Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1917-05-03
SEED POTATO Treatment
Department OF Agriculture A6vsves
Soaking In Corrosive subli~ate
or FormaldeAyde. n

department OF Agriculture A6vAvea
Soaking In Corrosive sublinste
or FormaldeAyde. n
the disinfection Of seed POTATOES Nv
soaking In corrosive sublimate or IN fhr.
maledhyde is recommended by the Omitted
states department Of agriculture a. n
measure that will tend to improve thu
termination and lessen the danger Of
scab.
such treatment is, on the whole, profit.
able. but has several limitations which
should be clearly recognised to prevent
disappointment. The object of disinfoct.
ing seed potatoes 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 in
fections are reached by this method. II
is only partially effective against deep
PITS or common scab. Neither corrosive
suolmate nor formaldehyde. as ordinarily
used. will destroy silver scurf. Either
one will kill surface infections Of black
leg. but neither will reach the internal
infections common in tuoers from black
leg hills. Neither Fusarium wilt nor late
blight infection in potato tubers can be
reached by any seed treatment, nor can
any Of the non-parasitic diseases Of pota-
toes. such as mosaic. leaf roll. and curly
dwarf. thus be prevented. See Farmers'
Bulletin 5A for descriptions of these
troubles.
SELECT DISEASE-FREE SEED.
Clearly. therefore. the most important
precaution against these diseases ID to
select clean. disease-free seed potatoes
from healthy, vigorous plants, as deter
atvSAI AL
ing season and at harvest Seed treat
tional precaution. 1t will not b effective,
however. IL the soil where the potatoes
are to be planted is already full Of diB.
ease.
Soil conditions have an important rcla-
ton to potato tuber diseases, and many
Of these are widely spread throughout tho
country. and perhaps native to some soils.
Common scab Is favored by a neutral or
slightly alkaline soil, and seldom gives
trouble in acid SOILS 1t therefore Is in
creased by lining and by fresh stable
manure, wood ashes. and alkaline ferti,-
izers, such as nitrate Of soda and ground
bone. while acid phosphate and sulphats
of ammonia tend to diminish scao.
Rhizoctonia occurs in some extent in
nearly all soils. but appears to attack
potatoes most when the conditions are
unfavorable to the best development Of
the potato plant Bring the land to an
ideal state Of tilth to minimize loss from
Rhfzoctonia.
powdery scab is worst on cold, vet, Or
poorly drained soils. Blackleg. on the
other hand. is carried by infected seed.
No potatoes showing a deep brown dis
coloration at the stem end should BE-
planted.
Sulphur tends to prevent common scab.
1t Is not a substitute for corrosive sub
Innate or formaldehyde. but Is a good
drier for cut seed. Applied to scab-in-
fected soils at the rate Of 500 pounds pc:
acre It reduces the scab. but such heavy
applications can not generally be recon-
mended as profitable. Preliminary ex-
perimentai trials are advised.
HOW TO DISrNFDCT SEED.
1t is considered oetter to treat potatoes
before they are cut into seed, especially
into the solution all the potatoes 1t will
cover and keep the batch covered BY the
solution for the period named under the
treatment being used.
The formaldehyde treatment consists IN
soaking the potatoes. before cutting. for
two hours In a solution made BY adding
one pint Of formaldehyde to 70 gallons Of
water. The solution can be used repeat.
eddy. The gas treatment is no longer rec.
commended.
The corrosive sublimate treatment is
more effective than formaidehyde. partic-
ularly against Rhixoctonia. or russell
scab and powdery scab. Corrosive sub
Innate is used at the rate of one ono
thousandth for one and one-half to two
hours. Dissolve two ounces OF the salt
in hot water and dilute to Ii gallons.
This is a deadly poison. Use with great
care. 1t must be kept In wood, porcelain.
or glass vessels. as it attacks metal.
Seed so treated must not be used In the
household or left where animals can reach
1t.
In using the corrosive sublimate dip Il
has be an found that the solution becomes
weaker each time it Is used The degree
to which the disinfectant is taken out vt
the solution varies according to the
amount Of dirt on the potatoes. the char
acter Of the water. and the kind OF con.
tainer For practical purposes It will b.
suff,cient to add one ounce Of dissolved
corrosive sublimate to each 80 gallons
of solution after each batch Of potatoes
has been treated. When this has bean
done four times. throw away the old -.
luton and prepare now solution.
To treat large quantities OF potatoes.
set several barrels on slightly elevAtea
platform. Fit plug In . hole In the
bottom of each barrel. All with potatoes.
cover with solution. let stand two hours,
draw on solution, and pour into another
barrel. Increase the number Of barrels
in proportion to the quantity to be treat.
cd. Another method 10 to use large
wooden vat or trough. into which the po-
tatoes In sacks are lowered by rope ana
pulley and later hauled out, drained. and
dried on Slated racks.
Seed potatoes may be treated several
weeks before planting. provided they arc
not reinfected by storing In old contain.
ers or storage bins.
sprouted potatoes are injured by treat.
ment but viii throw out new sprouts. In
general, however. potatoes will not be in
jured by following the above directions
Many growers believe termination 70 I'm.
proved by treatment.
a.