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similar to the preceding. Spores of this stage remain viable until
the following spring when they germinate and infect the young
plants. Treatment. — Clean up and burn all dead stems after
the seasons growth has ceased. This will destroy great quantities
of spores, which are the source of infection. During dry seasons
flour of sulphur dusted over the plants while they are wet with
dew will keep the disease in check. A 5-5-50 solution of Bordeaux
mixture will prove effective.

The Palmetto variety is reported to be more resistant to the
rust than other varieties. •


Anthracnose (Colletotrichum Lindemuthianum). This disease
attacks pods, stems and leaves. The most conspicious injury is
done to the green pods. The disease first appears as small brown
spots, which enlarge rapidly, forming dark depressions. Under
favorable conditions these spots become pinkish in color, due
to the formation of spores. The mycelium of the fungus extends
through the pod into the bean, causing a discoloration of the
latter. Distribution of the fungus another year is assured through

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such infected seed, as the fungus mycelium remains dormant here
until it is placed under favorable conditions of warmth and
moisture. Warm damp soil is aii ideal place for its development.

(From Bui. No. 239 New York (Cornell) Agr. Exp. Sta.)

Remedy. — Seed selection is the most important means of con-
trolling this disease. It is not, however, sufficient to select seed
apparently free from infection for many minute infections will be
overlooked. The surest method is to select seed from healthy
pods, preferably from a field which is free, or practically free of
the disease.

Spraying with Bordeaux mixture, 5-5-50 formula is to be
advised when the dist:ase first appears. Crop rotation must also
be practiced.

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Indiana State Entomologist. 79

RitsL — (Uromyces appendiculatus). The rust causes a yellow-
ing and subsequent dying of the leaves with a production of dusty
red rust spores. The disease is usually more destructive to late
plantings than to the early crop. In severe cases the fungus
attacks not only the leaves, but stems, petioles and pods. Rota
tion of crops and burning of the vines and leaves are the only
practical means of keeping the disease in check.


Leaf -Spot (Cercospora Beticola). This causes spots to
occur over the entire surface of the leaves. In color these spots
range from brown to grayish, surrounded with a purplish margin.
Severe cases entirely kill the infected leaves, causing them to
drop from the plant. A 5-5 50 Bordeaux mixture will materially
check the disease.

(Prom Farmer's Bui. No. 618, U. S. Dept. Agr.)

Beet Scab (Oospora scabies). The beet scab is caused by
the same organism causing the common potato scab. It causes
a rolighened, and sometimes almost warty condition of the beet
surface. Beets should not be planted in soil that has previously
grown scabby beets or potatoes.


Club Root. — (Plasmodiophora Brassicae) produces large swell-
ings on the roots, stunting and frequently causing death of the
plants. The club root organism also attacks turnips, mustard,
rutabaga and other closely related plants. The disease lives in

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80 Ninth Annual Report

the soil and may survive there for several years. Soil once
inoculated with the organism should be planted in such crops as
corn, wheat or some non-cruciferous crops for a number of con-
secutive years before it is again planted in cabbage. Experi-
ments have proved that an application of 76 to 80 bushels of fresh

(FYom Bui. No. 185, Vermont Agr. Ex. Sta.)

stone lime per acre, thoroughly incorporated into the soil will
materially reduce the danger of infection. No other practical
means of controlling the disease is known at present.

Black Rot (Pseudomonas campestris). This is a compara-
tively new disease of cabbage and other closely related plants as
kale, turnips, cauliflower and mustard. The causitive organism,
which is a bacterium, enter the cabbage plants through the pores

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Indiana State Entomologist. 81

at the margins of the leaves, causing them to first present a burnt
edge appearance. Later the infected leaves turn yellow, except
the veins, which become brown or black. Presumably the disease
passes down through the leaves and up through the stem to the
head, ultimately rotting the entire head.

