Elmore County Republican. [volume] (Mountain Home, Idaho) 1910-1915, 1913-05-24
POTATO DISEASES

trip through certain parts Of Idaho.
and l have found In various parts two
potato diseases that should receive
attention at this time. These are the
Fusarium dry rot and potato scab.
In view of the fact that both Of these
diseases may spread rapidly. and In
time may become serious troubles.
| 1t is necessary for potato growers to
practice certain methods Of culture
that will hold the diseases in check.
Both of these diseases will cause
great financial loss II no efforts are
made to eradicate them. Both are
caused by parasitic fungus organ
isms living at the expense OF the
potato tuber. They are plant beings
as much as the potato. but they
cannot make their own food. They
have numerous minute reproductive
bodies that cannot be seen without
microscope. These bodies, called
spores, may live three or four years
in the soil. Consequently when q
field becomes infested with the di.
sease, considerable time is required
to rid the field Of it.
IDENTIFICATION
Scab-The grower recognizes read
lily the rather circular, more or less
pitted, brownish spots which are
characteristic Of scab.
Dry Rot-This Is strictly disease
Of the tuber during storage. The
organism causing the disease enters
the tuber only through broken places
in the skin. It continues slowly In
to the tuber, leaving behind decayed
tissue which is dry or powdery.
Sometimes other kinds Of organisms
will enter the decayed portion giving
it wet appearance. These wet rots
sometimes have foul odor, due to
the presence Of bacteria. In badly
infested tubers, the skin becomes
shriveled and discolored.
ECONOMIC IMPORTANCE
There are estimates on record in
Nebraska where the loss from dry rot
alone has been put as high as twen-
ty per cent of the stored crop. In
certain parts of California the finan-
cial loss from potato scab has been
estimated as high as seventy-five per
cent. These are extreme cases but
they are not the only cases of the
kind On record where scab and dry
rot having become an epidemic.
METHODS OF CONTROL
/. Use only land free from the
disease organisms. It Is usually
best to grow only one potato crop in
four year rotation.
2. Use only seed tubers free from
the disease.
Tubers affected with scab and per-
fectly sound ones taken from lot
where dry rot is present may be
treated as follows:
(a) Formalin Solution Treatment
Use one pint Of forty per cent for.
malin to thirty gallons Of water.
Suspend the tubers In the solution
for two hours; more than three
hours may be injurious.
(b) Formalin Gas Treatment, place
potatoes in an air tight room In such
a manner that the air can circulate
all about them. Have the tempera'
ture at sixty-five degrees or above;
and, for every one thousand cubic
feet Of space in the room, use three
pints OF forty per cent formalin and
twentyIthree ounces Of Potassium
permanganale. Spread the Latter
over the bottom Of large containel
which is. placed in the room at leas'
three feet from the nearest tubers
This container Is usually placed In
side another one, such as tub
me formalin is then poured over tht
potassium permanganate, and thu
door is quickly closed and made all
tight The room is left closed TWEEN
ty-four to forty-eight hours.
(c) Corrosive Sublimate Treatmen
The proportion is two ounces OF cor
rosive sublimate to fifteen gallons o
water. Soak the tubers one and one
half hours. This Is the strength US
ed generally by physicians for steril
izing purposes. This solution shoul'
not be placed in metal container.
/ The kind OF treatment to be EN-
ployed will depend largely on tn
amount Of potatoes to be treated, tn
solutions being best suited for treat
ing small quantities and the gas 10
treating large quantities. BY the ga
method q carload or more can D.
easily treated at once, but 1t woul'
require much more labor and tim
to treat the same amount by dippin'
1t In q solution.
! The three methods OF treating d
seased potato tubers are equally 81
ficient in killing disease-causing OF
ganisms, when care 10 taken to 10