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LHXAS AGRICULTURAL EXPERIMENT STATION.

BULLETIQT N0. "z,

NOVEMBER, 1889.

COTTON ROOT-HOT

AGRICULTURAL AND MECHANICAL COLLEGE,

College Station, Brazos County, Texas.

BY ORDER OF THE COUNCIL: F. A. GULLEY, DIRECTOR.

 
    
     
 
  

    
     
    
  

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AUSTIN:
STATE PRINTING OFFICE.
l8 9 0

TEXAS AGRICULTURAL EXPERIMENT STATION.

OFFICERS.

BOARD OF DIRECTORS OF A. AND M. COLLEGE.
MAJ. A. J. ROSE, President . . . . . . . . . . . . . . Salado.
Hon. L. L. FOSTER, State Com. Agriculture. .Austin.
W. R. CAVITT, Esq . . . . . . . . . . . . . . . . . _ . . .Bryan.
DR. J. D. FIELDS . . . . . . . . . . . . . . . . . . . . . . .Manor.
J. ADRIANCE . . . . . . . . . . . . . . . . . . . . . . . . . . .Co1umbia.
PRoF. L. L. McINms, Secretary . . . . . . . . .Co11ege Station.

EXPERIMENT STATION COUNCIL.

L. L. MGINNIs . . . . . . . . . . . . . . . . . . . . . . . . Chairman of Faculty.
T. M. SooTT . . . . . . . . . . . . . . . . . . . . . . . . . . . Agent of the Board.
F. A. GULLEY . . . . . . . . . . . . . . . . . . . . . . . . . .Director of the Station.

STATION STAFF.

F. A. GULLEY, M. Sc . . . . . . . . . . . . . . . . . . . .Director.

G. W. CURTIs, M. S. A . . . . . . . . . . . . . . . . . .Agricu1turist.

H. H. HARRINGTON, M. Sc . . . . . . . . . . . . . . . .Chemist.

T. L. BRUNK, B. Sc . . . . . . . . . . . . . . . . . . . . .Horticu1turist.

M. FRANCIS, D. V. M . . . . . . . . . . . . . . . . . . . .Veterinarian.

W. WIPPREcHT, B. S. A . . . . . . . . . . . . . . . . .Assistant Chemist.

J. W. CARSON . . . . . . . . . . . . . . . . . . . . . . . . . .Assistant to Director.

D. ADRIANCE . . . . . . . . . . . . . . . . . . . . . . . . . .Asst. Chemist and Meteorologist.

J. M. OARSOII . . . . . . . . . . . . . . . . . . . . . . . . . .Assistant to Agriculturist.

C. K. FUQUA . . . . . . . . . . . . . . . . . . . . . . . . . . .Sugar Chemist.

COTTON ROOT-BOT.

1n a preliminary bulletin on “Root Rot”1 a brief account of the character of
the soil, some of the theories, and the fungous nature of the disease was given.
To make the account 0f this disease as nearly complete as possible, some of
the facts already published will be used in this report.

Planters quite generally believe that the character of the soil has much to do
with the diseasefi but from observations in the field for two seasons, and the
answers received to a circular postal card sent out by the Station, it is evident
that nearly all classes of soil are more or less subject to it, though the alluvial
bottoms of the Brazos and Colorado rivers. and the Gulf prairie region near
the coast, are exempt so far as I can learn. It occurs, however, in the north-
ern tier of counties of the Gulf prairie region, as in Washington, Fayette, and

. Austin. It is, then, in the central black prairie region of Texas and just

south of it where planters suffer most from the disease.
Its northern boundary is the Red River as far east as Paris, Texas, extend-
ing in a southwesterly direction to San Antonio and thence westward. Its

western boundary in the north is Montague, Wise, Parker, and Hamilton,

counties. A white rotten limestone, which often crops out, underlies the
entire region. The soil of these rolling and black waxy prairie lands is very
retentive of moisture, especially so when limestone comes near the surface.
A certain amount of moisture is essential for the growth of the fungus. It
is not uncommon to see cotton dying on these limestone ridges and slopes
when none is affected in any other part of the field. On these limestone
slopes I have frequently noticed that water collects in the form of drops on
‘the tap-root. But it must be borne in mind that cotton is not always afiected
in such places.

The character of the forest growth is frequently mentioned as indicative of
the disease, thus hickory, sumach, shittim, mesquite, and post oak are all
said, in localities where these trees abound, to be associated with the disease.
‘Careful investigation has shown that they are not at all indicative. Though
the live, post, and black jack oaks, osage orange, prickly ash, pecan, mesquite,
sand others are found on particular soils, the disease occurs alike on the live
oak glades of Washington county, on the post oak soils of Eastern and North-
ern Texas, and on the osage orange soils of Grayson, Collin, and Dallas Coun-
ties, or on the mesquite soils of Milam, Travis, and Hays Counties.

It will be seen from the list in the foot note?’ that the character of the forest
growth of the different regions is not alike, yet in each case the disease occurs.

lTexas Agricultural Experiment Station Bulletin 4, p. 18; also first Annual Report, p. 50.

21. The timbered upland region of East and Central Texas, including the Upper and
Lower Cross Timbers, pineries, long leaf-pine hills and flats.
2. Southern coast prairies.
3. Central black prairie region.
4. Northwestern red-loam lands.
5. Western and northwestern region, including gypsum lands, Llano Estacado or Great
Plain, and mountain region.
6. River alluvial lands, including the Brazos delta and Sugar Bowl.

3The trees in this list were found growing in close proximity of dying cotton. Washing-
ton County is in the Gulf prairie region, and the following trees were noted: Water Oak
(Quercus aquatica, Walt.), Live Oak (Q. virens, Ait.,), Black Jack (Q. ndgra, Linn.), Post Oak

6 Tsxas Agrzku/Zura/ Experiment Slalzbn.

THEORIES.

It is not surprising that theories of various kinds should be formulated to
account for the sudden dying of cotton. Much prominence is given to the
idea that certain chemical or physical conditions of the soil cause the root to
decay, and therefore the subject of “root rot” can not be solved in any other
way except by a chemical analysis; but a careful chemical analysis of affected
and not affected soils does not show any appreciable difference so far as its
makeup is concerned/i

Dr. Yoakum believes that the “dying of cotton ”5 is due to an excess of
sulphuric acid in the soil, which is formed from sulphideiof iron which exists
everywhere in Texas. Sunlight and air acting on sulphuric acid form sul-
phate of iron, which is destructive, not only to man, but to vegetation also.
But analysis made at the Station by Mr. Wipprecht, and those given by Hil-
gardfi in his report on Cotton Production, only show traces or small amounts
of sulphuric acid. Experiment has shown that a two and a half per cent so-
lution of copperas does not act injuriously on the roots of cotton. Many be-
lieve that an excess of lime in the soil causes death of the plant. In some
cases the percentage of lime in the affected land is high, as at San Marcos. At
Independence it is just the reverse. Lime as it exists in the soils of Texas
can do little injury to vegetation. It is, moreover, a very valuable ingredient
of soils, being especially important in the process of nitrification.

In 'Washington and Grimes counties snail shells abound in the prairie soils,
but also in the alluvial bottoms of the Brazos. In the prairie soils where they
exist the shells are supposed by decomposition to cause death of the cotton
root. These shells are made up largely of calcium carbonate, which, as stated
before, is a valuable ingredient of soils. Not a single cotton plant at Allen
Farm, or in the Brazos bottom opposite Washington, or at Calvert, dies from
this disease, though snail shells are exceedingly common. An analytical chem-
ist attempts to account for the disease as follows: Sulphuric acid is absent,
a large amount of humus, which in the fresh soil exists as humic acid, in com-

Q. obtusiloba, Michx.), Hackberry (Gem's occidentalis, Linn.), Cedar Elm (U lmas crasszfolia,
N uttall), Yaupon (I Zea Oassine, Walt), Prickly Ash (Xanthowylum Olava-Herculis, Linn.),
Persimmon (Diospyros Wrginana, Linn.), Shittim (Bumelia Zanuginosa, Ait.), Hickory (Oarya
tomentosa, N uttall), Mock Orange or Cherry-Laurel (Prunas Caroliniana, Ait).

In the timbered upland region of East and Central Texas, in the counties of Grimes, Brazos,
and Robertson: Oaks (Qaercas aqaatica), (Q. obtasiloba), (Q. nigra), Spanish Oak (Q. falcata,
Michx.), Cotton Wood (Populus monilifera, Ait.), Red Mulberry (Morus rubra, Linn.), Black
Walnut (Jaglans nigra, Linn.), Pecan (Oarya olivazformis, N uttall), 0'. tomentosa, Diospyros
Wrginiana, Sumach (Rhus copallina, Linn.), Honey Locust (Gleditschia triacanthos, Linn.),
Bumelvla Zanuginosa, Mesquite (Prosopis juliflora, D. C.)

In Burnet, Travis, and Hays Counties: Prosopis jalijiora, Rhas copallina, Linn., var. Zan-
ceolata, Gray., Mexican Persimmon (Diospyros Tswana, Scheele), Oeltis occidentalis, Barberry
(Berberis Wzfoliolata, Moric), Qaercus obtasiloba, Q. lyrata, Red Cedar (Juniperas Wrginiana,
Linn.), Ungnadia speciosa, Endl., I lea; decidua, Walt.

In Ellis, Dallas, Grayson, and Collin Counties of the central black prairie region: Red Bud
(Oercis Oanadensas, Linn.), Gleditschia triacanthos, Rhas copallina, Dogwood (Oornus pain-
culata, L’Her.), Chicasaw Plum (Prunus Oh/Zcasa, Michx.), Diospyros Wrginiana, Bumelia lana-
ginosa, Geltis occidentalis, Sassafras ofiicinalis, Juglans mjgra, Sycamore (Plantanus occidentalis),
Garya olivceformis, U lmas crasszfolza, Bois d’Arc or Osage Orange (Maclura aurantiaca,
N uttall), Morus rubra, Populas monilzfera, Sapindas marginatas, I lax decidua, Xanthoxylum
Glava-Hercalis, Junzperas Wrginiana, Qaercus lyrata, Q. obtasiloba, Q. nigra, Q. llflcnauxiz’,
N uttall, Crataegas sp.

‘First Annual Report of Texas Agricultural Experiment Station, p. 24.

‘Texas Farm and Ranch, October 7, 1,886.

‘Tenth Census Report, Cotton Production, vols. 5 and 6.

Cation Root-Roz‘. 7

bination with alumina and iron forming insoluble humates of these bases.
Where the subsoil is saturated with water for a portion of the year the usual
decomposition into carbonic acid, ammonia, and water will not take place, but
instead humic acid will be found. The surface soil being more exposed to
the air is not so saturated, hence humic acid will not be formed, and there-
fore surface rooted plants are not subject to the disease.

Mr. Wellborn’s views are given belowfi

“We know that on swamp lands or ponds when first drained the vegetable
matter in the soil and subsoil has too much acid by being submerged, where
the air could not penetrate, but when exposed to the air it sweetens; so the
surface is in condition to start vegetation, but of coursethe deeper the longer
it takes. It takes several months’ air to sweeten when it has fair play at it;
but if air can not penetrate the soil on account of either excess of water or
compact condition of the surface, how can it be sweetened? And of course,
as the humus is taken from the surface soil by plants, it cements or runs to-
gether more closely. This would naturally bring the acidity nearer the sur-
face, and would cause the root rot to commence earlier and be more severe.
If the land cannot be thoroughly drained it should be kept in beds or ridges,
with deep furrows run deep in the water furrows as soon as convenient in the
spring. and use manures or fertilizers containing nitrogen or potash, or both.
Bury them as deep as possible under the beds when heading up, which should
be done during fall if convenient, and before the subsoil saturates with water.
It seems that the blight confines itself almost if not wholly to the ‘hog wal-
low prairies’ and ‘post oak flats.’ It is evident that both the prairie and flats
have, in times past, received an excess of vegetable matter, but still the sur-
face is hard and compact instead of loose and friable, as soils filled with
humus and which have perfect drainage should be. But where this vegetable
matter is submerged eight months out of twelve, instead of turning into plant
food (ammonia) it must turn into acids and eat off the roots. We see that
timber on swamp lands keep all their roots near the surface, occasionally
showing above ground.” .

