CORN INSECTS 227 



Control. 



Owing to the eggs of the western corn root-worm being 

 deposited only in corn fields, injury may be avoided by not 

 planting land to corn for more than two years in succession. 



References 



Forbes, 12th Rept. 111. State Ent. for 1882, pp. 10-31. 

 U. S. Dept. Agr. Bull. 8. 1913. 



The Colorado Corn Root-Worm 



Diabrotica virgifera Leconte 



In Colorado, sweet corn is sometimes seriously injured by 

 a larva similar to that of the southern corn root-worm that 

 burrows into the stalk below ground. The female beetle is i 

 inch in length and closely resembles the striped cucumber beetle 

 in general appearance, but in the male the wing-cover is black 

 except for a narrow yellow margin and a yellow spot near the 

 tip. The beetles are often troublesome in vegetable-gardens 

 where they feed on a variety of plants. The eggs are pale 

 yellow and about xV ii^ch in length. They are laid in the fall 

 in the ground near the corn plants and do not hatch till the 

 following spring. The larva is a little less than ^ inch in length, 

 pale yellow, with the head and anal plate black. The insect 

 is apparently single brooded in Colorado. 



Injury by this species may be prevented in large measure by 

 not growing corn for successive years on the same land. 



Reference 

 Gillette, Jour. Econ. Ent., 5, pp. 364-366. 1912. 



