoes are delayed in ripening at temperatures of 50° to 55°, however, the rot, although

developing more slowly, may become more prevalent and thus

may cause more loss than in tomatoes ripened promptly. Phoma

rot may be worse on tomatoes harvested after extended periods of

rain.

The decay progresses much more rapidly on ripe than on green

fruits.
36 AGRICULTURE HANDBOOK 28, U.S. DEPT. OF AGRICULTURE

' "; ..- •¡::'ii . ' "U \-jJ'ja:!i:A Control : ' ;^JT •^n:.: j-rO \>i , -v, ¡.s.

The leaf-spot phase of the phoma disease must be controlled in

the field if the fruit rot is to be prevented. The scarcity of the

decay on tomatoes during marketing is probably due to the effective fungicides used in the field.

If phoma rot becomes a problem, the follovdng precautionary

measures virill be useful. Tomatoes should not be picked while

the plants are vs^et. They should be handled carefully during picking and packing. Particular care should be taken to avoid sand

scarring and shoulder scarring by dirty or rough picking containers and field crates. Tomatoes shovi^ing cracks and injuries

should not be packed, particularly during seasons when phoma

rot is prevalent on the market. The tomatoes should be ripened

promptly and chilling temperatures should be avoided.

For field control follow the recommendations of the State

agricultural extension service or experiment station.

^ (See 61, lOi, 105, lU, lU.) „.....,, ,,.._... ...„,.., ,„ .

' ï-,i, : . . --' .

PHOMOPSIS ROT

.:.--.• Diaporthe phaseolorum (Cke. & Ell.) Sacc. í-í;J '

ü; -i' var. sojae (Lehman) Wehm.

' ' i '< ..u, ,. Occurrence and Importance " '

Phomopsis rot is a decay of minor importance that has been

reported on tomatoes from New York, Hawaii, and a number of

South Atlantic and Gulf Coast States. It has been reported also

on tomatoes from Mexico, the West Indies, and Southern Rhodesia.

o^.u-Á^,'^ni, .-, Symptoms -n .......v., ! .,>^^:!„- .,;

The first symptom of phomopsis rot is a somewhat soft and

water-soaked lesion that may occur anywhere on the fruit. Usually, there is but a single lesion on a tomato. At moderate temperatures the lesions enlarge rather rapidly and eventually

involve the entire fruit. As the lesions enlarge, the tissues in the

center turn brown to dark brown and become very firm. Older

lesions are firm over much of their area and nearly black at the

center. At this stage the dark pimplelike pycnidia, or fruiting

bodies, of the causal fungus break through the epidermis and

become conspicuous at the center of the lesion. Further development of great masses of these bodies gives the lesion a rough,

blackened appearance (pi. 4, C).

The lesions of phomopsis rot are at first smooth and very turgid. Later, the affected tissues wrinkle, shrivel, and crack.

The most prominent internal symptom is a firm spongy "core"

that is composed of decayed flesh profusely permeated with the

causal fungus. The core extends well into the tomato at the center of the lesion.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 37

Causal Factors

As indicated by the name, the decay is caused by a species of

Phomopsis. It is an imperfect (asexual) stage of the fungus

Diaporthe phaseolorum var. sojae (the sexual stage). The leaves,

stems and fruits are attacked in the field, but a blemish or wound

is needed for infection after harvest. Phomopsis grows best and

the decay advances most rapidly at temperatures of 80° to 85° F.

Little growth and decay takes place at 40° to 45°.

Control

Elimination of fruits with scars, cuts, and other blemishes

is important in the control of phomopsis rot. There would probably be little development of the decay at the recommended

transit temperature range of 55° to 65°.

(See 18, 51, 77, 160.)

PHYTOPHTHORA ROT

Phytophthora sp.

A tomato fruit rot caused by a species of Phytophthora has

recently been observed in the market on California- and Mexicangrown tomatoes. The rot occurs both on mature-green and ripening fruits.

The symptoms are distinct from those of late blight and buckeye rots. Affected areas are firm and water soaked and show

little external or internal discoloration. In advanced stages the

decayed surface develops an appressed, white mold (pi. 2, G),

which is tough and may become wet. The decayed area finally

becomes wrinkled.

Similar symptoms on Mexican tomatoes have been attributed to

P. mexicana. It is debatable, however, whether this is a valid

species. One investigator has found P. mexicana not sufficiently

distinct from P. erythroseptica to stand as a separate species.

Another investigator would make P. mexicana a synonym of P.

parisitica. More work is needed to resolve this question.

The rot on the tomatoes in question has a striking resemblance

to that on bell peppers caused by P. capsici. Since P. capsici has

been reported on tomatoes in Colorado, it is entirely possible that

the California and Mexican rot is due to the same species.

This is a field disease and the recommendations of the State

agricultural extension service or experiment station should be

followed for control.

(See 58, 69, 72, 73, H9.)

PLEOSPORA ROT

Pleospora lycopersici El. & Em. Marchai

Occurrence and Importance

Pleospora rot of tomatoes was first observed in California shipments in November 1919. Since that time the disease frequently
38 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OF AGRICULTURE

has been observed on the eastern and middle-western markets. It

has often caused serious loss in shipments of California tomatoes

during November and December and in winter shipments from

Mexico. So far, the disease has not been observed in tomatoes

from other areas or in other seasons of the year. In some seasons

carlots of tomatoes on the eastern markets have shown an average of 50 percent of the stock aifected with pleospora rot. Usually, mature tomatoes of good quality ripen during transit or

soon enough after arrival to escape great loss. But immature and

poor-quality stock that ripens slowly and has to be held for more

than a week for ripening is subject to very heavy decay by this

disease.

Symptoms

Small, brown, oval spots at the edge of the stem scar or in

mechanical injuries on the fruit are the first visible signs of

pleospora rot. These lesions appear somewhat similar to phoma

rot. But as they enlarge the brown color is retained and usually

a small amount of gray or grayish-brown mycelium is noticeable,

whereas in typical phoma rot lesions of the same size the affected

tissues are black and there is no visible surface mold. Decayed

areas '/^ inch or more in diameter generally have black pimplelike perithecia at the center (pi. 1, F). The presence of these

black fruiting bodies is one of the best diagnostic characters of

this disease. In the absence of these fruiting bodies, it is impossible

to determine without microscopic or cultural studies whether the

decay is pleospora rot or alternaría rot. (See Alternaría Rot.)

Under humid conditions there is usually a development of mold

over the lesions. This grayish-brown mold is the Stemphylium

stage Pleospora, and in mass it resembles Altemaria. Alternaria

rot may occur wherever tomatoes are grown, whereas pleospora

rot has been found only on tomatoes from California and Mexico.

Consequently, if the black, pimplelike fruiting bodies are absent

and the disease cannot be positively identified, it is usually advisable to call all decays of this nature alternarla rot.

Pleospora rot is inconspicuous in the tomatoes at packing time,

but it is believed that the initial infection at the edge of the stem

scar commonly occurs in the field, as tomatoes arriving on the

market after a 5- to 8-day transit period often show large lesions.

Causal Factors

Pleospora rot is caused by the fungus Pleospora lycopersici,

which apparently is prevalent in the tomato fields along the

coastal areas of California and Mexico. No studies have been

made of the development and spread of pleospora rot in the field,

and consequently no data are at hand regarding its prevalence on

tomato plants.

Pleospora rot develops slowly during the first 3 or 4 days in

transit while the tomatoes are green, but as they ripen it progresses more rapidly. Spots % to % inch in diameter may de-
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 39

velop during transit. Greenish-brown to brown, moderately firm,

decayed areas involving a fourth of the fruit may develop in

ripening tomatoes within 10 days after shipment.

Moisture seems to be one of the most important factors favoring infection of tomato fruits, as the seasons when this decay

becomes most serious are those when foggy weather prevails or

when rains keep the plants wet for several hours. The night

temperatures at this time often drop to 55° to 60° F. or lower

and the daytime temperatures are generally below 80°. Although

tests have not been made, the decay may also be inñuenced by

field chilling. The most rapid development of decay is between

65° and 70°. Temperatures higher than 80° are unfavorable to

the growth of Pleospora. Experimental evidence indicates that

the decay that develops during transit is the result of infections

of the fruit that occur in the field and during harvesting and

packing. No significant spread of the fungus to sound neighboring fruit in the package has been observed.

Control

Care should be exercised that tomatoes with infections at the

stem scar are discarded when grading the fruit. During November and December in California, only the most mature and best

fruit should be packed for shipment to the eastern markets. During January, Mexican tomatoes should also be graded closely for

maturity and quality, as practically all shipments of these tomatoes are for distant markets.

(See 119.) _ ,

¡w PUFFINESS

;-ii

' Occurrence and Importance ^"^ , ' ' '"'' "

'''' í;.:-.."5UJíiín Hü

Pufiîness, or pockets, is a physiological trouble of tomato fruits.

It may occur on tomatoes that are grown anywhere, but it is

most prevalent in crops grown during the winter and early

spring. It causes considerable loss in tomatoes grown in California, Florida, Mississippi, and Texas. The condition develops

entirely in the field, usually at an early stage in the growth of

the fruits. Seriously affected fruits are unmarketable and slightly

affected fruits have reduced market quality.

Symptoms

Puffy tomatoes are easily detected because they feel hollow and

are light in weight. The surface is usually flattened or sunken in

the areas between the internal cross walls. Less severely affected

fruits may be of normal shape. When puffy fruits are cut, large

air spaces are found in the cavities normally occupied by the

seed-bearing tissues (pi. 8, H). No decay or discoloration follows

as a result of puffiness.
40 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OF AGRICULTURE

.'—•^ •''- * ---•- ' '- - Causal Factors "''" il-- -> .. -

PufRness in tomatoes apparently is caused by environmental

and nutritional conditions that interfere with normal pollination

and thus affect the later development of the seed-bearing tissues.

Normal pollination is adversely affected by temperatures above

100° F. and below^ 60°. Extremes such as excessive soil moisture

or drought may also interfere with the normal development of

the seed-bearing tissues. Unbalanced nutritional conditions created by heavy applications of nitrogen are thought to favor the

development of puffiness. ,1.^!

viJß- ujfcivTi ;/:;. Control J

Because weather conditions are largely responsible for causing

puffiness, definite control measures cannot be recommended. The

adequate use of superphosphate together with moderate amounts

of nitrogen may be of some value in reducing puffiness.

(See 34, 164, 165.)

? PYTHIUM ROT h iiiU'>ii;î.' «'1.. sjo rf'í

iifji Ml!,! ifir Pythium sp. ; 0 .îi;t'XÎ,î;'.,'y.;;!

Pythium rot at times has caused serious losses in tomatoes

grown along the east coast during hot, wet weather. The species

of Pythium that causes the rot was not identified, and the distribution of the fungus in the United States is unknown.

A tomato fruit rot caused by P. aphanidermatum (Edson)

Fitz. has been reported from Japan, South Africa, and Honduras.

The tomato fruit rot in the United States occurs in the same area

where P. aphanidermatum causes cottony leak of certain vegetables, and this species may be the cause of the tomato rot.

On mature-green tomatoes the rot appears as an extensive,

firm water-soaked area (pi. 2, H) that may eventually involve

the entire fruit.

No control has been developed for this rot. Careful sorting will

help to hold down decay at the market, but decay may develop

from infections that were invisible at time of packing.

RHIZOPUS ROT i > t

Rhizopus stolonifer (Fr. ) Ehr.

Occurrence and Importance

Rhizopus rot is a fungus disease that may occur on tomatoes

from any region. It may affect them when they are ripening or

ripe either in transit or in the ripening room; it has been observed to cause serious losses in tomatoes shipped some distance

after being prepackaged in consumer units. Occasionally it affects green fruits. Fruits affected with this decay are a total loss.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 41

.: '.. ^■■- ,-..i «.«•,->•,.•; \'.^ Symptoms !.>'-.,:>a- •,,-¡,;,-.i ?. ;.'n,;»»i:.

The symptoms of rhizopus rot are generally quite characteristic and distinct from those of other tomato-fruit rots. The lesions are usually large, with the affected areas at first somewhat

distended. There is no discoloration, and the soft consistency of

the rot gives it a water-soaked appearance as seen through the

distended red skin (pi. 3, E). The rot develops deeply and rapidly

and soon affects the entire fruit. If infection takes place through

a slight wound, the skin may remain intact after decay is complete, without any external signs of mold. Frequently, however,

the total decay causes the fruit to split open and to collapse into

a wrinkled, soft, water-soaked, formless mass that is overrun by

the causal fungus. The gray appearance of the coarse mold, because of the presence of a mixture of raised, immature white and

mature black spore heads, is a characteristic symptom.

The presence of coarse mold filaments on the surface (pi. 3,

F) or within the diseased tissues, along with external evidence

of mold at skin breaks, serves to distinguish rhizopus rot from

bacterial soft rot. Also, the diseased tissues tend to hold together, particularly in early stages, even though very soft,

whereas the tissues affected by bacterial soft rot disintegrate

comoletely. Fruits decayed with rhizopus rot have a slight fermented odor rather than the putrid odor that characterizes bacterial soft rot.

Causal Factors

The cause of rhizopus rot is Rhizopiis stolonifer, a fungus that

is responsible for serious decays of a number of different fruits

and vegetables. Undoubtedly, other species of Rhizoptis may at

times be involved as causal agents.

