SPRAYING CROPS 



PRINCIPLES OF SPRAYING 



HABITS OF INSECTS — DEVELOPMENT OF PARASITIC 

 GROWTH MIXTURES AND METHODS EMPLOYED 



Growing plants are liable to injury from two classes 

 of organisms, — namely, noxious insects and parasitic 

 fungi. Although these tiny foes are often considered 

 too insignificant to merit serious attention, they 

 annually destroy about $500,000,000 worth of crops 

 in the United States. By an intelhgent use of the 

 spraying machine — a simple apparatus by which cer- 

 tain substances that destroy insect and fungous life 

 may be distributed over the surfaces of plants — a large 

 proportion of this loss may be prevented at compara- 

 tively slight expense. The object of this little manual 

 is to indicate why, when, and how to spray, to get 

 the best results. 



The philosophy of spraying will be better under- 

 stood if one has a general knowledge of the habits and 

 methods of development of the insect and fungus 

 pests against which the spraying machine is used. 

 Nearly all of these organisms are weaker and easier 

 to destroy at some one period of their existence than 

 at any other : consequently, a knowledge of their habits 

 and history is often necessary to success. 



SPRAYING AGAINST INSECTS 



The insect against which the spraying machine 

 has been most generally used in the northern United 