Treatment. — The disease may be carried from field to field
by infected plant parts, or by farm implements being dragged
from an infected field to a field free of the disease. The disease
may also be carried from one section of the country to another on
cabbage seed. Just previous to planting, seed should be soaked
for fifteen minutes in a solution of mercuric bichloride one part
to one thousand parts water; or formaldehyde one part to two
hundred' parts water for twenty minutes. The seed bed should
be changed frequently, as this is often the principal source of in-
fection. Practice a crop rotation or cease planting cabbage in
your fields for a few years. Insects, especially grasshoppers are
very largely responsible for the distribution of the disease in the


Blight or Leaf Spot. — Two species of leaf spot fungi attack
celery. One (Cercospora apii) causes large irregular spots on the
leaves during the summer. This disease is common here, but is
not considered especially injurious to the crop.

The Winter Blight, — (Septoria petrosetini) causes smaller
but more numerous spots than the preceding. This disease
causes a stunting in growth, and a decay of the leaves and stems
in storage and shipment. Frequent applications of Bordeaux
mixture will lessen the injury by this fungus.

Root and Stem Rots. — Under such conditions as wet cold
weather, poorly drained soil with a high acid content, soil fungi
will frequently cause decay of the roots and stems. Such troubles
can only be prevented by removing the unfavorable condition.

CUCUMBER (See Melons)

Anthracnose. — A fungus causing depressed spots on the
fruit. Not serious.

Bacterial Wilt. — Causing wilting and subsequent dying of
the plants. It is caused by the same organism (Bactarium
solanacearum) that causes tomato wilt. Wilted plants should be
promptly pulled and burned.


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82 Ninth Annual Report

(From Cir. No. 73, Ohio Agr. Exp. Sta.)

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Indiana State Entomologist. 83


Downy Mildew, — (Bremia Lactucae). The symptoms of this
disease are downy covered areas on the under side of the leaves,
and is manifested on the upper surface as yellow spots. This
trouble can be controlled in the greenhouse by regulating the
heating, ventilating and watering of the beds. Avoid too high
temperature or too free applications of water.

Lettuce Drop, — This fungus (Sclerotinia Libertiana) causes
the lettuce grower more trouble than all others combined. The
plant rots off at the surface of the ground, and finally the entire
plant decays down in a soft mass. It has been clearly demon-
strated by experiments that the beds can be entirely freed of this
disease by promptly removing all plants when showing the first
symptoms of this disease.


Anthracnose, — (Collectotrichum Lagenarium). The Anthrac-
nose of melons, cucumbers and squashes is a disease of both fruit
and leaves. It causes irregular rusty spots on the latter, and
water soaked, sunken spots on the fruit. This disease does not
cause a deep rot, but it mars the appearance of the melon and
greatly reduces its market value. This disease can be partly
overcome by spraying the vines every ten days or two weeks
with Bordeaux mixture of a 5-5-50 formula.

Bacterial Wilt, — (Bacillus tracheiphilus). This is considered
the most serious disease among curcurbits in the United States.
The symptoms consist of a progressive wilting of the entire
plant. Infection usually takes place at the distal end of the vine.
From there the wilting gradually progresses to the main stem,
then other runners become infected and wilt. Insects, especially
the striped cucumber bettle, are largely responsible for the spread
of the disease. All wilting vines should be removed as soon as


Dry Rot, — (Sclerotium cepivorum). This is principally a
storage trouble, and is confined mainly to the white varieties, that
are grown for special markets, where it is the practice to harvest
early before the tops mature in order to produce an extra
white product. When onions are harvested at this stage the

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green tops are pulled off, leaving an inviting place for entrance
of disease. A decay sets in at this point, later forming con-
spicuous black masses at the top end. Crop rotation is the only
present known method of controlling this disease. Onions
decayed by this fungus should never be hauled to the field, but
should be buried or burned.

Smudge, — (Vermicularia Circinans). This disease is not a
serious one, as it causes no rot of the onions, only superficial
spotting of the outer layers. It is often, however, sufficiently
severe to reduce their market value.

