22 
settling of the poison to the bottom of the tank. This may be accom- 
plished by constant stirring with a paddle, by shaking, but preferably 
by throwing a stream of the liquid back into the tank. Many of the 
larger pumps are now constructed with two discharge orifices with this 
latter object in view or are provided with special agitators, and the use 
of such is recommended. 
For fruit trees of average size, or if apple, such as would produce 
from 10 to 15 bushels of fruit, from 3 to 7 gallons of spray are neces- 
sary to wet each tree thoroughly. For smaller trees, such as plum 
and cherry, 1 gallon to the tree will be sufficient. If an average of 5 
gallons to the tree be taken for an apple orchard of 1,000 trees, 5,000 



Fie. 3.—Gasoline power-spraying outfit of the Division of Entomology, U. S. Department of 
Agriculture (author's illustration). 
gallons of spray would be required. About 353 pounds of Paris green 
or London purple would be needed for one spraying if used at the rate 
of 1 pound to 150 gallons of water, and for the two applications ordina- 
rily recommended 66 pounds. This, for the Paris green, at 20 cents a 
pound, would amount to $15.20, and the London purple, at 10 cents 
a pound, to $6.60, or a little over 1 cent a tree for the former and one- 
half a cent for the latter. 
In spraying orchard trees it will be found convenient in going 
between the rows to spray on each side, half of each tree in the row 
at a time and finish on the return, rather than attempt to spray all 
sides of one tree before taking up another. 

