INTRODUCTION 



'Economic Entomology is that phase of Entomology which relates 

 to the control of injurious insects. Its scope is much wider than that of 

 applied entomology, for the latter, properly speaking, is the application 

 of the principles that have been formulated by the economic entomolo- 

 gist as a result of his investigation of insects and their relations to their 

 environment. Its scope embraces a study of the structure, habits and 

 life-histories of the injurious insects and of their relations to all the 

 natural and artificial conditions to which they may be subjected. It 

 also includes the investigation of the nature of the losses and the prac- 

 ticable means by which they may be prevented or lessened. 



Considering the great variety of insect forms, their diverse methods 

 of food habits, the large number of kinds of hosts which supply them 

 with food, and the enemies which tend to destroy them, it becomes 

 evident that the problem of insect control is most complex. As 

 Professor Forbes says: " The subject matter of this science is not insects 

 alone, nor plants alone, nor farming alone. One may be a most ex- 

 cellent entomologist or botanist, or he may have the whole theory and 

 practice of agriculture at his tongue's end, and at his fingers' end as well, 

 and yet be without knowledge or resources when brought face to face 

 with a new practical problem in economic entomology. The subject is 

 essentially the relation of these things to each other; of insect to plant 

 and of plant to insect, and of both of these to the purposes and opera- 

 tions of the farm, and it involves some knowledge of all of them." 



The Rise of Economic Entomology 



The records of the rocks reveal the existence of insects at an early 

 period in the world's history, long before man made his appearance. 

 Early historic records also show clearly that not only man himself but 

 also his crops and flocks sufifered from insect attacks. The ravages of 

 locusts, canker worms and palmer worms are frequently described in 

 graphic language by the Old Testament prophets. 



