CHAPTER XVII 



THE USE OF GASES AGAINST HOUSEHOLD 

 INSECTS 



IT is often advantageous to use some killing substance 

 that will penetrate all parts of a building and reach the 

 smallest cracks and crevices to which insects may retreat. 

 The material best suited to such a requirement is some 

 form of gas. Hydrocyanic acid gas and the gas from 

 burning sulfur are the two gases most used for fumigating 

 buildings to destroy insects. Heated air would be an 

 ideal insecticide if it were more easily available. 



HYDROCYANIC ACID GAS 



Hydrocyanic acid gas has been much used of late 

 years against insect pests of dwellings, barns, granaries, 

 elevators, mills, and greenhouses. It has also been exten- 

 sively used for many years in the fumigation of citrus 

 trees in California and Florida to control scale insects and 

 white flies. Nurserymen fumigate their stock with hy- 

 drocyanic acid gas to destroy any pests that otherwise 

 might be distributed to the purchasers. This gas is 

 undoubtedly a very effective agent for the destruction of 

 certain household insects if properly used. The gas was 

 perhaps first used in 1898 by C. L. Marlatt in fumigating 

 certain leather-covered furniture infested with book lice. 

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