The Somerset reporter., 1906-04-19
Potato Scab.
SUGGESTIONS FROM THE MAINE
AGRICULTURAL EXPERIMENT
STATION
STATION.


STATION.
Potato scab is more or less prevalent
all over Maine. Because in some years
II is uore troublesome than ia others,
add because the disease Itself is 30 Ii tie
understood by practical growers, there
Is Danger of its not being regarded with
the importance that II deserves For
hese reasons tie Name Agricultural
Experlment station has prepared the
to4Iosina statements
TIE common idea that potato scab Is
Produced by chip dirt. ashes or some
hug Of that kind is erroneous. Il Is
fungus disease and grows from spores,
the same az any other fungus. ertan
conditions favor lis growth and such
favorable conditions may be furnished
b, chip DIRT, lime, ashrs, etc When
once introduced INTO land DO practical
way has thus far been found of remov-
ing 1t. How long it will remain in the
soil is unknown. II certainly may con-
tinue for many years even when no po-
taioes are grown upon the field
There are many ways in which 1t is
possible for soil To becnme affected
! The germs may be introduced into the
manure pile by feeding scabby potatoes
10 stock, or putting them directly into
the compost heap. The fungus may
then propagate itself in the manure aud
II this is applied to the land, the disease
may be widely disseminated Alkaline
soil favorb the growth of the fungus and
on this account neither ashes nor lime
should ordinarily be used in connection
With potato growing. As farm manures
are slightly alkaline, they are beat not
nsed on potato land. The plowlng un-
der of green crop tends by is fermen-
tation to make the sol slightly acid.
This condition Is nnfavorable to the
growth of the fungus. There il more
or less common belief that sail is some
thing of preventive OF potato scab bnt
exact experiments have failed to demon
strate this
Probably the most common way in
which scab fungus il desseminated is
by the use of Infected seed Il is there
fore of the utmost Importance TO use
clean seed. Where l. is impracticable
to procure clean seed, or in case of
doubt, it should be treated with fun
gicide. While such treatment will help
scabby seed, it may not act az an entire
preventive 1t ia therefore best not to
use seed that is much affected.
Formaldehyde gas either in solution
or in the dry gaseous state can be et-
fectively used to clean suspected seed
Formaldehyde (formalip) 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 convent
emily treated as follows: Make up a
solution of tormalne of the desired bulk
using 16 ounces of formalin 40 per cent
solution of formaldeh yde gas) to each 80
gallons of water Soak the seed two
hours in this solution and then spread
out the tubers 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 potatoes by
formaldehyde gas, and while they have
not reached perfectly definite conclu-
sions, they recommend tho following
treatment for potatoes in bins
The bin or room whore the potatoes
are stored should be closed as tightly as
possibly 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 "a hours The
gas is generated by the action of forma-
I'm upon potassium permanganate For
this purpose 3 parts by weight of potas
sum peImanganate are mixed with 3
parts of formalin in an earthern jar
The jar should have capacity of about
a gallon for each pint (16 ounces) for.
malin. The required amount of per-
manganate should be placed in the bot
tom Of the jar, and the needed amount
of formalin poured over it, The opera
tor should leave the room at once, TAX
ing care to close the door as tightly as
possible The retail cost of the chemi-
calls to produce gas for 1000 cubic feet
will be about 81 30
For handlers of seed who wish to in
sure freedom from scab and for large
growers of potatoes, this gaseous
method Is more convenient than the wet
method. and experiments at the Yer
mont Station show it to be effective