UNITED STATES DEPARTMENT OF AGRICULTURE 



DEPARTMENT BULLETIN No. 1313 



Washington, D. C. T January 26, 1925 



FUMIGATION AGAINST GRAIN WEEVILS WITH VARIOUS 

 VOLATILE ORGANIC COMPOUNDS 



By Ira E. Neifert, F. C. Cook, 1 R. C. Roark, and W. H. Tonkin, Insecticide 

 and Fungicide Laboratory, Miscellaneous Division, Bureau of Chemistry, and 

 E. A. Back and R. T. Cotton, Bureau of Entomology 2 



Purpose of investigation 1 



Experimental procedure 2 



Effect of volatile organic compounds on 



weevils 3 



Relation between volatility and toxicity of 



fumigants 19 



Effect of fumigation on weevils in the presence 



of grain 24 



Eire hazard from fumigation 28 



CONTENTS 



Page 



Effect of fumigation on milled and baked 

 products... 34 



Additional fumigation tests with ethylacetate 

 and carbon tetrachloride 35 



Effect of ethyl acetate-carbon tetrachloride 

 fumigation on germination of seeds 38 



Summary 38 



Literature cited 39 



PURPOSE OF INVESTIGATION 



Weevils destroy many million dollars' worth of wheat and other 

 grains annually. Carbon disulphide is extensively used as a fumigant 

 against these insects, but, although efficacious, it has serious disad- 

 vantages. It has an extremely disagreeable odor and in moderate 

 concentrations its vapor is poisonous to man. Although carbon 

 disulphide is volatile, millers occasionally complain that wheat 

 which has been treated with it retains its odor, and it has been 

 shown that the baking quality of flour from carbon disulphide 

 fumigated wheat is sometimes injured (8). H 



The really serious objection to the U3e of carbon disulphide as a 

 fumigant, however, arises from the fact that it is readily inflammable 

 and that its vapor when mixed with air is highly explosive. For 

 this reason fire insurance companies refuse to carry the fire risk on 

 elevators during the time carbon disulphide is being used to treat 

 the grain contained in them. Even more important is the action 

 taken by the General Managers' Association of Chicago, representing 

 the leading railway systems of the United States, in adopting the 

 following resolution: 



That because of the highly inflammable character of solution of carbon disul- 

 phide and tetrachloride, its use for fumigating cars to be loaded with grain be 

 prohibited, except that the Illinois Central may continue its use at New Orleans 



1 Deceased June 19, 1923. 



• Credit is due Ma]. A . Gibson, formerly of the Chemical Warfare Service, for obtaining poisonous mate- 

 rials from tbel aboratories of Edgewood Arsenal; O. W. Kirby.ofthe Insecticide and Fungicide Laboratory, 

 Bureau of Chemistry, for assistance in the chemical work; J. II. Cox, Harold Anderson, and the Milling 

 and Baking Laboratory of the Grain Division, Bureau of Agricultural Economics, for assistancein carrying 

 out the car-fumigation tests. 



'Italic numbers in parentheses refer to Literature Cited, p. 39. 



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