Dr. Loughridge8 accounts for the “dying of cotton” either through lack of
drainage, or by some cause that arrests the extension of the tap-root down-
ward in its search for moisture. “A tap-root of cotton, in its search for mois-
ture, penetrates the earth many feet, and it is not improbable that it may
come in contact with an impervious stratum of clay or limestone, or a rock
may be in the way of a single root, thus producing decay.” Young cotton
plants are especially liable to succumb from a disease called “sore-shin”9 as
a result from mechanical injuries.

This disease is wholly different from “seedling rot,” which is often called
“sore shin.” An account of “seedling rot” will not be out of place in this con-
nection.

Throughout the South cotton planters are much annoyed by it. Young
cotton plants rot close to the ground; at first the parts turn brown, ultimately
shrivel up, and the plant wilts. In some cases “seedling rot” may be due to
the difficulty with which the germinating plantlet removes itself from the seed-.

 

iTexas Farm and Ranch, July 15, 1889.

STenth Census Report, Vol. V, Pt. I, p. 30.

9This term is also applied to older plants when injured mechanically. The injured surfaces
of such plants frequently contain a gummy exudation. It is not improbable that this helps
to repair the wound, as it does not allow the air to come in contact with the wound. Hartig
(Zersetzungserscheinungen des Holzes, Berlin, 187 8, p. 69) has shown this to be the case with
the exudation of liquid resin in Conifers.

8 Texas Agrzku/Zural Expemmenz‘ Sfafzbn.

coats, and thus becomesmore subject to this rot. Planters, however, attribute
it to sudden changes in weather, from warm to cold and moist. In some ex-
periments conducted in a green house, at Ames, Iowa, and College Station,
Texas, I found one-fifth of the young seedlings dying from “seedling rot,” and
this, I should say, is not an uncommon experience. 1 °

Diseased seedlings have been examined; the mycelium of a fungus was
found, but no fruit.1 0“

It hardly seems probable that a large number of plants in different parts
of the field should come in contact with a solid stratum of rock, or that the
tap-roots of a large number of plants should receive mechanical injuries, and
as a result death follow. It is a common practice of nurserymen to place
young seedlings on a rock to avoid the formation of a tap-root, and no inju-
rious effects ever come from this practice so far as I know. Investigation
has shown that the depth of the underlying strata varies greatly; that cotton
dies where the strata are superficial and where they are removed many feet
from the surface. Only a few plants have been found that were killed by
the fungus which had also received mechanical injuries. I can not insist too
strongly on the fact that the lower part of the tap root is often healthy while
the thickened upper portion is completely invested with the fungus. In such
cases some of the lateral roots also have their normal color.

The insect theory has many followers, but after a thorough examination of
a large number of affected plants, I am convinced that insects in no way cause
cotton to die. The insects and worms found in the roots of cotton and sweet
potatoes live on the decaying substance. Attention should be called to the
apple-root plant-louse (Schizoneura Zanigera, Hausm.), which is common on
apple roots in Texas. This will be referred to again in another connection.

1°Darwin. (The Power of Movements in Plants, London, 1880, p. 168). Could only make
few experiments to test the sensitiveness of the apex of the radicle, as they soon became un-
healthy when suspended in the air.

1 “It has long been known that clover, pepper grass, shepherd’s purse, millet, Indian corn,
and other seedlings are subject to the attacks of a parasitic fungus (Pythium De Baryanum,
Hesse), a fungus closely related to potato rot, Phytopthora mfestans, and the grape vine mildew,
Peronospera oiticola. The Pythium fungus causes the parts near the ground to turn brown.
The stem or root shrivels up and the plant soon Wilts.

Most of the species of the Pythium are saprophytic, while some are facultative parasites

to some extent. De Bary (Comparative Morphology and Biology of the Fungi Mycetozoa
and Bacteria, English translation, Garnsey and Balfour, Oxford, 1887, p. 382) says that Pythium
De Baryanum is not only a parasite attacking living and healthy plants with its germ tubes, but
grows equally well on decaying organic substances. It is parasitic on a large number of
Monocotyledons and Dicotyledons and the Prothallia of ferns. It does not, however, attack
such algae as Spirogyra and Vaucheria. The fungus is especially troublesome to members
of the mustard family (Oraciferce, also Amarantus). It destroys them completely in a very short
time. Full grown land plants are not so readily subject to its attacks, but when such plants
are placed in water they are readily attacked and destroyed. Another fungus belonging to
this group also attacks and destroys seedlings, especially trees; it is Phytopthora omnivora,
De Bary, and is closely related to the potato rot. This fungus was fully described and stud-
ied by Hartig. (Untersuchungen aus dem Forstbotanischen Institut, 1880, pp. 33-57; Lehr-
tbuch der Baumkrankheiten, 1882, p. 42). According to De Bary (Zur Kenntniss der Peron-
osporen, Bot. Zeitung, 1887, p. 593) and Sorauer (Handbuch der Pflanzenkrankheiten, Sec-
ond Part, p. 157) it occurs on the seedlings of Olarloia, Gilia capitata, Cleome violacea, etc.,
on seedling trees of Picea, ewcelsa, Pinus syZvestr/is, Strobus, P. Laricio, Lama; Earopwa, Acer
platcmoides, Fagus. This disease manifests itself by the blackening of the roots and rootlets.
The Cotyledons have a spotted appearance. Warm and moist weather causes the fungus to
grow rapidly, and in a short time the plant succumbs. In seedling beds the disease spreads
centrifugally, and reappears when resown with such plants as it attacks. The oospores are
probably formed in the soil and tide the fungus over till spring. Sorauer states that soil
where beeches had been killed by the fungus, when used four years later, was still capable
of infecting plants.

C0itun Root-Rot. 9

ALKALI THEORY.

This term is not at all understood by many who use it. There is so much
misapprehension, especially when applied to “root rot” of cotton, that I will
give a shortaccount: Prof. H. H. Harringtonl 1 says: “Alkali soil, as the
term is commonly employed, has reference usually to the saline or alkaline
matter present in the soil that exerts an injurious effect on vegetation. These
salts may or may not be alkaline in reaction.” Dr. E. M. Hilgardl? says:
“The immediate source of alkali is usually to be found in the soil water, which
rising from below and evaporating at the surface deposits there Whatever of
matter it may contain. Such water, when reached by digging, is by no means
always perceptibly salty or alkaline, and the same is mostly true of the soil
an inch or two beneath the surface; it is there of course that all the dissolved
matters accumulate until the solution becomes so strong as to injure or kill all
useful vegetation. The injury will usually be found to be most severe just at
or near the crown of the root where the stem merges from the ground.”

In this connection the following letter from W. C. Larkin, of Athens, Texas,
will be of interest: “The affected soil is dark and sandy, and at times is
covered with a whitish looking substance, resembling frost at a distance. It
tastes brackish, and when scraped together looks grayish or ash colored. It
is mostly in the low lands. In a gradual start, cotton will grow on finely to
a certain height, and stop as suddenly as if plowed up Sometimes a stalk of
cotton remains; it does not grow high, but bunchy, and makes a full crop
without any cultivation. Sometimes a weed also comes up and survives; but
generally speaking, cotton never germinates in-that land. Open the furrow
when the cotton seed is planted, ten or fifteen days after planting, and the
seed looks much cleaner than when planted. and seems sound, but take hold
of one and it is decayed. and is very easily mashed. If we could get cotton
up, I believe that it would grow and make cotton without cultivation. Corn
will germinate, but dies out before it gets knee high; I believe that these
spots, which increase in size every year, could be redeemed by application
of some proper substance. They increase more in a wet spring than a dry
one. I have tried to reclaim these spots by turning ditches on them, thereby
covering them over to a small depth with such soil as a ditch carries-—water
coming mostly from uncultivated land-but they seemed to grow larger than
the land not receiving such deposit. Nothing ever comes up on this land,
while on the “dead and mineral lands” everything grows to maturity except
cotton. I have spots in my plantation an acre in size, with luxuriant growth
all around them, and these spots are as bare as your hand; and the land or
soil looks richer in these spots than anywhere else.”

According to Dr. Hilgard,1 3 of California, cotton is especially to be recom-
mended, as fibrous rooted plants like cereals are especially subject to die from
the effects of “alkali.” During two years of field observation, I have never

seen a member of the grass family to die from the same fungus that destroys

cotton.

It is claimed by some that corn, oats, and wheat are affected. Jeff Well-
bornl 4 says:

“My prospects were very flattering until we had a soaking rain on May 18,

 

“Texas Farm and Ranch, June 1., 1889. .

“Tenth Census, Cotton Production, Vol. VI, Pt. III, Special Report California.
13L. C. p. ll.

“Texas Farm. and Ranch, July l5, and November l, 1889.

1O Texas Agricultural Experiment Siafzen.

when about two-thirds of the corn on one-half of the acre fell over on the
ground, rootless. The other third was wilted, but stood up. Mr. J. S. Peters
called my attention to a little patch of sorghum, the roots of which seemed to
be affected in some way. I made an examination of the roots, but could find
no traces of the cotton fungus.” From numerous answers received to the pos-
tal circular sent out by the Experiment Station, only a few have observed the
falling over of corn.

Prof. Burrill has lately shown that a Bacillus1 5 is the cause of a wide spread
disease in Indian corn. That the disease of Indian corn and cotton should
occur on the same ground must not be regarded as proof that the two diseases
are the same. The roots of the diseased corn do not show the cotton fungus.
The two diseases should be clearly distinguished, and in order not to cause
confusion I will give a brief account of the corn disease.1 6

The young plants are dwarfed. It occurs on spots of various sizes, from a
few square rods to an acre or more, or it may be widely scattered through the
field, affecting a hill or stalk here and there. It becomes yellow and unusually
slender, most of it dying. Occasionally a few stalks recover. When affected
plants are pulled from the ground the oldest and lowest roots are found to be
dead. The bottom portion of the stalk is dead or dying. On the surface brown-
ish corroded spots can be found. These corroded spots contain a semi-trans-
parent, rather firm, gelatinous material. This gelatinous mass is made up of
the minute organisms causing the disease.

In Bulletin No. 4 my reasons were given for calling this disease “root rot”
or “pourridie.” There can be no doubt that the “ dying of cotton ” and apple
trees and the rotting of sweet potatoes is caused by the direct action of a para-
sitic fungus, and as this term is well established for those diseases, and as it
is not likely to lead to confusion, it should be used. In talking about the
disease to farmers I have often been asked what a fungus is. In order to make
the matter of this report clear, I can do no better than give a brief account
of one of these low forms of plant life. Fungi are plants just as much as cot-
ton and wheat. In many cases they are small, and require a powerful micro-
scope to bring out their structure. Scientists have long since established that
“rusts,” “smuts,” “mildews,” and “blights” are caused by parasitic fungi.
The farmer and gardener have supposed that these diseases are caused by ex-
haustion of the soil, changes of the weather, or inherent weakness of the plant
affected, but these various diseases have appeared under very different con-
ditions of soil and atmosphere.

Fungus is a plant of low organization, having a vegetive as well as a re-
productive system. Chlorophyll, the green coloring matter found in leaves
and other parts of plants, which enables them to make starch (plant food) out
of unorganized material, is absent. The life history of many fungi is quite
complex; in some cases stages of the same fungus occur on different host
plants as in Grass-rust (Puccvlma Graminis, Pers.). Two stages are found on
oats, wheat, and other members of the Grass family, while the first stage oc-
curs on the Barberry. We can best illustrate the life history of a fungus by
taking a common mold (Mucor), which is not uncommon on rotting sweet
potatoes—possibly the cause of much of the cellar rot of sweet potatoes. At

1 5Bacillus is a plant of low organization. Many of these micro-organisms are the cause
of various diseases, such as tuberculosis, anthrax, pear blight, sorghum blight, etc.

