INSECTS AND DISEASES 



trees were scattered and few In number there 

 was not the opportunity for the development of 

 apple pests, but as soon as they became numer- 

 ous the prosperity of bugs and minute plant 

 parasites was wonderful to see. Another factor 

 which has been at least partly responsible for 

 the great increase in our insect life is that man 

 has upset nature's balance by destroying so 

 many birds, and, by interfering with their na- 

 tural surroundings, driven them away. Birds are 

 great destroyers of insects, and their presence 

 in the orchard should be encouraged in every 

 possible way. Add to these facts the marvelous 

 fecundity of the Insect tribe, and the increase is 

 less remarkable. Loss from these orchard 

 pests has now run up into the millions. It has 

 been estimated that the loss in the United States 

 from wormy apples alone is over $11,000,000 

 annually. Thus has the necessity for fighting 

 these enemies of good fruit arisen. 



In order successfully to combat an Insect or 

 a disease it is very necessary to have a somewhat 

 detailed knowledge of its life history and to 

 know its most vulnerable point of attack. It 

 is impossible to work most intelligently and 

 effectively without this knowledge, which should 

 include the several stages of the insect or dis- 

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