The Express.
London, England, 1852-08-21 00:00:00

A REMEDY FOl't THE POTATO DISEASE.

The following letter has been published. The
writer is the proprietor of an estate in the county of
Wicklow, and a practical agriculturist.
" It is now about seven years since the potatablight com-
menced its ravages in this country. Many causes have
been assigned, and many cures proposed for it ; but how
contradictory and unsatisfactory have been the results ?
The most esteems i theory now Is atmospheric influence, from
the blight coming on in damp, sultry weather, suoh
as we often have at this season of the year,
affecting the more succulent plants at a certain stage
of their growth ; and jet the advocates of this theory are
often puzzled on finding one drill or ridge in • field dis-
eased, and ono adjoining not —one variety bad, another
good ; the one good with A, though bad with B, and ewe
versa. The first symptoms of the disease ere always
small black spots on the leaves, as if some poisonous drops
had fallen on them, resembling thou on the leaf of the
teKceatt7loarcek temess,rzesusecad byd atyas.plim, d
or ifferent from
f/torsmt
soon increase—the stalks become blackened, the smell
offensive, and lastly, though often sooner, the tubers
show symptoms of decay. Cure, then, is out of the
question; the best thing to do is to make use of them.
Now, the spots on the potato are mused by insects. They
come about the middle of July, I think at night. It has
been remarked, that the dimmer in many places has ap-
peared on or about the seas day each year; how many
birds and ineeets do sot They are at first mostly in couples,
and are to be found on the under part of the leaf, on the
before-mentioned black spots, but are most difficult to find,
for, on touching the leaf, they spring off so quickly, and
with such force, that, although most invisible to the naked
eye, an acute ear may hear the sound of their jump. In a
few days they increase in else, and deposit their eggs,
which are white, end very pointed at the ends ; atter
which the female, from • bright yellow, becomes almost
white, and dies. I have found many of the mere skins of
them quite perfect in shape. The eyes are near the top of
the heed, and are very dark coloured. The young are soon
found in great numbers creeping over the whole plant, par-
ticularly on the stalk; these are much leas inclined to jump
than the first. Some days when even touched they would
not do so. I tried assay plans to destroy them—fumi-
gating with sulphur, tobacco, &c. &c.—but with little
effect ; in fact, a care would be but of little use anima
it could be easily put in practice. However, 1 soon
found from their being so easily disturbed, and that even
a very slight touch killed them, that by adopting the'
following simrle plan, the difficulty was overcome: I
put a drill harrow to work, having fastened to each
end of the ewingle-bar a few light branches of spruce
fir, then brushing over two drill, at a time, men fol-
lowed spreading fresh slacked lime, 21 barrels per acre;'
which, as the plants lay nearly flat from the brushing,
the lime came in contact with the under part of 'the
leaf where they were. Thousands in this way, with
their eggs, were destroyed or brushed between the
drills, there to be roughly used by the harrow. If at the
end of two or three days any are still to be found, the
brushing should be repeated, but only when the plants are
dry. The branches should not he so hesey es to break the
stalk', but sufficiently heavy to bend them downwards.
They will soon recover their former position. I have
thought it right to address the government on
this subjeet, and to request that scientific men
might be directed to examine these insects, some of
which I have preserved; and I sat happy to say that
his Excellency the Earl of Eglinton has taken up the matter
meet promptly ; but as some delay must necessarily occur,
I think it right to put the public at once in posseesion of
my plan, so that farmers may immediately set to work to
sweep away these vermin, as every day adds to the number
of the enemy, and thus to the difficulty of destroying them,
some of which I have even (bend on the specimen of the
solemn E. tuberosum, in the College Botanical Gardens.