74 



THE AGRICaLTURAL NEWS. 



March 5, 1910. 



INSECT NOTES. 



CARBON BISULPHIDE. 



PART I. 



Mention has frequently been made, in the publications, 

 of this Department, of carbon bisulphide and its use, 

 particularly as an insecticide. In the Agricultural News, 

 Vol. I. p. 110, there is to be found a brief article dealing 

 with this substance, and in more recent publications it has 

 been mentioned in connexion with various experiments that 

 have been carried out. 



An objection that has always been raised to the use of 

 carbon bisulphide in the- West Indies is the difficult)' of 

 obtaining it, since from its volatile and inflammable character, 

 most transportation companies do not like to carry it, and 

 also because the only form in which this material is supplied 

 is a comparatively pure product sold by the druggists. At 

 the present time, however, supplies can be obtained at fairly 

 reasonable cost, as will be shown later in this article. 



One of the most complete publications .setting forth the 

 uses, properties and history of carbon bisulphide is Farmera'' 

 Bulletin No. l-t5, of the United States Department of Agri- 

 culture, issued in 1902. Johnson's Famigalion Jfethods 

 (1902) also contains a very comprehensive chapter, on 

 fumigation by carbon bisulphide. 



PROPERTIES. Carbon bisulphide is a colourless, heavy 

 liquid, which is prepared on a large scale by passing the 

 fumes of burning sulphur over red-hot charcoal, and condens- 

 ing the resulting vapours to liquid form by cooling. This 

 liquid is c>ne-fourth heavier than water; it is very volatile, 

 evaporating freely when exposed to the air. The rapidity of 

 evaporation is proportionate to the extent of the exposed 

 surface, as well as to the temperature and the amount of 

 movement of the atmosphere above; evaporation in 

 partially closed vessels may be prevented by covering the 

 carbon bi.sulphide with a layer of water. The water being' 

 lighter, floats on the surface of the carbon bisulphide, in the 

 same way that kerosene floats on the surface of water. 



The vapour of carbon bisulphide is 2'63 times heavier 

 than air. It diffuses quite rapidly through the air, but 

 its tendency is to penetrate downwards faster than upwards, 

 and this characteristic of the gas has an important bearing 

 on its use in certain conditions. 



In the general use of carbon bisulphide, as an insecti- 

 cide, there is no fear of injurious effect to the operator, if ordi- 

 nary care is taken. If con.siderable quantities of the vapour 

 were to be inhaled for a long time, serious re.sults would follow. 

 A greater danger is that of explosion. Carbon bi.sulphide 

 vapour is very inttammable, and in an atmosphere impregna- 

 ted with this, an explosion may easily be brought about by 

 the slightest spark, or even by a rather warm surface, and 

 the greatest care should be taken that no fire or flame, even 

 of a pipe or cigar or cigarette, is brought into contact with 

 this vapour. The risk attending the use of carbon bisulphide 

 is not greater than that attending the use of gasoline, in many 

 ways. 



Carbon bisulphide was first used as an insecticide in 

 1 856-7 in killing weevils and their eggs in grain, and later, in 

 1 S59, it was emiployed in the control of phylloxera on the grape 

 vines of southern France. By 1873, over 200,000 acres of 

 vines were receiving annual treatment with carbon bisulphide. 

 Since that time, it has come to be very generally used in 

 connexion with certain kinds of pests. 



M'lDE OF Ai'PLiCATiox. Fiom the fact that success ia 

 the use of carbon bisulphide depends on the ability of the 

 user to cnnfine the vapour, this substance has its greatest 

 utility in connexion -with those insects which live in the 

 ground, and in stored grains and fither products. As a means 

 of control of those insects which attack stored vegetable pro 

 ducts, carbon bisulphide has been found extremely useful in 

 fumigating mills, granaries and warehouses, and it has 

 a fiirther application for the fumigation of foodstuffs, books, 

 clothing, etc., in households. In fumigating mills and similar 

 buildings, 1 lb. of carbon bisulphide to every 1,000 cubic feet 

 of space is the amount generally used. In employing it for the 

 purpose, it is necessary to apply the vapour at the top of the 

 bin or box in which the materials are to be fumigated, and 

 in the case of buildings or rooms, the carbon bisulphide 

 .should be expo.sed as high above the floor as po.ssible. Shallow 

 tins, or jpktes, are suitable for exposing the liquid, since the 

 evaporation is very rapid, in proportion to the increased 

 surface, and at least 1 square foot of evaporating surface 

 should be calculated for every 2.5 sc^uare feet of floor space. 

 The building that is being fumigated should be closed, if 

 possible, for twenty-four hours, and no one should enter it, 

 or bring into the immediate neighbourhood of it, anj' fire or 

 flame of any kind. In fumigating material in boxes, bins, 

 barrels, or other comparatively small containers, carbon bi.sul- 

 phide should be exposed in a .shallow dish at the top. The 

 civrbor. bisulphide should be used at the same rate, namely, 

 1 lb. per 1,000 cubic feet, as is already suggested for the 

 fumigation of buildings. A suitable proportion is i lb. to 100 

 bushels of grain. This is a somewhat stronger close than 

 1 lb. to 1,000 cubic feet, but it does not injure the germi- 

 nating power of seeds, even at that strength. 



For the destruction of ants, carbon bisulphide has been- 

 successfully used, by pouring into the nest 1 or 2 oz. of 

 the liquid, in several doses. This can be accomplished by 

 making holes with an iron stake, or a stick, and when the 

 carbon bisulphide has been poured in, securely closing the 

 holes. In the same way, it may be used, at the rate of 1 oz. 

 per square yard, for the control of grubs and mole crickets 

 in soils; it has also been successfully employed in the treat- 

 ment of root maggots attacking garden plants, and of 

 burrrwitig animals, such as squirrels, gophers, woodchucks, 

 moles, mice, etc. 



COST. Carbon bisulphide may be obtained from several 

 makers. It is sold by Kdward R. Taylor, Penn Van, New 

 Vork, U.S.A., under tlie trade name of 'Fuma '. This brand 

 ' is prepared specially for use in fumigating, and its price is 

 very reasonable. The Imperial Department of Agriculture 

 has recently received a trial shipment, and Messrs. Knight 

 it Co., General Druggists, Barbados, have a supply on order 

 which should be available soon. Druggists generally carry in 

 stock limited supplies of carbon bisulphide in small tins, but 

 in this form the cost is rather high for fumigation, on a large 

 scale, the retail price being something like Is. firf. to 2.s. 

 per lb. 'Fuma 'carbon bisulphide, on the other hand, costs 

 only about 10c. per ft)., with containers (which are screw- 

 capped iron drums), carriage, and duty, extra. These extras, 

 with the profits of the local dealer, will increase the cost very 

 materially; but, even then, Fuma carbon bisulphide ought tobe 

 available for use in the West Indies at a price sufficiently low ' 

 to warrant its employment on a large scale, if experiments 

 show that benettcial results follow its u.se. 



As is stated above, the objection has often been made 

 that steamship companies did not like to handle such inflam- 

 mable material, but there seems to be no great difticulty at 

 the present time; at any rate, recent orders were filled 

 very promptly. 



