CONTROL OF Two ELM-TREE PESTS 



493 



SPRAYING APPARATUS 



The first question which presented itself was that of the apparatus to 

 be used. It was necessary to procure machines that were not expensive. 

 Moreover, many of the trees were on steep hillsides and were difficult 

 to reach, so that the type of heavy machines used in work with the gipsy 

 moth did not seem suited to the present problem. Again, there were 



FIG. 165. Spraying a high elm with a Friend machine 



comparatively few trees and it seemed unwise to spend a thousand dollars 

 or more for a very large machine. It was necessary, however, to have 

 a machine that would maintain a high pressure in order to force a stream 

 to the tops of the trees. 



After a thorough consideration of all the points involved, it was decided 

 that two power spraying machines of the following specifications should 



