Insects and Diseases 159 



Before taking up the various insects and diseases 

 the following analysis and list will enable the reader 

 to get a general comprehension of the whole matter. 



Plant enemies are of two kinds — (i) insects, and 

 (2) diseases. The former are of two kinds, (a) 

 insects which chew or eat the leaves or fruit ; (b) in- 

 sects which suck the juices therefrom. The diseases 

 also are of two kinds — (a) those which result from 

 the attack of some fungus, or germ; (b) those which 

 attack the whole organism of the plant and are 

 termed "constitutional." Concerning these latter 

 practically nothing is known. 



It will be seen at once, of course, that the 

 remedy to be used must depend upon the nature of 

 the enemy to be fought. We can therefore reduce 

 the matter to a simple classification, as follows : 



PLANT ENEMIES 



Insects Class 



Eating a 



Sucking b 



Diseases 



Parasitical c 



Constitutional d 