,1 6A Bacterial Disease of Indian corn, Bulletin No. 6, 1889, Illinois Agricultural Experiment
Station, proceedings Tenth Annual Meeting of the Society for the Promotion of Agricultural
Science,1889, p. 19. Also an account in Original Investigation of Uattle Diseases in Nebraska,
1886-88, by Dr. F. S. Billings, Bull Experiment Station, Nebraska, p. 199; Iowa Homestead,
September 20, 1889; Orange Judd Farmer, August 10, 1889.

Colton Roof-Roz‘. 1 l

first a whitish or grayish mass of threads will be found to cover the potato;
this is called the mycelium. It is the vegetive part of the fungus, and enables
it to take nourishment from the substance upon which it lives. A single
thread of the mycelvjum is called a hyphen. If the fungus on the sweet potato
is carefully observed, in a short time (from twenty-four to forty-eight hours)
erect branches make their appearance. These are called comldiophores; at the
end of each a spherical body is found, at first whitish, but later blackish.
This is the sporomgium, and contains thousands of small spores. These spores
correspond to the seeds of higher plants. They are capable of germination,
and falling on a suitable substance develope into the same fungusl 7

Some of the lower forms of plant life, like "pond scums,” mosses, and ferns,
contain cholorophyll; these are therefore able to make their own food, but
fungi must obtain their food either from living organisms, when they are
called parasitic, or from decaying organic matter, when they are said to be sapro-
phytic. The lllucor on sweet potato is a saprophyte, while rust of wheat, blight
of pear trees, and cotton “root rot” are caused by parasitic fungi.

GENERAL CHARACTERS OF THE DISEASE.

The first thing observed is the sudden wilting of a single plant or a number
of them like Lucerene and Clover when affected with the Violet-Root fungus
(Rhizocionia Medicaginzls, D. (1)1 8

The sudden wilting of cotton is usually first noticed in the later part of June
or early in July. The time, however, x aries with the locality. Planters not in-
frequently associate the “dying of cotton” with the appearance of flowers and
bolls. From the condition of cotton fields early in July, 1888, I was of the
opinion that the disease must make its appearance much earlier in the season.
I therefore requested Mr. R. D. Blackshear to make some observations for
me. He reports that he noticed plants affected as early as the 6th of May.
Young plants are certainly often affected. I have seen the fungus on plants
six inches high. The sudden wilting of a large number of plants does not,
however, appear till about the middle of June and later. The wilting of a
single plant here and there in the field might easily be overlooked by the
planter, or, if seen, he might suppose them to be killed from some other cause.
But when the infection spreads to neighboring plants his attention is called to
them. Starting from a single dead stalk in May or June, areas of consider-
able extent will be found at the close of the season. The “dead patches” have
no definite boundary, extending in all directions through the field; occasionally
the black streaks and patches contain a few green plants. In riding on a rail-
road through the belt where the disease is so prevalent, a striking contrast is
formed between the black streaks, everywhere in fields, interspersed with green
cotton.

1 Ullucor is taken as an illustration because it is so frequently found on rotting sweet po-
tatoes.

“The perfect form of this fungus belongs to one of the Pyrenomycetes. In this group
of fungi the spores are found in sacs called asci. The ascz‘ are enclosed in capsules known
as perithecia. The asci contain small spores, the ascospores; these are usually not formed
till winter or the approach of spring, in the dead parts of plants affected. The sterile threads
of Rhizoctonia violacea, Tul., or R. Medicaginis, D. 0., have not been found in this country, al-
though the Snow mold (Lanosa nivales, Fr.) which Fuckel considered a stage of the perfect
form of Amphisphaeria zerbina, De Ntrs. (Byssothecium circinans, Fuckel, Bot. Zeit., 1861, p.
250, Symbolee Myco1., 187 0, p. 142; Hendersonia circinans, Sacc, Sylloge Fung., Vol. III, p.
431. Saccardo places it with Leptosphaeria circinans (Fuckel), Sacc. Syll. Fung. Vol. II,
p. 88) has been found at River Falls, Wisconsin, by Professor King. (Trelease, The Fungi
of Forage Plants, in BeaPs Grasses of North America, Vol. I, p. 426.)

12 '1 kxas Agv/icu/fura/ Experiment S/atizbn.

The suddenness with which plants die is governed somewhat by the condi-
tionsof the atmosphere and soil. Thus during the dry weather in August,
1888, few plants were dying, and planters frequently said that dry weather
did a great deal to check the disease In the latter part of August rains-set
in, and during the intervals of hot sunshine a large number of plants were
again wilting. In June and July of 1889 it was again found that more plants
were affected after a rainy day followed by warm sunshine, than during
several days of dry weather.

Healthy plants are frequently found close to diseased ones, often till late in
the season. It does not follow that green and apparently healthy plants are
not diseased, as I have repeatedly observed. The following will serve to illus-
trate. Eight plants were found growing in a bunch; two of these had wilted,
and in each case the tap-root was covered with the mycelium of the fungus.
In two cases the tap-root contained an abundance of the fungus, though these
plants had not wilted, but probably would have succumbed in a few days.
In two other specimens a small amount of the fungus was found on the tap-
root, while only a single one was apparently exempt.

If the roots of a dead cotton stalk or those which are wilting are examined,

I brown threads of a fungus, Ozonvjum aunieconzuviz, Lk., are found to closely

surround the tap-root and some of the lateral roots. Every plant dying from
the disease always contains this fungus. In numerous places on the tap-root
and lateral roots small wart-like bodies are found (see Plate I, Fig. 2, B, p);
these frequently occupy the lenticels on the roots. lf apparently healthy
plants are taken up in close proximity to dead and wilting ones, a whitish
mold-like fungus1 9 may be seen speading over the tap-root. The same thing
may be seen in such cases where the tap-root is covered with brown threads,
while the lower end of the tap-root and small lateral roots have their normal

“According to the investigations of Frank (Ueber die auf Wurzelsymbiose beruhende
erneehrung gewisser Baeume durch unterirdischer Pilze; Berichte d. deutschen Bot. Gesell-
schaft, 1885, Vol. III, Heft 4, Abst. Sorauer, Just Bot. Jahrh. 1885, 2, p. 513; Ueber die
physiologishe Bedeutung der Mycorhiza Formen, Ber. d. Bot. Gesell. VI, p. 395-409, pl. XIX;
abstract Hedwigia, Vol. XXVII, 1888, p. 28; J our. Royal Microscopical Soc., 1888, Pt. I, p.
268; Kamienski Die Vegetations organe der Monotropa hypopitys. L. Bot. Zeitung, 1881,
p. 457; Abst. Just Bot. Jahrh. 1881, 2, p. 717; Ueber Symbiotischer Vereinungen von Pilz-
mycelium mit den YVurzeln hoeherer Pflanzen; Arbeiten der St. Petersburger N aturforscher
Gesellschaft, XVII, 1886, p. 34-36; Abst. Soc. Bot. de France 1888, p. 42; Sorauer, Just
Bot. Jahresbericht, 1885, 2, p. 513; Rothert, Bot. Centralblatt, Vol. XXX, 1887, p. 2), and
others. Some plants, like the oaks, hazelnuts and chestnuts, are enabled to take up the
mineral elements of the soil by means of a white mold-like fungus which closely invests the
roots, often penetrating the epidermal cells. This fungus has been called Mycorhiza. If the views
of Frank are correct, then the White mold-like fungus covering the roots of many trees and
shrubbery plants cannot be considered a diseased condition. It is only when death or a di-
minished vitality results from the fungus on the roots that it can be looked upon as a parasite.
In this connection O. Penzig’s (Die Krankheit der Edelkastanien und B. Frank’s Mycorhiza,
Ber. d. Bot. Gesell, 1885, p. 513), Kamienski (Symbiotischer Vereinungen, etc.) and C. Freih.
V. Tubeuf’s (Mycorhiza on Pinus cembra, Beitreege zur Kenntniss der Baumkrankheiten, Ber-
lin, 1888, 61 pp., 5 plates, Abst. Hedwigi XXVII, p. 207), should be consulted. Tubeuf does
not believe that the fungus on the roots of Pinus cembm is a case of symbiosis, and Kamien-
ski holds that symbiosis cannot be applied to all the illycnrltiza forms described by Frank; that
in case of Carpmus Betulus and Pinus Sylvestris the m ycelium of the fungus causes hyper-
trophy of the tissues. Dr. Farlovv (Vegetable Parasites and Evolution, Vice-Presidential Addr.
A. A. A. S, New York meeting, 1887, Bot. Gazette, Vol..XII, p. 173), says: “The Word
‘symbiosis’ was originally applied to all cases where different organisms were associated to-
gether in a community, and in this sense included the true parasites‘ The application has
gradually been modified until at the present day symbiosis is generally understood to mean
the association of plants with plants, or plants with animals, in such a Way that the relation
between them is one of mutual benefit, or in which there is at least no injurious action of one
organism on the other.”

Cotton Root-Rat. 13

‘color. The white threads gradually assume a darker color, becoming either
dirty white or brown. In cross sections of a diseased root, the characteristic
branched threads of Ozonium are found on the surface, While the vessels and
meduallary rays also contain them.

Through the action of the fungus a fermentation is set up. This fermenta-
tion causes the tissues to shrivel up, thus leaving depressions. The borders»
of these depressions show at first a red discoloration; this ultimately becomes
brown. The fungus threads are often removed some distance from the part
which is taking on the red discoloration. This is not uncommon. Hartig,
Sachs,“ and others have shown that hyphae exert a decomposing influence
on the tissues of plants far beyond their immediate neighborhood, extracting
substances which serve to nourish the fungus. ,

Near the surface of the soil the cotton stalk usually shows an enlargement
(see Plate I, Fig. A, e), large when fungus and cotton are growing rapidly.
On poor soil and during dry weather it 1S not so perceptible. It is caused
through the shrinkage of the tissue below the point of attack, and the storage
of elaborated material in the enlargement. The enlargement contains a large
deposit of yellow oily matter contained in glands of a spherical or ovoid shape.
New rootlets are thrown out at the enlargement, as shown in the figure at r,
and under favorable conditions the plant is thus capable of maintaining itself.

In some cases the part of the stem containing the enlargement becomes dis-
eased, especially after rains have washed soil upon the stem. The immediate
cause of death is due to the small amount of water the rootlets are absorbing,
while the amount of water transpired is far in excess of what they are capa-
ble of taking up. Root absorption is necessarily reduced as the supply of
elaborated material is cut off, owing to the dead tissue of the main part of the
tap root. and thus the elaborated material cannot reach the developing
rootlets, and the lateral roots from the enlargement are often not sufficiently
developed to perform the entire work of absorption, especially so when the
surface soil is hard and compact.

WHAT PLANTS ARE AFFECTED BY THE COTTON FUNGUS.

Like Dematophora necatrzkiz? 1 (the fungus causing “pourridie ” of the vine in
Europe), Agaricus Mellens, 2 2 Rhizoctonzd rlledicaginzls, 2 3 and other fungi affect-

2°Hartig Wichtige Krankheiten der Waldbaeume, Berlin, 1874; Zersetzungserscheinungen
des Holzes, Berlin, 1878.

Sachs Vorlesungen ueber Pflanzen-Physiologie, Eng. translation, H. Marshall Ward, Ox-
ford, 1887, p. 388.

“Hartig Untersuchungen aus dem forstbotanischen Institut zu Munnchen, iii, Heft, 1883,
pp. 95-140, two lithographic plates and nine wood cuts, Der Wurzelpilz des Weinstockes,
(Dematophora necatrix It, Htg.), Berlin, 1883; O. Penzig et T. Poggi I1. malebianco delle
vitie degli allberida fruttaiee, 47 pp.; Pierre Viala, Les Maladies de la Vigne, Montpellier and
Paris, 1887.

"Hartig Lehrbuch der Baumkranklieiten, Berlin, 1882, p. 92, etc.

