INSECTICIDES AND EQUIPMENT FOR CONTROLLING INSECTS 47 
Power sprayers are the most satisfactory for the commercial grower. 
Numerous types are available, and the individual grower can or dinarily 
obtain one suited to his particular needs. 
FiguRE 8.—Power sprayer in operation in an orchard. 
DUSTERS 
Cheesecloth sack.—When a regular duster is not available, certain 
insects on low-growing row crops can be controlled by shaking the 
powdered insecticide onto the plants from a cheesecloth or similar bag. 
This method is not very effective for insects which feed on the under 
sides of the leaves, and is wasteful. 
Plunger-type dusters.—The plunger type of hand duster (fig. 9) 
consists of a chamber for the insecticide and a cylindrical metal cham- 
ber provided with a piston, piston rod, and handle. When the handle is 
epee back and forth an air current is developed that passes through 
the second chamber containing the insecticidal dust. In some types 
the pump and the dust Chamber are made entirely of metal, whereas in 
others the dust container is a glass mason jar, which is threaded so 
that it can be screwed onto the pump chamber. These usually have a 
capacity of about 1 to 2 pounds. 
Fictre 9.—Plunger type of hand duster. 
