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The progressive farmer. [volume] (Winston, N.C.) 1886-1904, June 30, 1886, Image 2

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The Bacteria Theory as Explained by
" Prof. Atkinson.
. Raleigh News and Observer.'
Ithaca, N.T., June 17, 1886.
A few weeks before my departure
from North Carolina my attention
was called to a disease affecting the
apple trees in the orchards of Prof.
Mangum and Mr. Martin at Chapel
Hill. President Battle also brought
me some infested twigs and said
that the disease appeared to affect
the upple trees pretty generally
throughout the State, and great an
xiety was felt among fruit growers
for -its effect upon the apple crop.
The disease affects the young twigs
of one or two years growth, causing
the twig and leaves to die and the
twig to blacken. The disease usually
sets in at the terminal portion of the
twig and advances toward the main
branch. In many cases it reaches
the portion of the twigon which the
apples are borne and of course de
stroys the young fruit. My first
care was to examine the twigs to be
certain that the trouble was not
caused by a minute inject, which
often bores into the twigs at a bud
or small branchlet and cutting off
the supply of sap causes the death
of the twig; or of larger insects,
which with their sharp beaks some
times pierce the tender and succu
lent branches and suck out their
juices. A few traces were seen of
both kinds of these insects, but on a
careful examination of a goodly
number of tSvigs it was plain that
these were the chance attendants
and not the cause of the disease, as
by far the larger number of twigs
bore no marks of insects. I then
came to the conclusion that it was
what is termed a " germ disease,"
caused by the presence of a micro
scopic plant belonging to the group
of bacteria.
As the "bacterian theory" of the
disease known for "ma ny years under
the name of "pear blight," "apple
blight," etc., was but recently pro
pounded, and only within the last
year confirmed by experiments that
were not open to criticism, the re
sults of some of which have not as
yet been published, I wished to have
access to the best and most recent
authorities before attempting to give
an account of this subtle and invisi
ble foe. That the credulous may not
think this a "yarn," spun to while
away the tedious months of sum
mer, I wish to state that . the facts
are based upon the investigations of
some of our most accurate, and sci
entific workers, and published in
such works as the following Proc.
Am. Ass'n Adv. Sci. vol. XXIX, 1880,
page 583 ; Rep. III. Ind. Univ. 1880,
p. 62 ; Trans. III. Hort. Soc. 1880, p.
157 ; Am. Nat. Vol. XI., 1881, p. 527 ;
Proc. Am. Ass'n. Adv. Sci. Vol.
XXXIV., 1885, p; 295; Bot. Gaz.
Vol. X., 1884, p. 343.
I also acknowledge the kind per
mission granted by Prof. Prentiss,
of the botanical department of Cor
nell University, of consulting a re
cent unpublished manuscript depos
ited in the Cornell University li
brary, by J. C. Arthur, of the New
York agricultural experiment sta
tion, which embodies the results of
the most recent and careful investi
gations upon this important subject.
The disease is known to appear in
the fruit trees of North America,
east of the Rocky Mountains, and
from Georgia and Mississippi on the
South to Canada and Minnesota on
the North. Thus far it is not known
outside of this area.
It was mentioned as long ago as
1817 in the oldest pomological work
published by an American author.
In 1826 and 1832 considerable in
jury was done to pear trees. The
great and widespread epidemic of
theear blight occurred in the year
1844.' Though it has never been so
prevalent and extensive in disas
trous effects, it has appeared in one
place or another at unequal periods
and in varying power ever since,
sometimes threatening to prevent
the cultivation of fruit trees.
Several: agencies have from time
to time been advocated as the cause
of the disease. In 1817 Coxe thought
the rays of the sun acting through a
moist or misty air deranged the phy
siological activities of the tree and
produced the disease.
For a time it was believed to be
produced by minute beetles which
lived UDder the bark of the trees.
The insect was supposed to poison
poison the sap, and being so small
, : - ! . I
was thought to be generally over
In 1884, II. W. Beecher, of In
diana, and A. J. Downing, of Down
ing's Horticulturist supposed the dis
ease to be caused by the freezing of
the sap in the winter. A poisonous
principle was thus induced, which
was carried to all parts of the tree
when the circulation became active
in the spring. It was called the
"Frozen Sap Theory " and was be
lieved for a number of years to be
the explanation of the disease.
