202 



INSECTS INJURIOUS 'lO N'EGETABLES 



with the sugar-cane borer of the South. In seasons of 

 abundance a loss of 25 to 50 per cent of the crop is not un- 

 usual. Sometimes a stalk contains as many as 30 or more 

 holes drilled by this borer. In addition to corn and sugar-cane, 

 the borer has been noticed on sorghum and gama or sesame 

 grass. 



The moth or parent of this stalk-borer is extremely variable 

 as regards size and markings. There is an individual variation 

 from an inch to nearly an inch and a half in wing expanse. 



Fig. 128.— Larger corn stalk-borer, a, Female moth; b, wings of male; c, pupa; d, e,f. 

 larvae. Near natural size. (After Howard, U. S. Dept. Agr.) 



The fore-wings are pale ochreous with fine darker longitudinal 

 lines, with a discal dot and marginal ones arranged as shown 

 (fig. 128, a, b) in the illustration. The larva when full grown 

 measures three-fourths of an inch or a little longer. Some 

 are white and some strongly marked with black or brown 

 arranged in round and elongate spots. This variation is well 

 shown in figures d, c, and /. 



Dr. L. O. Howard was the first person to investigate the 

 habits of this insect in the United States. The moths appear 

 in spring, and soon after young corn comes up lay eggs on the 

 leaves near the axils, and the borers on hatching penetrate 

 the stalks near the joint, tunnelling usually upward through the 

 pith. The borer grows rapidly, and frequently leaves a stalk 

 at one place and enters at another, making several holes in the 



