INSECTICIDES AND EQUIPMENT FOR CONTROLLING DiBECTB 47 



spray is directed as desired by an operator who manipulate- the -pray 

 gun or spray "broom." 



Power sprayers are the most satisfactory for the commercial grower. 

 Numerous types are available, and the individual grower can ordinarily 

 obtain one suited to his particular needs. 



Figure 8. — Arrangement of nozzles and boom for spraying the under surfaces of 

 the leaves. The nozzles are placed on rigid pipes, but the whole boom swings 

 freely. 



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. i> | 

 consists of a chamber for the insecticide and a cylindrical metal chamber 

 provided with a piston, piston rod, and handle. When the handle is 

 operated 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. 



This type of duster is well suited for dusting vegetable and orna- 

 mental plants in the home garden. 





Figure 9.- 



—4 



Plunger type of hand duster. 



