Thomas County cat. [volume] (Colby, Kan.) 1885-1891, 1886-03-11
POTATO DISEASE.
Rot Communicated to tho Tubers Only
Through the Parent Vine.

Through the Parent Vine.
Having for more than twenty years
observed the diseases of the potato. I
! have discovered certain facts which be-
lieve will be of use to all growers of this
important crop.
With regard to the disease known as
the rot, l am satisfied that it is COM
municated to the tubers only through
the parent vine, commencing after the
leaves begin to die, and ceasing when
the vine is so far dscayed that sap circu-
lation ceases between the vine and the
tuber. In from two to SIX, or possibly
eight weeks from the time the leaves are
dead. the disease is developed by the APP
pearance of dark spots or streaks in the
tuber. All that pass the time above
named in sound state are not likely tC
be. and think can not be, affected by
coming in contact with diseased tubers,
whether in the soil. in the cellar or
buried in a pit in the field.
In order to discuss the matter intelli-
gently, l will call attention to some of
the invariable symptoms of the disease,
which will call the ''black rot" to dis
tinguish it from other diseases which
have sometimes been COMPOUNDED with it.
The disease appears first, as stated
above, in dark spots under the skin, and
if the tuber is at once put in cool. dry
place, rs in a good cellar, it will remain
hard for a long time, and not become
soft. rotten MASS sooner than from two
or three to six months. The fact here
stated is very important in determining
the question of contagion. BY observ-
ing the progress osdecay it will be seen
that, rs soon as attacked, the tubers be-
gin to waste away by evaporsting. BY
cutting into different specimens, it will
be found that the black streak does not
usually extend deeper than half an inch
from the surface, and if the tubers are
small or flat they may, if exposed to- the
sir, wither away without becoming soft
But if they are two inches or more i'm
thickness the inner portion, not colored,
usually rOtS. If the affected tuber is left
in the soil in warm, wet weather, Il soft
rot will soon follow the appearance Of
the disease. Frequent examinations OF
the PROCESS of the disease will show that
there is little difference between those
thrown out and exposed in the cellar at
the time of storing. and those carelessiy
or Intentionally left deep down in boxes
Or barrels But it will be noticed that.
while the former will mostly decay with
out much moisture appearing :NbOut
them, those deeper in, where evapor:l-
ton is slow. will after about two. months,
exude moisture; and i'm it will grow a,
gummy mould, adhering firmly to- other
tubers so that they may sometimes be-
lifted by it. But after years of Observa-
ton, l have never found Il talber show
ing evidence of being recently affected in
winter or spring, or taking the disease
by contact with a decaying one: The
same holds true Of potatoes buried in
pits. 1t may be further remarked that
some specimens appear to- be more
strongly impregnatcd with the virus than
others, the whole surface being attacked
at once. In that case decay is quite
rapid. Others may show first an. aftec--
ton at one end, generally the seed end.
In that case. though the diseased endi
may be cut off generally the wholeta,ber'
will become diseased before spring; while
if the stem end of long tubers is,attsicked
the disease may stop after two or three,
inches have rotted, leaving the remain-
der apparently perfectly sound.
l have further noticed that early vari--
cites, ripening their leaves i'm July, may
be dug early in September anu remain
sound, while those ripening three. or,
four weeks later may, if dug ut the.
same time. though apparently sound,
rot after being put in the cellar.
Later varieties. holding their leaves
until dug or until killed by frost will
not rot This fact gives the: key to- a.
sure preventive of this, disease, which |
has caused SO much loss to. farmers,
through the country L will give OBJ
and tests by which L have.
reached conclusions upon this point.
About 1861 l dug part Of my cropo |
Reachblows as soon. as they shOwedi
signs of ripening, bnt before. mnnw
leaves had died, and put Them i'm my
cellar. As soon as all the leaxes, had
died, but before the wines. Were dEN,. I |
dug the remainder and stored them i'm
the barn, as intended to- market them
Several weeks LATER. when sonting for
sale, found fully one-third were, dis
aased. Upon examining those in tine
cellar not an affected tuber' w;ls, found
I then attributed the difference. i'm keep
ing to the warmer atmosphere. of the
barn. am now satisfied that, hinl, the
storing places been reversed the first
dug would have kept and the LAST rotted.
Cor. N. y. Examiner.