23C. Penzig Funghi Agrumicoli: Contribuzione allo studio dei funghi parassiti degli ag-
rumi, Padova, 1882, p. 124, with 136 colored plates. Text appeared in Michelia, Vol. VIII,
plates in Saccardo Iconograpliie Fungi italia, Faso 15 and 16. Abst. Penzig Just Bot.
Jahresbericht, 1882,‘p. 215, Bot. Centralblatt, Vol. XIV, p. 80), says: Rhizoctonia Medicaginis,
D. C. (synonomy R. violacea, R. Grocoruim), is widely distributed on lemon and orange roots
in Italy. According to E. Rostrup, (Sur quelques deformations des Phanérogames eausées
par les Champignons parasites, Botanisk Tidsskrift, Copenhagen, Vol. XIV, 1885. French
resume, p. 21, Abst, Sorauer Just Bot. Jahresbericht, 1885, p. 515. See also his paper Un-
dersogelser over Svampeslaegten Rhizoctonia, separate, from Oversigt over det K. Danske
Videns Srabernes Selskabs Forhandlinger, 2 plates with French resume, Copenhagen, 1886.,
Abstract J oergensen, Bot. Centralblatt, Vol. XXX, p. 98), occurs on TrifOZiuWLpratense, 71 hy-

14 Texas Agricultural Experiment Station.

ing roots, it also occurs on widely different hosts. In Texas thousands of bushels
of sweet potatoes are destroyed by Ozonmm aurzcomum. It is not the only
fungus, however, which causes a rotting of the roots. In New Jersey, where
sweet potatoes are often affected with a rot, Mr. J. B. Ellis“ did not find a
fungus. Dr. Halsted writes me that he has seen considerable of a sweet po-
tato rot in New Jersey upon which he has found Mucor (black mold), and
that the disease can be communicated to Irish potatoes, turnips, and beets.
Prof. Trelease has called my attention to a sweet potato disease in the penin-
sular parts of Maryland and Virginia, to which Dr. O. Lugger has given some
attention. He describes the disease as follows: “ In every case the original
and central plant showed the disease first; this was indicated by turning black
and then dying; when the central root was pulled up, it was also black and
decayed. The runners would keep on growing, but produced no tubers, or
only very small ones.”

Another sweet potato disease occurs in this country, Rhizoctonia Batatas,
Fr. Through the kindness of Dr. Farlaow I have been enabled to examine
a specimen from the collection of Schweinitzfl 5 Whether it is the cause of
the “Peninsular” sweet potato disease of Maryland and Virginia I am unable
to say. It certainly is entirely distinct from the Texas disease. W. G.
Smith? 6 has found the “seedling rot” fungus, Pythium De Baryanuwz, on New
Zealand sweet potatoes. (Ipomwa chrysorhiza.)

In the Texas disease the fungus begins to work on the surface, but in the
advanced stages the whole root is found to be covered with the brown t-hreads
of the fungus. In some specimens sent to me, and considered sound, I found
a number of depressions, in the center of each a small whitish protuberance
(see Plate I, Fig. 1, d) composed of a mass of fungus threads similar to those on
the roots of cotton. The cells adjoining the depression were soft and undergo-
ing decomposition. The rot may begin at the end and work gradually over the
entire root. The vines grow on vigorously and show no external symptoms,
but at the time‘ of maturity nothing else but the decayed remains of potatoes

can be seen, while on the borders of the patch diseased potatoes of all sizes

showing different stages of the fungus can be found.

After the Ozonium has attacked the root, a speedy decomposition of the
tissues takes place, due largely, however, to saprophytic fungi, such as Mucor,
VerticiZZ/tum, and various bacteria. This will be referred to again in another
connection.

THE FUNGUS ON FOREST AND APPLE TREES.

Texas farmers and horticulturists have long been familiar with a disease
that destroys forest and fruit trees in a manner similar to that of cotton, and
they have believed that the agent which destroys the one also destroys the
other. Whenever cotton dies from “root-rot” apple and forest trees are
likely also to die. In nurseries it is confined to spots, spreading centrifu-
gally, killing everything but the genus Prunus (such as plum and peach.) I
have seen diseased specimens of apple and forest trees from Burnet, Collin,
Ellis, Dallas, and Grayson counties. In Dallas the following trees were affec-

 

bridum, T repens, Medicago sativa, M Lupalina, Rumem crispus, Geranium pusillum, Sambacus
Ebulus, Coronilla varia, Ononis spinosa. In Bull. 4, Texas Agrl. Experiment Station, other
references to species are given.

“New Jersey State Agricultural Experiment Station, Report 1881, p. 65.

“Synopsis Fungorum * * * Am. B012, p. 264, No. 2396; Fries, Elencho Fungorum,
II, p. 45; Sorauer, 1. o. p. 359.

“Gardo Chronicle, 1884, II, p. 555, p. 447.

 

Cotton Root-Roi. l5

ted: Elm (U Zmas Americana), Basswood (TiZia Americana), White Ash
(Fraxiuns Americana), Apple trees (Pyrus Mains), Russian Mulberry (Moras
alba), China tree (Malia Azedarach); some Conifers (Thaja) Were dead, but as
they were killed the previous summer it was hard to say that Ozonium was
the cause. Near McKinney and in Sherman the following additional trees
were found: Japan Persimmon (Diospyros Kaki) grafted on the native Per-
simmon (D. Virginiana), Silver Maple (Acer dasycarpum), Paper Mulberry
(Broassonetia papyryera). ,

Of this list the China and Paper Mulberry trees suffer most. In August,
1888, the roots of a number of China trees were found covered with Ozon-
iuon. In July, 1889, the place was revisited; the old trees were dead, and
the infection had spread to neighboring young Paper Mulberry trees.

In many cases old and dying trees send up suckers; thus at Anna a num-
ber of old Paper Mulberry trees were almost dead; hundreds of suckers from
six inches to two feet high covered an area of several rods; among them also
a large number of Sida spinosa was growing. The suckers and the weeds
were wilting in large numbers, while many were dead. In every case the
roots were covered with the fungus.

The Pear (Pyras commanis) is said also to be affected. Specimens sent to
me from Mr. Ramsey, of Burnet County, had plenty of the Ozonium, but the
trees had evidently been dead for some time. In the pear orchard of Mr.
R. D. Blackshear, the leavesof trees covering an area of several acres be-
came yellow and soon died. The pear trees alongside of this patch were perfect,
showing no signs whatever of yellow leaves. The roots of the trees with
yellow leaves were examined carefully, but no fungus was found on the roots,
except in advanced stages, when numerous threads of the Ozoniam were
present, but I think in those cases the fungus was simply a saprophyte. It
should be stated that seven-eighths of the cotton in this patch was dying
from “root-rot.” Cotton was also dying, though not so bad, where the pear
trees had their normal appearance. This case has been given, as it has been
stated that the cause which killed cotton also produced the “yellows” of the
pear trees. A white rock comes close to the surface, but I can not say whether
it is in any way responsible for the disease or not. The area was sharply de-
fined. I am unable to account for this disease? "l

The leaves of the young apple trees affected with “root-rot” suddenly wilt,
become black, and in a short time perish. In older trees death is more
gradual. They have a sickly appearance one or more years previous to death.
It bears a heavy crop of fruit and then dies. If young seedlings are taken up
in close proximity to dead trees the tap-root will be found to contain the
same white fungus threads that diseased cotton roots show in its early stage.
In other bases the leaves are still green, no external symptoms are noticed,
but the tap-root is closed invested with the brown threads of Ozonium. At
McKinney eight affected trees were found in a row close to some which had
been dead some time. The fungus had completely surrounded the tap-root,
as well as some of the lateral roots, but in addition small knot-like bodies

27A disease called Ohlorosis causes a blanching of the plants from lack of iron, but it
does not seem that iron is lacking in the soil at Navasota. In Icteriosis, also called chlorosis
by some, the leaves are blanched, and by some supposed to be due to a want of potash. In
France the Herbemont grape is especially subject to this disease. (G. Foex, Des causes de
1a chlorose chez 1’ Herbemont, Ann. Ecol. Agrl.,Montpe11ier, 1886; Viala Les Maladies de
la Vigne, p. 430, Sorauer, 1. c., Vol. II, p. 188.) In this case there seems to be a non-adapta-
tion, but in some of the manifestations of the disease the cause does not seem to be clearly
understood. One correspondent writes that some of his pear trees showed this disease, and
they were restored by the use of iron.

16 Texas Agmku/Zural Experimenz‘ Statzbu.

were found on all the trees. I had not noticed these in the orchards at
Ennis nor Dallas. Later, however, I observed these knotty bodies on apple-
trees at Anna and Howe, and I am told that they are quite common in many
parts of Texas. This insect, the Apple-root Plant-louse (Sehizonleura Zanigera,
Hausm.), kindly determined for me by Prof. Osborn, was doing much damage-
at the above places. Many orchards presented a sad spectacle, and the‘
trouble was pronounced “alkali.” In order that the two diseases should not
be confused, I Wlll give a brief description of the insect which causes these
deformities on the roots. The insect? 8 is easily recognized by the bluish-white
cottony matter with which its body is covered, and the knotty roots it forms.
See Plate I, Fig. 5. It seriously diminishes the normal supply of nourish-
ment, and when so numerous as I have seen them at Anna, Howe, and Mc—
Kinney, certainly prepare the way for fungi, and other insects to get a foot
hold, and thus soon destroy the tree? 9

We must clearly distinguish between the two diseases. In the insect
trouble, death is much slower, while in “ root-rot ” of apple trees, especially in
younger trees, death is rapid. The Ozonitvm and Schizoneura frequently occur
on the same root, but often quite independent of each other, so that the
Ozonium does not attack the root, because the way has been prepared for it
by the insect.

The fungus on apple roots seems to have been known for a long time. Dr.
Riley writes me concerning it: “I have long been familar with the brown
fungus which you mention, and which years ago was very common in South-
ern Illinois.” There seems to be another disease affecting apple and pear
roots in Southern Illinois, but it has no likeness to the Texas disease. Mr.
F. S. Earle3 ° writes me: “While I have no proof that amounts to a demon--
stration that Polypoms versicolor causes rot of apple, pear, and cherry trees,
still I have no doubt it is a fact, and that it also injures many other trees and.
shrubs. I do not remember noticing the brown mycelium you mention. In
Southern Illinois the ‘root rot’ mycelium was usually white.” Rhizoctonzkz
Mali, D. C.,3 1 a description of which I have not seen, is said to occur on the-
roots of young apple trees in Europe. I can not say whether it is identical
with the Ozoniunt on apple roots or not.

WEEDS AFFECTED.

If fungicides will not destroy the pest, then a more judicious method of‘
cultivation must be resorted to. It will be of little use to rotate, if weeds

which harbor the fungus are allowed to grow in the field. Of the many weeds
growing in cotton and corn fields in Texas, the common Sida (Sida Spinosa).
(Plate I, Figs 1 and 2) is more subject to this disease than any other. It be-
longsto the same family that Cotton, Okra and Hollyhock do. In well worked

28C. V. Riley "Apple-IONS Plant-louse, First Annual Rep. on Noxious, Beneficial, and other

Insects of Missouri, 1869, p. 118, and numerous other papers.

“The following remedy has proved beneficial for destroying the Apple-root Plant-louse:
Use scalding hot Water around the roots of the trees. If the trees remain in the soil the
roots should be laid bare, and nearly boiling water can be used. If trees are taken up for
transplanting, the water should have a temperature of not over 150 degrees Fahrenheit.
Mulching the trees previous to the use of hot water Will bring the lice close to the surface.
Bisulphide of Carbon and Kerosene are excellent remedies when placed in soil around the
diseased tree.

"Pear Diseases caused by Fungi; from Transactions of Ill. Hort. So., vol. XX, 1886, p.
168.

“Sorauer Pflanzen Krankheiten, Vol. II, p. 359; De Candolle in Mém. Mus., 1815, p. 209;;
Freis. Syst. Myc. ii, p. 266.

