CORN ROOT WORM 337 



Life History.** The eggs from which this larva comes are laid in 

 the ground, an inch or more beneath the surface, and rarely outside 

 of the corn field. Here they remain during winter awaiting the warm 

 days of early summer, and about the middle of June the worm comes 

 forth in search of what is apparently its only food, the roots of the 

 corn plant. The corn roots are at once attacked, the larvae con- 

 cealing themselves within, not burrowing through the middle of the 

 root, but in a spiral, longitudinal direction in the woody portion which 

 lies just beneath the outer covering. This burrowing causes the roots 

 to decay and die. There is every evidence to lead us to believe that 

 the corn-root worm does not live on the roots of clover, timothy, oats, 

 wheat, barley or rye; although observations in Kansas indicate that 

 the roots of sorghum afford a home for the larvae. 



Some of the corn-root worms will have reached maturity by the 

 latter part of June. Others will be found working in the corn roots 

 as late as August. When the larvae have reached maturity, they leave 

 the roots of the corn, but remain in the ground about them and begin 

 to pupate, the worm transforming into the adult or beetle. Soon 

 small grass-green beetles will be seen, about one-fourth of an inch 

 in length, which come forth from the pupa and are found feeding 

 upon the silks; also upon the pollen grains which have fallen upon 

 the leaves of the plant, generally about the axis. 



The beetles represent the adult stage. They do very little damage 

 to the plarit, but may be seen throughout the months of August and 

 September, and often during October. During the latter part of 

 September and the first part of October, most of the female beetles 

 will have buried themselves in the ground a short distance from the 

 hill of corn. They will then deposit their eggs, which the following 

 spring will hatch out into the corn-root worms. Seldom are the eggs 

 deposited outside of the corn field. In fact, it may be said that the 

 corn-root worm is dependent for its food upon the roots of the corn 

 plant. 



How Its Injury Is Noticed. The corn-root worm may be found 

 in the corn field in spots and can be detected in the early part of the 

 season by the appearance of the corn, showing a tendency to grow 

 less rapidly, although it may keep green, due to the fact that the root 

 system has not been damaged to such an extent but that some nourish- 

 ment can be afforded the plant. Again, where the ground has been 

 in corn several years, it is not uncommon to find that the entire field 

 presents a dwarfed appearance throughout the season. It fails to 

 produce more than nubbins, many of the stalks being entirely barren, 



**See Eighteenth Beport of Illinois Slate Entomologist, by Forbes. 