The mycelium, or mold, of Rhizopus consists of coarse, whitish

threads. As indicated above, the fungus fruiting bodies, in

which innumerable spores are produced, are tiny, black, spherical bodies borne on raised stalks.

Rhizopus is widely distributed. It grows on plant debris and

there are numerous spores of this fungus in the air. Infection

usually occurs through wounds and other skin breaks. This fungus is also spread by the fruit fly (Drosophila melanogaster),

which lays its eggs in the growth cracks on tomato fruits. It is

commonly observed that the decay spreads during transit and in

the ripening room by contact between decaying tomatoes and

sound fruit that is ripening or ripe, even though no visible skin

breaks are evident.

R. stolonifer grows best and the decay advances most rapidly

at temperatures of about 75° to 80° F. The rate of development

falls rapidly with a decrease in temperature to near 50°.

Control

RhizoDus rot can be reduced by careful handling to prevent

mechanical injury, by eliminating fruits with serious growth
42 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OF AGRICULTURE

cracks or other injuries at the time of grading, by coohng the

load to about 55° to 65° F. as soon as possible in transit, and by

sanitary practices in the packinghouses, in the canneries, and in

the ripening room.

(See 3, 16.)

RING ROT ''':i:l ']:^; ¡r7[

Myrothecium sp.

Ring rot, formerly known as melanconium ring rot, is a fungus

decay that has occasionally affected market tomatoes from Mexico and certain islands of the West Indies. It has also been reported from Texas and on greenhouse-grown tomatoes in Ohio

and Wisconsin. The disease has not been a problem, however,

since 1955.

The decay is evident as large, conspicuous, sharply defined, circular to oval, flattened lesions. One or several lesions may occur

on a fruit. The affected tissues are brown to black. The decay

penetrates deeply into the fruits, and the affected tissues can be

removed readily as a single firm, spongy lump that separates easily

from the healthy tissues. The most characteristic sign of the disease is the presence over the lesions of the spore masses of the

causal fungus, Myrothecium sp., which develop in narrow concentric bands of alternating black spore masses and white mold

(Pl. 4, G).

Under moist conditions the spores germinate within a few

hours at about 70° to 80° F. and are capable of infecting both

green and ripe fruits through wounds. The most favorable temperature for growth of the pathogen and for development of the

decay is 80°. The decay advances faster in ripe than in green

fruits. Little advance occurs below a range of 35° to 40°. Although the decay is not known to spread from fruit to fruit

during transit, individual lesions will continue to enlarge at temperatures above 35° to 40°.

(See 105, 137, 145.) ,, „ ,

i ;; SCLEROTIUM ROT ^ ""

. '' ' ' Sclerotium rolfsii Sacc.

Occurrence and Importance

Sclerotium rot, or southern blight, is a fungus disease that affects a wide variety of vegetable and ornamental plants in the

Southern States. Tomatoes shipped to market from these areas

are affected occasionally with this decay, although it is seldom of

much importance as a cause of transit and market losses.

Symptoms

The decayed areas of the fruit are somewhat yellowish and

slightly sunken. When the spots reach a diameter of about i/^

to % inch the skin over them cracks. At moderate temperatures
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 43

the decay advances rapidly, penetrates deeply, and may rot the

entire fruit. Affected tissues are mushy soft and have a recognizable odor that resembles that of fresh, uncooked mushrooms.

Under moist conditions the causal fungus grows out over the

collapsing, decayed tissues in the form of an abundant, silky,

white mold in which coarse strands are conspicuous. Characteristically, the mold spreads fanlike at the outer limits of growth.

The resting bodies, or sclerotia, of the fungus soon develop

abundantly in the mold, first appearing as small, whitish tufts

that later become smooth, distinct, light-brown bodies about the

size of a mustard or cabbage seed. ..^f^ ,j¡„ . ^, i;..p

;->ft-:.. v."-.-!";,^, Causal Factors ,.'^H-:.^--- ii' ; '

The decay is caused by a soil-inhabiting fungus, Sclerotium

rolfsii, which is widely distributed through the southern United

States. It attacks tomato plants in the field with the result that

the outer tissues of the stems decay at or near the soil line and

the plants wilt and eventually die. The characteristic mold and

sclerotia becomes conspicuous over the decaying stems.

Tomato fruits may become infected by contact with the ground

or by becoming spattered with infested soil. The fungus is able

to penetrate the skin, so wounds or cracks are not necessary for

its entrance into the fruit. Practically all of this decay found on

the market probably arises through infections that occurred in

the field. The causal fungus is a high-temperature organism that

grows most rapidly at about 85° to 95° F. It develops relatively

slowly below 68°.

Control ' -'í-ji:¡ -- fíy..'x.

Control of the decay in transit or on the market depends primarily upon control of the disease in the field. Careful sorting

of the tomatoes at time of grading and packing to eliminate

fruits showing initial spots of decay is also quite important.

(See 27, 156, 165.)

.;• h* n SKIN CHECKS f-«=;

Tomatoes are found occasionally on the market with numerous tiny cracks in the waxy coating (cuticle) over the skin. These

commonly are referred to as skin checks or cuticle cracks. They

frequently occur in great numbers over the shoulders as short

segments of circles arranged concentrically around the stem scar.

They may, however, occur anywhere on the fruit. The cracks are

shallow, well healed, and somewhat darkened and for the most

part are important only as blemishes that mar the appearance of

the tomatoes. Where skin checks are numerous loss of moisture is

rapid, and serious shriveling and discoloration follow.

Skin checks are visible at the time of packing, but they may

become more conspicuous during transit and marketing because

of drying out and discoloration.
44 AGRICULTURE HANDBOOK 28, U.S. DEPT. OP AGRICULTURE

The cause of skin checks is not well understood. They probably result from fluctuations of temperature and of moisture in

the form of rainfall and dew.

(See 156, 166.) mausii» funi ^.mnjimio'j .;;íIC?;í! ■■¡. ¡[:{.\J

'•ÍWO'ííi '"^O SäJi-r 9\JH. K\Jt . , j^ ,j,i ; -fain-! -

goievab nw>ii s Rhizoctonia solani Kuehn „^ -nilgs-i í--r

Occurrence and Importance

iSoil rot is a fungus disease of tomato fruits that may occur

anywhere tomatoes are grown, provided weather conditions are

favorable. It is particularly important as a disease on tomatoes

from Florida, Mississippi, California, Texas, Cuba, and Mexico

that are harvested in a mature-green stage.

Symptoms

Soil rot develops on both green and ripe fruits. On green tomatoes in the field the first visible symptoms of soil rot are small,

circular, brown spots on the lower half of the fruits. Spots ^4 of

an inch in diameter and larger usually show very definite concentric-ring markings made up of alternating zones of light- and

dark-brown tissues (pi. 2, E). As the fruits ripen and the decayed areas enlarge, the concentric zones become less evident and

may even disappear. Affected tomatoes, therefore, do not always

show zoned markings when they reach the market. On ripe fruits

the spots are moderately firm and reddish brown, bordered by

reddish-brown water-soaked areas.

Green tomatoes shipped in bulk from Florida have been observed to be affected with soil rot on the market. Such fruits

showed spots that were % inch or more in diameter and had a

uniform dark-brown color (pi. 2, F).

Typical spots are firm when less than an inch in diameter and

have a definite margin and flattened surface. The skin over the

affected areas is often split.

The definite margin, flattened surface, and—when present—

the narrow, fairly regular concentric-zone markings, and the

cracked skin on the decayed spots distinguish this disease readily

from buckeye rot. (See Buckeye Rot.)

Causal Factors

Soil rot is caused by Rhizoctonia solani, which is a soil-inhabiting fungus that attacks not only the tomato but a wide variety

of other plants as well. The amount of damage to tomatoes during any one season depends upon weather conditions. If the surface soil is wet and the plants are large enough to cover the

ground and maintain a high degree of humidity underneath the

vines, the fungus may attack any or all of the tomatoes that come

in contact with the soil or that become spattered with soil during

heavy rains. Tomatoes shipped from wet fields where the disease
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 45

was abundant have been found to be as much as 60 percent infected with soil rot when cars were unloaded at the market.

Growth of the pathogen and development of the decay are

rapid at temperatures favorable for good tomato ripening. The

optimum temperature for the fungus and decay is 75° to 80° F.

There is little decay by Rhizoctonia below about 50°.

Tests have shown that the fungus can enter tomato fruits

through an apparently sound epidermis, although in about half

the cases the organism enters through wounds or stem and blossom scars. Soil rot may develop during transit in tomatoes that

were infected in the field but that showed no evidence of decay

when shipped. Such lesions, developing during a 5-day transit

period, may reach a diameter of % inch, and as many as 10

percent of the tomatoes may be affected. Small lesions, present

at the time of shipment but overlooked during grading and packing, may attain a diameter of % inch during a 5-day transit

period and an inch or more during 7 days.

Control

The only way to control soil rot is to stake the tomato vines so

that the fruit will not hang near or touch the soil. When this

disease is extremely prevalent in the field it is sometimes advisable to stop packing tomatoes for a few days so the infected

fruits may decay or develop spots large enough to be recognized ;

then the infected fruits can be sorted out before packing.

(See U, 105, 121, 156.) ' " . - ' - "' • ^ • " ;. "

SOUR ROT

Geotrichum candidum Pers. emend. Carmichael

.,iir.;l''9a; 'JKy/k Occurrence and Importance

Sour rot (also known as oospora rot and watery rot) is a common decay of tomatoes. It occurs wherever tomatoes are grown

and is equally important on mature-green and cannery tomatoes.

It is regularly found affecting tomatoes in transit and on the

market.

Symptoms

On green fruits sour rot lesions have a dull, greasy, watersoaked to bleached appearance (pi. 3, C). Although the decay

may originate at cracks, cuts, or skin punctures, it frequently

starts at the edge of the stem scar. From there, the decay may

extend in a sector over the shoulder and down toward the blossom end of the tomato, or it may develop all around the stem

scar and progress uniformly out over the shoulder area. The

affected tissues remain fairly firm until the decay is quite advanced; they have a pickled appearance and a definite sour odor.

Affected fruits either in transit or in the ripening rooms may
46 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OF AGRICULTURE

show a dingy white, scumlike growth of the causal fungus in the

stem scar or at points where the skin is broken.

Sour rot lesions on ripe or ripening fruits appear quite different from those on green fruits. The decay progresses rapidly,

and the affected tissues are soft and water-soaked in appearance.

The skin frequently cracks over the affected area and is usually

filled with a white, cheesy, or scumlike development of the fungus

(pi. 3, D). Bacterial soft rot often follows sour rot, hastening the

decomposition of the fruit and altering considerably the fermented odor characteristic of sour rot.

Causal Factors

Sour rot is caused by the fungus Geotrichum candidum, which

was formerly named Oospora lactis f. parasítica. This fungus is

widely distributed in soils and on decaying fruits and vegetables.

Most of the decay originates from infections in the field. Vinegar

flies (Drosophila melanogaster) carry spores and mycelial fragments on their bodies from decaying fruits to growth cracks and

wounds in healthy fruits, especially on canning stock when feeding and depositing eggs. Spores and fragments of the fungus

thread also are spread by splashing rain and during picking and

packing.

The fungus cannot enter through the unbroken skin ; therefore,

infections usually occur at stem scars, skin cracks, cuts and

punctures of various sorts, and in green fruits that have been

chilled for 7 to 10 days at 32° to 40° F.

The minimum temperature for germination of spores, growth

of the fungus in culture, and infection of tomato fruits is approximately 36° F., the optimum is 86°, and the maximum is

101°

Control

Sour rot can be reduced by careful handling to avoid mechanical injury, eliminating tomatoes with growth cracks at time

of packing, avoiding tomatoes that have been chilled in the field,

and reducing the temperature of the load to 55° to 60° F. as

soon as possible.

(See 13, H, 15, 16, 17, 113, 116.)

SUNSCALD

Sunscald may occur in any tomato-growing region if green

fruits are suddenly exposed to the sun. The extent of the injury

is more serious during periods of abnormally high temperatures.

Fruits most subject to sunscald are those that have been exposed

suddenly to the sun because of pruning, natural spreading of the

plant caused by the load of fruits, or loss of foliage from leafspotting diseases or because the plants have been turned over by

the picker. Sunscalded fruits are not marketable.

The injury is usually on the sides or upper half of the fruits.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 47

but it may occur wherever the rays of the sun strike most directly. The first symptom is a whitish, shiny, blistered area. The

killed, bleached tissues gradually collapse (pi. 8, C), forming a

slightly sunken area that may become pale yellowish and often

wrinkled as the fruits ripen (pi. 9, B). The killed tissues encourage the development of secondary decay. Alternarla rot is the

decay that is found most frequently following sunscald.

Recommendations of the State agricultural extension service

or experiment station should be followed to reduce sunscald. ^

(See 27.)

VIRUS MOTTLING

Tomato plants and fruits are affected by a number of plant

viruses and strains of these viruses. They may also be affected by

more than one virus at the same time. This creates a complex

problem requiring special knowledge and techniques for definite

identification.

For practical purposes, only the virus diseases that have been

found on the market on tomato fruits in past years are included in this handbook. They are tomato mosaic, double-virus

streak, and spotted wilt. Because of the difficulty in making visual

identification, they are grouped under the heading of "virus mottling," a term that has been used by the Federal-State inspection

service for several years.

Because of improved production practices, such as direct seeding and sanitation, virus diseases are rarely found on tomatoes

during marketing.

