INJURIOUS INSECTS. 83 



otherwise. The decoction will not keep more than a few 

 days without spoiling-. Tobacco is an excellent fertilizer as 

 well as insecticide. 



Kerosene emulsion is a valuable insecticide. It kills by con- 

 tact and is of greatest importance for destroying sucking- in- 

 sects such as lice, scale insects and soft caterpillars, but also 

 kills many biting- insects. It is made as follows: 



Kerosene oil, 2 gallons, 67 percent. 



Common soap, or 



whale oil soap, £ pound, 33 per cent. 



Two pounds of soft soap may be used in place of the soap 

 recommended. 



Dissolve the soap over a brisk fire and add the kerosene 

 while the water is hot. Churn the mixture or stir rapidly un- 

 til a creamlike emulsion is secured. If well made the kero- 

 sene will not separate but on cooling the emulsion will thicken 

 into a jelly-like paste that adheres without oiliness to the 

 surface of glass. Soft water will give far better results than 

 hard water for making kerosene emulsion, and soap that is 

 made with potash or soda lye, such as home made soap, is far 

 better than most of the soap of the stores, as they do not 

 emulsify easily. For plant lice, dilute the emulsion recom- 

 mended with from twenty to twenty-five parts of cold water. 

 The strength of the application will necessarily depend on the 

 insects to which it is to be applied. For such insects as 

 soft-skinned caterpillars, the emulsion should be diluted with 

 not more than ten parts of water. 



Kerosene and milk emulsion may be made as follows: 



Kerosene 2 gallons. 



Sour milk 1 g-allon. 



These should be thoroughly churned together until they 

 form an emulsion, which they do readily. It should be used 

 the same as thesoap and,kerosene emulsion mentioned. Sweet 

 milk does not emulsify readily but if a little sour or even if 

 very sour, it unites easily with the kerosene. This is the best 

 emulsion where the water is very hard. 



Carbon bisulphide is a very inflammable material with a dis- 

 agreeable odor and readily vaporizes. It should be handled 

 with the same precautions as gasoline, which resembles it in 

 appearance. The fumes which it gives off are very heavy and 



