22 INSECTS OF ECONOMIC IMPORTANCE 



Soap I lb. Soap , >^,lb. 



Soft water 2 gals, or Water i gal. 



Oil . .; 4 gals. Oil 2 gals. 



The soap is shaved fine and heated in the water 

 until dissolved. The oil is poured in and while the 

 mixture is hot it is briskly agitated until a white 

 creamy mixture is formed. The following dilu- 

 tions apply to first formula : 



To make a 10% solution for summer spraying add 34 

 gals, water. 



To make a 20% solution for dormant spraying add 14 

 gals, water. 



To make a 25% solution for dormant spraying add 10 

 gals, water. 



Crude Petroleum emulsion — It is made ex- 

 actly as the kerosene emulsion. The grade of oil 

 used is called ''insecticide oil." It should have an 

 amber color and its specific gravity should run from 

 43 to 45 degrees Baume. A 20 to 25 percent solu- 

 tion is valuable as a winter spray. 



Oil in mechanical emulsion with water ^'^ — 

 It has always been tedious to make oil emulsions 

 and to obviate the labor, pumps were designed to 

 mix the oil mechanically with water. These piimps 

 were supposed to throw any per cent of oil in water 

 desired, by the regulation of a valve. The pumps 

 proved unreliable and severe injuries often resulted 

 from using them. They are not now in use. 



MisciBLE oils *^ — These are proprietary mix- 

 tures containing mineral oils in combination with a 

 small quantity of vegetable oil and some alkali to 

 make them miscible with water. They are designed 

 especially for the control of scale insects. They 

 mix readily with water. There are several prom- 

 ts, 47 Marlatt— U. S. Dept. Agr., Ear's' Bull. 127, p. 20. 

 48 Marlatt— U. S. Dept. Agr., Ear's' Bull. 127, p. 23. 



