CONTROLLING INSECTS 



205 



amounts may be divided. When wanted for use, the emul- 

 sion is diluted by taking one part of emulsion to ten parts of 

 water for hard-bodied insects, or one part to fifteen of water 

 for soft-bodied ones. It should be applied with a very fine 

 spray. Kerosene emulsion kills by contact. 



Poisons are applied by various kinds of apparatus. For 

 large operations, as in orchards, spray-pumps operated by 



38. A POWER fePRAYER USED IN THE ORCHARD AT PURDUE UNIVERSITY 

 By courtesy of the Indiana Experiment Station 



compressed air are used. Spray-pumps operated by hand 

 are much used. For spraying potatoes and sugar beets a bar- 

 rel is mounted on a truck and the contents are forced out of 

 nozzles attached to a frame behind the truck. For gardens 

 and flower beds a garden spray-pump can be used, and even 

 a sprinkling-can is useful for small operations. For applying 

 dry powders various kinds of bellows are used. 



The time of spraying is important. It is often done too 

 late. Usually spraying should not be done when plants are 



