INSECTS AND DISEASES 



SI 



by which time the first hill will be too old for seri- 

 ous injury. As the breeding places and habits of 

 the insects are better understood more opportuni- 

 ties will arise for the successful use of these trap 

 crops. The above methods are not to be consid- 

 ered of general importance in the larger warfare 

 against insects, but only serve to emphasize the 

 importance of some knowledge of the pest to be 

 combated before it can be intelligently attacked. 



The use of poisons and caustics comprises the 

 most important method of direct destruction. This 

 covers what is commonly known as spraying. 

 Insect pests are generally classified into two great 

 groups, viz., sucking and biting. Sucking insects 

 may attack almost any part of the plant, either stem, 

 root or leaf, and do their damage by drawing or 

 sucking the sap or plant juices from the plant. The 

 parts attacked first shrivel, then dry up, and eventu- 

 ally die. The biting insects likewise may attack all 

 parts of the plant, but their injury is more striking 

 and more apparent because the various parts at- 

 tacked rapidly disappear as they are consumed. 



The first group of insects calls for some kind of 



POWER SPRAYING OUTFIT 



