The Advocate and news., 1897-11-24
Farm Department.
About Insecticides and Their Uses.
By w. A. PETER.


Clarence M. Weed, in American Guilt
vator, submits the following:
It IL we'll known that there are two
principal ways in which insects take
their food. Some insects bite and chew
the parts Of the plant upon which they
feed, while others are provided with
pointed, tube-like beak, which they In
sert into the tissues Of the plant and
suck out the sap. On account OF this
difference In feeding habits those tn-
sects which bite may be destroyed by
coating their food with poisons, while
the others must be treated with some
substance that kills by simply coming
in contact with their bodies.
The poisons most commonly used
against biting insects are certain chem
ical compounds, composed in part OF
arsenic. Paris green is the most I'M
portant of these. It Is chemical COM
bination Of arsenic and copper, contain
ing when pure about 55 per cent OF
arsenic. When placed In water the fine
particles of the green powder do not
dissolve, but remain In suspension. Be-
cause of this fact one of the most pop
ular ways of applying Paris green to
plants which are in danger OF the at
tacks of biting insects Is In a water
mixture by means of force pump and
spray nozzle. In Its simplest form this
consists in mixing about teaspoonful
of the poison In pail of water, stirring
thoroughly to get the powder evenly
distributed through the water. A small
force pump, to which Is attached rub
Der tube with a spraying nozzle at the
end, Is then set in the pail. BY work
ing the handle Of the pump the liquid
with the poison particles in suspesion
Is forced through the tube and nozzles,
coming from the latter In mist-like
spray which may be directed upon the
plant to be protected, covering each leaf
with the liquid. AS soon as the spray
Ing Of the plant ceases the water begins
to evaporate, and rapidly disappears,
leaving the particles of Paris green
evenly distributed over the foliage. The
poison particles will remain in place
upon the leaves for some time, so that
In case biting insect feeds upon the
poisoned surface, 1t will eat some OF
these particles and be killed. Fortu-
nately the poison is not absorbed into
the tissues of the plant, so that the
process can be carried on without dan
ger to the consumer Of the crop. In the
course of a few weeks the particles of
poison are washed away by rain or dew,
or are dissipated through the action OF
the sunshine.
A substance which Is used to destroy
insects is called an insecticide or insect
killer. Thus Paris green is an insecu-
eide, so, also, are London purple, helle-
bore and insect powder. Each Of these
substances may be applied to plants In
mixture with water, as already de-
scribed, or they may be busted on In
the form Of dry powder. Sometimes
one may use for this purpose simply a
porous bag, out of which the powder is
sifted It Is generally better, however,
to apply the insecticide by means Of one
OF the many kinds Of bellows manufac-
tured for this purpose. When whole
fields Of potatoes or other crops are to
be gone over, one Of the better forms
Of powder guns now upon the market Is
very desirable. With one Of these guns
a pound Of Paris green can be evenly
distributed over an acre Of potato vines.
Paris green Is so powerful a poison
that except when it Is applied with the
best powder guns, which distribute 1t
very finely and evenly, It Is desirable
to dilute it with some substance like
land plaster, air-slaked lime, -four or
road dust. The proportion OF poison to
diluent varies greatly with different
users. One part Of poison to twenty
parts of diluent serves the purpose II
the mixing be thoroughly done.