INSECTICIDES AXD EQUIPMENT FOE CONTROLLING ENSECTS 49 



through a small chamber, into which the dust is fed from the hopper. 

 Most modern types are equipped with an agitator that keeps the dust 

 stirred within the hopper and also with an adjustable feeding device 

 to insure an even feed through the discharge chamber. This type of 

 duster can be fastened to the operator by means of a body support and 

 a waist-and-shoulder strap. The discharge pipes of some are designed 

 so that dusting can be done either in front or to the rear of the body. 



This is a convenient and easily operated apparatus for use in situa- 

 tions similar to those described for the bellows duster. Since a con- 

 tinuous stream of dust is delivered, this type of duster is better suited 

 for closely planted crops than for crops where the plants are widely 

 spaced. 



Traction, dusters. — As with traction sprayers, these machines are 

 geared to the wheels. The principal parts are the hopper for holding 

 the dust, feeder, air chamber, fan, and discharge tubes. They range in 

 size from small outfits pushed by the operator to larger horse-drawn 

 machines. 



They are used principally on row crops and small fruits. In gen- 

 eral the dust is delivered in the manner described above for fan or 

 blower dusters. Traction dusters are not so satisfactory as power 

 dusters. 



Power dusters. — These dusters are operated by gasoline engines 

 and, like power sprayers, range in size from the small wheelbarrow 

 type (fig. 12) pushed Jay the operator to large horse- or tractor-drawn 

 rigs (fig. 13). Some outfits are mounted directly on tractors. 



Figure 12. — Small power duster, pushed by hand. 



The essential parts are the hopper, feeder, air chamber, fan, and 

 discharge tube or tubes. The dust mixture is carried in the hopper. 

 from which it is fed into the dust chamber, where it is caught by a 

 strong current of air and is expelled through the flexible discharge 

 tubes. The apparatus should have an agitator to stir up the dust so 

 that it will feed evenly. There should also be a device for regulating 

 the flow of dust into the discharge chamber. Power dusters are suited 



