INSECTICIDES AND EQUIPMENT FOR CONTROLLING INSECTS 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 peeey 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 by 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 
