The St. Mary banner. (Franklin, Parish of St. Mary, La.) 1889-1931, 1907-08-31
FumigatiOn For Insect Pests.

The fact has been we'll established
that for the thorough determination
of the insect pests that infest our
cultivated trees and plants there is
nothing that equals the fumigation
with hydrocyanic acid gas.
This is particularly true Of those
Insects that infest our greenhouses.
Here spraying with the ordinary
fungicide and insecticide mixtures is
not available, because Of the injury
to the appearance Of ornamental
plants and to the paint on these
structures Fumigation then be-
comes the only available and efficient
remedy.
This Is also true in the case of the
nurserymen who wish to avoid the
risk of sending out infected stock,
even when they are reasonably sure
that their stock is not infested. In
fact, in many States the law now re-
quires that all nursery stock shall be
fumigated before shipment. While
the great expense of tents, etc, may
operate in many instances against
efforts at fumigation in the orchard,
there is no doubt that even there the
complete eradication of the pests
would make the process cheap, as
compared with the partial destruc-
ton of the trees by spraying, since
one funaigation would certainly last
for the season at least.
But in the case of the florist and
the nurseryman, fumigation Is really
the only effective remedy. Hence it
becomes necessary for them to study
the methods and materials used in
order to learn the most economical
and practical way of doing the work.
The usual method has been to de-
velop hydrocyanic gas by dropping
cyanide of potash into sulphuric acid
in a closed house. But lately there
has been an effort made to show that
cyanide of potash may be more eco
nomically replaced by the cyanide OF
sodium. When a nurseryman Is told
that 100 Kilograms OF cyanide OF
sodium will produce as much hydro
cyanic gas as 1872 Kilograms Of cyan
lde of potash, he is apt to at once
Jump at the conclusion that the
sodium cyanide can be used as
cheap substitute for the potassium
salt. But a test will prove that the
actual amount of the gas liberated
IL less than the amount of gas re-
leased by the potassium cyanide. be-
cause when the sodium salt Is treated
with sulphuric acid, residue forms
consisting partly of solidif1ed sui
plate of soda and partly OF unde-
composed cyanide of soda.
On the other hand. the residue left
from the use of potassium cyanide
Il not a solidified mass OF useless
material, but crumbles to a powder.
This powder Is not valueless arti-
Gle to the cultivator, like the sodium
sulphate, but is the potassium sui
phate that commands high price as
fertilizer. This fact that the res
idue from the potash salt is a valua-
Bile fertilizer will of itself do away
with all claims made for the superior
economy of the sodium cyanide, even
II the claims for larger production
OF gas had to be granted, for the resi-
| due resulting from the use OF the
sodium cyanide is a perfectly worth
less article to the cultivator, while
the residue from the potash salt Is
sulphate of potassium in a readily
available form that would command
on the market over $3.50 per 100
pounds as fertilizer. From this we
see how important it is for the grow
er to study all the actual facts In
connection with the process.-Pro-
lessor w. F. Massey.