PRINCIPLES OF SPRAYING 



Spray Pumps. — The application of the fore- 

 going spray mixtures is fully as important as 

 the sprays themselves, for on the right appli- 

 cation at the right time depends the efficacy 

 of the spray. For this purpose a considerable 

 amount of special machinery has been devised. 

 Lack of space prevents us from going into much 

 detail on this question, so we must be con- 

 tent with merely outlining the different types 

 of machines and mentioning their accessories. 

 Sprays are forced through single, double or 

 triple acting pumps, either by hand or power. 

 The three types of power available are traction, 

 compressed air, and gasoline, the last being 

 the most used. Steam power is practically 

 obsolete. 



The knapsack Is the simplest type of hand 

 pump, but It Is of no practical use In the mature 

 apple orchard. For small orchards and small 

 trees several types of hand pumps are quite 

 effective. The lever type of pump, where the 

 handle Is pushed from and pulled toward the 

 operator, probably gives the most power with 

 the least tiring effect, because it enables one to 

 use the weight of the body to some extent. It Is 

 best not to have the pump attached to the spray 

 barrel or tank, but set on a movable base of its 

 119 