SmuL — (Urocystis cepulae). Only very young onions are
susceptible to attack of this fungus. It attacks the lower por-
tions of the first leaves, causing them to wither and fall. Later
longitudinal rifts are formed on leaves and bulb, these burst,
exposing masses of spores. Infected soil is the chief source of
trouble. In small plots or gardens the trouble can be prevented
by transplanting seedlings that have grown in disease free beds.
For field practice a solution of formaldehyde at the rate of one
pound to thirty gallons of water can be sprinkled in open furrows,
after the seeds have been sown, or applied with a special formal-
dehyde drip attachment on the seeder at the rate of one hundred
twenty-five to one hundred fifty gallons per acre. This method
of treatment is quite effective.


Anthracnose. — (Ascochyta Pisi). The anthracnose of the pea
is very similar to the bean anthracnose in its method of attack.
It infects stems, leaves and pods. The fungus thread extends
through the pod into the pea, thus infecting seed for the next
years crop. Diseased seed gives rise to diseased seedlings and
causes a loss of the crop. The most practical methods of con-
trolling this disease are to practice crop rotation and plant seed
grown from healthy plants. Spraying with Bordeaux mixture will
also aid in controlling the trouble.

Powdery Mildew. — (Erysiphe comminis). The mildew is
frequently quite severe in this state, and causes complete loss of
the crop; the fungus causing a whitish covering upon the leaves.
Thorough spraying with Bordeaux mixture will prevent the

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Fusarium Blight (Fusarium oxysporum). This fungus causes
both a disease of the vine and rot of the tubers. The trouble is
not distributed generally throughout the State, and its attack is
influenced very much by climatic conditions. During the rainy

(From Special Bui. No. 66. Mich. Agr. Exp. Sta)


Showing production of spores

(From Bui. No. 229. Ohio Agr. Exp. Sta.>

season of 1915, it caused a heavy loss to the growers of Indiana.
The fusarum disease causes wilting, yellowing, and in severe cases
dying of the tops. Infection seems to take place on the roots.
Insipient infection of the tubers cannot be detected unless they are

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86 Ninth Annual Report

cut crosswise, when the disease will show by the vascular ring
being discolored. In storage, however, Q.nd often in the field,
this ring will become black. A dry rot will set in at the stem end,
that will sooner or later involve the entire tuber. For control
practice crop rotation.

Early Blight (Macrosproium Solani). A leaf blight, causing
brown circular, or elliptical spots with concentric ring to appear
on the potato leaves. These spots are often so numerous as
to materially impair the functions of the leaves, consequently
reducing the yield. Frequently applications of Bordeaux mixture
will prevent the disease.

(From Bui. No. 135, Wisconsin Agr. Exp. Sta.)

Late Blight (Phytophthora infestans). The late blight of
potatoes is no doubt the most disastrous in the region where it
occurs. This disease is seldom seen south of the latitude of
Columbus, Indiana. It occurs in the northern section of the
State, periodically during season, accompanied by excessive
moisture and low temperatijre. The symptoms are very marked
and characteristic. Upon the leaves the fungus produces
spots, frequently beginning at the margin and under favorable
conditions rapidly involves the entire leaf. The spots have tf**'
dark water-soaked appearance, often with a purplish tint. Spore^' ^
are formed in abundance on these spots that are distributed ovef^-^'
the field by the wind. Plants infected with late blight wfll; ^ ^

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Indiana State Entomologist. 87

within a few days of good blight producing weather, present the
appearance of being severely frosted. Spores from the infected
leaves are carried into the ground by rain or insects and there
infect the tubers, causing a dry rot. Control methods consist
in spraying thoroughly every week or ten days, as long as practical
with Bordeaux mixture, during an attack of blight.

Potato Scab (Oospora scabies). This is a well known, and
widely distributed disease of the potato tuber, that needs no
description. The scab producing organisms have the power to live
over in the soil from one season to the other, therefore it is very
important to rotate. Potatoes planted in freshly manured, or
recently limed soil, are likely to produce a crop of scabby potatoes.
To secure potatoes free of scab, clean tubers should be planted in
soil free from the scab fungus.

Seed treatment consists in immersing the tubers for about
two hours in a solution of one ounce of formaldehyde to every two
gallons of water, or in a solution of bichloride of mercury, made
by dissolving one ounce of the compound to eight gallons of water
for the same length of time.

