1925 - Mackie, F. P. Boll weevil in cotton. Bombay Bact. Lab. Rpt. 1924:30-31 . Bombay. 



Tests were made with hydrocyanic acid gas, with a view to fumigating 

 American cotton to prevent the introduction of the boll weevil into India. In the 

 absence of this species, various native weevils were used in these tests, including 

 Calandra, which proved the most resistant. The time of exposure appeared to be 

 of greater importance than the concentration of the gas. All individuals of this 

 weevil were killed after exposures for 19 hours or more to a gas concentration 

 evolved from \ oz. each of sodium cyanide and sulphuric acid, whereas concen- 

 trations obtained with 1 oz. of each had no effect even after 6 hours. 



With formaldehyde vapor all the weevils were killed in 4 hours by a concen- 

 tration of 10 parts per 100,000 or in 2 hours by 20 parts per 100,000. 



A few experiments to test the absorption of hydrocyanic acid by various sub- 

 stances indicate that liquid paraffin does not absorb the gas but that cotton and 

 kerosene do. 



1926 - Jacobsen, W. C. Bureau of Plant Quarantine and Pest Control. Calif. Dept. Agr. 



Mo. B„ 14, 7-12:146-172, 3 fig. Sacramento. 



"The work of the bureau on vacuum fumigation is reported on by D. Mackie. 

 Shipments to the extent of 20,000 citrus trees have been successfully fumigated 

 with liquid hydrocyanic acid gas. This process may also be substituted for the 

 usual practice of steaming railway wagons; it is safer and more convenient. Used 

 at the rate of 1 oz. of liquid gas to 100 cu. ft., all boll weevils were killed. Suc- 

 cessful experiments were also made with 2 oz. sodium cyanide solution to 100 

 cu. ft." 



1927 - Turner, A. J., and D. L. Sen. The use of hydrocyanic acid gas for the fumigation 



of American cotton on import into India. Agr. J. 22(3):1 73- 1 75. May. Calcutta. 



A short account of the results of experiments with hydrocyanic acid gas for 

 fumigating cotton bales against Anthonomus grandis as a precaution against its 

 importation into India from America, the full details of which are to be published 

 later. The work in India was confined to Calandra ( Sitophilus) oryzae L. (grain 

 weevil) but it was subsequently arranged with the American authorities to repeat 

 the work using A_. grandis . 



The conclusion is drawn that under Bombay conditions the weevils would be 

 exterminated by an exposure for 4 hours to a concentration of 450 parts HCN per 

 100,000 by volume or for 20 hours to a concentration of 150 per 100,000 (calcu- 

 lated at normal pressure and temperature). For practical purposes it is best to 

 combine a short period (6 hours) at a high concentration with a long period (addi- 

 tional 14 hours) at a lower concentration. The minimum initial concentration for 

 the second period should be 200 parts HCN per 100,000. 



Fumigation can be satisfactorily carried out on a large scale in barges, 

 when these are sound and the bales are both dry and also compressed to a high 

 density, 1 pound of sodium cyanide being sufficient for about 5 bales of cotton. 

 These results have led the Government of India to issue a notification under the 

 Destructive Insects and Pests Act. Though cotton does absorb hydrocyanic acid 

 gas, it is fairly rapidly and completely discharged, and there is no evidence of 

 the occurrence of any irreversible chemical combinations. 



CONTROL - GENERAL 



1895 - Howard, L. O. The new cotton boll weevil. Insect Life, Div. Ent., U. S. D. A. 7: 

 281. Mar. 



Regarding the importance of the pest, and the investigation started by the 

 sending of Mr. C. H. T. Townsend to Texas in December 1894. The Assistant 

 Secretary of Agriculture reported the seriousness of the outlook to the governor 

 of Texas, and urged the importance of immediate legislation to provide for quar- 

 antining and remedial work. 



117 



