38 FAEMERS^ BULLETIN 804, 



tions as to the effectiveness of the spray should be made, however, 

 so that it may be strengthened if needed. 



In this connection it should be remembered that the stems from 

 which the extract has been made have a value for fertilizer purposes 

 of about $10 per ton. With tobacco refuse and stems costing about 

 $20 per ton, the spray solution will cost approximately 1 cent per 

 gallon, the fertilizer value of the extracted refuse covering the cost 

 of labor, etc., in the preparation of the spray. 



Tobacco sprays should be made up as needed, since after a day or 

 so fermentation begins. 



SOAP WASHES. 



Washes made of fish-oil ^ or laundry soap are effective against 

 aphids, and are especially suitable for use on a small scale where 

 only a few plants are to be treated, although fish-oil soap washes are 

 used by many orchardists in the treatment of aphids, the pear Psylla, 

 etc., and compare favorably in cost and effectiveness with nicotine 

 and kerosene emulsion sprays. Both potash and soda fish-oil soaps 

 are on the market. Potash soap is softer and hence there is less 

 trouble in dissolving it in water. Soda soap usually must be sliced 

 and dissolved in hot water before use. 



Fish-oil soap of different brands varies greatly in water content, 

 so it is not possible to indicate the precise quantity of soap to be used 

 with a given amount of water for all brands of soap. However, since 

 a statement, on the label, of the amount of the active ingredients 

 (soap) and the total inert ingredients is required by the Federal in- 

 secticide act of 1910. purchasers are advised of the amount of soap 

 and Avater present. In general fish-oil soap should be used against 

 aphids at the rate of 1 pound to from 5 to 7 gallons of water, depend- 

 ing upon the amount of water present in the soap. 



KEROSENE EMULSION. 



Kerosene emulsion is made up in stock solution according to the 

 following formula : 



Kerosene gallons 2 



Fish-oil or laundry soap poun(l__ i 



Water gallon__ 1 



First the soap should be dissolved in a gallon of boiling Avatei . and 

 after the vessel is removed from the fire the coal oil should be added. 

 Then the mixture should be agitated thoroughly for four or five min- 

 utes by pumping the liquid back into itself until it becomes a creamy 

 mass and the oil does not separate. The quantities of the ingredients 



1 The name " fish-oil soap " is now used in place of " whale-oil soap," since most of 

 the soap on the market is made of fish oil. 