Either treatment may be done several days previous to
planting, providing the treated potatoes are not exposed to
re-infection or placed in boxes or bags previously holding scabby
potatoes, unless the boxes or bags have also been soaked in the


Black Rot (Ceratocystis fimbriata). This fungus is directly
responsible for the abandonment of commercial growing of
Sweet Potatoes in some localities. The writer can testify to
this by his own experience with this crop in Southern Indiana.
The most dreaded phase of the disease is what is known as the
''Black Shank", by which name the disease is known by many
growers. This stage begins in the hotbed, and frequently before
the plants are transplanted to the field the roots and stems below
the surface of the ground are black and soft. Incipient stage of
''Black Shank" may appear as a brown or black spot on the stem
near the old seed-root. Dead blackened roots will often be the
first indication of the trouble. Diseased plants transplanted to
the field will refuse to grow, turn yellow and finally die. Or if
they should struggle through the season they will produce diseased
roots, that if planted the following spring will inoculate the seed

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88 Ninth Annual Report

bed and be the source of trouble for another year. The fungus
also causes spots and decay on the potato. We know of but one
sure method of overcoming this swjBet potato trouble, i. e., select
"seed" from fields absolutely free of the disease; plant only smooth,
clean roots, in soil you know is not inoculated by the disease
spores; discard all plants at transplanting time that show any
symptoms of the disease and plant in a field that did not grow
sweet potatoes the year previous.

Bin Rot (Rhizopus nigricans). The bin rot fungus is one of
our most common molds that attack many forms of vegetable
matter. It causes a soft rot of sweet potatoes in storage, if the
house is kept at too high a temperature and is not properly
ventilated. This same mold causes the soft-rot in the seed-bed.
The soft-rot in the seed-bed can be thoroughly controlled by
soaking the roots just previous to layering with bichoride of
mercury one ounce to eight gallons of water for fifteen or twenty


Fusarium Wilt. — The first symptoms of this disease is a
yellowing of the lower leaves, which soon dry up without spotting.
Later the entire plant becomes sickly looking of unhealthy color,
followed by symptoms of wilting. The disease attacks plants of
all ages. After they have begun to set fruit seems to be the most
susceptable' stage. The wilt fungus ordinarily does not aflfect
all the plants in the field at the same time, but the trouble comes
in gradually wilting a plant here and there. In badly infected
soil, however, all plants will die before the end of the season.

This trouble is not confined to field conditions alone, but also
causes enormous loss to greenhouse men.

Treatment. — As the wilt fungus is within the stem and roots
of the tomato plant, no advantage will be gained by spraying.
Only sanitary methods of control will yield results. Particular
attention should be given to the seed-bed. Seed should be sown
only in clean, disease free soil. The seed bed should either be
changed each year or the old bed treated with formaldehyde or
steam. Greenhouse soil once inoculated with spores of the wilt
fungus must either be changed or sterilized. Proper attention
given to the seed beds and a system of crop rotation will almost
assure immunity against this disease under field conditions.

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Indiana State Entomologist. 89

Mosaic Disease, — The symptoms of this disease are striking
and conspicious. The ordinary indications are that the leaves
become mottled with a coloring of yellow and green. Plants
afifected with this trouble often produce an abnormal growth,
either a lengthening of the leaves and internode or a narrowing
of the leaves, or a combination of all symptoms. Often the leaves
are narrowed to mere skeletons. Mosaic plants are nonpro-
ductive, arid should be destroyed as soon as observed. The
remedy is pointed out by
the fact that the disease
may be transmitted by
first touching diseased
then healthy plants.

Septoria Blight
(Septoria Lycopersici) .
This is the most widely
and generally] distribut-
ed tomato disease we
have to contend with.
It first appears as
small inconspicuous
spots on the lower and
older leaves. The disease
progresses upward
rather rapidly, killing
the leaves and causing
them to fall. During
seasons favorable for
the blight disease, the septoria blight op tomato

entire crop mav be An lower leaves have faUen off.

, (Prom Bui. No. 192, Virginia Agr. Exp. Sta.j


Treatment consists in planting the seed in disease free beds.
Many growers make the mistake of allowing unused plants to
mature , in their seed beds. These plants invariably become
diseased and thoroughly inoculate the seed bed soil. Plants
grown in soil infested beds will become diseased before trans-
planted to the field.

