86 THE CONNECTICUT POMOLOGICAL SOCIETY. 



decidedly more convenient, and less destructive to spraying 

 equipment. In view of the absence of coloring matter it is 

 especially valuable around home grounds or roadsides and in 

 parks. The various commercial preparations, such as Scale- 

 cide, Kil-O-Scale, Sure-Kill, and Target Brand Scale De- 

 stroyer, are very convenient for the man with a few trees to 

 spray. In view of a ''soluble oil" prepared according to the 

 formula herewith recommended, being offered for sale by 

 several firms at a much lower figure, the cost of these prepara- 

 tions may ultimately be reduced. The chief advantage of the 

 lime-sulphur wash over oil sprays consists in its influence in 

 controlling the leaf curl, and its invigorating effect on the 

 tree. Where leaf curl is present, an occasional application, 

 one in two or three years, is recommended. 



The Emulsifier. 



The value of crude petroleum as an insecticide has long 

 been known. In its undiluted condition it is injurious to vege- 

 tation, yet under very favorable conditions it may be used 

 on dormant trees, for the destruction of San Jose scale. Not 

 only is the undiluted petroleum unsafe, but it is decidedly too 

 expensive. By means of mechanical contrivances or "emulsion 

 pumps" attempts have been made to apply oil in a diluted con- 

 dition. Such contrivances were a partial success, but were 

 not reUable, and their use has been practically discontinued. 

 Chemical reagents must, therefore, be depended upon to bring 

 the oil into such a condition that it may be readily diluted with 

 water. The combination of chemicals used to bring about 

 this condition is termed the emulsifier; the resultant oil after 

 it has been acted upon l:)y the emulsifier is termed the " soluble 

 oil;" and the diluted "soluble oil" is called the emulsion or 

 spray mixture. The formula for making the emulsifier is as 

 follows : 



Carbolic acid (liquid crude 100%) 2 quarts 



Fish oil ( Menhaden ) 2V2 quarts 



Caustic potash (granulated) 1 pound 



Heat to 300° F.. remove from fire and immediately add 



Kerosene 3^ quarts 



Water W2 quarts 