C 021012 Root-Roi. 1 7

fields the weed is isolated and scattered. If careful search is made, plants
here and there will be found to be affected with “ root-rot,” showing the same
symptoms that cotton does. Thus, in a neglected orchard, I saw hundreds
of specimens of this weed dying close to a number of Paper Mulberry trees.
I have occasionally seen one of the Ragweeds (Ambrosiapsilostchya), Cocklebur
(Xanthium Canadense), and a few other undetermined composites dying, but
in all cases I found that the plants had sustained some injury. The fungus,
no doubt, caused death, but it was easier for it to attack such plants because
of the injury. 3 2

The fact that Ozonium attacks such plants as Ambrosia and Xanthvjum
when they are injured may seem to some not sufficient reason for regarding
it as a parasite. The ScZerot/inia bclerotvlorum on the Common Bean does not
even attack all varieties of Phaseolus vulgaris, nor is the related species, Phas-
eolus multfilorzas, seldom attacked. Agaricus melleus attacks various conifers
as a true parasite, but it is seldom found on deciduous trees, except under
some conditions.

I have stated elsewhere that various species of Prunus, such as peach and
plum, do not show the Ozonvium disease, at least I have not been able to find
any specimens, though they may die from other “root rot” diseases? 3

BOTANICAL CHARACTERS.

Ozonmm auricom-um were described by Link in his Observationes Myco-
logicae.34 It is widely distributed in Europe as well as America, occurring

“Thus very many fungi do not attack sound and healthy parts of plants, but when, for

instance, the surface of an apple is injured, molds (Mucor, Zlrvlchothecium, Penicillium, etc.)

of various kinds make their way into the tissues, causing a rot. The Scelerotium disease
of the Common Bean is of interest in this connection. According to De Bary (Comparative
Morphology and Biology of the Fungi Mycetozoa and Bacteria, English translation, Garnsey
and Balfour, Oxford, 1887, p. 380; also Ueber Einige Sclerotinien und Sclerotienkrankheiten,
Bot. Zeitung, 1886, pp. 377, 393, 409, 433, 449, 465; Abstract Zimmermann, Bot. Central-
blatt, Vol. XXIX, pp. 97-107), when spores which have germinated in pure water are used
to infect young seedlings of the Garden Bean (Phaseolus Vulgar/is) the result will be a neg-
ative one, as they will not take the disease, but if the spores are made to germinate in a
nutrient solution, the germinating tube becomes strong enough to penetrate the epidermis,
soon produces a vigorous mycelium, and destroys the plant. '

“Hartig, Lehrbuch, p. 92, Der Wurzelpilz des Weinstockes, etc., p. 3; Viala Les Maladies
de 1a Vigne,:p. 357, Earle 1. c., p. 168, etc., etc.

341, p. 9; Id. Linne, Spec. plant, cura Willdenow VI, I, p. 138; Fuckel Symbolae myco-
logicae, p. 403; Saccardo Mycologia Veneta, p. 204; Sylloge Fungorum, Vol. VI, p. 345;
Michelia, vol. II, pp. 134, 490; Rabenhorst, Deutschl. Kryptogamen Flora, p. 60, No. 581;
Winter Die Pilze, Vol. I, p. 405; Wallroth, Flora Germanica, Crypt. II, p. 156; Cattaneo Es-
tratto dai Rendiconti del R. Instituto Lombardy, Ser. v, Vol. XII, fasc. VII, 1879; Abs.
Schroeter, Just Bot. Jahresbericht, 1879, I, p. 551; O. Penzig Nuovo Giorn. Bot. Ital.'XII,
pp. 132-143 two lith. plates; Abst. Penzig Just Bot. Jahresbericht, 1881, I, pp. 244, 248;
Holuby Oesterreichische, Bot. Zeitung, 1874, pp. 311-313; Abst. J . Schroeter, Just Bot. J ahr-
esbericht, 1874, p. 204; Felix von Thiimen Die Pilze und Pocken auf Wein und -Obst,
Vienna, 1878, p. 165.

AMERICAN REFERENCES.

Schweinitz, Syn. Am. Bor. No. 2788, p. 287 ; Grevillea, Vol. V, p. 74; Vol. VII, Sept., 1878;
Curtis Cat., p. 154; Harkness and Moore Cat. Pacific Fungi, p. 27; Langlois Cat., p. 32 and
34; Cragin, Bull. Washburn Lab. I, p. 69; Pammel, Texas Agricultural Exp. Station, No. 4,
p. 14, Abst. Humphrey Bot., Centralblatt, Vol. XL, p. 59, Bot. Gazette, Vol. XIV, p. 113, Ag-
ricultural Science, 1889, p. 100.

SYNONOMY.

Ozonium fulvum, Persoon Myc01.Europ. I. p., 87; Byssusfulva Humb. Fl. Freiberg, p. 62, No.
109; B. aurantiaca, De Candolle, F1. Franc.  p. 68; Lamarck Encycl. I, p. 524; B. aurea arborea,
Weiss, Fl. Goett, p. 14; B. ba/rbata, Engl. Bot. Fig. 701; B. SGTMGCZ, Scopoli, Dis. I, p. 90, Pl. II,

18 Texas AgrzeuZZm/al Experiment Stallion.

in damp places on the decaying bark and wood of various trees. What or-
dinarily passes for Ozonium auricomum, Lk., is a saprophyte. The specimen
of Ozonium auricovnum distributed in Ellis’ North American Fungi, and Fungi
Gallici and some herbarium specimens which I have examined, are morpho-
logically distinct from the Texas material.

In Italy Ozonium auricom/uwz is not uncommon on orange roots,35 but so
so far as known it has not been found on the roots of orange and lemon trees
in this country. It has long been known that Ozonium, Rhizoctonia, Rhzeo-
morpha, etc., are only sterile stages of some fruiting fungus. Thus Rhizomor-
pha fragilis and R. subcortalis have been placed with Agaricus meZZeus, Rhizoc-
tonia, Medicaginis‘ with Trematosphwria circinans, Rhizocton/Ja Querci with R0-
sellina Querczina.

Opinions differ in regard to the perfect form of Ozmziu-m. Schroeter3 6 be-
lieves that it develops into Coprinus ¢adians—-0ne of the toad stools. Pen-
zig, 3 '1 however, states that it develops into a species of Copwjnus, which he has
called C’. intermedius. Mr. J. B Ellis writes me that Langlois has found in
Louisiana what appears to be this species. Winter3 8 and Saccardo3 9 place
it with Trametes oolorata, Wulff. Holuby“ with Agaricus delvfguescens, Bull.
No doubt the ordinary damp wood form of Ozonium is probably connected
with some Hymenomycete, but I am inclined to believe that the Texas fungus
is connected with some Rz/renomycete. It should be stated here that yellow
strands much thicker than Ozonwm are of common occurrence on dead stalks
of cotton, and sometimes even found on plants that are wilting and those that
have received mechanical injuries. This fungus is probably connected with
one of the Poly/pared (fleshy fungi). In several cases these strands were seen
to develop into a Polyporus or a Trametes, but not enough was found to en-
able me to determine the fungus. These yellow strands are exceedingly com-
mon in the soil not only where cotton is dying, but also in places where the
disease does not occur. I think little harm 1s done by this fungus.

In 1888, and again the past season, diseased roots were placed in a cham-
ber kept moderately moist, but in no case did a Hymenomycetous fungus make
its appearance. Verticillium, Trichothecium, Penicillium, and other saprophytic
fungi frequently occurred but not a single Hymenomycete.

- In sweet potatoes which were undergoing decay, the interior, and parts as

Fig. 2; Zflmantia fulva, Sprengel Syst. IV, p. 559; flvimantia strigosa, Persoon, Mycol. Eu-
rop. I, p. 704; Rhizomorplza capiilaris, Roth, Oat. I, p. 234; Racodium strigosum, Persoon
Mycol. Europ. I, p. 69; Oemtonema capillare, Roth, Oatalecta II, p. 251; Amphiconium Stri-
gosuvn, N. Syst., p. 344; Dematiam strigosum, Persoon, Despositio fung., p. 75; Schweinitz
Syn. Gar. No. 1328, p. 128 [I02]; Mesenterica Zutea, Alb. et Schw., Conspectus, p. 374, No.
1126.
EXICOATI.

Roumeguere, Fungi Gallici No. 899; Ellis, North American Fungi No. 832 (distributed as
O. parietinuwz), but Ellis writes that it is the same as Fung. Gallici No. 899. Mr. Ellis has
been kind enough to send me a specimen of Fung. Gall, 899, and I should certainly say the
two specimens are identical; Seymour and Earle Economic Fungi No. 2.

“Michelia, Vol. II, p. 490: “Hyphis repentibus, ramosis, irregulariter intertextis, in
fasciculos plus minusve crassos coalitis, parce septatis, rigidis luteis v. aurantiacis, junioribus
tenuissirnis albis. Hab. in truncis vetustis radicibusque Gitrorum, frequens.”

A. Oattaneo, I, Miceti degli agrumi (Estratto dei Rendiconti, etc., l. c).

“Kryptogamen-Flora von Schlesien, Breslau, 1889. p. 519.

“Sui rapporti genetici tra Qzomium et Coprinus, Nuovo Giorn. Bot. Ital. XII, p. 132-43.

“Die Pilze, Vol. I, p. 405.

39Saccordo Sylloge Fung., Vol. VI, p. 345.

4°Zur Kryptogamen Flora von Ns. Podhrad Oest. Bot. Zeitung, 1874.

Coiton lfaot-Rot. 19

far as the disease had spread, contained the mycelium of a fungus. Morpho-
logically this fungus is the same as the Ozonium found on the surface; the
characteristic branches as shown in Plate III, Fig. 1., at b, are not present, owing
to the development of the fungus in the interior of the tissues. Like the cells
of the Ozonduwz strands on the surface, they are more or less rounded out at
the extremity. In numerous places black perithecia-like bodies (Plate III,
Fig. 3 1) occur. It seemed that by cultivating the fungus in a nutritive me-
dium made from sweet potato that the life history of the fungus might possi-
bly be determined. A small portion of the sweet potato containing the black
bodies was placed in a test tube containing gelatine. It was well mixed with
the gelatine and carried on to the third dilution. The gelatine in each of the
tubes was then poured out on plates and carefully observed each day. I had
much disappointment, as Mucoirs, Penicillium glaucum, Aspervlgillus glaucus, and
other Aspergzllz, Cladosporium harbor-rum, Bacillusprodzytosus and other Bacteria
grew so rapidly that it was difficult to get pure cultures. Then the tip of a few
threads was brushed with the point of a sterilized platinum needle in order to
get a single spore, or at most only a few spores, from a single thread. In this
way, after a short time, a pure culture of some fungus was obtained. It was
transferred from the gelatine over to sweet potato agar agar and boiled sweet
potato. The white fiuffy fungus produced an abundance of spores. The
cultures were then placed away, and in May, 1889, the cotton plug contained
a large number of perithecia (Plate III, Fig. 4) filled with small spores.

These spores germinate readily, and develop into the white fluffy form of the
fungus. At the same time when the black perithecia-like bodies were being
isolated from the rotten sweet potato, a few of the brown Ozonvjum threads
on the surface of a diseased potato were carefully washed with water contain-

ing a small amount of acetic acid to prevent the appearance of bacteria. Then
a few of the washed threads were placed in a hanging drop culture of sweet

potato gelatine. Soon an abundance of threads and spores like those from the
black perithecia-like bodies of the sweet potato were produced. In one instance
it seemed as though these came from the brown threads, yet it was difiicult to
determine positively. The hanging drop culture contained but few impurities,

so that a pure culture of the fungus was soon obtained on sweet potato gela-
tine, afterward transferred to agar. Detached spores of similarappearance
are frequently found among the brown threads of the Ozonium, and of course
a single spore which I may not have detected might have been in the hanging

drop culture, germinated and developed into the white fluffy fungus, so that

perhaps no special significance can be attached to the result.

