12 BULLETIN 783, U. S. DEPARTMENT OE AGRICULTURE. 
A steam pressure of from 75 to 100 pounds may be employed advan- 
tageously. Since bags of compact material are heated to the center 
with difficulty, so far as possible they should be separated before 
treatment to facilitate uniform heating, for insects and their larva? 
become more active upon the application of the heat and may work 
their way to the center of the bags in their efforts to escape it. 
Better results may be obtained by providing the radiators with 
water traps or vents. 
Bice and cacao beans should not be exposed to a temperature above 
130° F. for more than one hour, as excessive splitting takes place in 
rice, especially if bleached, and, owing to the excessively oily nature 
of cacao beans, they may become rancid. 
Germination in the case of some seeds, such as peanuts, is not af- 
fected even by an exposure of six hours to a temperature as high as 
140° F., but it is best to be on the safe side in the treatment of com- 
modities affected by this moth until we have had more experience 
along this line. It should be added that a temperature of 140° F. is 
fatal to most forms of insect life in a short time — larvse, pupae, and 
adults. The Indian-meal moth, it has been learned by experiment in 
the Bureau of Entomology, dies in less than half an hour when so 
exposed. 
FUMIGATION METHODS. 
HYDROCYANIC-ACID GAS. 
For the fumigation of buildings and other structures inhabited by 
the rice moth, the hydrocyanic-acid gas process is the most useful. 
Indeed, it is now the standard remedy for practically all insects 
affecting stored products. It has been in use for this purpose for 
about 20 years and most progressive millers are familiar with the 
method of application. Information in regard to hydrocyanic-acid 
gas fumigation has been furnished by the Bureau of Entomology in 
various bulletins and other publications. In the earlier ones the use 
of cyanicl of potash or potassium cyanid was advised, but owing to 
conditions brought about by the war it is now impossible to secure 
this chemical, and as a result cyanid of soda or sodium cyanid is 
being used, and while somewhat expensive, is much cheaper than the 
corresponding potash salt. The formula is as follows: 
Sodium cyanid avoirdupois ounce 1 
Sulphuric acid fluid ounces 1^ 
Water do 3 
Information in regard to this method is furnished in Farmers' 
Bulletin 699, " Hydrocyanic-acid Gas Against Household Insects." 
"While this, as the title shows, is especially for dwellings, the methods 
advised can be adapted readily to mills and storehouses. 
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