This was set forth as a cause of
the pear blight in 1863, and pub
lished in one of the Ohio agricultur
al reports. It found many support
ers. Some thought it due to elec
trical disturbances, as it was often
more noticeable after a thunder
We come now to the theory which
is supported by the best investiga
tions and experiments of the present
day. Although bacteria had been
noticed in connection with the dis
ease prior to 1877, it was not sup
posed to be the cause. Prof. Burrill,
of Illinois, noticed bacteria in con
nection with it, and in 1878 stated
his belief that these organisms were
the cause of the disease. He per
formed experiments in 1880 by inoc
ulating healthy trees with the germs
from diseased ones and succeeded in
infecting those inoculated. In 1882
he named it " micrococcus aniylovo
rus," which being interpreted means
the minute starch-eating berry. To
be certain that these germs caused
the disease Dr. J. C. Arthur in 1885
separated the germs from the liquid
in which they were cultured. Trees
inoculated with the liquid show no
signs of the disease, while those in
oculated with-the germs became in
fected. This demonstrated beyond
a doubt the truth of the bacterian
The micrococcus amylovorus bur
is a one-celled organism generally
believed by scientists to be a plant.,
but some eminent men believe the
bacteria to be animals. They lie on
the " border land " between plants
and animals. That is, they possess
the characters of both animals and
plants in so marked a degree that it
is difficult to say with certainty to
which kingdom they belong. Poli
ticians would say that they were
" straddle the fence."
It has been found by numerous
experiments that the germs will not
enter through the bark except of
very tender twigs and when but lit
tle moisture is present ; but the main
point of entrance is at the growing
bud or opening flowers. Wounds
produced by insects in the bark may
afford an entrance. The germs can
not penetrate through the skin of
the fruit, but when the fruit is af
fected by an insect or when from
some other cause the skin becomes
punctured they can enter. It re
quires some time, from two to three
or four weeks, after the germs enter
the tissues for the disease to become
apparent. The organisms consume
the oxygen in the starch of the
cells, thus breaking down the tissues
and causing death. When growing
these minute organisms hop about
with great alacrity, as can be seen
with the aid of a powerful micro
scope. By this movement and
through the circulation of the sap
they are transported along the
branch. They are oval in shape, and
4-100,000 to 6-100,000 of an inch
long by 2-100,000 to 3-100,000 of an
inch broad. Arranged in single file
it would require about 25,000 to make
a line one inch long, or 50,000 placed
side by side to make a column of the
same length ; or again, it would re
quire 1,250,000 of these little organ
isms to make a solid phalanx of an
inch square!
The disease is of the nature of an
epidemic. It may appear in a local
ity so as to do great harm with or
without a preceding year of slight
damage, and may be followed by one
or two years during which it may
be less virulent, followed by a longer
or shorter period of absence.
Earlier than 1846 it was some
times spoken of as "first cousin to
cholera," "a species of vegetable fer
ment," etc., In the year 1846 it was
believed by some to be of the nature
of an epidemic, but not until 1878
were the bacteria . believed to bo the
agency in causing and spreading the
disease. ; .- -.
" , . , REMEDIES.
It is a cause for regret that for
such an enemy to fruit trees as mi
crococcus amylovorus bur, after so
much that is wonderful has been
said about it by learned men, there
is no efficientfemedy for its destruc
tion. All that at present can be done
is to lessen the numbers and in this
way check its multiplication. This
should be done by watching the
trees and. cutting off all infested
twigs and limbs about a foot below
the infected part as soon as it is ob
served. All these should be imme
diately burned. This should be done
as early as possible, for with the ap
pearance of the disease there is a
gum which exudes from the diseased
tissues, bearing out with it numer
ous bacteria. The rains wash off
this gum, it dissolves, the bacteria
are set free and live upon any vege
table substance under the tree; en
dure the coldest winter and are ready
the next spring to be carried in the
air to the opening buds and flowers
of the trees. Care should be exer
cised in cutting off the limbs not to
let the knife cut the diseased part,
for in cutting afterwards a healthy
part this is liable to be inoculated
with the bacteria clinging to the
blade. It has been found by "cul
tures in solid mass" that the rapid
ity of the multiplication of the germ
is in direct ratio to the water pres
ent. An economic suggestion comes
from this, that moderate cultivation
which will produce healthy trees
and not very succulent stems is a
factor in resisting the disease. Some
varieties of fruits, especially of the
pear, resist it more effectually than
others. It affects apple trees differ
ently from pear trees in this respect,
that when a pear tree is attacked
the disease advances into the large
branches and eventually kills the
whole tree, while only the twigs of
the apple as a rule are affected.