It was necessary now to determine whether the fungus from the black bodies i

in the sweet potato could induce decay. In order to test this, the surface of
some sound sweet potatoes were thoroughly washed with a disinfecting solu-
tion (corrosive sublimate), then sterilized knives were taken and pieces cut
out small enough to readily pass into a five inch test tube also previously ster-
ilized. Two series were started; in one some of the conidia from the black
bodies were placed, the other was kept as a check. The infected blocks were
soon covered with the white threads of the fungus, which caused the tissues
to turn black. The checks remained free till the first of June, when they were
destroyed. In September the material from one of the infected tubes was
taken out. The cotton plug was found to contain a large number of perithecia
filled with small spores, while the piece of sound sweet potato placed in the
tube was thoroughly rotten.

I do not think the proof is conclusive that the above fungus is connected
with Ozonium, for the brown threads have not appeared in any of my cul-

2O Texas Agricultural Expm/imenz‘ Stafion.

tures, but according to Meyer4 1 and Crasperini4= 2 parasitic fungi, when grown
as saprophytes in a nutritive medium do not always show the different forms.

It will make little difference from a practical standpoint whether the white
fluffy fungus from the sweet potato is connected with the Ozonizmz or not.
It should be guarded against, however, as there is no doubt that it induces
decay in young cotton roots as well as sound sweet potatoes.

OTHER FUNGI ON THE ROOTS OF COTTON AND SWEET POTATO.

In “ root rot” diseases it is no easy matter to decide what particular fungus
is the real cause of rot. Speerschneider,“ De Bary,44 and numerous other
investigators since have shown beyond any doubt that the Potato Rot fungus
(Phytopthora injesta-ns, De Bary) attacks both the leaves and tubers of the po-
tato, that the mycelium works its way down through the stem, till the tuber
is reached, where it causes a dry rot. Many other fungi have been found on
rotting potatoes, and according to Reinke and Berthold45 wet rot is caused
by bacteria and various fungi which come in after the potato has been at-
tacked by Phytopthora. The complete destruction of the sweet potato is also
caused by other fungi, the Ozomuwz only preparing the way. Thus several
species of Mucors, Bacillus prodigiosus, Vertzcil/um (see Plate V, Fig. 3), a whitish
saprophytic fungus common on decaying substances, Yrichotheciuwz rosemmAs-
pergillus gZa/wcus, and Asp. Sp, PeniciZZ/zlum glaucwn, Clctdosporium herbarum, and
others; all common fungi found every where on decaying organic matter, or
in some cases restricted to a narrow parasticism. So that on examination of
rotten sweet potatoes and the stalks of cotton which have long been dead, it
would be useless to endeavor to determine the cause of death. It is only by
experimental method or in studying the successive stages of the fungus on
the living root that conclusions can de drawn.

When roots just killed with the Ozomuwz are placed in a moist chamber,
Trichothecium, l/rerticillium, and Cladosporium are most common; but when
cultures are made in a nutritive medium species of Mucors and liquefying
bacteria are usually more common than anything else. Some of these prob-
ably came from the air, but when they appear in the majority of cultures with
as little exposure to the air as possible, it is not unreasonable to suppose that
some of these organisms came from the roots and that they play an important
part in the complete destruction of the roots.

THE CHARACTER OF THE LINT OF DISEASED COTTON.

Cotton pickers know that when cotton is affected with “root-rot” bolls not
more than half mature, and those nearly mature will open, and contain some
cotton. Often it is not touched, but when in fairly good condition it is picked,
and thrown in with the other cotton. Such a boll-is shown at Plate IV, Fig. A.
On the same plate at B is a boll from a good stalk not affected, grown on the
same soil. A microscopic examination of the lint taken from the different

“Untersuchungen iiber di Entwickelung einiger parasitischer Pilze bei saprophytischer
Erneehrung, Landw. J ahrbiicher, Vol. XVII, pp. 915-945. Abst. Sachsse Biedermann’s Cen-
tralblatt, fiir Agrl. Chem. 1889, p. 200. "

“La biologia e piu specialmente il polimorfismo di varie specie d’ Ifomiceti (Polymorphism
of the Hyphomycetes) Atti Soc., Tosc. Sci. N at., VI, 1887, pp. 20-26; Abst. J our. Roy. Mic.
Soc., 1888, Pt. I, p. 468; Abst. Solla Just Bot. Jahresberict, 1887, p. 544.

“Bot. Zeitung, 1857, No. 8.

“Die gegenwaertige herrschende Kartoffelkrankheit, Leipzig, 1861.

“Die Zersetzung der Kartoffel durch Pilze. Untersuchungen aus dem Botanischen Lab-
oratorium der Universitset Goettingen, Heft I, 9 Lith. plates, p. 100, Berlin, 187 9.

Cation Roof-Rot. 21

bolls shows a great difference. In the cotton froma diseased stalk, the fibers
are very much wider and larger; it has little spirality (Plate V, Fig. l) and is
very uneven. In the good cotton, the fibers are much narrower and of uni-
form width, the spirality is much more pronouncedfi 6 (Plate V, Fig. 2.)

THE SEED OF DISEASED COTTON.

Some planters claim that “root rot” results from poor seed. To determine
this point, I took one hundred and fifty seeds indiscriminately from a package
of seeds from diseased stalks gathered in 1888. I then selected seventy-five
seedseach from two samples of Jeff. Wellborn and Hopkins’ Improved, gath-
ered in 1887. I then set out alternate rows each of Wellborn, Diseased, and
Hopkins’ Improved, Diseased, etc. The seeds were planted on August ] 1th in
the propagating house of the Iowa Experiment Stationfi-fi“ On August llth
some of it had germinated, and on August 29th when the experiment ceased.
Eighty per cent of the diseased germinated and doing as well as either of the
others. Fifty per cent of the Hopkins germinated, while only forty per
cent of the Wellborn germinated.“ In no case did the Ozomum appear,
though many of the young plants died of “seedling rot.” What the quality

_ of the lint would be. and the susceptibility of the plants taking the disease,

when seed is used from plants which have been killed by the Ozonium, I can not
say, though it is not improbable that the lint will be of a much poorer quality.

TREATMENT.

First of all we should recognize that the disease is an infectious one. It
makes its appearance in cotton fields, where sweet potatoes, apple, and forest
trees have been killed. That infected soil taken to places where the disease
has not been before is capable of infecting plants when grown in such places.
Strands of the Ozonvjuvn can be taken and cotton infected with it. A. W. Kerr,
of Sherman, showed me a Red Mulberry tree which was killed by “ root-rot”
in 1887. The following year a small patch of ground where the Mulberry
tree stood was planted in sweet potatoes, and where the Mulberry tree stood
every potato was rotten; from this point it spread centrifugally, till it became
less and less. Dr. Fears, of Waxahachie,“ took soil from an affected area to
an unaffected. The disease then made its appearance in the unaffected places,
causing plants to die of “root-rot.”

Hope had been entertained by many that some fungicide might prove bene-
ficial in preventing the disease. From the experiments made Mr. R. D. Black-
shear under the direction of Prof. F. A. Gulley, the treated as well as the un-
treated plots showed the disease badly. The experimental ground was one
which had been in cotton many years, and in 1888 seven-eighths of it died.

“Thomas Pray (a lecture delivered before the Franklin Institute, Friday, December, 2
1888, Journal of the Franklin Institute Vol. OXXVIII, p. 241) gives an interesting account
of different cotton fibers and the use of the microscope in the purchase of cotton. He says:
“Just imagine a man going into a darkened room to buy silks, and depending upon ‘feeling’
with his fingers; he might tell that the fabric was silk, but what could he tell about color or
texture‘? So in buying cotton what could a man tell about a cotton fiber which is all the
way from 971m of an inch in diameter for the coarsest upland, and film- of an inch in diameter
Ior the best New Orleans or Gulf, and @6151; for the best Sea Island, which is raised in the
United States?” In upland Georgia cotton raised from seed in 1881 or 1882, by Major J. F.
Jones from seed carefully selected of the first picking, and the most perfect bolls, the cotton
fiber is beautifully developed, clear in its outline, full of oil deposits, and a good spirality pro-
ducing one and one-fourth bales per acre, when before the war one-half hale per acre was
considered a good yield.”

‘maOaptain Speer, the Director, kindly allowed me to use the same.

“The low percentage of the Wellborn is probably due to an undue amount of earth which
covered one of the rows. i

“J. B. Stephens in-Texas Farm and Ranch, June 1, 1889.

22 Texas Agricultural Expemmenz‘ Slalzbn.

EXPERIMENT OF R. D. BLACKSHEAR.

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Coiton Ram-Rot. y 23

RESULTS OF EXPERIMENTS.

June 6,1889. July s, 1ss4. Aug. 6, 1889. "5
O
a z a g a e = i? 3
3 gig g goai 3g‘ g W‘ _ m7;
3w: m1 as s3 32 as 4a 3 g3
w; a? 4: a2 3g ~52 as 3E
o d S; O m, S; 5,5,5 a :05 4s p.
o’ 3'" 0' 2'" s5 <5 a e-
z <1 z <1 z z m {E
1 Kainit . . . . . . . . . . . . . . . . . . . . . . . . . . . 6O 12 6O 4O 9 29 45 14
2 C. S. H. Ashes . . . . . . . . . . . . . . . . . . . 60 14 5O 36 13 18 41 1O
3 Muriate of Potassium . . . . . . . . . . . . . . . 6O 1O 51 33 6 20 39 8
4. Sulphate of Magnesium. . . . . . . . . . 6O 16 51 37 7 21 45 6
5 Seed Meal . . . . . . . . . . . . . . . . . . . . . . . 6O 12 55 4O 2 28 28 11

6 Chloride of Lime.. . . . . . . . . . . . . . . . . Small 3 27 10 18 27 26 27

7 Sulphate of Iron . . . . . . . . . . . . . . . . . 6O 15 49 36 15 15 4O 5

8 Alum . . . . . . . . . . .' . . . . . . . . . . . . . . . . . 60 14 37 29 8 3 40 1

9 Sulphate of Copper . . . . . . . . . . . . . . . . . 6O 12 53 33 9 32 39 8

1O Chloride of Sodium . . . . . . . . . . . . . . *52 11 51 38 1 22 48 12

11 White Arsenic . . . . . . . . . . . . . . . . . . *45 10 45 4O 2 32 48 15

12 Verdigris.. . . . . . . . . . . . . . . _ , . . . . 6O 15 56 42 3 23 48 1O

13 Lac Sulphur . . . . . . . . . . . . . . . . . . . . . . 6O 14 52 39 7 27 48 15
14 Carbolic Acid in two buckets of water. . *6O 1O 6O 42 14 41 48 17
15 Lime . . . . . . . . . . . . . . . . . . .. . . . 6O 13 59 36 4 23 37 1O
16 Salt and Lime. . . . . . . . . . . . . . . . . . *6!) 14 44 36 13 13 42 2
' 17 Lime and Sulphate of Copper, dry. . . . 6O 14 52 35 4 31 4O 10
18 Lime and Sulphate of Copper, solution. . 6O 14 42 35 1O 4 36 1
19 Manure . . . . . . . . . . . . . . . . . . . . . . . . . Fine 6O 17 51 48 17 6 48 4
2O Nothing . . . . . . . . . . . . . . . . . . . . Good 6O 15 53 36 4 14 48 6
21 Salt and C. S. H. Ashes . . . . . . . . . . *6O 11 58 38 6 2O 48 13
22 Salt and Kainit . . . . . . . . . . . . . . . . . . . . *6O 11 5O 36 1 14 42 8

* Irregular in growth.

N AVASOTA, TEXAS, September 14, 1889.
Professor F. A. Gulley: '

DEAR SIR:--I send you herewith my copy of the “experimental plats,”
showing condition of cotton throughout the season, observations being re-
corded on the sixth of each month. “Root-rot” began about the fifteenth
of May in adjoining rows to experimental plat, a few plants only being affec-
ted on the sixth of June. No plants were found dead in the plats, but soon
afterwards; began to die very fast from the fifteenth to the last of June.
During July it died very rapidly, and by the first of August half of the cot-
ton was dead, many bolls of the dying cotton having matured and continued
to open. The living plants continued to grow till the middle and latter part
of August, when it reached its full growth. In most plats the growth has been
very uniform, except in No. 6 (Chloride of Lime). In this plat the young plants
turned brown soon after coming up. I thought it was dead, and replanted on
the eighteenth of May. The second came upwell, but soon turned brown.
It was left in this condition, and on June 6 was about three inches high, and
growing a little. The plat was chopped out leaving twenty-seven plants, one-
third of what was left on the others. It grew slowly, making only a few bolls
to the plant. Not a plant of it has died. The roots of some of the green
plants have a white mold near the surface of the ground, but the root is not
dead, as are other cotton plants when affected with “ root-rot.”