Tomato Mosaic ' '

,, Marmor tabaci Holmes - ,rOccurrence and Importance ^-^

Tomato mosaic is a virus disease that may be found in fields

and greenhouses throughout the United States. It is one of the

most common virus diseases of tomato plants, but its seriousness

depends on the time of infection and the strain of the virus

present. Fruits affected by certain strains of the virus show a

superficial pattern of mottled color that is retained after they are

ripened. This detracts from their appearance and perhaps causes

more wastage through paring because the affected parts do not

ripen thoroughly. The fruits are not necessarily a total loss,

however, nor does the disease cause them to be more subject to

decay. Mosaic causes very little loss in tomatoes for fresh use.

Symptoms

The symptoms of tomato mosaic on the fruits are distinct from

those caused by other viruses. The difficulty of identification

largely is caused by confusing marks and patterns on ripened

tomatoes from other causes of blotchy or irregular ripening.
48 AGRICULTURE HANDBOOK 28, U.S. DEPT. OP AGRICULTURE

The mottled pattern caused by tomato mosaic is entirely superficial. Affected areas do not collapse, become sunken, or turn

brown. The most typical diseased fruits in the field or on the market are green with cream-colored marks radiating from the stem

scar over the shoulder area (pi. 7, A). These cream-colored

marks may be continuous streaks, but more often they are broken

up by small areas of darker green tissues. The latter condition

causes the mottled or marbled appearance so typical of the disease. The margin between the green and cream-colored areas is

usually distinct and not diffuse. When affected tomatoes ripen,

the green areas become red, but the cream-colored areas turn

yellow, thus the mottled appearance is maintained (pi. 7, B).

Although shoulder markings are most typical, the mottled areas

may extend over any part of the fruit, especially on fruits seriously affected. Mosaic fruits found on the market were affected

when shipped, and the only change is that of color caused by

the ripening of the fruits, as described above.

Causal Factors

The virus causing tomato mosaic is the same as that causing

common mosaic of tobacco. It also affects peppers and eggplants.

The ordinary green strain of this virus is the most abundant

strain in the field. It causes various leaf symptoms on the plants,

but unless infection occurs when the plants are small, no serious

reduction in yield results. The green strain of mosaic does not

affect tomato fruits.

Certain yellow strains of this virus cause a striking yellow

mottling of leaves and may also mottle the stems. It is the yellow

strains that cause the mottling of tomato fruits, and they may

cause a serious reduction in yield.

The principal means of infecting tomato plants with the mosaic

virus is by human transmission. Workmen get the virus on their

hands and clothing when handling plants with mosaic, and they

infect the healthy plants handled thereafter. The tobacco mosaic

virus is commonly present in smoking tobacco, and smokers are

likely to carry the virus on their hands. Aphids can transmit the

virus from diseased to healthy tomato plants and possibly from

virus-infected weeds that belong to the tomato family. They are

not so important in spreading mosaic, however, as insect vectors

are in the spread of some other viruses. The virus does not ordinarily live over winter on tomato debris in field soil, and in

commercial practice, transmission of the virus by the seeds is of

little or no importance.

Control

Recommendations of the State agricultural extension service or

experiment station should be followed.

. (See 27, 92.)
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 49

Double-Virus Streak

Occurrence and Importance "^ "

Double-virus streak can occur in any region where tomatoes

are grown. It is the most common form of streak on tomatoes.

Tomato plants are severely damaged by this disease, and affected

fruits are worthless. Although the disease is more common in the

greenhouse than in the field, it has occasionally been found on

field-grown tomatoes on the market.

*5f»smaq' i7^'

Symptoms

Fruits very severely affected by double-virus streak are often

rough and misshapen and have small, raised, irregularly shaped

areas that may appear glassy or brown and corky. Such fruits

would not reach the market. Specimens more typical of those

found on the market have numerous small irregular or angular

spots anywhere on the surface of the fruit; the spots are first

glassy, then brown, and are usually slightly sunken (pi. 7, C and

D). Independent spots often merge, forming larger irregular

brown areas. Fruits on the market with double-virus streak were

affected when shipped. Sinking and discoloration of affected

areas increase with time and can be expected to change to some

extent in transit.

It) íTi :lí)a¿ : ' liíOilB ?oqg vvo-rstnuf vfon:-.

Causal Factors '--^Q^i- ' 7^^ ^^ifii^Hn/n

When plants already infected with the tomato mosaic virus

Marmor tabaci later become infected with the so-called latent

potato virus Marmor dubium var. vulgäre Holmes, the disease

produced by this combination is known as double-virus streak.

The potato virus is present in nearly all the older varieties of

potatoes grown in the United States, but it produces little or no

visible mottling in the potato plant. When it is inoculated into

healthy tomato plants, only a mild mottling of the leaves results

and there are no fruit symptoms. The severity of the doublevirus streak symptoms varies on tomatoes with the virulence of

the strain of the potato virus with which they are infected. Some

spotting of the leaves and streaking of the stems occur, however,

with all strains.

The latent potato virus can be carried on the hands of workers

who have cut potatoes before handling tomato plants. In the field

it may be carried on the hands, clothing, and tools of those who

have previously worked in a nearby field of potatoes, or it may

be in volunteer potatoes in the tomato field. The potato virus is

not spread by aphids. The combined viruses are very infectious

and are spread easily by contact. If the disease develops early in

the season it may be very destructive, especially in the greenhouse.

. -Á. hi!) ^>di ii: ' - '
50 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OF AGRICULTURE

vi ,vrf Control "^^

Recommendations of the State agricultural extension service or

experiment station should be followed.

(See<?^.) ^ii'i-i'^ ^':,/;;'• - :'.

- ¡-nui .;'vMîî >:if'* t: ^i -iVi'/i.;'

:. i:i< ' " ' í->.Wí-:í -W:: '

^flT i-\ ííOffífnc . -nom >i s Spotted Wilt ,í¡.V ;-;-: Ir^:-

•^'' *• Lethum australiense var. typicum Holmes

Occurrence and Importance

The virus disease known as spotted wilt has caused serious

losses in some sections of California and in Oregon. A very damaging strain of the virus there causes what is known as tip

blight. This disease has been reported also from Texas. Spotted

wilt occasionally occurs in the field in some of the East North

Central and Atlantic States and at times has caused serious

losses on tomatoes grown in greenhouses. Seriously affected fruits

are worthless, and the disease is rarely seen on tomatoes shipped

to market.

f:' ' Symptoms

The fruits from older plants seriously affected by spotted wilt

show numerous spots about V-, inch in diameter, with circular

markings that appear as concentric bands of red and yellow on

ripe fruit. The centers of these spots are sometimes raised, thus

the spots have a roughened appearance. Such seriously affected

fruits are not likely to be found on the market. Fruits with

milder symptoms, such as may be found on the market, usually

show a number of ring patterns over the surface of the fruits

and are often accompanied by mottling caused by the lack of

normal ripening in the surrounding tissues (pi. 7, E and F). The

ring appearance is due to a slight sinking and shriveling of the

tissues around the margin of the affected area, and this condition

causes the center of the ring to appear raised. These affected

areas may be practically normal in color or may appear bronzed

or reddish brown. Diseased fruits found on the market were infected when shipped. Changes such as roughening of the surface

and discoloration may occur during transit.

Causal Factors

Spotted wilt is caused by a virus that infects many ornamental

plants, weeds, and vegetable crops, including peppers and eggplants. The virus is transmitted by flower and onion thrips. It

can be transmitted mechanically, but the disease apparently does

not occur to any extent unless the thrips are present in considerable numbers. The cause of serious outbreaks of the disease in

tomato fields frequently has been traced to nearby plantings of

infected dahlias and infected chickweed in the dahlia field.

In addition to those described, certain other virus diseases that
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 51

affect tomatoes may cause mottling of the fruits during ripening

(pi. 7, G and H).

Control

Recommendations of the State agricultural extension service or

experiment station should be followed.

(See 26, 27, 112, 143.)

PEPPERS

ALTERNARíA ROT

' Alternaría tenais, auct.

Occurrence and Importance

Alternaría tennis is a weak pathogen that occurs in the field on

dead and dying plant materials, and also on peppers that have

injured areas such as blossom-end rot and sunscald. Peppers

carry the spores on the surface of the pods at harvest, and at

times, alternarla rot causes appreciable losses during transit and

marketing. The disease may occur on peppers from any locality.

Symptoms

Typical alternarla lesions first appear as small, circular, grayish-green, water-soaked spots anywhere on the pod (pi. 12, C).

The fungus appears to infect the tissues without a skin break.

The margin is well defined and the spots are flattened or slightly

sunken. Gradually the lesions enlarge, become tannish brown to

muddy brown or may eventually become black. Advanced lesions

are sharply sunken and usually have some loose gray mold over

the surface (pi. 12, D). Under moist conditions the decayed surface may develop a dense growth of sporophores and spores that

are olive green and velvety. Internally, old lesions are usually

black and somewhat leathery and some gray mold may be

present.

Causal Factors

Although alternarla rot may follow slight sunscald and blossom-end rot, these conditions occur infrequently in the commercial pack. Alternarla rot of this nature is unimportant on the

market.

Under present commercial handling practices, however, alternaría rot may become a serious problem on pods with severe

wounds if they are held for more than 2 weeks at moderate temperatures (50° to 55° F.) or on pods injured by chilling.

The Alternaría fungus grows and infects peppers slowly at 32°

to 40° F. and the rot is usually not evident when the peppers are

removed from low temperatures. Moderate to serious alternarla

rot develops rapidly, however, at 65° to 70° on peppers that had

previously been held at 32° for 15 days or longer or at 40° for

18 days or longer.
52 AGRICULTURE HANDBOOK 28, U.S. DEPT. OP AGRICULTURE

::-:u.^-iri 7í.-í'<ijl- -..'ui-à 'M Control fn :-:--|;i.:'> y,:v!i ..MJí.ICC ^DíH!:^

Alternaria rot can be controlled by handling peppers carefully

to avoid mechanical injuries, by providing a temperature range

of 45° to 50° F. during transit or storage, and by avoiding delays and low temperatures during all phases of marketing. Peppers should not be held longer than 12 to 15 days from harvest.

(See 55.)

ANTHRACNOSE

Colletotrichum gloeosporioides Penz.

Occurrence and Importance

Anthracnose may occur on peppers from any region. On the

market it seldom causes much loss unless the fruits are ripe or

beginning to ripen. The common bell pepper that is marketed

green rarely shows anthracnose except at wounds or following

other diseases such as blossom-end rot. During some seasons anthracnose is responsible for serious losses of fruit in the field.

Symptoms

Anthracnose spots range up to an inch or more in diameter.

They are small and water soaked at first; later they turn dirty

green to greenish brown and become slightly sunken. The margins of the spots are definite and circular in outline. The spots

become covered with raised black pustules, which are sometimes

arranged in concentric rings (pi. 11, D). Under moist conditions

these pustules exude creamy to pink spore masses. With one

type of anthracnose (Colletotrichum) the spore masses become

black as they age. This decay penetrates the pod walls and discolors the seed cavity and seeds.

Causal Factors

Several species of Colletotrichum have been reported as causes

of anthracnose. In the United States C. gloeosporioides appears

to be the only valid species. C. piperatum (Ell. & Ev.) Ell. & Ev.

and C. nigrum Ell. & Hals, are presently considered synonyms of

C. gloeosporioides. In Canada C. coccodes (Wallr.) Hughes is

also reported as a cause of anthracnose. These fungi can invade

both green and ripe pepper pods without wounds. Colletotrichum

is a weak pathogen, however, that usually follows wounds or

other diseases. These organisms usually cause most rapid decay

in ripening fruit. Warm, humid or rainy weather favors the

spread of the spores to the fruit in the field and the rapid development of decay. It is believed that early infections of fruit

in the field, too small to be graded out at packing time, are responsible for the few anthracnose spots found on the market.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 53

Control

Peppers shipped at temperatures ranging from 45° to 50° F.

will show no appreciable development of anthracnose during

transit. The disease, however, should be controlled in the field. Recommendations of the State agricultural extension service or

experiment station should be followed.

(See 7, 55, 59, 134.) >.-,i , vi

BACTERIAL SOFT ROT

Ertpinia carotovora (L. R. Jones) Holland

Occurrence ond Importance

Bacterial soft rot is a common decay of peppers from all growing areas. During some seasons it is particularly prevalent in

peppers from California, Texas, Florida, and Mexico.

Symptoms

Bacterial soft rot on peppers is characterized by water soaking

and rapid softening of the tissues. Infection initiated at the stem

end progresses rapidly through stem and calyx lobe tissues (pi.

11, E) into the pod. Under humid conditions and optimum temperatures (75° to 85° F.) the entire pod can be reduced to a

soupy mass within 3 to 6 days after infection. Infections occurring in wounds on the pod tend to spread lengthwise on the fruit,

macerating the underlying tissue and leaving a sunken, wrinkled,

fragile skin covering that is easily ruptured (pi. 11, F). The

foul odor that is associated with bacterial soft rot on most produce, however, is lacking on pepper fruits.

Causal Factors

Bacterial soft rot of peppers, Erwinia carotovora (L. R.

Jones) Holland, is identical to the organism causing serious market losses in many vegetable crops. Peppers are inoculated by

contact with contaminated soil and by picking and packing equipment. The organism is a wound parasite; it commonly enters by

way of broken stems or other wounds incurred in the harvesting

process. It is apt to be especially troublesome if peppers are

harvested during warm, wet weather.

