INSECT CONTROL 331 



that contact insecticides hit the insects which they are to 

 destroy, for the mere spraying of the foliage is of no value 

 whatever. 



Kerosene emulsion is one of the oldest remedies for plant 

 lice and other sucking insects and is often used because it is 

 readily made and the materials can always be secured. 

 Dissolve one-half pound of hard soap (or one quart of soft 

 soap) in one gallon of boiling water. Add two gallons of 

 kerosene and churn by pumping back and forth into itself 

 for five or ten minutes until the oil is thoroughly emulsified, 

 forming a creamy mass with no drops of free oil visible. This 

 stock solution can then be diluted so that the resulting mix- 

 ture will contain the desired per cent of kerosene. Thus for 

 aphides one part of the stock solution should be diluted 

 with 10 to 15 parts of water, giving 4 to 6 per cent of kero- 

 sene in the spray, while for a winter wash, for the San Jose* 

 scale it should be diluted only three or four times, giving 

 16 to 22 per cent kerosene. It should be applied with a 

 nozzle throwing a fine spray. There are other formulas 

 for making the emulsion with buttermilk and it may be 

 made with crude oil instead of kerosene. 



Miscible Oils are made by making petroleum soluble by 

 the addition of vegetable oils, "cut" or saponified with an 

 alkali, and are really a sort of liquid petroleum soap which 

 will combine readily with water. They are used principally 

 as winter washes against the San Jose* scale, for which they 

 are diluted 8 to 10 times. For a summer wash they have 

 been used effectively against plant lice and other insects for 

 which kerosene emulsion would be used, diluted 25 to 30 

 times. 



Whale-oil and Other Soaps. Any good laundry soap made 

 into a thick solution one-half pound per gallon is an excel- 

 lent remedy for aphides on house plants and small bushes. 



