Washington, D. C. January 26, 1925 
FUMIGATION AGAINST GRAIN WEEVILS WITH VARIOUS 
VOLATILE ORGANIC COMPOUNDS 
By Ira E. Nerrert, F. C. Coox,! R. C. Roark, and W. H. Tonkin, Insecticide 
and Fungicide Laboratory, Miscellaneous Division, Bureau of Chemistry, and 
K. A. Back and R. T. Cotton, Bureau of Entomology? 
CONTENTS 
: 3 Page | acai : Page 
Purpose of investigation ._.............-.--.-- 1 | Effect of fumigation on milled and baked 
Experimental procedure _____..-.-_-=--.-_--- Ql RRO ROL US tee tent tee ee eee ee ee 34 
Effect of volatile organic compounds on | Additional fumigation tests with ethylacetate 
eh SS at is ee aeesigs vane em 3 | _ and carbon tetrachloride_-_.______-______- 
Relation between volatility and toxicity of | Effect “of ethyi acetate-carbon tetrachloride 
HOD OUre2 SOULS Sk shee teeter Rees SSRN toe ee ee ee Pee 19 fumigation on germination of seeds___-_-_-_- 38 
Effect offumigation on weevils in the presence SPIER ete ee ee ee ee en el eae 38 
ORRrAIN as a rs es eee Peete ee een 242) Siiteratine cited2 2 sso). tee a eit eets ss 39 
Fire hazard from fumigation____..___________ 28 
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). 
The really serious objection to the use 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 tafbon 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. 
2 Creditis due Maj. A. Gibson, formerly of the Chemical Warfare Service, for obtaining poisonous mate- 
rials from thelaboratories of Edgewood Arsenal; G. W. Kirby, ofthe Insecticide and Fungicide Laboratory, 
Bureau of Chemistry, for assistance in the chemical work; J. H. Cox, Harold Anderson, and the Milling 
and Baking Laboratory ofthe Grain Division, Bureau of Agricultural Economics, for assistance in carrying 
out the car-fumigation tests. 
8 Italic numbers in parentheses refer to Literature Cited, p. 39. 
15685°—25j}—_1 