-'- ''^t " ,.• ,p: ji ? <- Control -'"■■■- ''- ' : ' "'''

Peppers should be handled carefully during picking and packing to eliminate pod wounds. Significant reduction of bacterial

soft rot from stem wounds resulting from picking has been

achieved in controlled tests by submerging inoculated fruits for

1% minutes in water heated to 128° F. Hydrocooling the fruits

following this treatment resulted in greater decay in inoculated

fruit. It is important, however, to reduce the temperature of

the pods by other means to 45° to 50°, as quickly as possible, and
54 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OF AGRICULTURE

to maintain the fruits at this range in temperature throughout

the marketing period.

(See 62. 63.)

BACTERIAL SPOT

Xanthontonas vesicatoria (Doidge) Dowson

Bacterial spot on peppers is the same disease that affects tomatoes. (See Tomato, Bacterial Spot.) This disease may occur

on peppers from any region, but on most markets it is more

prevalent on peppers shipped from Florida and Texas. Typical

spots are small, raised, brown to black scablike lesions. In time

some of the oldest spots may crack and become grayish in the

center.

Bacterial spot is a superficial disease that detracts from the

appearance of peppers. The disease becomes seriously damaging

when the spots are present in large numbers on the pods (pis.

12, F, and 14, A).

Bacterial spot must be controlled in the field. Recommendations of the State agricultural extension service or experiment

station should be followed.

(See 37, 52, 57, 155.)

BLOSSOM-END ROT

Blossom-end rot is a physiological disease that frequently occurs on peppers on the market. It is serious because it disfigures

the fruit and opens the way for secondary bacterial and fungus

invaders that cause extensive decay. Alternarla rot is the most

common secondary decay that follows blossom-end rot, but in

many peppers anthracnose (see Anthracnose) follows in this

broken-down tissue.

Small, water-soaked spots on the lower half of the fruit near

the blossom end are the first symptoms of this disease. As the

spots enlarge they become light brown to brownish black and

dry, so that the affected tissues are more or less leathery in texture (pi. 14, F). No soft rot is produced unless secondary organisms invade the diseased tissues; however. Alternaría or some

other secondary organism is present on most of the peppers that

show blossom-end rot on the market.

Blossom-end rot of peppers is similar to, if not actually the

same as, the blossom-end rot of tomatoes. (See Tomato, BlossomEnd Rot.) It is associated with calcium deficiency and can be

greatly reduced by soil applications of gypsum.

Recommendations of the State agricultural extension service or

experiment station should be followed for control of blossom-end

rot.

(See 47, 53, 75, 99.)
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 55

CHARCOAL ROT

Macrophomina phaseoli (Maubl. ) Ashby

Charcoal rot of peppers is seldom found on the market. This

disease, however, causes damage to peppers in the fields of New

Jersey, Texas, California, Georgia, and Kansas.

Pepper fruits affected with charcoal rot show very little external evidence of the disease except a shriveling of the epidermal

tissues. The interiors of the pods are discolored, however, and a

great number of small black specks, sclerotia, are visible within

the tissues and on the seeds. The fungus will enter through

wounds and become established within the tissues in 4 days. Affected fruits are completely decayed in about 2 weeks. No control measures are known.

{See H, 150, 167.) ' ' » ; -

CHILLING INJURY

Occurrence and Importance

Bell peppers are subject to chilling injury and should not be

over-refrigerated or held beyond a normal marketing period.

Chilling injury has been observed primarily in shipments during the late-fall and winter months, and during warm weather

when mixed loads of vegetables, including peppers, were top iced.

Although losses are not as serious as in past years, the problem

continues to warrant attention.

Symptoms

Peppers that have been injured by low, but nonfreezing, temperatures may develop such physiological disorders as sheet

pitting and surface scald or certain kinds of decay.

Sheet pitting develops on the most tender part of the pods.

Slightly affected pods may develop only a few scattered pits, but

those seriously affected may have one half or more of the surface

covered in a sheet effect. Sheet pitting anpears first as watersoaked spots, which may be scattered or close together. Affected

areas are grayish green, and individual spots are flat or slightly

sunken. En masse, affected areas have a dappled appearance

(pis. 12, A and 14, C). Affected tissues lose moisture, sink irregularly (pi. 14, D), and often appear pebbly. The pattern of sheet

pitting varies according to the spacing of the pits. Sheet pitting

develops while the peppers are at 32° F.

Surface scald does not develop until after the peppers have

been removed from low temperature. Affected pods are a dull

grayish brown.

The calyxes of peppers are seriously injured by holding the

pods at 32° to 40° F. When placed at higher temperatures the

calyxes deteriorate rapidly and develop alternarla rot with visible mold (pi. 12, B).
56 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OF AGRICULTURE

Numerous lesions of alternaría rot over the surface of the pods

are also an indication of chilling injury. (See Alternaría Rot.)

The occurrence of numerous lesions of gray mold rot that have

developed without the aid of visible skin breaks indicates chilling

injury perhaps of a less serious nature than that described for

alternaria rot. (See Gray Mold Rot.)

Causal Factors

In tests, sheet pitting developed on pods held at 32° F. 4 days

or longer. Sheet pitting has been observed in peppers that were

in transit during periods of low outside temperatures, and during

warm weather in mixed loads of vegetables that were top iced.

Although sheet pitting is a symptom of chilling, its presence does

not necessarily indicate serious chilling injury; that is, extensive

decay does not always follow.

Surface scald, dying and moldy calyxes, and numerous lesions

of alternaria rot follow serious injury, which occurs in 12 to 15

days at 32° F. and 18 days or longer at 40°.

Control

Chilling injury can be prevented by avoiding temperatures below 45° F. in transit, storage, and at the market. Peppers should

not be held longer than 12 to 15 days from harvest. A holding

temperature of 48° to 50° is best.

(SeeS5.)

CLADOSPORiUM ROT

Cladosporium herbarum Fr.

Occurrence and Importance

The Cladosporium fungus is a weak pathogen, and although

widespread, it does not cause serious losses in peppers except

under special conditions.

Most of the cladosporium rot seen on the terminal markets

has developed in California peppers shipped from the fall and

early-winter crops. Peppers that become susceptible usually develop extensive decay. , , , ,,

Symptoms

.1, . .. ; ail-]

The lesions of cladosporium rot develop slowly; they never become large; and from the early stages they have characteristics

that set them apart from other rots.

Lesions no larger than the head of a pin are slightly depressed

and a light-tan color. Although the fungus may enter through a

wound, most of the numerous lesions on pods show no sign of a

skin break. As the spots enlarge they become more sunken and the

center is dark brown in contrast to a light-brown border. Finally

the central area becomes jet black and shiny (pi. 12, E) and the
MARKET DISEASES OP TOMATOES, PEPPERS, EGGPLANTS 57

border remains brown. The lesions are shallow and can be readily lifted out on the point of a knife. The decayed tissues are

spongy and grayish brown. Lesions that have been developed

for a long time eventually penetrate the pod wall and may cause

some internal discoloration. Under moist conditions short sporebearing stalks and spores form a dense, velvety, dark olive-green

mass over the old lesions.

Causal Factors

Shipments that are unloaded after only 6 days en route usually

show little evidence of infection. Peppers that are shipped under

refrigeration and are delayed and those that have been refrigerated and held on track or held in storage at 36° to 40° F. for a

week or more develop serious decay.

Damp, foggy weather in the field has previously been considered to be an important predisposing factor in cladosporium rot.

Moist weather would cause an increase in the Cladosporium spore

population, but the weakening effects, of chilling injury appear to

be the principal cause of pods becoming susceptible.

Control

Maintain peppers at 45° to 50° F. while in transit or storage.

Avoid prolonged exposure to temperatures below 45° during

marketing.

{Seel23.) '.''-- ■■' "'" -'' ' ';-"'^ ' - ''■■'':• ' '"

'r^^^yr.- ' m..,f CLOUDY SPOT ' ''" ''^^ '^^ " ' '''^-^

Cloudy spot on peppers is the same kind of blemish, as that on

tomatoes and has the same general symptoms (pi. 14, B).

Cloudy spot does not occur as extensively, however, on peppers

as on tomatoes. (See Tomato, Cloudy Spot.)

GRAY MOLD ROT

Botrytis cinérea Fr.

e'íJ lio g?.!"*i ?-y> jytvi^'I

Occurrence and Importance

Gray mold rot, also called botrytis rot, may occur on peppers

from any source, but it has often been a sporadic problem on

peppers shipped from California during the fall and winter. Although conditions are favorable for the spread of the fungus in

the field during cool, moist weather, there is little decay after

harvest if the pods are carefully handled and not over-refrigerated. Peppers that are over-refrigerated and delayed in reaching

the market often develop extensive gray mold rot.

Symptoms

If pods are weakened by over-refrigeration, numerous lesions

may develop anywhere over the surface without the aid of skin
58 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OP AGRICULTURE

breaks. At temperatures of 40° to 45° F. gray mold rot starts as

small, cream-colored specks with a tendency to first spread in a

rhizoid pattern. These specks gradually develop into round watersoaked lesions (pi. 11, A). As the spots enlarge they develop a

grayish to grayish-brown color (pi. 11, B and C).

Decayed tissues are wet, but relatively firm. Under humid conditions a mass of brownish-gray mold with a surface layer of

granular spores of the same color are characteristic.

Causal Factors

Freshly harvested unwounded bell peppers are quite resistant

to gray mold rot at 50° and 55° F. even at high relative humidity. Similar pods can be expected to become susceptible at 45°

and to develop visible lesions in about 15 to 18 days. Pods become more susceptible at 40° than at 45°, but require about 18

to 21 days for lesions one-fourth inch in diameter or larger to

appear.

Nonchilled peppers are readily infected by Botrytis through

wounds in the pod or through the cut or broken stem end.

Chilling injury is cumulative and near-freezing temperatures

in the field may predispose peppers to gray mold rot if the peppers are over-refrigerated after harvest.

Control

Gray mold rot can be controlled by providing a temperature

range of 45° to 50° F. during a normal period of transit and by

avoiding delays and low temperatures during all phases of marketing. Peppers should not be held longer than 12 to 15 days from

harvest. A holding temperature of 48° to 50° is best.

(See 90.)

PHYTOPHTHORA ROT

Phytophthora capsici Leonian aiid P. parasítica Dast.

Phytophthora rot of peppers seldom causes much loss on the

market. Phytophthora capsici has been associated with a blight

of the plants and a fruit rot in most of the growing areas. P.

parasítica has been reported as a fruit rot on peppers from

Illinois, Indiana, and New Jersey.

The causal fungus migrates from the blighted plant through

the fruit pedicel and invades the fruit at the stem end. The first

symptom of this disease is the presence of small, green, watersoaked spots that tend to elongate down the sides of the ood as

they enlarge. Usually by the time one-fourth of the fruit is decayed a superficial, fine, grayish-white to tan mold is evident

over the lesion (pi. 11, G). This decay eventually involves the

whole pod, and under humid conditions mold develops extensively

over the entire surface. Peppers on the market seldom show more

than one-fourth of the fruit pod decayed. Apparently the rot
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 59

found on the market develops from inconspicuous infections that

are not observed when the fruit is packed. The usual refrigeration temperatures in transit retard the development of the decay.

Control measures for this disease on harvested peppers have

not been developed. For field control, consult the State agricultural extension service or experiment station.

(See 71, 7U, 150, 153.)

RHIZOPUS ROT

Rhizopus stolonifer (Fr.) Ehr.

Occurrence and Importance

Rhizopus rot is a soft decay of peppers that is found occasionally on the market and may be responsible for serious losses.

Symptoms

Rhizopus rot, bacterial soft rot, and gray mold rot are sometimes confused. Rhizopus lesions are softer to the touch than

those of gray mold, and the lesions tend to be stretched and flattened, in contrast to gray mold lesions, which follow the natural

contour of the fruit. Both rhizopus and bacterial soft rot decays

are very soft, but the tissues invaded by Rhizopus hold together

somewhat and tend to be "mushy" in consistency, whereas tissues

attacked by the bacterial soft rot organism are "soupy." If affected tissue is gently pulled apart the coarse threads of the

Rhizopits mold may be observed. A whitish surface mold may

appear at the point of original entry of the fungus or at any

break on the lesion surface. Shortly thereafter the fruiting stage

appears, consisting of raised stalks each with a small spore ball

at the end. These spore balls are white when immature and shade

into black with maturity. This blend of immature to mature

fruiting bodies lends a grayish cast to the coarse mold growth

and provides the surest rneans of identification of rhizopus rot.

Causal Factors

Rhizopus is a fungus of worldwide distribution, and inoculum

is present throughout the harvest and postharvest period. It is a

wound parasite that enters through any skin break. On peppers

it is often noted on fruits broken through crushing. This fungus

is capable of spreading by contact from diseased to healthy fruits.

Control

Control of rhizopus rot depends mainly upon careful handling

of the pods to avoid injury. Since little growth of this fungus

occurs below 50° F., cooling the peppers as quickly as possible

to 45° to 50° F. and maintaining that temperature throughout

the marketing period will minimize losses from rhizopus rot.
60 AGRICULTURE HANDBOOK 28, U.S. DEPT. OF AGRICULTURE

RIPE ROT

Colletotrichum capsici (Syd. ) Butl. & Bisby

Ripe rot is the most serious and destructive disease of pimento

peppers in certain areas in Georgia, where they are grown for

canning. In these areas the growers sometimes lose 50 percent of

their crop. It also has been found on ripe fruits on the market.

