Grant County herald. [volume] (Lancaster, Wis.) 1850-1968, 1916-04-05
CONTROL POTATO SCAB
FOrmaldehyde Recommended AS
Preventative of Parasite.
Destroys NOXIOUS GERMS
Select Clean, DiSeaSe-free Seed PO-
tatOes- Distinction Treatment
Is An Added PrecautiOn.
Destroys NOXIOUS GERMS

mate has been recommended for many
years as a preventative of scab and
other diseases carried on the tubors.
Such treatment is, on the whole,
profitable but has several limitations
3, 100000 which should he clearly RECOGNIZED 70
prevent disappointment according to
the specialists of the Department of
Agriculture. The object of disinfect-
ing seed potatoes is to destroy the
100000 germs of scab and other surface par
asites which might otherwise be
planted with the seed and infect the
100000 new crop. ONLY surface infections
are reached by this method. 1t is on
ly partially effective against deep
pits of common scab.
1850 Some Insects Cannot Be Reached.
Formaldehyde is less effective than
corrosive sublimate against the black
O ooo m sclerotia or resting bodies of Rhizoc-
tonia, russo scab, and against pow
derry scab. Neither chemical as or
dnarily used will destroy silver
scurf. Either one will kill surface
infections of blackleg, but neither
4,OOO.OO will reach the internal infections COM
mon in tubers from blackleg hills.
Neither fusarium wilt nor late blight
oe9 m infection in potato tubers be
reached by any seed treatment, nor
can any of the non-parasitic diseases
of potatoes, such as mosaic leaf roll
100000 and curly dwarf, be prevented.
Clearly, therefore, the most import
ant precautiOn against these diseases
10000 ~ 500 60 I hI+h Seeu
as determined by field inspection
during the growing season and at
harvest Seed treatment should then
be applied as an additional precau-
ton. 1t will not be effective, how
ever, if the soil where the potatoes
80 are to be planted is already full of
Law disease.
Soil Conditions and Potato Diseases.
Soil conditions have an important
l'oVV'VU relation to potato tuber diseases and
many of these are widely spread
throughout the country, perhaps nat
i've to some soils. Common scab is
10000 favored by a neutral or slightly aka
line soil, and seldom gives trouble in
acid soils. 1t is therefore increased
by lining and by fresh stable man
ure, wood ashes and alkaline fertil-
1'oV izers, such as nitrate of soda and
ground bone, while acid phosphate and
sulphate OF ammonia tend to diminish
500 90 scab
Rhzoctonia occures to some extent
in nearly soils, but appears to attack
potatoes most when the conditions
4, 10000 are unfavorable to the best develop
ment of the potato plant. Bring the
land to an ideal state of filth to mini
mize loss from Rhizoctonia.
5 100000 Powdery scab is worst on Sold wet
or poorly drained soils. Blackleg, on
the other hand, is carried by infected
seed. No potatoes showing a deep
100000 brown discoloration at the stem end
should be planted.
Sulphur tends to prevent common
3, 100000 scao. II is not substitute 1or cor.
is a good drier for cut seed. Applied
to scab-infected soils at the rate of
2, $4,000 500 pounds per acre it reduces the
scab, but such heavy applications can
not be generally recommended as
30 profitable. Preliminary experiment.
OO al trials are advised.
How To Disinfect Seed.
The formaldehyde treatment con-
1'ooU'UO sists in soaking the potatoes, before
cutting for two hours in a solution
6o4 Ok made by adding 1 pint of formalde-
hyde to 80 gallons of water. The So
luton can be used repeatedly. The
SOAPS gas treatment is longer recon-
mended.
Corrosive sublimate is used at the
- rate of 1000 for one and one-half
o'VUo.Vo to two hours. Dissolve 2 ounces of
the salt in hot water and dilute to
Is gallons. This is deadly poison.
9. 500. 90 Use with great care 1t must also
be kept in wood, porcelain, or glass
vessels, as it attacks metal. 1t is
more effective than formaldehyde,
particularly against Rhzoctonia and
p zo'oV powdery scab. Do not use the same
solution more than three times, as
Q ooO M the strength diminishes with each lot
of potatoes soaked.
How To Treat Large Quantities.
:, o1o oo To treat large quantities, set sever
al barrels a slightly elevated plat
form. Fit plug in hole in the bot
tom of each barrel, fill with potatoes,
100 cover with solution, let stand two
hours, draw off solution, and pour in
to another barrel Increase the num-
4,OOO.OO Der of barrels in proportion to the
quantity to be treated. Another
method is to use large wooden vat
. 5oo m or trough, into which the potatoes in
sacks are lowered by a rope and pull
ley and later hauled out drained, and
LEo' dried on Slated racks.
Seed potatoes may be treated sew
mailed eral weeks before planting, provided
Friday they are not infected by storing in
z, 1854 old containers or storage bins.
he reg Sprouted potatoes are injured by
onth of treatment but will throw out new
suit tax sprouts In general, however, pota-