198 SPRAYING MATERIALS 



is discovered the test "will lose its value. However, with our 

 present laws and methods of enforcing them, there is relatively 

 little danger from adulterated materials. 



It is usually recommended to use Paris green at the rate of 

 four ounces to 50 gallons of water, but many orchardists use 

 it at the rate of five or six ounces to 50 gallons on the theory that 

 poison is cheaper than labor, and at the latter strength they are 

 sure of killing the insect enemies. It is well to add an equal 

 weight of lime when the Paris green is not used in combination 

 with a fungicide. The lime combines with any soluble arsenic 

 Avliieh may be present. 



Contact Insect Sprays. — There are four contact insecticides 

 which are verj^ commonly used, each one of which has its 

 good points. 



Miscible Oils. — First of all there are the soluble, or, more 

 properly, the miscible, oils. There are several of them, but they 

 all agree in being made from crude petroleum and in mixing 

 more or less readily with water. They are intended for use only 

 on dormant trees and in particular for fighting the San Jose 

 scale, and for this purpose the writer has found them very 

 satisfactory indeed. They have the advantage over lime-sulfur 

 that they are much less disagreeable to apply, which is certainly 

 an important consideration. They will also " creep " on the sur- 

 face of the branch, thus insuring a somewhat better distribution. 

 While these oils are usually bought already prepared, they can 

 be easily made at home and frequently at some saving in cost. 

 However, the commercial forms are usually so satisfactory and 

 they are sold so cheap that it is doubtful whether it would pay 

 the grower to make his own. It certainly would not except where 

 he is in the orchard business in a large way. 



Whale Oil Soap. — A second material frequently used for suck- 

 ing insects is whale oil soap, which comes as an ill-smelling 

 sticky, brown soap. Only very distant relatives of the whale 

 enter into its manufacture, as any cheap fish-oil is used in making 

 it. For orchard use it is well to prepare it beforehand by boiling 

 the soap with a certain quantity of water. This gets it into a con- 