Fruits may become infected at any stage of their development,

but decay does not become apparent until they begin to ripen.

Warm, wet weather favors the spread of the causal fungus and

the rapid development of fruit decay. Seemingly sound fruits

harvested from infested fields have been observed to deteriorate

overnight to such an extent that more than half of them had to

be discarded at the cannery.

The first symptoms appear on ripening pods as yellowish to

light-pink circular spots about % to ^4 inch in diameter. As

these spots enlarge they become water soaked and soft, with

dirty-brown to black centers and reddish-brown borders. Over

the central areas of the larger spots masses of pink spores appear. The spore masses and other general characteristics of the

decay are very similar to anthracnose. (See p. 52.) Ripe rot extends through the pod wall and affects the seeds.

The optimum temperature for growth of Colletotrichum capsici in culture is 84° F.

Ripe rot must be controlled in the field. Recommendations of

the State agricultural extension service or experiment station

should be followed.

(See 19, 5Jt, 13i.)

SUNSCALD

Occurrence and Importance

Sunscald is caused by the sudden exposure of fruits to direct

sunlight. Partial defoliation by the bacterial spot or the cercospora leaf-spotting organisms may result in considerable loss of

the fruit from sunscald. This is a disease of minor importance on

the market.

Symptoms

Sunscald on peppers appears as a light-colored, soft, sometimes

wrinkled area on the surface exposed to the sunlight. As the injured tissues dry out the lesion sinks somewhat, becoming

bleached and papery (pi. 14, E). This type of sunscald rarely

reaches the market. There is, however, another type of injury

that is not apparent at packing called delayed sunscald, wherein

the bleaching characteristic is lacking. The affected tissues have

a slightly water-soaked appearance and eventually become desiccated and somewhat brown (pi. 11, H). This manifestation of

sunscald on peppers is not easily recognized while they are being

packed and may appear on the market.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 61

Cultural practices to promote the health and vigor of the

plants, and a spray program to control bacterial spot and cercospora leaf spot should reduce sunscald.

(See;^?'.)

VIRUS MOHLING

Peppers from most of the important shipping regions sometimes show various types of mottling of the fruit similar to

virus mottling of tomatoes. Virus diseases such as mosaic, cucumber mosaic, spotted wilt, and tobacco etch are serious problems in the production of peppers. Stunting, distortion, yellow

and green mottling, and definite rings or loops on the pods are

characteristics of these virus diseases (pi. 13). Pods with ring

markings are rarely seen on the market, but pods showing a

slightly puckered side with pale yellowish longitudinal streaks

are frequently seen.

Recommendations of the State agricultural extension service or

experiment station should be followed for the control of virus

diseases.

(See 7.)

EGGPLANTS

ALTERNARIA ROT

, i„ . ,r Alternaría tennis, auct.

As indicated in the discussion of alternarla rot of tomatoes

and peppers, the fungus is present in the field as a saprophyte or

weak parasite. While alternarla rot may occur on eggplant fruits

from any locality, the extensive occurrence of the disease depends

on chill-injured fruits.

In the early stages, the lesions range from % to % inch in

diameter. They are shallow, circular spots with definite margins

and rich brown color. Decay usually develops around the calyx

and over the surface of the fruits (pi. 16, B), without visible

skin breaks. In advanced stages, the spots often coalesce to form

larger areas which penetrate the flesh % inch or more. The decayed flesh is spongy and tan to grayish tan. Surface mold often

develops on the old spots. The mold may be dark gray or, if the

fungus is sporulating heavily, the mass will appear olive green

and velvety.

Eggplant fruits that have been in contact with top ice during

transit for 6 days and those that have been held at 32° to 40° F.

for 10 days or longer can be expected to develop a serious amount

of alternarla rot after removal to higher temperatures.

To control alternarla rot maintain a transit temperature of

45° to 50° F. Avoid shipping eggplant fruits in mixed loads of

vegetables with top ice. Avoid prolonged holding and chilling

temperatures.

(See So.) ':'úíh' .íytíitf-í imtM:-) o-'.^ r.d hfia-'l'-'Vii'^ bh'u
62 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OF AGRICULTURE

BACTERIAL SOFT ROT ^^

'* Erwinia cartovora (L. R. Jones) Holland

Bacterial soft rot on eggplant may develop through slight skin

breaks especially following periods of hot, rainy weather.

The decay develops rapidly at temperatures of 70° F. or above.

Extensive lesions are a dingy, grayish brown (pi. 15, A) with

tender skin. The rot is soft and watery and lacks the foul odor

that accompanies bacterial soft rot on tomatoes.

On the basis of size and color of the lesions this disease might

be confused with rhizopus rot. Bacterial soft rot may be distinguished, however, by the watery nature of the decay, the absence

of coarse mold filaments within the decayed tissues, and the lack

of external mold growth.

Bacterial soft rot can be controlled by careful handling and

by holding the fruits at temperatures of 45° to 50° F. during the

brief period of transit and marketing.

CHILLING INJURY

Eggplant fruits are subject to chilling injury if held at temperatures below 45° F. for a week or more.

The problem of chilling injury is not extensive, but occasionally

shipments during the winter show some degree of injury. Chilling injury has been noted especially on eggplant in mixed loads

of vegetables that were top iced.

The symptoms of chilling injury are pronounced, but usually

do not show until after the fruits are removed from low temperature. Fruits held at 32° F. for 10 days or 40° for longer periods

may develop extensive areas of scaldlike browning of the skin

(pi. 16, A) and may also show browning of the flesh when cut.

Other signs of chilling injury are the decline, decay, and loosening of the capstems, and the occurrence of numerous spots of

alternaría rot (pi. 16, B) over the surface of the fruits.

To prevent chilling injury, eggplants should be market-ed

promptly and held at temperatures of 45° to 50° F. during the

brief marketing period. Avoid the use of top ice as a refrigerant.

(See86.)

COnONY LEAK

Pythium aphanidermatum (Edson) Fitz.

Cottony leak may be found on market eggplants, particularly

during wet seasons. Seldom, however, is it of great importance.

The first symptoms of decay are a bleaching of th« ournle

color, the development of a tan discoloration, and a slight wrinkling of the skin (pi. 15, B). The affected tissues underneath are

very watery and are light brown. Slight pressure causes a brownish liquid to flow freely from the diseased tissues. The chief

distinguishing feature, however, is the abundant cottony, white

mold developed by the causal fungus, which covers the surface of
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 63

the decayed spot. This is most conspicuous under humid conditions. It is the characteristic, together with the "leaky" nature

of the decay, that suggests the name "cottony leak."

The decay is caused by the soil-inhabiting fungus Pythium

wphanidermatum. Wet weather favors its development. Fruits

that are in contact with the soil or that become splattered with

infested mud may become affected with the decay, which usually

originates at the blossom end. Wounds are not necessary for entrance of the fungus.

Since the decay progresses rapidly, fruits showing even slight

spots should be discarded at the time of packing. All fruits affected at shipping time are sure to decay, and adjacent fruits in

the package may likewise become infected during transit or on

the market.

{^ee29.)

GRAY MOLD ROT

Botrytis cinérea Fr.

Gray mold rot may occur wherever eggplants are grown, but

the disease ordinarily causes very little loss during marketing.

The fungus flourishes in the ñeld during cool, moist weather.

Fruits harvested following periods of weather favorable to the

fungus may occasionally develop the decay through wounds or

old blemishes. But if the fruits are held at 45° F. for 10 days or

longer they may develop gray mold rot anywhere on the fruits

without the aid of skin breaks.

Decayed tissues are bleached from dark purple to medium

brown with a grayish cast. Actively developing lesions usually

have a reddish-purple margin (pi. 15, D).

The lesions are relatively firm and those of 2 to 3 inches in

diameter may penetrate the flesh for % to 1 inch. The decayed

tissues separate readily from the healtifiy flesh and, if a cut is

made around the margin of the lesion, the decayed mass can be

lifted free from the fruit.

To control gray mold rot move eggplant fruits ranidly through

the marketing channels. Avoid delays at 40° to 45° F.

PHOMOPSIS ROT

Phomopsis vexons (Sacc. & Syd. ) Harter

Occurrence and Importance

Phomopsis rot, or fruit rot, is the most common and the most

destructive transit and market decay of eggplants. It affects eggplants from all regions, but it causes greatest damage on those

from the Southern States, Puerto Rico, and the Philippines. Important losses of marketable fruits frequently occur in the field,

and a serious blight of the plant often reduces fruit production

and quality.
64 AGRICULTURE HANDBOOK 28, U.S. DEPT. OP AGRICULTURE

\i '.''s:\'\^ >: Symptoms i'""-;

The decay appears on eggplant fruits in the form of small,

more or less circular, tan to light-brown, slightly depressed spots.

These may occur singly or severally anywhere over the fruit, but

frequently the decay originates under or at the edge of the calyx

lobes. The decayed spots become darker brown with age and

somewhat zoned in appearance; they enlarge rapidly (pi. 16, C),

sometimes to a diameter of 2 or 3 inches. Often two or more

spots coalesce to cover much of the fruit. The decay is soft and

spongy and penetrates throughout the tissues of the fruits, causing a light-brown discoloration of the flesh. The borders of the

decayed tissue are distinct on the surface, but internally they

are not always sharply defined from the healthy flesh.

The presence of the fungus fruiting bodies (pycnidia) helps

identify the decay (PI. 16, D). They appear as tiny black pimples that develop in abundance just under the epidermis. When

the pycnidia break through the surface, their tiny beaks are

readily visible. In advanced stages of decay the pycnidia literally

cover the surface.

Causal Factors

Phomopsis rot is caused by the fungus Phomopsis vexans. It

attacks not only the fruits but the leaves and stems of the plant

as well. The decay is greatly increased by a rainy season. Rots

found in transit or on the market originate from infections that

occurred in the field. In most instances, however, there may be

no visible evidence of decay at the time of shipment.

Growth of the causal fungus and development of decay are

greatest at temperatures of about 80° to 85° F. There is little

development of either at 45° or lower.

• - :••:; -d'' rr.-- ; •• • ' Control '^' :., ' .-=- ^ .-f T. :- --

Transit temperatures of about 45° F. should be maintained.

Eggplant fruits showing evidence of spotting should be discarded at time of shipment. For field control the recommendations of the State agricultural extension service or experiment

station should be followed.

(See SO, 45, 106, 109.)

PHYTOPHTHORA ROT

Phytophthora spp.

This disease occurs in the field as a blight and fruit rot, and

sometimes infected fruits are found on the market. The decayed

areas of the fruits are dark brown, with conspicuously lighter

colored borders. The decay extends well into the flesh. Vascular

tissues extending between the decayed spots and the stem may

appear as darkly discolored strands. The decay is caused by soilborne species of the fungus Phytophthora, similar to or identical
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 65

with those responsible for buckeye rot of tomatoes. (See Tomato,

Buckeye Rot.)

(See 65, 126.)

RHIZOPUS ROT

Rhizopus stolonifer ( Fr. ) Ehr.

Occasionally, eggplants on the market are affected with rhizopus rot. The lesions are usually extensive, as the decay progresses

rapidly at moderate temperatures. The affected area of the skin

is brown (pi. 15, C). The brownish, soft, wet decay penetrates

deeply into the fruit. This decay can be distinguished from

phomopsis rot by the soft and watery nature of the diseased tissues, and from that of bacterial soft rot by the coarse strands of

mold that can be exposed by gently pulling apart the decayed

tissues.

(See Tomato, Rhizopus Rot.)
66 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OP AGRICULTURE

LITERATURE CITED hV:

(1) AiNSWORTH, G. C, OYLER, ENID, and READ, W. H.

1938. OBSERVATIONS ON THE SPOTTING OF TOMATO FRUITS BY BOTRYTis CINÉREA PERS. Ann. Appl. Biol. 25: 308-321.

(2) ARK, P. A.

1944. STUDIES ON BACTERIAL CANKER OF TOMATO. Phytopathology

34: 394-400.

(3) BAKER, K. F.

1946. AN EPIPHYTOTIC OF RHIZOPUS SOFT ROT OF GREEN-WRAP TOMATOES IN CALIFORNIA. U.S. Dept. Agr. Plant Dis. Rptr.

30: 20-26.

(4) BERAHA, LOUIS, and SMITH, M. A.

1964. A BACTERIAL NECROSIS OF TOMATO. U.S. Dept. Agr. Plant Dis.

Rptr. 48: 558-561.

(5) BERRY, J. W., CAROLUS, R. L., JR., and DEDOLPH, R. R.

1964. THE RELATION BETWEEN LOCULAB SEED DENSITY AND THE EXPRESSION OF BLOTCHY RIPENING IN TOMATO. Amer. SoC. Hort.

Sei. Proc. 85: 497-501, illus.

(6) BEWLEY, W. F., and WHITE, H. L.

1926. SOME NUTRITIONAL DISORDERS OF THE TOMATO. Ann. Appl.

Bid. 13: 323-338.

(7) BoswELL, V. R., DOOLITTLE, S. P., PULTZ, L. M., TAYLOR, A. L., and

CAMPBELL, R. E.

1959. PEPPER PRODUCTION, DISEASE AND INSECT CONTROL. U.S. Dept.

Agr. Farmers' Bui. 2051, 33 pp.

(8) BoYLE, J. S., and WHARTON, D. C.

