Montgomery County sentinel. [volume] (Rockville, Md.) 1855-1974, 1858-07-23
IFrcm the Buffalo Commercial, June 20. ]
THE POTATO ROT.


Ever since the disease known as po-
tato rot first appeared, various hypothc-
ses have been offered as to It's cause and
cure. A malady attacking an esculent
so important and forming so large por-
ton Of our daily food, was at once rec
egnized as a national disaster, and re-
searches of scientific men were directed
to its study. Up to the present time no
satisfactory theory has been promulga-
ted. In giving publicity to that which
we are now about to notice, we shall
eonfine ourselves mostly to what has been
done by actual experiment, and to the
legitimate conclusions which inductive
reasoning from these experiments affords.
Our personal knowledge is confined to
the following facts:
On the morning of the 24th Of June,
Mr.. Alexander Henderson, of this city,
left at our Office a glass jar, containing
sound and healthy potato plant, COW
cred in by a perforated paper, so as to
afford air. lie had placed it there at
a. NJ, and with it were confined some
six or eight insects, which Mr.. II. be-
lieves to be the source Of the potato rot.
The insect itself we cannot describe sci
entifcally. 1t is about half the size of
the common house-fy, Of a brownish
color, has six legs, two pairs Of light
diaphanous wings, two anten@, and a
long, strong proboscis Mr.. ii. thinks
1t is the Phytocoris, but is not positive as
to that. At the end of twenty-four
hours the plant was evidently diseased
The insect was actively engaged upon
its various portions, Which became brown
and mouldy in the leaf, while the stalks,
IN the course of two or three days, suf-
iered putrescent change, until, on the
2Sth, some of them fell over by their
own weight, the stalk being swollen and
softened, in some places quite to Jelly
OF a slckly green color. This process,
MIR. Henderson informs us, takes place
uniformly, but most rapidly when the
plant is freely watercd and exposed to
sun and air, as the specimen exposed was
not. TOT all external appearance, the dis
ease was identical with the ordinary po-
tato rot as it attacks the vines. Some
pieces of early (this years. potatoes,
placed in the jar, were also plainly at
tackled by the rot during the four days Of
exposure.
Mr.. Henderson states that he has been
engaged in this research since 1915:
that in 1850 he discovered the bug on
the vines, but thought it was confined to
them. During the last year he has found
it on the tubers, and watched its effect
upon them. 1t appears on the vines in
from two and half to three months after
planting, according to soil and manure,
richly manured soil producing the per-
feet insect sooner.
The natural history of the insect be-
gins with the development of the egg.
This is invisible to the naked eve, but
can be seen with the aid of lens ag-
illuminated to the skin of the potato. -
1t is of an oblong form and is planted
with the seed potato. The egg may be
Matched in warm, moist place. The
entire period of development is not set
lied. Mr. II. exposed a plant to the in
sect, under proper precautions, and from
the time of the exposure to the time the
young insect of the next generation o5-
tanned his wings was three months. The
process of reproduction has been inge-
niously watched by Mr.. Henderson.
The egg planted with the seed potato is
Matched, and the young insect stays in
the ground until he gets wings. In the
meantime he is engaged in singing the
tubers, each perforation poisoning the
root and begetting the rot While yet
in the ground, and as early as the tenth
day Of existence, the young insects CO.
habit, and from the great rapidly with
which they propagate, Mr.. II. argues
that the egg is deposited before the first
emcrgence from the ground, although in
case Of cold, wet weather, the insect
sometimes leaves the vines and returns
to the tuber. Only few days are re-
CURED for the entire destruction of the
vine. The insect is remarkably indus
trious, but the destruction'of the vines
does not effect the tuber except to stop
its growth.
Mr.. Henderson finds ready exp!ana-
tion for the greater healthfulness of the
potato in sandy soil. He finds that the
grains of sand greatly annoy and cripple
,he insect, and the light soil is heaved
up by the growth of the root, the sand
imparts or falls down, preventing the ac-
cess Of the fly. In stiff soil the insect
readily leaves the ground through the
cracks opened by the growth of the tu-
Der, and having stung it comes to the
surface and attacks the vine, especially
after heavy showers. During the past
winter Mr.. Henderson has had thousands
Of the young insects. hatched under
glass, and to try their power of mischief,
has experimental with bugs only quar-
ter grown. The plants exposed, showed
unmistakeable signs of disease on the
fourth day.
These statements we regard as impor-
tant. So much is evident, Mr.. Hen.
derson, by means of this insect, produces
potato rot at will When healthy
plant is shown us, the insect applied, and
the rot'follows in four days with uner.
ring certainty, there is good reason to
suppose that the problem has been
solved.
AS to cure, Mr. Henderson thinks
there is no serious difficulty. If we pu,
u stop TO the planting of the egg with
The seed potato, We stop the propaga.
lion OF the insect The egg being invi.
sible, any means applied should be tho,
rough, and reach the whole surface O
the root. Mr.. Henderson states tina
sprinkling quicklime over the potato a