CHAPTER IX. 

 INSECTS INJURIOUS TO CORN 



The Western Corn Root-worm * 



THROUGHOUT the corn States of the northern Mississippi Val- 

 ley, wherever corn is grown upon the same land it is subject to 

 serious injury by the Western Corn Root-worm, so called because 

 it first became injuri- 

 ous in Missouri and 

 Kansas and gradually 

 spread eastward to 

 Ohio, though not in- 

 jurious south of the 

 Ohio River. 



Though the life 

 history of the insect 

 has not been entirely 

 determined, the fol- 

 lowing' summarizes 

 it as observed by 

 Professors S. A. 



Forbes and F. M. Webster in Illinois and Indiana. The eggs 

 are laid in the early fall, within a few inches of the base of the stalk, 

 and just beneath the surface of the soil. The egg is a dirty white 

 color, oval in shape, and about one-fiftieth inch long. The winter is 

 passed in the egg stage, differing from most nearly related beetles in 

 this, and the eggs hatch in the spring or early summer. At first 

 the larvae eat the small roots entire, but later burrow under the 

 outer layers of the larger roots, causing the stalks on rich loam to 



* Diabrotica longicornis Say. Family Chrysomelidce. 



157 



FIG. 117. The western corn root -worm: a, 

 beetle; b, larva; c, enlarged leg of same; d, 

 pupa all enlarged. (After Chittenden, U. S. 

 D. Agr.) 



