134 PRACTICAL CORN CULTURE 



Since the corn root worm is dependent for its food upon 

 the roots of the corn the eggs are seldom deposited outside 

 of the cornfield. It is due to this fact that a cornfield is 

 never injured by the corn root worm the first year and 

 even the second year the damage done is usually very slight. 

 But if the field is put in corn three or four years in succes- 

 sion it is very doubtful if the last two crops ever escape 

 without serious injury. In some cases we have known the 

 yield of corn to be lowered from thirty to forty per cent 

 as a direct result of the ravages of these insects. 



The corn root worm lives on the roots of the corn plant. 

 They often eat off the ends of the roots of the plant and 

 then burrow just under the outer covering of the root the 

 entire length of the root. The corn root worm can be easily 

 found by carefully splitting an injured root. It is usually 

 about three-eighths of an inch long and about the thickness 

 of a pin and of a white or flesh color. 



It can safely be said that the damages resulting from the 

 corn root worm are due entirely to the bad practice of con- 

 tinuous corn cropping. If a rotation of crops is adopted in 

 which corn is never grown longer than two years in suc- 

 cession we shall soon have the corn root worm under easy 

 control. If crop rotation were only as effective in checking 

 other insects as it is in heading off the corn root worm, the 

 insect problem would not present the serious aspect it does. 



White Grub (several species of lachnosterna:) This is 

 the larvae of the common May beetle. These beetles usually 

 deposit their eggs in fields of grass, timothy and small grains, 

 and especially in the vicinity of timber where they feed. 



The eggs hatch into small brown-headed grubs, which 

 feed on the grass and corn roots. They do not attain their 

 full growth until the third or fourth year. They are most 

 abundant in old blue-grass pastures. Their presence can 