1957. THE EXPERIMENTAL REPRODUCTION OF TOMATO INTERNAL

BROWNING BY INOCULATION WITH STRAINS OF TOBACCO MOSAIC

VIRUS. Phytopathology 47: 199-207.

(9) BREWER, P. H., KENDRICK, J. B., and GARDNER, M. W.

1926. EFFECT OF MOSAIC ON CARBOHYDRATE AND NITROGEN CONTENT

OF THE TOMATO PLANT. Phytopafhology 16: 843-851.

(10) BRYAN, M. K.

1930. STUDIES ON BACTERIAL CANKER OF TOMATO. U.S. Dept. Agr.

Jour. Agr. Res. 41: 825-851.

(11)

1933. THREE BACTERIAL SPOTS OF TOMATO FRUIT. U.S. Dept. Agr.

Cir. 282, 2 pp.

(12) BURKHOLDER, W. H., and SMITH, W. L., JR.

1949. ERWINIA ATROSEPTICA (VAN HALL) JENNISON AND ERWINIA

CAROTOVORA ( JONES) HOLLAND. Phytopathology 39: 887-897.

(13) BUTLER, E. E.

1959. FUNGI AND ROTS IN CALIFORNIA CANNING TOMATOES. U.S.

Dept. Agr. Plant Dis. Rptr. 43: 187-192.

(14)

1960. PATHOGENICITY AND TAXONOMY OF GEOTRICHUM CANDIDUM.

Phytopathology 50: 665-672, illus.

(15)

1961. TRANSMISSION OP GEOTRICHUM ROT OF TOMATO FRUIT BY

DROSOPHILA MELANOGASTER. Phytopathology 51: 250-255,

illus.

(16) and BRACKER, C. E.

1963. THE ROLE OF DROSOPHILA MELANOGASTER IN THE EPIPHYTOLOGY

OP GEOTRICHUM, RHIZOPUS AND OTHER FRUIT ROTS OP TOMATO.

Phytopathology 53: 1016-1020.

(17) CARMICHAEL, J. W.

1957. GEOTRICHUM CANDIDUM. Mycologia 49: 820-830.

(18) CEPONIS, M. J., and FRIEDMAN, B. A.

1955. THE OCCURRENCE OF PHOMOPSIS ON TOMATOES IN NEW YORK.

U.S. Dept. Agr. Plant Dis. Rptr. 39: 989-990.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 67

(19) CHOWDHURY, S.

1957. STUDIES ON THE DEVELOPMENT AND CONTROL OF FRUIT ROT OP

CHILLIES. Indian Phytopathology 10: 55-62.

(20) CONOVER, R. A.

1949. VASCULAR BROWNING IN BADE COUNTY, FLORIDA GREEN-WRAP

TOMATOES. U.S. Dept. Agr. Plant Dis. Rptr. 33: 283-284.

(21) COOPER, A. J.

1957. BLOTCHY RIPENING AND ALLIED DISORDERS OF THE TOMATO: A

~ CRITICAL REVIEW OF THE LITERATURE. Glasshouse Crops Res.

' '• Inst. Ann. Rpt. 1956, pp. 39-47.

(22) COTTER, D. J.

1961. THE INFLUENCE OF NITROGEN, POTASSIUM, BORON AND TO-

^ BACCO MOSAIC VIRUS ON THE INCIDENCE OF INTERNAL BROWN-

"• ING AND OTHER FRUIT QUALITY FACTORS OF TOMATOES. Amer.

Soc. Hort. Sei. Proc. 78: 474-479.

(23) CROSIER, W.

1934. STUDIES IN THE BIOLOGY OF PHYTOPHTHORA INFESTANS

(MONT.) DE BARY. N. Y. (Cornell) Agr. Expt. Sta. Mem.

155, 40 pp., illus.

(24) DARBY, J. F.

1954. RECENT DEVELOPMENTS IN THE CONTROL OF THE MAJOR DISEASES OF UNSTAKED TOMATOES GROWN ON THE SANDY SOILS

OF SOUTH FLORIDA. Fla. Hort. Soc. Proc. 66: 103-107.

(25)

1955. A PROGRESS REPORT ON GRAY MOLD AND GHOST SPOT OF TOMATOES AND THEIR CONTROL. U.S. Dept. Agr. Plant Dis. Rptr.

39: 91-97.

(26) DOOLITTLE, S. p., and SUMMER, C. B.

1934. PROBABLE OCCURRENCE OF AUSTRALIAN SPOTTED WILT OF TOMATOES IN WISCONSIN. Phytopathology 24: 943-946.

(27) TAYLOR, A. L., and DANIELSON, L. L.

1961. TOMATO DISEASES AND THEIR CONTROL. U.S. Dept. AgT. Handb.

203, 86 pp., illus. "• —

(28) DowsoN, W. J. ""'''' ■■ ' : -

1949. MANUAL OF BACTERIAL PLANT DISEASES. 183 pp., London.

(29) DRECHSLER, C.

1926. THE COTTONY LEIAK OF EGGPLANT FRUIT CAUSED BY PYTHIUM

APHANIDERMATUM. Phytopathology 16: 47-50, illus.

(30) EDGERTON, C. W., and MORELAND, C. C.

1921. EGGPLANT BLIGHT. La. Agr. Expt. Sta. Bui. 178, 44 pp.

(31) EVANS, H. J., and TROXLEB, R. V.

1953. RELATION OF CALCIUM NUTRITION TO THE INCIDENCE OF BLOSSOM-END ROT IN TOMATOES. Amer. Soc. Hort. Sei. Proc. 61:

346-352.

(32) FELIX, E. L.

1953. SUSCEPTIBILITY TO TOMATO BUCKEYE ROT FUNGUS IN TENNESSEE. Phytopathology 43: 290.

(33) FERRER, J. B., and OWEN, J. H.

1959. BOTRYTIS CINÉREA THE CAUSE OF GHOST SPOT DISEASE OF TOMATO. Phytopathology 49: 411-417.

(34) FOSTER, A. C, and TATMAN, E. C.

1937. ENVIRONMENTAL CONDITIONS INFLUENCING THE DEVELOPMENT

OF TOMATO POCKETS OR PUFFS. Plant Physiol. 12: 875-880.

(35) FRAZIER, W. A.

1935. A STUDY OF SOME FACTORS ASSOCIATED WITH THE OCCURRENCE

OF CRACKS IN THE TOMATO FRUIT. Amer. Soc. Hort. Sci. Proc.

(1934) 32: 519-523.

(36) FULTON, J. P.

1948. INFECTION OF TOMATO FRUITS BY COLLETOTRICHUM PHOMOIDES.

Phytopathology 38: 235-246, illus.

(37) GARDNER, M. W., and KENDRICK, J. B., SR.

1921. BACTERIAL SPOT OF TOMATO AND PEPPER. Phytopathology 13:

307-315.
68 AGRICULTURE HANDBOOK 28, U.S. DEPT. OF AGRICULTURE

(38) GARDNER, M. W., and KENDRICK, J. B., SR.

1921. BACTERIAL SPOT OF TOMATO. U.S. Dept. AgT. Jour. Agr. Res.

21: 123-156.

(39) GERALDSON, C. M.

1956. THE USE OF CALCIUM FOR CONTROL OF BLOSSOM-END ROT

OF TOMATOES. Fla. State Hort. Soc. Proc. (1955) 68: 197-

202.

(40)

.. (41)

1957. EVALUATION OF CONTROL METHODS FOR BLACKHEART OF CELERY

AND BLOSSOM-END ROT OF TOMATOES. Fla. State Hort. Soc.

Proc. (1956) 69: 236-241.

1960. NUTRITIONAL FACTORS AFFECTING THE INCIDENCE AND SEVEBr-i ITY OF BLOTCHY RIPENING OF TOMATOES. Fla. State Hort. SoC.

Proc. 73: 111-114.

(42) GONZALEZ, L. C., and OWEN, J. H.

1963. SOIL ROT OF TOMATO CAUSED BY BHizocTONiA soLANi. Phytopathology 53: 82-85.

(43) GROGAN, R. G., and KENDRICK, J. B., SR.

1953. SEED TRANSMISSION, MODE OF OVERWINTERING AND SPREAD OF

BACTERIAL CANKER OF TOMATO CAUSED BY CORYNEBACTERIUM

MiCHiGANENSE. Phytopathology 43: 473.

(44) HAENSELER, C. M.

1949. INTERNAL BROWNING OF TOMATOES IN NEW JERSEY. U.S. Dept.

Agr. Plant Dis. Rptr. 33: 336-337.

(46) HALL, C. B., and DENNISON, R. A.

1955. ENVIRONMENTAL FACTORS INFLUENCING VASCULAR BROWNING

OF TOMATO FRUITS. Amer. Soc. Hort. Sei. Proc. 65: 353-356.

(46) HALSEY, L. H.

1955. PRELIMINARY STUDIES OF BRUISING OF "TXJRNING" AND "PINK"

TOMATOES CAUSED BY HANDLING PRACTICES. Fla. State Hort.

Soc. Proc. 68: 240-243.

(47) HAMILTON, L. C, and OGLE, W. L.

1962. THE INFLUENCE OF NUTRITION ON BLOSSOM-END ROT OF PIMENTO PEPPERS. Amer. Soc. Hort. Sei. Proc. 80: 457-461,

illus.

(48) HARRISON, A. L., and BROOKS, A. N.

1943. CONTROL OF BACTERIAL SOFT ROT OF TOMATOES. Fla. Agr. Expt.

Sta. Press Bui. 592, 2 pp.

(49) HARTER, L. L.

1914. FRUIT ROT, LEAP-SPOT, AND STEM-BLIGHT OP THE EGGPLANT

CAUSED BY PHOMOPSis VEXANS. U.S. Dept. Agr. Jour. Agr.

Res. 2: 331-338, illus.

(50) HAYSLIP, N. C, and ILEY, J. R.

1965. N-K RATIO MAY INFLUENCE TOMATO GRAYWALL. Better Crops

With Plant Food. March-April, 28-29.

(51) HENDRIX, J. W. <; i.j

1950. A PHOMOPSIS DISEASE OF TOMATOES IN HAWAII. Phytopathology 40: 966.

(52) HIGGINS, B. B.

1922. THE BACTERIAL SPOT OF PEPPERS. Phytopathology 12: 501-516.

(53)

1925. BLOSSOM-END ROT OF PEPPER (CAPSICUM ANNUUM L.). Phytopathology 15: 223-239.

(54)

1930. A PEPPER FRUIT ROT NEW TO THE UNITED STATES. Ga. Agr.

Expt. Sta. Bui. 162, 10 pp., illus.

(55) '

1934. IMPORTANT DISEASES OF PEPPER IN GEORGIA. Ga. Agr. Expt.

Sta. Bui. 186, 20 pp., illus.

(56) HOLMES, F. 0.

1950. INTERNAL BROWNING DISEASE OF TOMATO CAUSED BY STRAIN

OF TOBACCO MOSAIC VIRUS FROM PLANTAGO. Phytopathology

' 40: 487-492.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 69

(67) HORSFALL, J. G., and MCDOWNELL, A. D.

1940. VARIETAL SUSCEPTIBIUTY OP PEPPERS TO BACTERIAL SPOT. U.S.

Dept. Agr. Plant Dis. Rptr. 24: 34-36.

(58) HOTSON, J. W., and HARTGE, LENA.

1923. .A DISEASE OF TOMATOES CAUSED BY PHYTOPHTHORA MEXICANA

SP. NOV. Phytopathology 13: 520-531.

(59) ILLMAN, W. I.

1960. IDENTITY OP AN INCITANT OF ANTHRACNOSE IN SWEET PEPPERS.

Canada Dept. Agr. Canadian Plant Disease Survey 40: 46.

(60) LUDWIG, R. A., and FARMER, JOYCE.

1969. ANTHRACNOSE OF CANNING TOMATOES IN ONTARIO. Canadian

Jour. Bot. 37: 1237-1246, illus.

(61) JAMIESON, C. O.

1915. PHOMA DESTRUCTIVA, THE CAUSE OP A FRUIT ROT OP THE TOMATO. U.S. Dept. Agr. Jour. Agr. Res. 4: 1-20.

(62) JOHNSON, H. B.

1964. EFFECT OF HOT WATER TREATMENTS AND HYDROCOOUNG ON

I POSTHARVEST BACTERIAL SOFT ROT IN BELL PEPPERS. U.S. DEPT.

Agr. AMS-517, 6 pp.

(63)

1966. BACTERIAL SOFT ROT IN BELL PEPPERS—CAUSE AND COMMERCIAL CONTROL. U.S. Dept. Agr. Mktg. Res. Rpt. 738, 6 pp.

(64) JONES, L. K., and BURNETT, G.

1936. VIRUS DISEASES OF GREENHOUSE-GROWN TOMATOES. Wash.

state Agr. Expt. Sta. Bui. 308, 36 pp.

(65) KENDRICK, J. B., SR.

1923. PHYTOPHTHORA ROT OP TOMATO, EGGPLANT, AND PEPPER. IND.

Acad. Sei. Proc. (1922) 38: 299-306, illus.

(66) KENDRICK, J. B., JR., and WALKER, J. C.

1948. ANTHRACNOSE OF TOMATO. Phytopathology 38: 247-260, illus.

(67) KiDSON, E. B., and STANTON, D. J.

1953. "CLOUD" OR VASCULAR BROWNING IN TOMATOES. New Zeal.

Jour. Sei. and Teehnol., See. A, 35(4) : 368-374.

(68) and STANTON, D. J.

