April, "09] JOURNAL OF ECONOMIC ENTOMOLOGY 161 



CARBON DI-SULFID FUMIGATION FOR GRAIN INFEST- 

 ING INSECTS 

 By W. E. HiXDS, Aitbiir)/. Ahi. 



It is now fifty years since Doyere discovered that tli<' vapor of 

 Carbon di-sulfid was an effective agent in destroying grain-infesting 

 insects. In 1876 two other French investigators, working particularly 

 with the grape Phylloxera and a few other species of insects, an- 

 nounced that "one part of Carbon di-sulfid vapor in ninety parts of 

 air killed all insects in a few seconds, while one part of the gas in 254 

 parts of air Avas fatal in 75 minutes." 



An examination of the literature of the United States Bureau of 

 Entomology and the state experiment stations discloses no extended 

 experimental work in this country. This strongly suggests that the 

 recommendation which has been most commonly made, i. e., for the 

 use of "one pound of the liquid Carbon di-sulfid for each one thousand 

 cubic feet of fumigated space during a period of twenty-four hours." 

 has been based upon the report of the two Frenchmen. Cornu and 

 jMouillefert, and that their conclusions have been accepted with little 

 question and little subsequent confirmation. The possible injurious 

 effect of the gas upon the germination of seeds seems to have attracted 

 more attention from station Avorkers in the United States than has 

 the question of killing insect stages. The most extended experiments 

 of which we have found record in this country were conducted by Os- 

 born and ]\Ially in Iowa. Webster in Ohio, and Pettit in Michigan. It 

 is quite possible that other reports of importance may be found in 

 papers which we have not yet been able to examine. 



'In most of the records which we have seen it is stated that the gas 

 was used at a "saturated atmosphere," but no consideration seems to 

 have been given to the effect of temperature upon the actual amount 

 of Carbon di-sulfid contained in a "saturated atmosphere." Accord- 

 ing to data furnished by the United States Bureau of Chemistry sev- 

 eral years ago, the amount of Carbon di-sulfid in a saturated at- 

 mosphere varies with the temperature as follows : At 50 degrees F., 

 53.5 lbs. of CS2 ; at 59 degrees, 64.6 lbs. ; at 68 degrees, 77.6 lbs. ; at 

 77 degrees, 92.4 lbs., and at 86 degrees, 109.3 lbs. Thus at 86 degrees 

 slightly more than twice as much of the gas is required to saturate the 

 air as is needed at 50 degrees. Obviously the air temperature at the 

 time of treatment makes a most essential differeiice in the effective 

 strength of the gas and should be taken into account in all careful ex- 

 perimental work, although it seems to have been disregarded heretofore 

 in the treatment of both seeds and insects. At a temperature of 72 de- 



