Kingsbury County independent. (DeSmet, Kingsbury County, S.D.) 1894-1929, 1906-06-15
ScAR.

Because In some years potato scab Is
more troublesome than in others, and
because the disease itself Is so little
understood by practical growers, there
Is danger OF it's not being regarded
as of the Importance that IL deserves.
The common Idea that potato scab Is
produced by chip dirt, ashes or some
thing of that Kind Is erroneous. 1t Ia
a fungous disease, n grow from
spores, the same as any other fungus.
Certain conditions favor its growth,
and such favorable conditions may be
furnished by chip dirt, lime. ashes,
etc. When once introduced into land.
no practical way has thus far been
found OF removing It. How long II viii
remain in the soil Ii unknown 1t GER
tainly may continue for many years
even when no potatoes are grown Upon
the field.
There are many ways In which 1t Is
possible for soils to become affected.
The germs may be introduced into the
manure pile by feeding scabby potatoes
TO live stock, or by putting them direct
ly into the compost heap. The fungus
may then propagate itself in the ma
nure. and IL this is applied to the land.
the disease may be widely disseminated.
Alkaline soil fayors the growth of the
fungus, and on this account neither
ashes nor lime should ordinarily be
used in connection with potato grow
lIlS. AS idIIH IldIluItS dT6 SllkUliyt
alkaline, they are best not used on po-
tato land. The blowing under Of a
green crop tends by its fermentation to
make the soil slightly acid. This con-
dition is u~nfavorable to the growth OF
the fungus. There is a more or less
common belief that salt is something
Of a preventative OF potato scab, but
exact experiments have failed to DEM
onstrate this.
Perhaps the most common way in
which the scab fungus Is disseminated
is by the use of infected seed. Ii Is
therefore OF the utmost Importance to
use clean seed. Where ii is impractic-
able to procure clean seed, or In case
of doubt. 1t should be treated with a
fungicide. While such treatment will
help scabby seed, IL may not act as
an entire preventive. 1t Is therefore
best not to use seed that is much az
fected.
Formaldehyde gas, either In solution
or in the dry, gaseous state, can ba
effectively used to clean suspected
seed. Formaldehyde (formalin) Ia sold
in a solution OF about 40 per cent
strength, and can be obtained at n
drug store. A few bushels Of seed are
most conveniently treated as follows:
Make up q solution of formalin of the
desired. bulk, using 16 ounces OF for
malin Gao per CEN solution of formal
dehyde gas) to each 80 gallons of wa
ter. Soak the seed two our in this
solution, and then spread out the tu-
bers to dry. After drying the potatoes
should be cut and planted in the usual
way, but care should be taken not to
allow them to touch any box, bag or
bin where scabby potatoes have been
kept.
The Vermont experiment station is
studying the treatment of formalde-
hyde gas, and while they have no.
reached perfectly definite conclusions.
they recommend the following treat
ment for potatoes In bins:
The bin or room where the potatoes
are stored should be closed as tightly
as possible. Ten ounces OF formalin
should be used for every 1000 cubic
feet of room. and the potatoes should
be left exposed to this gas for twenty
four hours. The gas is generated by
the action of formalin upon potassium
permanganate. For this purpose three
parts by weight of potassium perman-
ganate are mixed with eight parts OF
formalin In an earthen Jar. The Jar
should a q capacity of about q GAL
lon for each pint (16 ounces) of for
malin. The required mount of per-
manganate should be placed in the bot
tom of the Jar. and the needed amount
of formalin poured over II. The op-
orator should leave the room at once,
taking care to close the door as tight
ly as possible. The retail cost OF the
chemicals to produce gas for 1000 Gu
bic feet will be about $3.50.
For handlers OF seed who wish to In
sure freedom from scab and for large
growers of potatoes this gaseous meth
cd is more convenient than the wet
method, and experiments at the Yer
mont station show 1t to be effective
Charles d. Woods, Maine Experiment
Station.