It may be that chloride of lime properly applied may have some beneficial
effect, but the growth is slow and little fruit was made.

24 Texas Agricultural Experzment Slatzbn.

Continued cultivation on the same field certainly increases the disease with
each succeeding year.

Cotton in plat 19, heavily manured with barnyard manure, made rapid
growth, and reached a height of forty-eight inches, but when the plants began
to die they died rapidly; only four plants are now living. This plat made no
more cotton than the others; in fact there is very little difference in the yield.
On a space of over one acre, including the experimental plat of ground, nearly
all the cotton has died, not more than five per cent being alive now. About
fifty of my young pear trees have died on the same ground where cotton has,
and from the same cause. Most of the trees have died since the first of July.

In conclusion, I don’t know as we have gained any definite knowledge
about the use of fungicides and “root rot,” unless chloride of lime is of some

benefit. Yours, respectfully,
~ I R. D. BLACKSHEAR.

Experiments were also made by Mr. E. S. Peters, but “root-rot” did not
appear to any great extent in the treated as well as the untreated plats, so that
the experiments were of no value. '

It should be stated in this connection that the claim made by some, that
the disease does not always reappear in the same spot, though the ground is
planted with cotton, is partially confirmed by the experiments of Mr. Peters,
and also by what I have seen at Millican. In 1888 affected plants were found
here and there in a patch of cotton. None was found dead in this patch on
the twenty-fifth of June, though it is not improbable that some may have died
later. Several rows of corn were planted near one end of apatch where most
of the cotton died the year previous. In most cases, however, the disease
regularly reappears on the same ground, as I have observed at N avasota, Cal-
vert, Ennis, Dallas, Sherman, and Melissa.

The distribution of parasitic fungi is sometimes peculiar and not at all un-
derstood. A curious case is reported by Kuehnfi 9 The Violet-root fungus
(Rhizoctonzkt Medicagzbzzls) did much injury to mangolds near Bunzlau, Ger-
many, from 1848 to 1854, some years worse than others. From 1854 to 1858
it was not again observed.

THE USE OF FERTILIZERS AND MANURE.

In Bulletin 4 I expressed an opinion, from some observations made, that
barnyard manure would prove valuable. The experiment of Mr. Blackshear,
however, shows that when the soil is filled with the fungus that the disease
can not be prevented. In fact all but four plants died in the plat so treated.
On the 20th of June, when some observations were made on the condition of
cotton in the experimental plats at N avasota, the plat treated with barnyard
manure had a perfect stand and not a single stalk was dead. while plants in
the check row were dying in large numbers. The treated cotton had a much
greener shade, and was growing much more vigorously. See second and
fourth columns of Mr. Blackshear’s report.

Of the fertilizers Kainit has proved most beneficial, fourteen plants remain-
ing alive on September 6. Many correspondents in other cotton States men-
tion Kainit as valuable in checking the disease. Both common salt and salt
and cotton seed hull ashes had respectively twelve and thirteen plants alive
September 6.

Mr. Blacklshear has referred to the effectiveness of Chloride of Lime. It

“Die Krankheiten der Kulturgewaechse, ihre Ursache und ihre Verhutung, Berlin, 1858,
p. 232.

 

Cotton R 001-]? oz‘. 25

is also interesting to note that Lac Sulphur, White Arsenic. and Carbolic
Acid are more effective than any other substance with the exception of Chlo-
ride of Lime. a

If the soil is comparatively free from the Ozonium, and then a free applica-
tion of barnyard manure, wood ashes, Kainit, are used to give young plants
a good start, the disease can no doubt be materially checked.

ROTATION OF CROPS.

The class of diseases to which “ root-rot” of cotton belongs can no doubt
be largely governed by a judicious method of cultivation. Is it surprising
when cotton is grown year after year on the same soil that a diseased stand
should appear? When crops are grown successively on the same soil for years
parasites of all kinds become more numerous, and finally the crop will not
grow at all. Many insect pests can not be destroyed in any other way except
by rotation of crops. So with “root-not ” diseases; it is very difficult to reach
the fungus with a fungicide, as anything which is likely to kill the fungus
will act injuriously on the tissues of the plant.

HOW AND WHAT PLANTS TO BE USED IN ROTATION.

In rotation of crops care must be taken not to use such plants upon which
the fungus grows. They have been given elsewhere in this Report. Corn,
sorghum, millet, wheat, oats, and other members of the Grass family do not.
die from this cause, and consequently should be used after cotton. The plants
to be used will depend somewhat on the locality. In Northern Texas all of
these will do, but in South Texas wheat and oats are not a success, owing to
“rust,” but corn, sorghum, and millet, and grasses do well, and can be used
with advantage. Mr. W. W. Stell5 0 says: “The proper way to farm, in my
opinion, is to third our crops; plant one-third corn, one-third small grain and
the grasses, and the remaining third in cotton. Plant corn after cotton, and
cotton after small grain, and small grain after corn. As soon as the corn is
gathered run your stalk cuttcr and otherwise prepare for small grain, and in
August and September, while there is a green coat of vegetation on the stub-
ble, turn it under as deep as possible. Up to 1884 I had a certain tract of
one hundred acres on my plantation planted almost entirely in cotton for
several years. The cotton died more and more on it each year. In 1884 I
planted the one hundred acres in oats; in 1875 I planted in cotton, and made
more than one five hundred pound bale to every acre, and not a dead stalk
on, the one hundred acres. I then kept up planting cotton on it for a few
years, and the cotton began to die. In 1881 I planted the one hundred acres
in wheat, and in the spring of 1883 I had a good volunteer stand of wheat
and let it stand, so that this land was in wheat two years. Since then it has
been alternated in cotton and corn, and not one dead stalk have I ever seen
on it since it was planted in wheat.”

Mr. H. R. Von Bieberstein writes as follows: Rotation of crops will count-
eract to a very great extent. The best plan is to introduce a three year rota-
tion. Divide your field in three parts, plant one part in cotton, one part in
small grain, oats and millet; rye and wheat being to uncertain. Small grain

» will be removed in June; in the summer you will find time to manure the land

and plow. This can then be put in with fall crops, such as Irish potatoes, or
rye, using it for winter pasturage, and in the spring cotton should be planted;
in the third year plant corn. In this way the disease can be reduced to a
trifle.

“Texas Farm and Ranch, February 15, 1889.

26 Texas Agricultural Experiment Station.

TREATMENT OF FOREST AND APPLE TREES.

In this case we can only suggest preventive manures. Where fields are af-
fected with the Violet root fungus, ditches are dug, as deep as the roots ex-
tend, to prevent it from spreading. In Rosellina Quercina, the fungus attacking
seedling oaks, and Agaricus melleus similar measures have been proposed and
used very successfully in Europe. In orchards and nurseries where the
Ozomum occurs this method can be applied. The following from Von
Thuemen5 1 on “the root mold of the grape vine" is applicable to “root rot” of
apple and forest trees caused by Ozoniuwt. “ In the greater number of cases
man himself is the guilty party--the keeping clean of the soil being only too
often grossly neglected. Upon the surface, indeed, the industrious and me-
thodical vineyardist does not fall into error so easily, since several times a year
the entire vineyard will be carefully cleaned and weeded. But this alone
does not long suffice; the deeper portions of the soil must also be carefully
cleaned, and this unfortunately is almost everywhere slighted, probably en-
tirely neglected. If the branches and twigs lying in the open air form a.
most favorable soil for those tender white fungous threads, how much more
must the same objects favor their growth when buried deep in the earth,
where the air supply is so much more scanty.” Orchards, vineyards, and
nurseries should be kept rigidly clean; the rubbish should be destroyed. Any
trees dying from “root-rot” should at once be taken up and burned. The
place where the trees stood should not be replanted again, until sufficient time
has elapsed for the fungus to disappear (from three to five years).

When trees are purchased every precaution should be used not to plant
those which have come from an infected nursery. Care should be used in
planting sweet potatoes; do not set out plants which have come from an in-
fected spot, or even near it, as in digging potatoes threads of the fungus may
remain to the hoe or plow, and thus the disease is often carried to remote
parts of the field The greatest care should be taken not to carry infected
plants from field to field, as a small thread of the fungus falling from the root
is a starting point for the fungus, and the disease appears, much to the surprise
of the farmer, where he did not expect it.

Weeds, especially the Common Sida, no matter whether occuring in cotton
fields, in orchards, or grain fields, should not be tolerated, for these certainly
harbor the fungus.

SUMMARY OF ANSWERS TO POSTAL CIRCULAR.

The following circular postal card was sent out by the Experiment Station:

1. Please make an approximate estimate of the amount of cotton dying
in your county from “ root rot,” variously called “dead land,” “alkali,” etc.?

2. What is the character of the soil? .

3. What plants die from the same cause?

4. Have you noticed any weeds apparently dying from the same cause?

5. Will you please mail parts of root, stem, and leaves to me of plants
which are dying?

6. Do these spots seem to increase or diminish in size when rotation of ~

crops is practiced?

5 1 Die Bekaempfung der Pilzkrankheitien unserer Culturgewaechse (Versuch einer Pafianzen-
therapie zum praktischern Gebrauche fur Land und Forst wirthe, Gaertner, Obst und Wein-
ziichter). Vienna, 1886, p. 157. A good English Abstract by E. F. Smith, Journal of My-
cology, Vol. V, p. 107; also Abst. Sorauer Just Bot. Jahresbericht, 1885, p. 500.

Cotton Root-Roz‘. 27

7. Has the application of commercial fertilizers, wood ashes, or barnyard
manure proved beneficial? -

8. Have you drained any of these dead spots? If so, does it seem to alle-
viate the trouble?

9. Does subsoiling have a beneficial influence?

l0. Have you noticed the falling over of corn, sorghum, oats, or wheat
when grown on these “dead spots”?

Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Yours respectfully,
Ames, Iowa. L. I-I. PAMMEL.

1. Fifty-seven replies have been received, representing forty-seven counties.
The percentage of loss varies from one-tenth of one per cent in Smith county,
to twenty-five per cent in Fayette. Four to five per cent represents the
average loss in counties like Bell, Ellis, Grimes, and Washington. The loss
computed on the percentages given by correspondents amounts in round num-
bers to one million dol1ars.*

2. Soil: Hard clay, deep sandy loam, heavy black waxy, black sandy,
mesquite lands, red mulatto, yellow alluvial, shelly land, orange drift, and
chocolate.

3. Cotton, sweet potatoes, watermelons. sweet peas, tobacco, cow peas,
Irish potatoes, okra, Apple, Pear, Black Ash, Pecan, Bois d’Arc, Mulberry,
China, Black Locust, Peach, Walnut trees, and Rose bushes); a

4. The following weeds have been noticed: Cocklebur and Careless (Amar-
antas, Boerhaavia).

6. Of the fifty-seven replies received, twenty-two say that when rotation
is practiced the disease diminishes, while four have seen it increase.

7. Manures and fertilizers are not generally used, only sixteen having
tried them, eleven of which have had good results with barnyard manure, and
five with wood ashes and potash.

8. Only four have drained, and that only by ditching and subsoiling; six
find that drainage relieves the trouble. '

9. Ten find that subsoiling will relieve, while four believe it is a disad-
vantage. The others have had no experience.

10. Forty-two have never seen corn, sorghum, oats, or wheat fall over

when it follows cotton. Four find that sometimes it does, and will not pro- '

duce much. In some cases the falling over is due to the chinch bug.

