336 CONTROLLING INSECTS AND DISEASES 



{h) Consider Important Mechanical Features of Duster 

 and Equipment. The duster is a simple machine compared to 

 the liquid sprayer. It consists essentially of a gasoline engine, 

 a hopper for the dusting materials, and a blower or fan which 

 forces the material through a discharge pipe on to the trees 

 (Figs. 126 and 127) . It is usually mounted on a truck, or on 



(Niagara Sprayer c& Chemical Oo.) 



Fig. 127. This duster operates by means of a power take-off from the 



tractor. 



skids for easy transfer to wagon trucks. Trailer dusters to 

 attach to tractors are also available. 



The material feeds through small apertures in the bottom 

 of the hopper into the fan chamber. The fan, propelled by the 

 engine and revolving rapidly, forces the dust out of the dis- 

 charge pipe in a strong air blast. The operator manipulates 

 the discharge pipe to send the materials to all parts of the 

 trees. 