A 5-5-50 formula of Bordeaux mixture applied every ten
days or two weeks until the plants become too large, will effective-
ly control this disease. The first two sprayings should be done in

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90 Ninth Annual Report

the beds, while the plants are small. A good practice to follow
is to spray just previous to transplanting, then allow an interval
of about three weeks after the plants have been transferred to the
field before giving the next application.

Bacterial Blight — Causing sudden wilting of the plant, and
later death. The bacteria which causes this trouble lives within
the tissues of the plant, thus clogging the vascular system, pre-
venting the movement of water and food from one part of the
plant to another. Spraying will not control or prevent this
disease. Wilting plants should be pulled and removed from the
field as soon as noticed.

End Rot. — Tomatoes rotting at the blossom end, especially
during the beginning of the ripening season is a very common
occurence. This is a physiological trouble due to scant water
supply. The end rot is especially severe during a drouth. Culti-
vation in the field is usually impossible at the ripening season,
owing to the large size of the vines. The trouble in the green-
house can be controlled by supplying the plants with a greater
quantity of water.

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Indiana State Entomologist. 91



It is generally understood by those who are engaged in garden-
ing and greenhouse work that the soil is inhabited by insects
and other organisms, microscopical in nature. Also it is under-
stood that some of these organisms are useful in breaking down
compounds, making them available for plant food, while other
soil organisms are extremely harmful to the plants growing in the
soil. How to treat the highly valuable soil in such a way as to
destroy the undesirable soil organisms without injuring the
productivity of the soil is one of the intricate problems the in-
tensive gardener and greenhouse man have to, solve.

The cost of producing flowers and vegetables is high and
is on the incline, and the grower cannot afford to plant a crop
that may result in only a partial stand, sickly, slow growing
plants, or a low yield.

The grower may have built his soil up to a high state of
fertility; he may have planted his seeds, plants or cuttings at the
proper time in soil of good till ; he may follow proper methods of
watering, heating and ventilating, but if his soil has been used for
several years without treating, it may be so badly infested with
parasitic micro-organisms that the crop will be unable to produce
its maximum yield.

In order to be able to combat an insect or fungous enemy
one must first understand its nature. These harmful soil organ-
isms may be either low microscopic forms of animals or plants,
generally either fungi or bacteria. Some forms are capable of
living, thriving and multiplying while subsisting upon the decay-
ing vegetable matter in the soil, in fact these organisms cause the
manure, compost, and other forms of vegetable matter in the soil
to decay and thus liberate the imprisoned plant foods. We
would not object if the fungi and bacteria were content to pro-
cure their subsistence from the dead matter in the soil, as they
render us a great service in doing this, but on the other hand they
persist in attacking the seeds that are planted in the soil, causing
them to rot. They attack the young seedling underneath the
top of the soil, or just at the surface, causing the plants to "damp
off''. These soil organisms also attack mature plants, causing
such common maladies as lettuce rot, tomato wilt, cucumber

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92 NrNTH Annual Report

wilt, carnation yellows, rotting of cuttings, damping ofif of seed-
lings, and have been reported to attack other plants of less im-
portance as ornamental asparagus, china aster, sweet william,
violets, begonia, coleus, verbena, phlox, snap dragon, etc.

The last two decades have witnessed the recommendation
of a number of methods for the destruction of these plant disease
producing soil organisms. Only three are sufficiently important
to consider in this paper. These three methods essentially
involve two principles: First, sterilizing the soil by subjecting
it to a high temperature by steam, either by the perforated pipes
or the inverted pan method. Second, sterilizing the soil by
drenching it with formaldehyde. These three methods will
allow sufficient elasticity to be adaptable by all. The steam
sterilization methods can be used by forcing — house mm and those
having a portable boiler or engine.


This method of soil sterilization consists in a system of per-
forated pipes of convenient length to handle, about thirty feet,
plugged at one end. The opposite end is connected to crossheads
with high pressure boiler connection. The pipes should be about

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