The weekly pioneer and Democrat. [volume] (Saint Paul, Minn. Territory) 1855-1865, 1858-10-28

THE POTATO ROT OF iss7.

Among the conclusions that seem best es
tablished by the facts observed in former
years is this : that heavy rains followed by
q humid and bot atmosphere powerfully ia.
vor or rapidly develop the potato disease
in England. thunder storms, accompanied
with heavy falls Of rain, occurred this sea.
son in the second week in August. On
the succeeding days, observations showed
that the blight bad appeared, and was rap
idly developing itself in the tuber. So
rapid was the progress, that In many in
stances within ten days onehalf OF tubers
were diseased" Another prevalent opin.
ion, upon which some light has been thrown
by thefacts observed during this season, il,
that the character Of the soil upon which
the crop is grown has powerful influence
upon this disease. II has been observed fire.
quently, and here as well as in Europe, that
where the soil and subsOil were damp, The
disease was more active than where the soil
and subsoil were both parus. Calcareous
soils, such as those resting on chalk, have
generally produced comparatively sound
crops. The presence Of carbonate OF lime
in excess appears TO be q certain specific
against the development Of the fungus
This season, as formerly, the crop has been
less Effected on calcare0us than on sandy
soils. The practice which has prevailed for
some years OF preierring sandy soils for the
cultivation OF potato crops, may require
some modification or Q reconsideration Of the
basis upon which it rests, as the crops on
light sandy soils, on the eastern side OF Scot
land, are, in most instances, seriously af-
fected. On the western side, however, this
immunity from disease is magnified mainly
to the dry, porous, sandy and peaty soils.
As to the influence Of diierents kinds and
amounts Of manure, nothing new seems to
have been developed. Farm.yard manure
applied at the time of planting is found to
increase the per centage Of disease. Lime
composts, and also peat and peat composts
have been found to favor the production Of
healthy tubers. Ground bones, the genuine
er-phosphates, have been found benef-
cial. The results from guano have been
various but on the whole it has acted as a
partial preventive. SCOT has been found
| Of all measures the most effective in ward
ing of the disease. When applied at the
rate Of several hundred weight at the period
of planting, the crop has generally been
large and comparatively sound. When up
piled on the surface after the potatoes have
been hoed, the preserving power seemed to
be even greater An experiment has been
tried with sulphur without success. The
| experimenter has since thought that the
cause why the sulphur busted upon the
leaves of the fungus, was that the pores are
first developed on the under side OF the leaf.
Sulphur, when applied to grape vines, Is
forced upward against the leaves by means
Of a machine for the purpose.
The period of planting it is pretty gen
orally admitted, has decided influence up
on the extent and virulence Of the disease.
Experience is in favor of early planting, 90
as to admit OF the more early ripening Of
the crop This years observations tend to
confirm this preference Of early planting, tho
autumnal rains, followed by high temper
allure, having obviously developed or inten-
sitied the disease.
The observations of this year seem also
to bear out the belief that deep covering up
the soil lessons the attack, and that those
tubers which are nearest the surface are
generally first attacked, and most commonly
on the end of the potato nearest to the sur
face.
Observations made this year favor the
impression that tubers which were stored
previously to full maturity, or while the skin
is yet thin and easily ruiiled, (the skin being
thicker and tougher in the ma,ured STACEY
are more favorable to healthy growth,
when used as seed, than those fully matured
before storing.
The observations Of this year would seem
to warrant the undertaking of additional
experiments with the carbonate Of lime as
topdressiDg, &c. Several varieties which
were formerly comparatively exempt from
the blight, have this year been very gener.
ally affected - Couutru (,sntls,n1D