1963. "CLOUD" OR VASCULAR BROWNING IN TOMATOES. New Zeal.

Jour. Agr. Res. 6(5) : 376-381.

(69) KREUTZER, W. A., BODINE, E. W., and DURRELL, L. W.

1940. CUCURBIT DISEASES AND ROT OF TOMATO FRUIT CAUSED BY

PHYTOPHTHORA CAPSICI. Phytopathology 30: 972-976.

(70) KREUTZER, W. A., and BRYANT, L. R.

1946. CERTAIN ASPECTS OF THE EPIPHYTOLOGY AND CONTROL OP TOMATO FRUIT ROT CAUSED BY PHYTOPHTHORA CAPSICI LEONIAN.

Phytopathology 36: 329-339, illus.

(71) LEONIAN, L. H.

1922. STEM AND FRUIT BLIGHT OF PEPPERS CAUSED BY PHYTOPHTHORA

CAPSICI SP. NOV. Phytopathology 12: 401-408.

(72)

1926. PHYSIOLOGICAL STUDIES ON THE GENUS PHYTOPHTHORA. Amer.

Jour. Bot. 12: 444-498.

(73) and GEER, H. L.

1929. COMPARATIVE VALUE OF THE SIZE OF PHYTOPHTHORA SPORANGIA OBTAINED UNDER STANDARD CONDITIONS. U.S. Dept. Agr.

Jour. Agr. Res. 39: 293-311.

(74) LEYENDECKER, P. J., JR.

1947. AN EPIPHYTOTIC OF PEPPER BLIGHT CAUSED BY PHYTOPHTHORA

CAPSICI IN SOUTHERN NEW MEXICO. U.S. Dept. AgT. Plant

Dis. Rptr. 31: 421-422.

(76)

1950. BLOSSOM-END ROT OF PEPPER (CAPSICUM ANNUUM L.) IN NEW

MEXICO. Phytopathology 9: 497-520.

(76) LINN, M. B., and EMGE, R. G.

1949. DEVELOPMENT OF ANTHRACNOSE AND SECONDARY ROTS IN

STORED TOMATO FRUITS IN RELATXON TO FIELD SPRAYING AND

FUNGICIDES. Phytopathology 39: 898-906.
70 AGRICULTURE HANDBOOK 2 8, U.S. DEFT. OF AGRICULTURE

(77) LUTTRELL, E. S.

1947. DiAPORTHE PHASEOLORUM VAR. sojAE ON CROP PLANTS. Phytopathology 37: 445-465.

(78) LUTZ, J. M.

1942. FACTORS INFLUENCING SHOULDER BRUISES OF GREEN-WRAP TOMATOES. Amer. Soc. Hort. Sei. Proc. 40: 455-459, illus.

(79)

1944. MATURITY AND HANDLING OF GREEN-WRAP TOMATOES IN MISSISSIPPI. U.S. Dept. Agr. Cir. 695, 12 pp., illus.

(80) LYON, C. B., BEESON, K. C, and BARRENTINE, M.

Of.; >i 1942. MACRO-ELEMENT NUTRITION OF THE TOMATO PLANT AS CORRELATED WITH FRUITFULNESS AND OCCURRENCE OF BLOSSOM-END

ROT. Bot. Gaz. 103: 651-667, illus. v K,.,.. ,.,,

(81) McCOLLOCH, L. P. > . ,„,.

1951. ALTERNARLA TENUIS THE CAUSE OF A TOMATO FRUIT ROT. U.S.

Dept. Agr. Plant Dis. Rptr. 35: 234-236.

(82)

(83)

(84)

(85)

(86)

1955. EFFECT OF LOW FIELD TEMPERATURES ON QUALITY OF TOMATOES. Fla. state Hort. Soc. Proc. 68: 188-192, illus.

1960. SALVAGING TOMATOES FROM FROZEN VINES. U.S. Dept. Agr.

Mktg. Res. Rpt. 423, 11 pp., illus.

1962. BRUISING INJURY OF TOMATOES. U.S. Dept. Agr. Mktg. Res.

Rpt. 513, 31 pp., illus.

1962. CHILLING INJURY AND ALTERNARÍA ROT OF BELL PEPPERS. U.S.

Dept. Agr. Mktg. Res. Rpt. 536, 16 pp., illus.

1966. CHILLING INJURY OF EGGPLANT. U.S. Dept. Agr. Mktg. Res.

Rpt. 749, 5 pp., illus.

(87) and POLLACK, F. G.

1946. HELMINTHOSPORIUM ROT ON TOMATO FRUITS. Phytopathology

36: 988-989.

(88) and WORTHINGTON, J. T.

1952. LOW TEMPERATURE AS A FACTOR IN THE SUSCEPTIBILITY OF

MATURE-GREEN TOMATOES TO ALTERNARÍA ROT. Phytopathol-

' ogy 42: 425-427, illus.

(89) and WORTHINGTON, J. T.

1954. WAYS TO PREVENT CHILLING MATURE-GREEN TOMATOES. PrePack-Age 7: 22-25, Feb., illus. -- - -

(90) and WRIGHT, W. R. '' '-- -'-*''

1966. BOTRYTIS ROT OF BELL PEPPERS. U.S. Dept. Agr. Mktg. Res.

Rpt. 754, 9 pp., illus.

(91) MCLEAN, D. M., and BJORNSETH, E. H.

1946. CONTROL OF ANTHRACNOSE ON CANNERY TOMATOES. Mich. Agr.

Expt. Sta. Quart. Bui. 28: 287-293, illus.

(92) MACNEILL, B. H.

1962. A SPECIALIZED TOMATO FORM OF THE TOBACCO MOSAIC VIRUS IN

CANADA. Ganad. Jour. Bot. 40: 49-51.

(93) MADHOK, M. R., and FAZAL-UD-DIN.

1943. BACTERIAL SOFT ROT OF TOMATOES CAUSED BY A SPORE FORMING ORGANISM. Indian Jour. Agr. Sei. 13: 129-133.

(94) MARTIN, W. H.

1917. SCLEROTIUM BATATICOLA, THE CAUSE OF A FRUIT ROT OF PEPPERS. Phytopathology 7: 308-312.

(95) MASSEY, A. B.

1924. A STUDY OF BACILLUS AROIDEAE, TOWNSEND, THE CAUSE OF A

SOFT ROT OF TOMATO, AND B. CAROTOVORUS JONES. Phytopathology 14: [460]-477. ; >. -,

(96) MASSEY, L. M., LABELLE, R. L., and ROBINSON, W. B.

„.;^ 1962. MECHANICAL HARVESTING EFFECTS ON TOMATO FRUITS. N. J.

State Hort. Soc, Hort. News, 44: 194-195.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 71

(97) MAYNARD, D. N., GERSTEN, B., and MICHELSON, L. F.

1959. THE EFFECTS OF BORON NUTRITION ON THE OCCURRENCE OF

CERTAIN TOMATO FRUIT DISORDERS. Amer. Soc. Hort. Sci. Proc.

74: 500-505.

(98) MiLBRATH, D. G.

1928. LATE BLIGHT OF TOMATO. Calif. Dept. Agr. Monthly Bui. 27:

271-274.

(99) MILLER, C. H.

1960. THE EFFECTS OF LOW AND HIGH LEVELS OF NUTRIENT ELEMENTS ON BELL PEPPERS. Assoc. South. Agr. Workers Proc.

57: 179.

(100) MiNGES, P. A., NicKLOw, C, and WILKINSON, R.

1959. TEMPERATURE AS A POSSIBLE FACTOR IN THE DEVELOPMENT OF

BLOTCHY RIPENING OR GRAY WALL IN TOMATO FRUITS. Amer.

Soc. Hort. Sei. Proc. Abst. p. 36.

(101) and SADIK, SIDKI.

1964. BLOTCHY RIPENING SYMPTOMS OF TOMATOES AND PROCEDURES

FOR RATING. Fla. State Hort. Soc. Proc. 77: 246-247.

(102) MORRISON, W. W.

1962. PREPARING FRESH TOMATOES FOB MARKET. U.S. Dept. Agr.

Mktg. Bui. 19, 14 pp., illus.

(103) MURAKISHI, H. A.

1960. COMPARATIVE INCIDENCE OF GRAYWALL AND INTERNAL BROWNING OF TOMATO AND SOURCES OF RESISTANCE. Phytopathology

50: 408-412.

(104) NIGHTINGALE, A. A., and RAMSEY, G. B.

1935. DEVELOPMENT OF PHOMA ROT OF TOMATOES IN TRANSIT AND

STORAGE. U.S. Dept. Agr. Cir. 371, 8 pp.

(105) and RAMSEY, G. B.

1936. TEMPERATURE STUDIES OF SOME TOMATO PATHOGENS. U.S.

Dept. Agr. Tech. Bui. 520, 36 pp.

(106) NOLLA, J. A. B.

1929. THE EGGPLANT BLIGHT AND FRUIT ROT IN PORTO RICO. Porto

Rico Dept. Agr. Jour. 13: 35-57.

(107) OBRERO, F. C., and ARAGAKI, MINORU.

1965. SOME FACTORS INFLUENCING INFECTION AND DISEASE DEVELOPMENT OF PHYTOPHTHORA PARASÍTICA DAST. ON TOMATO. U.S.

Dept. Agr. Plant Dis. Rptr. 49: 327-331.

(108) OAVEN, J. H., and FERRER, J. B.

1957. STUDIES CONCERNING THE GHOST SPOT DISEASE OF TOMATO.

Phytopathology 47: 530-531.

(109) PALO, M. A.

1936. THE PHOMOPSIS DISEASE OF EGGPLANT AND ITS CONTROL. Philippine Jour. Agr. 7: 289-315.

(110) PAULUS, A. 0., and POUND, G. S.

1955. EFFECT OF AIR TEMPERATURE ON INITIATION AND DEVELOPMENT

OF GRAY LEAP SPOT AND NAILHEAD SPOT OF TOMATO. Phytopathology 45: 168-174.

(111) PENTZER, W. T., and MCCOLLOCH, L. P.

1953. REFRIGERATION OF TOMATOES IN TRANSIT. Indus. Refrig.

125(3): 24-28, Sept., illus.

(112) PiRONE, p. p.

1935. SPOTTED WILT OF TOMATOES AND PEPPERS IN NEW YORK. U.S.

Dept. Agr. Plant Dis. Rptr. 19: 244.

(113) POOLE, R. F.

1922. A NEW FRUIT ROT OF TOMATOES. Bot. Gaz. 74: 210-214, illus.

(114) PORTE, W. S.

1934. NOTES ON THE CONTROL OF TRANSIT AND STORAGE DECAYS OF

TOMATOES BY THE USE OF CHEMICAL WASHES. Phytopathology

24: 1304-1312.

(115) PBASHAR, D. P., and LAMBETH, V. N.

1960. INHERITANCE OF RADIAL FRUIT CRACKING IN TOMATOES. Amer.

Soc. Hort. Sei. Proc. 76: 530-537, illus.
72 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OP AGRICULTURE

(116) PRITCHARD, F. J., and PORTE, W. S.

1923. WATERY-ROT ÓP TOMATO FRUITS. A PHYSIOLOGICAL FORM OP

OOSPORA LACTIS; EFFECT ON THE HOST; PENETRATION OF THE

CELL WALLS BY ENZYMIC ACTION. U.S. Dept. Agr. Jour. Agr.

Res. 24: 895-906, illus.

(117) RALEIGH, S. M., and CHUCKA, J. A.

1944. EFFECT OF NUTRIENT RATIO AND CONCENTRATION ON GROWTH

AND COMPOSITION OF TOMATO PLANTS AND ON THE OCCURRENCE OF BLOSSOM-END ROT OF THE FRUIT. Plant Phvsiol.

19: 671-678.

(118) RAMSEY, G. B.

1932. SULPHUR DIOXIDE INJITOY OF TOMATOES. Phytopathology 22:

267-268, illus.

(119)

1935. PLEOSPORA ROT OF TOMATOES. U.S. Dept. Agr. Jour. Agr.

Res. 51: 35-43.

(120) and BAILEY, A. A.

1929. DEVELOPMENT OP NAILHEAD SPOT OF TOMATOES DURING TRANSIT AND MARKETING. U.S. Dept. AgT. Jour. Agr. Res. 38:

131-146.

(121) and BAILEY, A. A.

1929. THE DEVELOPMENT OP SOIL ROT OP TOMATOES DURING TRANSIT

AND MARKETING. Phytopathology 19: 383-390, illus.

(122) and BAILEY, A. A.

1931. TOMATO LATE-BLIGHT ROT, A SERIOUS TRANSIT AND MARKET

DISEASE. U.S. Dept. Agr. Cir. 169, 11 pp., illus.

(123) and HEIBERG, B. C.

1952. CLADOSPORiUM ROT OF PEPPERS. U.S. Dept. Agr. Plant Dis.

Rptr. 36: 481-482.

(124) WiANT, J. S., and MCCOLLOCH, L. P.

1952. MARKET DISEASES OF TOMATOES, PEPPERS, AND EGGPLANTS. U.S.

Dept. Agr. Handb. 28, 54 pp., illus.

(125) RAYCHAUDHURI, S. P.

1952. STUDIES ON INTERNAL BROWNING OP TOMATOES. Phytopathology 42: 591-595.

(126) REITSMA, J., and SLOOFF, W. C.

