The Cook County news-herald. [volume] (Grand Marais, Cook County, Minn.) 1909-current, 1917-04-11
TREAT SEED POTATOES
BEFORE PLANTING
Soaking in Disinfecting Solution
Tends to Improve termination
and Lessen Danger Of Scab.

anu Lessen Odn0eT OF SCdUs
The disinfection of seed potatoes
by soaking in corrosive sublimate or
in formaldehyde is recommended by
the United States Department of
Agriculture as measure that will
tend to improve the termination and
lessen the danger Of scab.
Such treatment, is on the whole,
profitable, but has several limita-
lions which should be clearly recog-
nized to prevent disappointment.
The object of disinfecting seed po-
tatoes is to destroy the germs of
scab and other surface parasites
which might otherwise be planted
with the seed and infect the new
crop. Only surface infections are
reached by this method. 1t is only
partially effective against deep pits
of common scab. Neither corrosive
sublimate nor formaldehyde, as or
dinarily used, will destroy silver
scurf. Either one will kill surface
infections Of blackleg, but neither
will reach the internal infections
common in tubers from blackleg
hills Neither Fusarium wilt nor
late blight infection in potato tubers
can be reached by any seed treat
ment, nor can any of the nonparasi-
tic disease of potatoes, such as mo-
sale, leaf roll, and curly dwarf, thus
be prevented. See Farmers Bulletin
544 for descriptions of these trou-
bles.
Clearly, therefore, the most impor-
tant precaution against these disea-
ses is to select clean, disease-free
seed potatoes from healthy, vigorous
plants, as determined by field in
spection during the growing season
and at harvest. Seed treatment
should then be applied as an addi-
tional precaution. 1t will not be ef-
fective, however, if the siol where
the potatoes are to be planted is al
ready full of disease.
Siol conditions have an important
relation to potato tuber diseases,
and may of these are widely spread
throughout the country, and perhaps
native to some soils. Common scab
is favored by neutral or slightly
alkaline soil, and seldom gives trou-
BILE in acid soils. 1t, therefore, is
increased by lining and by fresh
stable manure, wood ashes, and al
kaline fertilizers, such as nitrate of
soda, and ground bone, while acid
phosphate and sulphate of ammonia
tend to diminish scab.
Rhizoctonia occurs to some extent
in nearly all soils, but appears tc
attack potatoes most when the con
ditions are unfavorable to the best
development of the potato plant
Bring the land to an ideal state Of
filth to minimize loss from Rhizoc
tonia.
Powdery scab is worst on cold
wet, or poorly drainedsoils. Black
leg, on the other hand, is carried b,
infective seed. No potatoes shown.
deep brown discoloration at tn
stem end should be planted.
Sulphur tends to prevent commo,
scab. 1t is not substitute for cor
rosive sublimate or formaldehyde
but is a good drier for cut seed. AID
piled to scab-infected soils at tn
rate of 500 pounds per acre, it re
duces the scab, but such heavy ap
plications cannot generally be re
commended as profitable. Prelimin
airy experimental trials are advised
It is considered better to treat 30
tatoes before the yare cut into seed
especially if the cut seed is to b
very small. Put into the solution al
the potatoes it will cover and kee1
the batch covered by the solution
for the period named under tn
treatment being used.
The ''formaldehyde treatment
consists in soaking the potatoes, be
fore cutting, for two hours in a Sc
luton made by adding / pint or for
maldehyde to 80 gallons of water
The solution can be used repeated,
The gas treatment is no longer re
commended.
The corrosive sublimate treat
ment" is more effective than forma
dehyde. particularly against Rhizot
tonia, or russell scab, and powder
scab. Corrosive sublimate is use
at the rat of 1000 for one and on,
half to two hours. Dissolve 2 our
ces of the salt in hot water and d
lutte to Is gallons. This is dead1