TREE INSECTS AND THEIR CONTROL 193 



gear of a wagon, and the pump fastened to a small plat- 

 form at the top of the tank or at the rear end of the wagon. 

 Instead of the tank, a barrel, or a 100 gallon hogs- 

 head, may be used, placed at one end of the wagon 

 bed to leave room for pump and operator. A suction hose 

 extends into the container which holds the spray material. 

 The pump is double action with double cylinder, and gives 

 pressure for two lines of hose and for double nozzles. 



For results in spraying mature street trees, power 

 sprayers, operated by gasoline engines, must be used, as the 

 other outfits mentioned are not effective for this purpose. 

 It is important that communities and neighborhoods should 

 act together in their purchase and use where no municipal 

 outfit is at hand. The ideal plan, of course, is to have all 

 spraying operations conducted by the local government, 

 since this plan makes it feasible to have even more com- 

 plete and efficient outfits than are to be expected in com- 

 munity or neighborhood cooperation. The power sprayer 

 gives steadier spray than the hand-pump, insuring a more 

 even and more thorough distribution of the application 

 and makes it possible to reach the tops of the trees. 

 Power sprayers as small as one horsepower may be pur- 

 chased, while there are larger sprayers of as much as 

 12 horsepower, with capacity of 50 gallons or more to the 

 minute under pressure of from 150 to 300 pounds. Where 

 a pressure of less than 100 pounds per square inch is used, 

 the material is delivered in the form of a mist within a 

 short distance from the nozzle, which necessitates the 

 nozzle being carried near to the foliage to be sprayed. 

 This practically limits the use of hand pumps to trees not 

 over 30 to 40 feet high and then only after climbing into 

 the trees. The compressed air pumps are not practicable 

 for trees over 10 feet high. For tall trees, a solid stream 

 delivered from a nozzle at a pressure of 150 to 200 pounds 

 13 



