EFFECTIVE USE OF HYDRO CYANIC-ACID GAS IN THE 
PROTECTION OF CHICK-PEAS (CICER ARIETINUM) 
WAREHOUSED IN 240-POUND SACKS 1 
By E. A. Back, Entomologist in Charge , and It. T. Cotton, Associate Entomologist , 
Stored Product Insect Investigations t Bureau of Entomology , United States Depart - 
ment of Agriculture 
One of the desiderata connected with the protection from insect attack of food 
commodities in storage is complete information regarding the penetration of 
fumigants. Hydrocyanic-acid gas is recognized as an effective and standard 
fumigant for the control of many pests under a wide range of conditions, but 
always in situations where the gas can be confined sufficiently long to reach and 
kill the insects. This fumigant as ordinarily used is most effective in the treat¬ 
ment of containers that are reasonably empty; in other words, in fumigation 
work which requires no great penetration of the gas. It is used with excellent 
results in the fumigation of houses, hospitals, railway passenger and sleeping 
cars, certain freight cars, ships from which cargoes have been removed, flour 
mills and similar structures. It is generally conceded that in the protection of 
commodities stored in bulk, such as wheat and corn in farmers* bins, grain cars 
or commercial elevators, or stored in sacks and stacked tightly in warehouses, as 
in the case of many animal feeds, rice, and other seeds, hydrocyanic-acid gas is 
far less effective and can not be depended upon for sufficient penetration to rid 
the commodity of its living insect inhabitants. 
The use, however, of hydrocyanic-acid gas is much to be desired over that of 
carbon disulphid, which is a standard fumigant for such commodities, inasmuch 
as it can be used in large bulks in congested city districts where the generation 
of an equally large volume of the inflammable and explosive carbon disulphid 
gas would be quite out of question because of the fire hazard. For these reasons 
data bearing upon the power of penetration of hydrocyanic-acid gas into the 
usual warehoused commodities habitually affected by insects have a most prac¬ 
tical application in conservation work. Food commodities in storage are of 
great value, under private ownership, subject to removal on short notice from 
storage and to shipment according to trade conditions, and therefore are not 
often available for prolonged scientific study. These are facts which enhance the 
rare opportunities that are offered Federal investigators to study privately owned 
stored products. 
An unusual opportunity was presented the writers during the years 1918- 
1920 to observe the disastrous attack of the four-spotted bean weevil Bruchus 
quadrimaculatuSy the lesser grain borer Rhizopertha dominica t the rice weevil 
Sitophilus oryza t the Angoumois grain moth Sitotroga cerealella f the Indian 
meal moth Plodia interpunctella f and the tobacco beetle Lasioderma serricorne , 
upon a large supply of chick-peas, Cicer arietinum, These edible legumes, 
amounting to about 137,000 sacks of 240 pounds each, represented for the most 
part the greater portion of the crop of this food grown in northern Mexico during 
1918 and diverted from storage in New York City by congested war conditions 
to six warehouses in New Orleans. This crop had arrived at New Orleans by 
rail during the summer of 1918 and had been stored under both favorable and 
unfavorable conditions in space permitted in lots of 15,000, 12,000, 30,000, 
30,000, 30,000, and 20,000 sacks, respectively, in the six warehouses. During 
1 Received for publication April 22, 1924. 
Journal of Agricultural Research, 
Washington, D. C. 
( 649 ) 
Vol. XXVIII, No. 7 
May 17,1924 
Key No. K-142. 
