146 INSECTS INJURIOUS TO STAPLE CROPS. 



insects for the first crop will largely prevent so serious 

 injury to a subsequent corn crop. The burning over of 

 grass- and swamp-land infested with the beetles will-also 

 be of considerable value. 



The Larger Corn Stalk-borer {Diatrcea saccharalis Fab.).* 



I)) jury. — Every season corn throughout the district from 

 Alabama to Maryland is more or less seriously injured by 

 large, white, brown-spotted caterpillars, which bore into 

 the stalks, especially the young stalks. When abundant 

 a loss of from "Zh to 50 j^gi' cent of the crop results. In 

 Louisiana and the West Indies this pest is known as the 

 Sugar-cane-borer. It is found as far west as Kansas, and 

 is frequently injurious in the southern parts of Maryland, 

 Delaware, and New Jersey. 



Life-liistorii. — In the fall when the caterpillars become 

 full-grown they burrow down into the tap-root and there 

 pass the winter in a small cavity at or near the surface of 

 the ground. In the spring they transform to pup^ (Fig- 

 81), from which the adults soon emerge. The eggs are laid 

 upon the leaves of the young corn near the axils, and the 

 young larvae hatching from them bore into the stalk and 

 upward through the pith. As the borers grow they 

 become very active and frequently leave and re-enter the 

 stalk, thus making several holes. When the caterpillars 

 are full-grown they bore outwards to the surface of the 

 stalk, making a hole for the escape of the adult moth, and 

 then transform to pupa? in the burrows. This takes 

 place from the middle of July (m, and the adult moths 

 emerge from ten days to two weeks later. The second 



*SeeL. O. Howard, Circular 16, n, s,, Div. Entomology, U. S, 

 Dept. Agriculture, 



