16 BULLETIN 363, U. S. DEPARTMENT OF AGRICULTURE. 
The additional handling incident to the husking process is also of 
benefit, as many of the larve are dislodged thereby, and the husked 
ears afford little concealment for pupation and for the feeding of 
the larve. 
The best ears when dry could be saved to a considerable extent 
by placing them in an isolated weevil-and-mouse-proof fumigator 
such as a metal crib, to be made as nearly air-tight as possible. 
CARBON BISULPHID. 
In the South, where the pink corn-worm is so injurious, bisulphid 
of carbon is the best remedy and has already been used for its control. 
Carbon bisulphid, or bisulphid of carbon (CS,), is a heavy liquid, 
colorless when pure, and is one of the standard chemicals for the 
control of insects injurious to stored products. Its value lies in the 
fact that it is extremely volatile, passing into the open air as a heavy 
gas which settles to the bottom of receptacles in which the liquid i is 
exposed and, by replacing the air, causes suffocation. It is much 
used seagate the Angoumois grain moth and various other insects 
injurious to corn and other cereals. It is less poisonous to human 
pelags than hydrocyanic- acid gas and, while there is danger from 
fire owing to its inflammability, with a reasonable amount of care 
this chemical may be cheaply and effectively applied to almost any 
stored product infested by insects. 
It is more effective at a high temperature, 76° to 90° F. proving 
the best for its use. It is less effective under 70°, and not efficient as 
low as 50° F. 
DIRECTIONS FOR USE. 
Since carbon bisulphid is extremely volatile, it is best evaporated 
in flat vessels—milk pans, pie tins, and cheap plates serving this 
purpose admirably. An average application is 2 or 3 pounds to 1,000 
cubic feet of air space, or 1 pound to 100 bushels. Less may be used, 
but it has been found that in a structure which can not be made 
positively air-tight it is necessary to use this amount to insure 
success. The liquid is poured mto the evaporators, a half pint or 
more in each, and, as the gas is heavier than air, the evaporators are 
then placed in the higher parts of the bin or fumigator. Evaporating 
pans are frequently set on the top of the grain, allowing the gas to 
penetrate to the bottom, or, in the case of shelled corn, a perforated 
tube, such as a drive-well point, may be thrust into the grain and the 
requisite amount of the liquid poured therein. 
When the gas is used in open bins or other receptacles the surface 
of the grain should be covered with heavy tarpaulin or canvas. The 
bin should be kept closed as tightly as possible for about 36 hours; 
this will not destroy the germinating power of the seed. With grains 
not desired for planting the bins may be allowed to remain closed as 
long as the gas evaporates. 
