CARBON DISULFIDE EMULSION 15 



Preparation of Carbon Disulfide Emulsion 



A stock emulsion of carbon disulfide is prepared by first mixing together the 

 required amount of soap and water, then adding the carbon disulfide. The water 

 should not be cooler than 60 F.; otherwise the soap will not readily dissolve. 

 Any amount of stock emulsion can be made by multiplying the total number of 

 gallons wanted by .26, .06, and .68, the results representing water, soap, and 

 carbon disulfide in gallons, respectively. Thus, to make a 50-gallon barrel of 

 stock emulsion, 13 gallons of water, 3 gallons of soap, and 34 gallons of carbon 

 disulfide are required. 



Application of Chemicals 



One gallon of stock emulsion is added to 50 gallons of water and stirreil, and 

 this diluted emulsion is applied at the rate of 1 gallon to the square foot of bed. 

 If formaldehyde is warranted, 2/3 gallon is added to each barrel of diluted emul- 

 sion. If the chemicals are diluted in barrels, pails are used to apply the solution 

 (Fig. 2). If a large tank is used, the solution may be run out into the beds by 

 gravity through lines of hose, or by pressure through an irrigation s\'stem (Fig. 3). 

 The solution must be agitated frequently. 



The volume of the tank must be known in order to determine the number of 

 gallons of concentrated chemicals needed to make the proper strength. The vol- 

 ume of a cylindrical tank in cubic feet is determined by multiplying .7854 by the 

 square of the diameter of the tank and this result by the height. The volume of a 

 rectangular tank is determined by multiplying the width by the length by the 

 height. In either case, the result is then multiplied by 7.5 (representing the 

 number of gallons contained in 1 cubic foot), to obtain the capacity of the tank in 

 gallons. Since a 1-50 concentration of carbon disulfide is to be used, the capacity 

 of the tank is divided by 50. The result represents the number of gallons of stock 

 carbon disulfide emulsion needed. If formaldehyde is used alone or in combina- 

 tion with carbon disulfide emulsion, the volume of the tank is divided by 75 (2/3- 

 50 or 1-75) and the result represents the number of gallons of formaldehyde needed. 



Treatment should begin in the far end of the greenhouse. The soil should be 

 in a moist condition and the beds should be dug over as the chemical is applied to 

 insure thorough soaking of the soil. It may be convenient to treat the soil in 

 sections corresponding to the areas between posts. The number of barrels of 

 chemical required is determined and this amount is used for each section in the 

 greenhouse. After the house has been treated in the manner described, the beds 

 should be wetted further with water. If carbon disulfide alone is used, the beds 

 may be planted in 6-7 days. If formaldehyde is used, an interval of 10 days may 

 be necessary, especially in cold weather. The safety of the beds for planting 

 may be determined by setting out a few plants; if the plants manifest no sign of 

 injury after 24 hours, the beds should be safe to plant. 



Caution 



Prolonged exposure to the carbon disulfid^gas causes severe headache, dizzi- 

 ness, and vomiting. It increases the heartbeat, and therefore persons having any 

 heart weakness are cautioned not to use it. The harmful features may be over- 

 come by shifting the help at the end of five hours, or by engaging the help for 

 not more than five hours each day until the work is completed. The men should 

 be cautioned to provide all available greenhouse ventilation during application. 

 Cool circulating air furnishes a more desirable atmosphere than warm, stagnant 

 air. The stock enuilsion of carbon disulfide should be located outdoors or in a well- 

 ventilated spot in the greenhouse, and the men should be cautioned to avoid its 



