CHAPTER VI 

 FUMIGATION 



FUMIGATION, in entomology, consists of the application of 

 poisonous gases to kill insects. Disregarding a discussion of ben- 

 zine derivatives, the use of which is yet in the experimental 

 stage, we find available for use in fumigation the following: 

 Tobacco discussed before ; sulfur, either in powdered form or in 

 the shape of " candles"; formaldehyde of little or no value 

 against insects; carbon bisulfid, and hydrocyanic acid gas. The 

 last two deserve most careful consideration as being of the greatest 

 economic importance. 



Carbon Bisulfid. A cheaper grade is known as Fuma. The 

 commercial grade is excellent for use against clothes moths, buf- 

 falo beetles, and insects infesting stored grain or seeds. It has a 

 most striking odor, that of the pure article reminding one of ether, 

 the poorer grade like that of decaying eggs. The gas generated, 

 when mixed with air, is highly inflammable; it is heavier than air, 

 and is thus adapted to sinking down among furs, woollens and 

 grain. If breathed for any length of time, it gives rise to unpleasant 

 symptoms, and may, if inhaled to excess in a closed room, cause 

 sickness and even death. It is not, however, as dangerous in 

 this connection as hydrocyanic acid gas. It is evident that no 

 light of any kind should be brought near bisulfid of carbon when 

 employed as a fumigant. 



How to Use. Commonly, it is used at the rate of two pounds 

 of the liquid for every 1000 cubic feet of space when the tempera- 

 ture is about 70 F. In actual use against the Angoumois grain 

 moth it has been found that six pounds for each 1000 cubic 

 feet are necessary. The granary, bin, room, chest, barrel, or jar 

 must be made as nearly tight as possible, and when the liquid is 

 used in quantity it should be placed in shallow dishes or pans to 

 facilitate evaporation. The higher grade will not injure clothes, 

 and in any form it will not affect the germination qualities of seed 

 or render any product unfit for human food. Its various uses are 

 discussed in the following chapters, under the heads of the insect 

 pests against which it is employed. 



Treating Grain in Bins. In using this on stored grain, the 



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