The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1875-06-21
The Ravages OF the Potato Eeetle
and tho Remedy.

Tho Ravages OF the Potato Eeetle
and tho Remedy.
That formidable scourge Of agriculture, the
Colorado beetle, whose native habitat is the
region at the base Of the Rocky Mountains,
has made its way eastward to the Atlantic
coast and threatens the potato crop of all
New Jersey and other extensive districts. 1t
is only ten years since this noxious insect first
crossed the Mississippi, and the rapid spread
and multiplication of its devouring progeny
make it national calamity. 1t has been
found that these pests can be exterminated by
poison, and Paris green "a mixture Of arsenite
and acetate of copper is the cheapest and
most easily applied poison adapted to this
use But fears have been raised that the poi
son which kills the grubs of the beetle may
enter into the composition of the plant
making the remedy worse than the evil This
subject is 80 important and requires such i'm
mediate action if this years potato crop is 10
be saved that the HERALD has taken pains to
procure such correct and authentic informa-
ton as may be safely accepted for their guild
ance by the suffering agriculturists.
We print to-day most timely and instruc-
tive letter from Professor McMurtrie Of the
National Department of Agriculture at Wash
ington. lie is reputed to be the most thor
oughly and infinitely informed scientific man
in the country on the subject which he dis
cusses in our columns with SO much clearness
Of statement and fulness of detail Not the
Z IL. = u. -.
Professor McMurtrie communicates is the
account Of his own original researches and
experiments. Since the eastward progress Of
the Colorado beetle last year he has been en-
gagged in constant experiments with view to
ascertain the effect Of mineral posons, and
particularly those containing arsenic, on the
health Of plants. He has also made himself
thoroughly acquainted with the results Of the
most recent Investigations in Great Britain,
France and Germany but his own diversi-
fed and decisive experiments are Of more
value, as bearing on the immediate problem,
than those Of oil the other inquirers to-
gether. In relation 70 Paris green Professor
McMurtrie has found that the intermixture
of this poison with the soil in large quaint
ties destroys vegetable growth, but that in
the small quantities requisite for destroying
insects it docs not interfere with or impede
it at all But there Is a mora important
question than the destruction Of the plant. II
would only multiply the mischief to kill the
grubs and at the same time poison the food
Of man. Upon this great point Professor
McMurtries decisive and manifold exper-
imonts should allay all fears. In the plants
that were killed, in the plants that were
stunted, and in the plants which grew to full
perfection, with the varying amounts Of Paris
green mingled with the soil Of his potts. the
most rigorous chemical analysis could detect
no trace Of arsenic in the composition Of the
plant itself. Whether little Of this poison or
much of It exists in the soil mono Of it
enters into the structure Of the veg
etable. The danger Of its excessive
use is not danger TO human life
but to the growth or health Of the plant But
the quantity Of Paris green necessary for
destroying the Colorado beetles is too small TO
have any perceptible effect on the growth Of
crops. 1t is possible that If potatoes were
planted in the same field for a series Of years
with constant necessity for the application
Of the poison the capacity Of the soil for
crops might be destroyed but the system Of
rotation, so valuable in other respects, would
obviate this danger. 1t is a great satisfaction
70 be assured on competent scientific authority
that there is no peril to human life in the
freest application Of this poison to the soil,
and no detriment TO vegetation itself from the
quantity needed to kill the beetles. We sug-
gest 10 the agricultural journals that they
cannot render more useful service than by
copying Professor McMurtrie's letter to the
HERALD. The substance Of it will also appear
in the monthly report Of the Department Of
| Agriculture, whose publication we anticipate.