Forest City press. (Forest City, Potter County, D.T. [S.D.]) 1883-19??, 1906-06-14
POTATO scAR.

Because In some years potato seal is
more troublesome han in others. and
because the disease itself is so little
understood by practical growers. there
Is danger of its not being regarded
as OF the Importance that ii deserves.
The common idea that potato scab Is
produced by chip dirt, ashes or some
thing of that kind Is erroneous. 1t is
Il funEous disease. and grows from
spores, tie same as any other fungus.
Certain conditions favor it's growth.
and such favorable conditions nay be
furnished by chip dirt, lime. ashes.
etc. When once introduced into land,
no practical way has nus far been
found of removing it. How long 1t will
remain I'm the soil is unknown. 1t GER
tainly may continue for many years
even when no potatoes are grown upon
the field.
There are many ways i'm which it is
possible for soils to become affected.
h germs may be introduced into the
manure pile by feeding scabby potatoes
to live stock, or by putting them direct
~ into the compost heap. h fungus
may then propagate itself in the ma
nure. and If this is applied to the land,
the disease may be widely disseminated.
Alkaline soil favors the growth of the
fungus, and on this account neither
ashes nor lime should ordinarily be
used in connection with potato grow
n x AS fitinl manures are slightly
HlkallHc. tHeN are DeSt not uSeu on po-
tato land. The blowing under of n
green crop tends by It's 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 hav failed to DEM
onstrate this.
Perhaps the most common way in
which the scab fungus is disseminated
is by the use of infected seed. 1t is
therefore of the utmost Importance to
use clean seed. Where it Is impractic-
able To procure clean seed, or in case
of doubt. il should be treated with a
fungicide. While such treatment will
help scabby seed. ii may not act az
an entire preventive. 1t is therefore
best not to use seed that is much af-
fected.
Formaldehyde gas, either in solution
or in the dry, gaseous state, can be
effectively used to clean suspected
seed. I'ormaldehyde GorInalin) is sold
in a solution of about 40 per cent.
strength. and can be obtained at any
drug store. A few bushels of seed are
most conveniently treated as follows:
Make up II solution of formalin of the
desired bulk, using 16 ounces of for
malin Gao per cent. solution of formal
dehyde gas) to each 80 gallons of wa
ter. Soak the seed two hours 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 not
reached perfectly definite conclusions.
they 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 oom 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 per1nan-
ganate are mixed with eight parts Of
formalin in an earthen jar. The jar.
should have a capacity of about Il gall
Ion for a pint az ounces) of for
malin. The required amount of per-
manganatc should be placed. in the bot
tom Of the jar. and the needed mount
of formalin poured over it. The OBJ
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 $1.50.
For handlers OF seed who wish to in
sur< freedom from scab and for large
growers of potatoes thisg gaseous meth
Cd is more convenient than the wet
method. and experiments at the YER
mont station show it to be effective
Charles d. Woods, Maine Experiment
Station.
Professor Henry says that from seven
to fifteen days should be taken to fill