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Diseases of Economic Plants 



Knapsack sprayers. — These consist of 3 to 5-gallon 

 tanks, with straps so attached that the outfit can be car- 

 ried upon the back in the manner of a knapsack. The 

 handle is so adjusted that it is operated in front of the 

 carrier. These pumps are best adapted to spraying crops 

 which grow breast high, as grapes. They may also be 

 used in spraying small trees. For general garden use. 



Fig. 226. — Modern power sprayer, equipped with high-pressure, 

 slow-speed pump, with large bearings, ball valves, modern pressure 

 regulator, etc. Such a machine is constructed to turn in a small 

 space. A tower can be set on the tank for spraying tall trees with 

 extension rods. 



or small areas, a half acre to an acre, they are to be 

 recommended. 



Barrel pump. — For home orchard work the barrel sprayer 

 is of most importance. The pump is adjusted to a 

 barrel, at either the side or end. It should be provided 

 with a good agitator to keep the spraying mixture stirred 

 while in use. 



Field sprayers. — This sort of sprayer is used in spray- 