REMARKS

J. N. Rose: “Dies worse after wet weather, and begins on the tap root,
while the lateral roots take it later. Frequent rains keep surface roots alive.”

J. B. Tanner: “This year cotton died more than usual, as we had a wet
spring and summer.”

T. M. Scott: “ The limestone underneath gives good drainage.”

PW. P. Miles: “ The rot in cotton has been worse than any previous year.

Our spring was one of more than ordinary rainfall until the tenth of July,
then a drouth till the sixth of September. Sweet potatoes are‘ affected with
a dry rot, first making its appearance on the outside of the tuber. A white

*Based on L. L. Foster’s Report for 1887.

1:1 have noticed the following: Gossypium herbaceum, Ipomaea Batatas, Dolichos Sinensis,
Pyrus Malus, Mawinas Americana, Moms aZba, Malia azedarach, Broassonetia papyrzfera,
Sida spinosa, and Ambrosia psilostachya.

28 Texas Agrzku/Zura/ Exjfierimenz‘ Slazzbn.

spot of mold precedes decay. This spot becomes brown, and penetrates the
potato.”

John P. Lair: “The land upon which cotton dies need not be planted to
apple trees and sweet potatoes, as they will take the disease. Peaches will do
well in such places.”

W. P. Darby: “The spots diminish when rotation of crops is practiced.
I have reinstated the worst patches on my farm by planting corn for a few
years, and turning weeds and all under, allowing it to rot. My experience is
that where cotton dies it makes good corn, but the stalk will fall soon after
it is mature.”

Geo. H. Hogan: “Corn seldom falls over; when it does it is due to chinch
bugs”
T. V. Munson: “Ten or more years ago I saw a circular ‘patch’ of weeds,

Osage hedge, vegetables, etc., killed. The disease spread in concentric rings
for two or three years from an original undrained basin. A fruit grower
here found that peach trees planted upon a flat rock laid on surface of soil,
then mounded up, did well; but when set in the ordinary way ‘root rot’ would
set in, the locality being seapy.”

Nat Stevens: “Constant deep plowing in the fall lessens the trouble.”

L. W. Moore: “Rotation will check the disease, using millet, sorghum
and corn, then cotton.”

W. G. Crockett: “Sweet potatoes seem to distribute the disease through
the soil. Cotton always dies after it.”

SUMMARY.

The soil upon which the disease occurs is very variable. It is worse on the
black cretaceous soils. These are very poorly drained. Wet seasons, and
especially rain followed by hot sunshine, is favorable for the disease. The
character of the forest growth has nothing to do with the disease. lit occurs
alike on the mesquite soils of Travis and Hays counties and the post oak lands
of Eastern and the bois d’arc lands of Northern Texas. The various theo-
ries are not founded on scientific facts. Chemical analysis of the soil does not
show any appreciable diiference in soils where cotton dies and where it does
not. “Alkali,” as the term is used, is very vague, and does not apply to the
Texas soils where cotton dies. Fibrous-rooted plants suffer from “alkali” in
California and other places. In California cotton succeeds admirably on such
lands. The fibrous-rooted plants, like grasses, do not die from “rot root” in
Texas. “Seedling rot” and “sore shin” should not be confounded with
“root-rot.” “Seedling rot” only afiects young plants. The “Bacterial Dis-
ease of Corn” sometimes occurs in fields where cotton died the previous
year from “root-rot,” but 1S entirely distinct from “root-rot” of cotton, sweet
potato, etc.

“Root-rot ” of cotton is caused by a parasite— Ozonitom auricomuwz. The
fungus has been found on all roots which have died from this disease. Plants
should be examined before they have wilted; in such cases a white mold-like
fungus, the early stage of Ozonium, will be found on the surface of the roots
as well as in the meduallary rays and vessels. Threads of the Ozonium were
taken, and young plants in pots were inoculated. These died of the disease.
Wart-like bodies are found on the roots of cotton and other plants affected.
These are masses of the fungus, and retain vitality for a long time. A large
number of plants are affected, as sweet potatoes, apple, and some forest trees;
also the Common Sida. On some of the roots of apple trees Schizoneura Zaml
gem occurs. The Schizoneura and Ozonmm occur independent of each other.
The Ozonium does notproduce the knotty bodies.

 

Cation Root-Rot. 29

The Ozoniunz prepares the way for a large number of saprophytic fungi,
like Mucor and Penicillium, and unless care is taken wrong conclusions may
be formed. A fungus has been isolated from rotten sweet potatoes, but it is
not definitefy settled whether it is connected with (Jzonium or not. It is
capable of producing rot in sweet potatoes and young cotton.

The lint from plants affected with “root rot” is much inferior in quality.
Seeds from diseased stalks showed good capacity for germination.

Treatments-Fungicides have not checked the disease, except Chloride of .

Lime, and where this was used no cotton was produced,
Rotation of crops is practically the only thing, so far as I know, which will
stop the disease. Members of the grass family are to be used, allowing three
years to intervene before cotton is again planted. Care should be taken not
to obtain plants of any kind from an infected nursery or field.5 2
In conclusion, I wish to thank the various planters and numerous corre-
spondents who have given me assistance in prosecuting the work.
a L. H. PAMMEL.
Ames, Iowa, January 6, 1890.

"Articles on cotton “root-rot.” It is not intended to be complete as I have not been able
to see all of the agricultural papers, where much that has been written on the subject has
appeared. Crockett, Willis G., Losses in Cotton Culture, Texas Farm and Ranch, April 15,
1889; Dabney, W. S., Cotton Blight, Texas Farm and Ranch, Feb. 15, 1889; Derrow, A. N.,
Practical Hints on Cotton Raising, Am. Agriculturist, 1866, p. 133; Fruit Growers’ Journal,
Oct. 1, 1888; Hinkle, C. F., Cotton Blight, Texas Farm and Ranch, -Jan. 1, 1889; Hinkley,
Dr. H., Cotton Culture—Costs and Risks, Am. Agriculturist 1866, p. 433; J. M. H., Poisons
Soils of Texas, Coleman’s Rural World, May, (i?) 1878; J. M. Q, Root Blight in Young Apple
Trees. Coleman’s Rural World, March, (‘.?) 1878; Loughridge, Dr. H. H., Tenth Census Report,
Cotton Production in the United States, Vol. V, Special Report of Texas; A. W. Kerr, Cot-

ton Blight, (i?) Texas Farm and Ranch, Sept., 1886; Meitzen, Herman J ., Cotton Blight, Texas '

Farm and Ranch, Nov. 1, 1888; Morrow, Dr. W. B., “Cotton Blight” or “Root Rot,” Texas
Farm and Ranch, April 1, 1889; Root Rot, Texas Farm and Ranch, Oct. 1, 1889; Pammel,
L. H., Root Rot of Cotton or “Cotton Blight,” Bulletin No. 4, Texas Agricultural Experiment
Station, Dec. 1888; Abst. Agricultural Science, 1889, p. 100; Bot. Gazette, Vol. XIV, p. 113;
Humphrey, Bot. Centralblatt, Vol. XL, p. 59; N. O. Atwater in Digest of the Annual Reports
ports of the Agricultural Experiment Stations of the United States for 1888, Bulletin N0.
2, Department of Agriculture, p. 189; Texas Farm and Ranch, Nov. 1, 1889; Root-Rot
of Cotton or “Cotton Blight,” Texas Farm and Ranch, Sept. 1, 1889; Ramsey, A. M., Soil
for Orchards in Texas, Coleman’s Rural World, May 1, 1878; Stell, W. W., “Cotton Blight,”
Texas Farm and Ranch, Feb. 15, 1889; Stelle, J . P., Fourth Entomological Report, Appen-

_ dix III, p. 25; Stephens, J . B., Cotton Blight, Potato Blight, Texas Farm and Ranch, Jan.

1, 1889; Stringfellow, H. M., Cotton Blight, Texas Farm and Ranch, Feb. 15, 1889; Texas
Farmer, September, 1888; Texas Farm and Ranch, August, September, and October, 1886,
April 15, 1889; Wellborn, J elf, Root Rot or Blight, Texas Farm and Ranch, July 15, 1889;
The Practical Farmer vs. the “Ologist,” Texas Farm and Ranch, Nov. 1, 1889; Red Rust in
Cotton, Home and Farm, Louisville, Ky, August 1, 1889; Yoakum, Dr. F. L., Texas Farm
and Ranch, October 7, 1886; Texas Farm and Ranch, September 1889.

March 15, 1890.—The following additional articles have come to my notice since the
above was written: W. R. Cole, Texas Farm and Ranch, Dec. 1. 1889; Cotton Blight,
Texas Farm and Ranch, Dec. 15, 1889; Farm and Home, Springfield, Mass., Oct. 1, 1889;
Wm. Lomas’ Review of Dr. Yoakum, Texas Farm and Ranch, Feb. 15, 1890; W. B; Mor-
row, A Criticism, Texas Farm and Ranch, Aug. 15, 1889; Texas Farm and Ranch, Harvest.-
ing and Saving Sweet Potatoes, articles by H. M. Stringfellow, W. B. Morrow, J . W. Sim-
mons, and C. N. Eley, two articles on Root-Rot by Jeif. Wellborn, Dec. 15, 1889, and Jan.
15, 1890; Dr. F. L. Yoakum, The Root Blight of Tap Rooted Exotic Plants, Texas Farm
and Ranch, Jan. 15, 1890. .

3O Texas Agricultural Experiment Sfalzbn.

EXPLANATION OF PLATES.

PLATE I.

Fig. 1. Showing depressions and fungus at d. Adventitious buds at b. (Original).

Fig. 2. A, diseased root, showing fungus strands f, somewhat exaggerated. Enlarge-
ment at e. r. roots at the enlargment. B, portion of a root covered with fungus threads.
Brown pseudo-sclerotia at p. O, diagramatic section of p, showing fungus threads. (Original).

Fig. 3. a, galls on apple roots; b, apterous, female, showing cottony covering; c, winged
individual; d, leg; e, beak; f, g, antennae. (After Riley).

PLATE II.

Fig. 1. Sida spinosa, slightly reduced.

Fig. 2. End of a small branch of Sida spinosa, natural size. Both figures drawn by Miss
Mattie H. Hoke.

Fig. 3. Strands of Ozonium auricomum, Lk.; a, showing branches of the strands, with
fine thread-like branches comin from the larger ones; b, the small threads more magnified,
showing mode of branching. F om photographs by Dr. M. Francis; a, magnified about 100
times; b, 200 times. Drawn on plate, from the photographs, by Miss Mattie H. Hoke.

PLATE III.

Fig. 1. ‘ a, part of a strand of the fungus, showing cells with a branch coming from it, with
the ultimate sharp-pointed branches shown at b. B, a young strand with a branch going out
from it. Both figures magnified 37 5 times. (Original).

Fig. 2. a, spore from Fig. 4, s, germinating after 48 hours; b, an enlargement in one of
the threads; h, hypha, with vacuoles; e, part of one of the hyphae with a second kind of
spore. Magnified 375 times. (Original).

Fig. 3. Some of the cells of a rotting sweet potato, showing starch grains, a: ; l, black, peri-
thecium-like body, lying over the cell; m, the mycelium between the Walls of the cells.
Magnified 450 times. (Original).

Fig. 4. Perithecium, p, from culture of sweet potato which contained the black perithe-
cium-like bodies shown in Fig. 3, l; c, fungus thread with a spore-like body, from cultures;
s, spores; the upper part of the perithecium broken, and the cells lengthened out. (Original).

PLATE IV.

Fig. A. A, diseased boll; B, boll from a healthy plant, opened. Bolls furnished to“, me
by Mr. Geo. H. Hogan, Ennis, Texas. Grown on the same soil, a short distance apart. From
a photograph.

PLATE V.

Fig. l. Fibers from a diseased plant, magnified 3'75 times. (Original).

Fig. 2. Fibers from a healthy plant, magnified 37 5 times. (Original).

Fig. 3. Verticillium; b, strand; s, spores; c, hypha; the fruiting branches are borne at
the end. (Original). g

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