There is a large field for investiga
tion to discover an efficient reme
dy for this and similar diseases.
Judging from the wonderful pro
gress in the arts and industries re
sulting from the investigation of
trained scientific workers we may
confidently hope that some time in
the future a remedy will be found
for this enemy to the horticulturist,
though as yet no indication of the
remedy has appeared.
There is much that is useful to sci
ence and to horticulturists in having
accurate observations of the effect
and nature of such a disease taken
by careful men. I wish to publish
a few questions hoping that at least
a few men in the State will note
down their observations during the
summer and send them to me at
Chapel Hill, N. C, in September of
this year. Careful attention to this
by one owner of an orchard will be
of service. It would still be better,
however, if some would be responsi
ble for counties, so that data for
reference could be obtained from the
whole State.
1. When did the disease first make
its appearance in 1886?
2. Did it apj)ear on apple trees in
immediately preceding years?
3. If so, how many years and
what the extent of damage?
4. Varieties of trees most affected?
5. Condition of trees affected as
regards succulency of twigs ?
6. Length of diseased twigs (ex
tremes and average)?
7. Number of years growth in
eluded in the diseased part ?
8. Time of season when the dis
ease seems to be at its height?
9. Time when progress of disease
10. Amount of damage done to
trees (the average proportion of
limbs of a tree killed)?
11. Amount of damage done to
this year's apple crop?
Thismorning just as I had finished
my letter a package of infested twigs
arrived which were sent at my re
quest by Prof. Love, Chapel Itill,
N. C. I placed some very thin shav
ings from the inner bark on a glass
slide and added a drop of water. The
water immediately became clouded
with a dull, milk-white color, from
the presence of millions of the germs.
Examining this with a microscope
which magnifies 500 diameters, the
one-celled germs could be distinctly
seen, some quiet and collected in
clusters, "others independent and
hopping and tumbling about in a
very active manner. In some cases
three or four cells were united. This
happens from the manner of growth.
A single cell, or plant, by assimila
ting nutriment elongates, and a par
tition forms, dividing it into two
cells. It may grow so rapidly as to
form three or four cells in a line with
the partitions ; developed, but not
quite mature enough to, separate
them into independent cells. Such
;d polios) a rvilonv. .bach
cell soon separates, from the colony,
becomes independent and capable
under proper conditions of produc
ing others. Geo. F. Atkinson.
gwm gjott.
In this season, when the rot in po
tatoes is so prevalent, the white va
rieties are least affected by disease.
As some of these are good quality
and good yielders, they will be large
ly planted hereafter.
Excessive feeding of new oats will
cause scours in horses, even if they
do not induce more dangerous colics.
Old horses especially should be fed
only ground feed, as whole new oats
pass through them doing little or no
Some farmers are trying to con
sole themselves with the idea that
rotten potatoes left on the ground
will be worth considerable as ma
nure. The idea is fallacious. The
potato is mainly carbon and has
very little manurial value.
In selecting seed corn the main
point is to have it dried in the Fall
before severe frosts have had a chance
to injure it. The difficulty with
much poor seed corn is that it is
frozen first and the germ injured
ana then thoroughly anea auer
It is a general fact that cultivated
fields are more free from weeds than
those seeded down and left for either
pasture or hay. The pasture lot is
seldom ever mown as it should De,
and as stock crop the clover and
grasses weeds grow and seed with
out check.
The flavor of mutton can be great
ly improved by fattening upon the
best of food and removing the vis
cera with all possible despatch after
the animal is bled", using care not to
cut or rupture the entrails, so as to
bring their contents in contact with
the carcass.
The failure of squashes and other
vines to truit is generally due to im
perfect fertilization. It may be that
pinching back will check the growth
of vine and thus induce fruit produc
tion, but a more certain way is to
artificially fertilize by transferring
pollen to the female flowers.
The trainers of successful trotters
have justly claimed great credit for
the performances of their charges.
But it is just as true on the farm as
on the road that what a team can
do depends largely on their driver.
