INSECT P]NK]MIES OF WES^^ERN FORESTS 



177 



spray by means of power spraying apparatus. Such methods are 

 commonly used in the control of park- and shade-tree defoliators, 

 but under forest conditions can be used only alon<> roads or at camp 

 sites and resorts where it is possible to transport the heavy eqidp- 

 ment. Because of the height of forest trees, high-power spraying- 

 pumps are a necessity. Even the largest spraying equipment so far 

 developed is not adequate for the tallest trees. 



Figure 85. — A long hose permits reaching out for distances of 1,500 to 5,000 feet from the 



spray pump. 



Spraying for the control of the spruce budworm has been carried 

 on for several years in the Shoshone National Forest, Wyo., along 

 highways and around summer resorts. One of the largest spraying- 

 outfits so far developed has been used in this work. This consists 

 of a three-cylinder powder sprayer with a capacity of 25 gallons per 

 minute through i/4-inch tip under a nozzle pressure of 150 to 300 

 pounds. This pump is mounted on a motor truck that carries from 

 1,500 to 5,000 feet of hose to reach out on either side of the road 

 (fig. 85). This equipment can shoot a stream to a height of 90 feet 

 when a ^/iQ-inch tip is used. But even this powerful equipment 



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