CHAPTER XVIII 

 ANIMAL AND INSECT ENEMIES 



The corn crop is more easily protected from its animal 

 and insect enemies than most of the important crops. 

 Of those insects that live on the roots of com, practically- 

 all are effectively controlled by rotation. At present the 

 corn rootworm and root-louse do considerable damage 

 throughout the corn-belt, wherever several corn crops are 

 grown in succession on the satne land. 



Rodents and birds do some damage every year, but 

 are only considered serious, where corn is grown in small 

 areas. The corn ear woiTn is difficult to control, but this in- 

 sect seldom does serious damage except in the Southern 

 States. 



BIRDS 



147. Crows give some trouble in regions where they are 

 plentiful and the acreage of corn is comparatively small. 

 They pull up the plants for a period of two weeks after 

 the shoots appear, in order to get the kernels for food. 

 Scarecrows or strings stretched with pieces of paper at- 

 tached are effective in small fields. Coating the seed with 

 coal tar is a deterrent, but not a complete preventive. 

 The treatment consists in dipping a paddle in hot coal tar 

 and stirring in the seed corn until every seed is coated with 

 tar. The seed js allowed to dry and is then planted. 



RODENTS 



148. Small ground squirrels of several varieties dig up 

 seed one to two weeks after planting. The coal-tar treatment 



214 



