The Iola register. [volume] (Iola, Allen County, Kansas) 1875-1902, 1889-05-10
scAs m POTATOES.


Nature Of the Disease and How to Pre-.
vent It's Appearances
This Is not new disease, nor is it
confined to our own country. but it also
occurs in Europe and is the subject Of
many papers in German works on plant
diseases Notwithstanding its prevail
ence and the discussions it has ELECTED
there is no settled agreement. either
among scientists or agriculturists, as to
the cause. By some it has been held
due to fungi, while others attribute it
to the depredations of worms in the
soil
In a recent article on the subject by
the chief of the section Of Vegetable
Pathology it is said that it Is now the
belief of those who have given the
matter careful study that it is not as
a general thing. due to either one of
the above mentioned causes. but is the
result of certain physiological changes
that take place in the tuber when
grown under certain conditions. The
outer covering of the potato consists of
as protection to the tender parts
within. This enveloping coat is made
up of minute cells, by means Of which
an exchange OF gases taxes place be-
tween the interior and exterior of the
tuber When from excess of moisture
or other cause the cells become en-
larged and the skin is weakened decay
sets in. In its efforts to heal the wound
the tuber gives rise to new layers OF
cells beneath the diseased parts. and as
the result of this dying of the outer
cells and the formation of a new growth
beneath a scab is produced.
There is prevailing belief that ex-
treme humidity favors the development
of the disease, but what further infu-
ence the character of the soil has in
producing it is not positively known
During the year 1887 number of trials
were made at the New York Agricul-
tural Experiment Station. in which it
was shown that an excess of moisture
and the use of fresh stable manure in
creased the number of scabby potatoes.
The data obtained are summed up as
follows: QD The scab is not primarily
caused by fungus. (2) 1t is not due
to the work of insects. (0 In nearly
every instance an increased yield was
accompanied by an increased percent
age of scabby potatoes. (D Any mark
ed change in the rapidity of growth,
either an increase or a decrease, tends
to an increased production of scab. (5)
A continuous growth from the time of
first vegetation until the tubers are
fully matured. appears to be the condi-
ton least favorable to the production
of scabby potatoes.
Extensive experiments with remedies
for scab make it appear that special
commercial fertilizers. while not infal-
lible specifics againt scab, are more or
less efficient. Mr.. E. S. Carmen says
on the subject: 1--WE have used as
much as a ton of the potato fertilizer
which is strong in potash-to the acre,
and yet we harvested clean potatoes,
with smooth skins and without scabs.
Not so when fresh farm manure is used.
This with us almost always causes scab
by attracting wire worms, which eat
into the skin and give the potato the
same corroded surface as the fungus
causes" Those who were present at the
harvesting of the Rural New Workers.
potato contest plot, where the fertilizer
used was the potato manure, at the
rate of LOO pounds to the acre, with a
sprinkling of sulphur in the trenches.
will remember that the large product
was singularly free from scab. DR.. F.
NJ. Hexamer and DR.. Henry Stuart are
numbered among other experimenters
who have expressed the opinion that
special commercial fertilizers are eff
cacious and to be preferred in potato
culture to fresh farm-yard manure
n. Y. World.