1947. A DISEASE OF EGGPLANT FRUITS CAUSED BY PHYTOPHTHORA

PARASÍTICA DASTUR AND PHYTOPHTHORA PALMIVORA BUTLER.

Chron. Nat. 103: 60-63. Indonesia.

(127) RICH, SAUL.

1958. FERTILIZERS INFLUENCE THE INCIDENCE OP TOMATO INTERNAL

BROWNING IN THE FIELD. Phytopathology 48: 448-450.

(128) ROSE, D. H., WRIGHT, R. C, and BRATLEY, C. O.

1944. FREEZING INJURY OF FRUITS AND VEGETABLES. U.S. Dept. Agr.

Cir. 713, 31 pp.

(129) SEATON, H. L., and GRAY, G. P.

1936. HISTOLOGICAL STUDY OP TISSUES FROM GREENHOUSE TOMATOES

AFFECTED BY BLOTCHY RIPENING. U.S. Dept. Agr. Jour. Agr.

Res. 52: 217-224.

(130) SEGALL, R. H., HAYSLIP, N. C, and WALTER, J. M.

1963. EFFECT OF POSTHARVEST TEMPERATURES ON SEVERAL TOMATO

VARIETIES HARVESTED AT THE MATURE-GREEN STAGE. Pia. State

Hort. Soc. Proc. 76: 172-177.

(131) SHERBAKOFP, C. D.

1917. BUCKEYE ROT OF TOMATO FRUIT. Phytopathology 7: [119]-

129, illus.

(132) SHOEMAKER, R. A., and CREELMAN, D. W.

1958. THIRTY-SEVENTH ANNUAL REPORT OP THE CANADIAN PLANT

DISEASE SURVEY, 1957. Canada Dept. Agr. 132 pp.

(133) SiMONDS, A. 0., and KREUTZER, W. A.

1944. INFECTION PHENOMENA IN TOMATO-FRUIT ROT CAUSED BY

PHYTOPHTHORA CAPSICI. Phytopathology 34: 813-817, illus.
MARKET DISEASES OF TOMATOES, PEPPERS, EGGPLANTS 73

SMITH, R. W., and CROSSAN, D. F. '" -^ a-a-.-.-^^Jf if-f.

1958. THE TAXONOMY, ETIOLOGY, AND CONTROL OF COLLETOTRICHUM

PIPERATUM AND COLLETOTRICHUM CAPSICI. U.S. Dept. Agr.

Plant Dis. Rptr. 42: 1099-1103.

SPENCER, E. L., and BECKENBACH, J. R.

1949. BLOSSOM-END ROT OF TOMATOES. Fla. Agr. Expt. Sta. Clr.

S-6, 7 pp., illus.

SPURR, A. R.

1959. ANATOMICAL ASPECTS OF BLOSSOM-END ROT IN THE TOMATO

WITH SPECIAL REFERENCE TO CALCIUM NUTRITION. Hilgardia

28(12) : 269-295.

STEVENSON, J. A., and MCCOLLOCH, L. P.

1947. MYROTHECIUM AS A TOMATO FRUIT ROT ORGANISM. U.S. Dept.

Agr. Plant Dis. Rptr. 31: 147-149.

STONER, W. N., and HOGAN, W. D.

1950. A REPORT OF GRAYWALL OR INTERNAL BROWNING OF TOMATOES

IN SOUTH FLORIDA. U.S. Dept. Agr. Plant Dis. Rptr. 34:

379-380.

SWANK, G.

1953. THE PERFECT STAGE OF COLLETOTRICHUM FHOMOIDES ON TOMATO. Phytopathology 43: 285-287.

TAUBENHAUS, J. J., and EZEKIEL, W. N.

1931. LATE-BLIGHT ROT OF TOMATOES AND POTATOES. TeX. Agr. Expt.

sta. Cir. 60, 15 pp., illus.

TAYLOR, G. A.

1956. THE INFLUENCE OF SOME ENVIRONMENTAL AND NUTRITIONAL

FACTORS ON THE INCIDENCE OF INTERNAL BROWNING OF TO-

,,„ ., MATO. Ph.D. Thesis, Pa. State Univ., 90 pp.

1958. INTERNAL BROWNING OF TOMATOES. N. J. State Hort. Soc,

Hort. News 39(5) : 3333-3335.

THYR, B. D.

1965. BACTERIAL CANKER AND SPOTTED WILT OF TOMATO IN THE

iv. 1 P WEST-CENTRAL GREAT PLAINS. U.S. Dept. AgT. Plant Dis.

Rptr. 49: 386-387.

TiSDALE, W. B., and HAWKINS, S. 0.

1937. EXPERIMENTS FOR THE CONTROL OF PHOMA ROT OF TOMATOES. Fla. Agr. Expt. Sta. Bui. 308, 28 pp.

TiSDALE, W. H.

1916. A MBLANCONiUM PARASITIC ON THE TOMATO. Phytopathology

6: 390-394.

TOMPKiNS, C. M., and TUCKER, C. M.

1941. BUCKEYE ROT OF TOMATO IN CALIFORNIA. U.S. Dept. Agr.

Jour. Agr. Res. 62: 467-474, illus.

TOMPKiNS, D. R., and STARK, F. C.

1964. FACTORS ASSOCIATED WITH INTERNAL BROWNING OF TOMATO

FRUITS. Md. Agr. Expt. Sta. Bui. A-137, 29 pp.

TRESHOW, MICHAEL.

1955. THE ETIOLOGY, DEVELOPMENT, AND CONTROL OF TOMATO FRUIT

TUMOR. Phytopathology 45: 132-137.

TUCKER, C. M.

1931. TAXONOMY OF THE GENUS PHYTOPHTHORA DE BARY. MO. AGR.

Expt. Sta. Res. Bui. 153, 208 pp.

UNITED STATES DEPARTMENT OF AGRICULTURE.

1960. INDEX OF PLANT DISEASES IN THE UNITED STATES. U.S. Dept.

Agr. Handb. 165, 531 pp.

WALTON, C. L.

1937. THE CAUSE OF A "SPOTTING" OF TOMATO FRUITS (STIGMONOSE) .

Gardener's Chronicle 101: 12-14.

WEBB, R. E.

1962. AN UNUSUAL LOCAL EPIDEMIC OP TOMATO GHOST SPOT. U.S.

Dept. Agr. Plant Dis. Rptr. 46: 260.
74 AGRICULTURE HANDBOOK 2 8, U.S. DEPT. OP AGRICULTURE

(153) WEBER, G. F.

1932. BLIGHT OF PEPPERS IN FLORIDA CAUSED BY PHYTOPHTHORA CAPSICI. Phytopathology 22: 775-780.

(154)

1939. NAILHEAD SPOT OF TOMATOES. Fla. Agr. Expt. Sta. Bui. 332,

54 pp.

(155)

1940. BACTERIAL SPOT OF PEPPERS. Fla. Agr. Expt. Sta. Press Bui.

549,2 pp. ,... .r.r^ ,,, ,-.. -. : .

(156) and RAMSEY, G. B. '•,»,■■.re -,,.vs^, ..

1926. TOMATO DISEASES IN FLORIDA. Pia. Agr. Expt. sta. Bui. 185,

pp. 60-138.

(157) WHARTON, D. C, and BOYLE, J. S.

1957. THE PATHOLOGICAL HISTOLOGY OF THE INTERNAL BROWNING

DISEASE OF THE TOMATO. Phytopathology 47: 208-212.

(158) WHITE, H.L.

1938. FURTHER OBSERVATIONS OF THE INCIDENCE OF BLOTCHY RIPENING OF THE TOMATO. Ann. Appl. Biol. 25(3) : 544-557.

(159) WHITEMAN, T. M.

1957. FREEZING POINTS OF FRUITS, VEGETABLES, AND FLORIST STOCKS.

U.S. Dept. Agr. Mktg. Res. Rpt. 196, 32 pp.

(160) WlANT, J. S.

1941. PHOMOPSis FRUIT ROT OF TOMATO. Phytopathology 31: 24. ' ' '

(161) and BRATLEY, C. 0.

1948. SPOILAGE OF FRESH FRUITS AND VEGETABLES IN RAIL SHIPMENTS UNLOADED AT NEW YORK CITY, 1935-42. U.S. Dept.

Agr. Cir. 773, 62 pp.

(162) WILSON, A. R.

1963. SOME OBSERVATIONS ON THE INFECTION OF TOMATO STEMS BY

BOTRYTIS CINÉREA. FR. Ann. Appl. Biol. 51: 171.

(163) WiNGARD, S. A.

1924. BACTERIAL SOFT ROT OF TOMATO. Phytopathology 14: [4511-

459.

(164) YARNELL, S. H., FRIEND, W. H., and WOOD, J. F.

1937. FACTORS AFFECTING THE AMOUNT OF PUFFING IN TOMATOES.

Tex. Agr. Expt. Sta. Bui. 541, 64 pp., illus.

(165) YOUNG, P. A.

1946. TOMATO DISEASES IN TEXAS. Tex. Agr. Expt. sta. Cir. 113,

66 pp.

(166)

1947. CUTICLE CRACKS IN TOMATO FRUITS. Phytopathology 37: 143-

145.

(167)

1948. CHARCOAL ROT IN PEPPER ROOTS. U.S. Dept. Agr. Plant Dis.

Rptr. 32: 482-483.
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 1

FUNGUS DISEASES

A, Alternaría rot following growth cracks; B and C, alternaria rot at faulty

blossom scar; D and E, phoma rot; F, pleospora; G, anthracnose (early stage);

H, anthracnose (advanced stage).
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 2

FUNGUS DISEASES

A and B, Late blight rot; C, buckeye rot (early stage); D, buckeye rot (zoned

stage); E and F, soil rot; G, phytophthora rot; H, pythium rot.
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 3

B

FUNGUS AND BACTERIAL DISEASES

A and B, Gray mold rot; C, sour rot initiated on green fruit; D, sour rot on

vine-ripened fruit; E, rhizopus rot (early stage) ; F, rhizopus rot (advanced

stage) ; G, bacterial soft rot (early stage) ; H, bacterial soft rot (advanced stage).
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 4

FUNGUS DISEASES

A and B, Fusarium rot; C, phomopsis rot; Ö, early blight rot; E, cladosporium

rot; F, helminthosporium rot; G, ring rot; H, ghost spot.
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 5

H

BACTERIAL AND FUNGUS DISEASES AND INSECT INJURY

A and B, Bacterial spot; Cand D, nailhead spot; E, bacterial canker; F, bacterial

necrosis; 6 and H, cloudy spot.
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 6

'"ii^ '"

FUNGUS AND BACTERIAL DISEASES

A and B, Nailhead spot; C and D, bacterial spot; E, bacterial canker; F,

bacterial speck.
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 7

VIRUS MOTTLING

A and B, Tomato mosaic; C and D, double-virus streak; E and F, spotted wilt;

G and H, unidentified virus mottling.
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 8

B

PHYSIOLOGICAL DISEASES, INJURIES AND DEFECTS

A and B, Fruit tumor (waxy blister); C, sunscald; D, blossom-end rot; E, growth

cracks (radial); F, growth cracks (concentric); G, shoulder scars; H, pufflness.
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 9

PHYSIOLOGICAL DISEASES AND INJURIES

A, Fruit tumor (waxy blister); B, sunscald; C, pressure bruise; D, impact bruise;

E, blossom-end rot; F, G, and H, internal browning.
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 10

FREEZING AND CHILLING INJURY AND DECAY

A, Freezing injury (severe) ; B, freezing injury (moderate) ; C, freezing injury

(slight) ; D, chilling injury (severe) ; E and F, chilling injury with alternarla

rot following; G, severe chilling injury with alternaría rot following; U, chilling

injury with superficial scars caused by Mlernaria.
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 11

FUNGUS AND BACTERIAL DISEASES AND INJURY

A, Gray mold rot (early stages); B and C, gray mold rot; D, anthraonose; E,

bacterial soft rot at calyx; F, bacterial soft rot on pod; G, phytophthora rot;

H, sunscald.
Agriculture Handbook 28, U.S. Dept. of Agriculture i PLATE 12

CHILLING INJURY AND DECAY AND BACTERIAL SPOT

A, Sheet pitting, a symptom of chilling injury; B, death of calyx following chilling

injury; C and D, alternarla rot following chilling injury; E, cladosporium rot

following chilling injury; F, bacterial spot.
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 13

VIRUS MOTTLING

Various kinds of virus mottling.
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 14

BACTERIAL AND PHYSIOLOGICAL DISEASES AND INJURIES

A, Bacterial spot; 5, cloudy spot; C and D, sheet pitting, a symptom of chilling

injury; E, sunscald (severe); F, blossom-end rot.
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 15

FUNGUS DISEASES

A, Bacterial soft rot; B, pythium rot (cottony leak); C, rhizopus rot; D,

gray mold rot.
Agriculture Handbook 28, U.S. Dept. of Agriculture PLATE 16

iNJURIEñ AND FuNGUS DISEASES

A, Pitting and scald following chilling injury; B, alternarla rot following chilling

injury; C, phomopsis or fruit rot (early stages); D, phomopsis or fruit rot

(advanced stage showing fruiting pustules).
NATIONAL AGfilCULTURAL LIBRARY

1022414666

CAUTION

If pesticides are handled or applied improperly, they

may be injurious to humans, domestic animals, desirable plants, and pollinating insects, fish, or other

wildlife, and may contaminate water supplies. Use

pesticides only when needed and handle them with

care. Follow the directions and heed all precautions

on the container label.

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