9 
BISULFID OF CARBON FUMIGATION. 
This treatment of the melon aphis has been used successfully for 
some time, and is valuable-in small fields, but less profitable where 
cucurbit or other crops are grown over large areas. It consists in 
evaporating bisulfid of carbon under tubs, or similar tight receptacles, 
such as pails, buckets, or boxes. The chemical is employed at the 
rate of a dram (about a teaspoonful) to each cubic foot of space; a 
tablespoonful will serve for ordinary small tubs. This method of 
treating the plant does not injure it, and if the tub fit tightly to the 
ground, so as to retain the vapor of the bisultid, all of the aphides 
which are covered will be killed. This method may be followed sue- 
cessfully in iarge fields if the grower be careful to watch the vines for 
the first appearance of the insects, and to treat such hills as require 
fumigation, removing and destroying plants that are badly affected to 
prevent the spreading of the insects to others.“ 
Caution.—In the use of bisulfid of carbon as a fumigant for aphides 
the usual precaution should be observed not to expose the fumes to fire. 
The operators must not smoke during this process! As the gas is 
heavier than air there is no danger, if ordinary care is observed, that 
the fumes will be inhaled by human beings. 
HYDROCYANIC-ACID GAS TREATMENT. 
This gas, as has been demonstrated by Prof. E. D. Sanderson, can 
be used in the field in much the same manner as the bisulfid of car- 
bon, with wooden tubs or buckets. It has not, however, been adopted 
by growers and we do not recommend it. It possesses an advantage 
over bisulfid of carbon in that the cover used in gassing need not fit 
closely to the earth. On the other hand, it is deezdedly more danger- 
ous to human life and must therefore be handled with the greatest care! 
As a greenhouse insecticide this gas isa perfect remedy for aphides 
and other small and soft-bodied insects. It is used where tobacco is 
unsafe; for example, in violet houses, violets being especially subject 
to ‘‘spot” after fumigation with tobacco. The method of applying 
hydrocyanic-acid gas is described in Circular No. 37 of this Office. 
PYAR ETHRUM POWDER. 
Pyrethrum or buhach insect powder, administered dry with a pow- 
der bellows to the lower surface of leaves, will kill the insects, altho 
these sometimes do not appear to be affected at first. A second or 
third application is sometimes necessary. This is an expensive rem- 
edy and can not be used with profit on large fields or on plants with 
large leaves, like squash. 
«In New Jersey and Colorado many growers simply take out and bury such badly 
infested plants as are noticed when the hills are turned for cultivation. 
