2 INSECTS INJURIOUS TO STAPLE CROPS. 



upparent. But the native insects are by no means entirely 

 responsible for this condition. Foreign insects are con- 

 stantly being imported in one way or another, sometimes 

 already being established pests in other lands and some- 

 times only becoming so under their new surroundings. 

 These are even more injurious than those native, for 

 whereas many of our native birds, insects, and diseases 

 constantly prey upon native insects and thus keep their 

 numbers in check, the enemies of imported pests rarely 

 accompany them, and they thus increase at an alarming 

 rate and do enormous damage before they are attacked by 

 the natural enemies of similar native pests. 



American farmers have learned from sad experience 

 of the severe losses occasioned by insects, but few realize 

 their enormity when considered as a whole. Several cal- 

 culations of these losses have been made by competent 

 authorities, who practically agree that one-tenth of the 

 total agricultural product of the United States, or $300,- 

 000,000, is but a conservative estimate of the loss annually 

 sustained by this country. But when this statement has 

 occasionally been made by the author it has been met with 

 a look of incredulity which very plainly indicated that he 

 was thought to have a very elastic imagination. A careful 

 collection of such data as may be confided in as accurate 

 shows that the above estimate is entirely correct. Con- 

 siderably over one-half of this loss is upon the staple crops, 

 the remainder being upon truck crops, fruits, domestic 

 animals, and timber. 



Growing Cereals. — Probably no other insect does so 

 wide-spread damage as the Hessian Fly, attacking our chief 

 staple, wheat, as well as rye and barley. One-tenth of 

 the whole crop, valued at 140,000,000, is generally con- 



