The National tribune. [volume] (Washington, D.C.) 1877-1917, 1882-01-07


The conductor of Rural Topics is very DESTROYS
that the publisher of THE NATIONAL TRIBUNE
should be placed in possession of the address OF
either the Master, Secretary, or Lecturer OF each
and every Subordinate Grange, so that copy OF
the paper may be furnished for perusal by its
members II is proposed to make the paper
welcome visitor to the home of every member of
the Order and the Raral Topics column will, if
possible, be kept up to the progressive plane of
other departments of the paper.
PYRETHRUM AS AN 1NSECTICIDE (continued)
, application Of PyrethTWm IN FUmeS.-The pow
der burns freely, giving off considerable smoke
and an odor which is not unpleasant. 1t will
burn more slowly when made into cones by wet
ting and molding. In a closed room the fumes
from small quantity will soon kill or render
inactive ordinary flies and mosquitoes and will
be found most convenient protection against
these last where no bars are available. A series
OF experiments made under our direction .indi-
Gates that the fumes affect all insects, but most
quickly those of soft and delicate structure.
This method is impracticabe on large scale
in the field but will be found very effective
against insects nfesting furs, feathers ,herbaria,
books, &c. Such can easily be got rid of by en-
closing the infested objects in a tight box or case
and then fumigating them. This method viii
also prove useful in greenhouses, and, with suit
able instruments we see no reason why it should
not be applied to underground pests that attack
the roots of plants.
3. Alcoholic Extract Of Pyrethrum Po,cder.-The
extract is easily obtained by taking flask fitted
with cork and a long and vertical glass tube.
Into this flask the alcohol and Pyrethrum are
introduced and heated over steam tank or other
apparatus. The distillate, condensing in the YER
teal tube, runs back, and, at the end of an hour
or two the alcohol may be drained off and the
extract is ready for use. Another method Of OBJ
tanning the extract is by Representation after the
manner prescribed in the American Pharmaco-
pGia The former method seems to more thor
oughly extract the Oil than the latter; at least
we found that the residuum of quantity Of Ply
rethrum from which the extract was obtained by
Representation had not lost great deal of power.
The first method is apparently more expensive
than the other but the extract is in either case
more expensive than the other preparations,
though very conveniently preserved and han
died
The extract may be greatly diluted with water
and then applied by means of any atomizeT.
Professor E. A. Smith of Tuscaloosa, Ala, found
that, diluted with water at the rate of one part
Of the extract to fifteen of water and sprayed on
the leaves, it kills cotton worms that have come
in contact with the solution in few minutes.
The mixture in the proportion of one part of the
extract to twenty parts Of water was equally
eficacous and even at the rate of one to forty it
killed two-thirds of the worms upon which it
was sprayed in fifteen or twenty minutes, and the
remainder were subsequently disabled. In still
weaker solution, at the rate of one to fifty it
loses in efficacy, but still kills some of the worms
and disables others. Professor Smith expert
mented with the extract obtained by distillation,
and other series of experiments with the same
method was carried on last year by Professor r.
w. Jones, of Oxford, Miss. He diluted his ex-
tract with twenty times its volume of water and
applied it by means Of an atomizer on the cotton
worm and the boil worm with perfect success.
Dir. E. A. Schwarz tried, last summer, the extract
obtained by Representation and found that ten
drachms of the extract, stirred up in two gallons
OF water and applied by means Of Whitman's
fountain pump was sufficient to kill all cotton
worms on the plants. Four drachms Of the ex-
tract to the same amount Of water was sufficient
TO kill the very young worms.
f. Pyrethrum IN simple tCater S0lutiOn.-So far as
our experiments 60, this method is by far the
simplest, most economical and efficient. The
bulk Of the powder is most easily dissolved in
water, to which it at once inparts the insecticde
power. No constant stirring is necessary and
the liquid is to be applied in the same manner
as the diluted extract. The finer the spray in
which the fluid is applied the more economical is
its use and the greater the chance of reaching
every insect on the plant. Experiments with
Pyrethrum in this form shows that 200 grains of
powder stirred up in two gallons of water is
amply sufficient to kill the cotton worms except
very few full-grown ones, but that the same
mixture is not sufficiently strong for many other
insects, the boil worm the larva of the Ierias
aicippe and such species protected by dense,
long hairs. Young cotton worms can be killed
by 25 grains of the powder stirred up in two
quarts Of water
The Pyrethrum water is most efficacious when
first made and loses power the longer it is kept
The powder gives the water light greenish color
which, after several hours, changes to a light
brown. On the third day a luxuriant growth of
fungus generally develops in the vessel containing
the liquid and It's efficacy is then considerably
lessened. TO be continued next week.