INTRODUCTION 



XI 



if excrement is exuding. Common species which do this in- 

 jury are the common and corn stalk-borers and the grass-worm. 

 When plants like corn make unequal starts, a hill here and 

 there showing greater thrift than elsewhere, injury is apt to 

 be due to root-aphides. As a rule, these insects are ac- 

 companied by ants, which in most cases foster the "lice," and 

 sometimes feed on the seeds. 



When the leaves of plants are seen to be withering, and 

 aphides or other sucking insects cannot be de- 

 tected above ground, search will usually reveal 

 the presence of white grubs, wireworms or other 

 insects working below the surface, and the same 

 is true of corn plants that fall after windstorms, 

 root-worms also being present at such times. 

 Another manifestation of the presence of root- 

 worms is in the plants requiring too long a time 

 for maturing, and producing sterile stalks, and, 

 in the case of corn, yielding nubbins instead of 



complete ears. 

 When young 

 leaves are 

 found with 

 small round 

 holes of about 

 the size of a 

 pea or a little 

 smaller, leaf- 

 beetles are usually present, while much smaller holes occurring 

 in great profusion over leaves usually betoken the presence of 

 flea-beetles. Extremely large and irregular holes in leaves of 

 older growth are made by grasshoppers, crickets, and the larger 

 caterpillars such as "woolly bears." 



Fruits such as melons are attacked by the melon worm and 

 pickle worm; tomato, beans and corn by the bollworm, tomato 



Fig. 2.— Bollworm entering bean pod. Somewliat enlarged 

 (Author's illustration, U. S. Dept. Agr.) 



