70 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



purchasing, as they differ greatly in efficiency. The better types 

 cost from $60 to $100, and usually have attachments adapting 

 them fcr all sorts of row crops, such as potatoes, strawberries, 

 bush fruits, grapes, etc., which require different styles of piping 

 to properly direct the nozzles. 



Several traction sprayers are sold for orchard work but, though 

 they are fairly satisfactory for small trees, they do not develop 

 enough power for spraying large trees, and have a heavy draft. 



Gas Sprayers. A very handy and efficient spraying outfit is now 



FIG. 41. Row sprayer applying 'arsenate of lead to potatoes, showing 

 arrangement of nozzles to cover vines. (After Britton.) 



made which uses carbonic-acid gas as the power (Fig. 42). The 

 liquid is placed in a steel-tank, to which is attached a tube of 

 carbonic-acid gas, the same as is used for soda fountains. The 

 gas is admitted to the tank by a valve until the desired pres- 

 sure is secured, and the gas then forces the liquid out, thus 

 obviating the need of a pump. The outfit is mounted on a 

 steel truck with steel tower, or may be mounted on any wagon, 

 and is also mounted on two wheels with suitable attachments 

 for row spraying. The cost of the gas is somewhat higher 

 than gasoline or hand power, but less labor is required 