A poor driver will worry out a team
on a light load, while a good team
ster will do the same work without
The best time to prune grape vines
is as soon as possible after the leaves
drop off in the Fall. Then the cut
ends get dry during the Winter; and
there is no danger of bleeding when
the sap starts in the Spring. Trim
ming is very generally delayed until
a leisure spell in Winter. There are
many objections to this plan : If the
work is done in very cold weather it
is a slow job and takes double the
time that would have been required
if done in October or November. At
the same time the canes are full of
frost and are very brittle and liable
to be injured by being broken off too
short. If the work is done during a
warm, thawy spell in Winter the
ground is usually muddy or else cov
ered with slush, and the job is a
sloppy and disagreeable one.
A successful Pennsylvania farmer
believes red clover the most valuable
of vegetables as a green manure or
a mulch. Sowing late in the Spring
on wheat lands, and harrowing it
down with a common harrow, which
will not hurt the wheat, in his judg
ment produces the best results. Clo
ver growth is helped by lime and
plaster. Large quantities of nitro
gen are contained in the earth and
air, and clover absorbs nitrogen more
than any other plant. The plant and
air work together: in furnishing an
exhaustless supply of food for all
kinds of- food plants. Wheat and
other cereals cannot obtain enough,
nitrogen from the air to sustain them,
but clover and other plants with
dense foliage can do so. ami
they are plowed' down will hirnU
the' cereals. (,r
M. Houles, the French discover
of the method of open air or
silo, reports the continued success 0f
his method. The secret of the suc
cess of this method lies in such unj
form and continued pressure as ili
secure the expulsion of the air ail(j
thus prevent decomposition. The
material is carted to the place of
stacking as fast as cut without wait
ing for any drying, and is built'un
slowly and uniformly, allowing fe.
mentation to start, making the for.
age more tender, care being taken
to prevent the stack from leaning as
it settles. When the stack isfin
ished the top is covered with inch
boards projecting a few inches over
the sides, and then weighted at the
rate of about 2,000 pounds to the
square yard, with any convenient
material, stones, earth or firewood.
The only drawback to the plan i$
said to be the difficulty in keeping
the sides perpendicular. "
Care in gathering and barreling
fruit for storing and keeping is Jf
the utmost importance, and yet how
often is fruit gathered when it would
seem as if the chief end and desire
was to promote decay as early as
possible ! They must be picked from
the trees and handled carefully.
Barrels are found to be convenient
packages for apples, but they should
be washed, cleaned and dried before
using. Any nails on the inside should
be removed. The fruit should be
packed in the barrels as close as
possible, and should be shaken down,
to prevent any movement of the
fruit after the barrel is headed. Each
should be marked and placed where
the temperature is as low and uni
form as possible. If apples are to be
stored for winter the sooner they
are placed in a low degree of tem
perature the better. A fruit houo
is undoubtedly the best place, but
most growers have to resort to their
Farmers are generally of the opin
ion that their business is more large
ly overdone than any other. BuU
it is the pursuit which men go into
when other avocations fail, then
they are liable to have additional
competition from most unexpected
sources. The labor strikes have
mostly failed, and with this failure
employers are frequently discrimi
nating against those most conspicu
ous in exciting discontent and strikes.
On the (rould railroads in Missouri
the management have refused work
to all Knights of Labor. Many of
these will be obliged to betake them
selves to the farm, and mighty poor
work they will make of it unless
they are willing to labor on the farm
under far severer rules than those
from which they have revolted in
the city. But all the same they will
be nominally transferred to the list
of agricultural producers rather than
consumers, even though they grow
little more than enough for their
own consumption.
The borer is fatal to all peach trees
not fully protected against its rav
ages. This can be successfully done
by the application of the following
wash :
Four gallons whitewash,
Two quarts clay,
Two quarts fresh cow droppings
One quart lye that bears an egg
Mix these ingredients to a proper
consistency with water. Remove
the ground from the top of the roots
close to the tree, and apply the wash
to the exposed roots and to the whole
trunk of the tree, including the hol
low between the lowest branches.
Cover the roots again with earth.
The wash can be applied very expe
ditiously by means of a corn broom;
and no special pains need betaken
against splashing any of the sub
stance oh the ground, for the women
will raise no objection to such a mis
hap and the tree will eagerly appro
priate the drippings, and put them
where they will do the most good
The wash should be applied twice
every season ; namely, about the end
of May and the end of August. A
have found this an infallible protect
ion of neach and armlfi trees against
- . x X 1
the borer. For apple trees one ap
plication of 'the wash every season
is sufficient.- From essay by Charles
Shearer, read before Pennsylvania Stati
Horticultural Society.

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