130 INSECTS INJURIOUS TO STAPLE CROPS. 



least two years. Thus a simple rotation, which is also to 

 bo recommeuded on many other grounds, is entirely 

 effectual. * 



The Corn-root Web-worm (Crambus caliginosellus Clem.). 



Injury. — When young corn-plants are seen to stop 

 growing, become deformed, and to die off in such numbers 

 as to frequently necessitate replanting, upon examination 

 of the roots the iujury will often be found to be due to 

 the work of a small caterpillar. Two or three, very often 

 five or six, and sometimes as many as eight or nine will 

 be found at the base of a plant about an inch below the 

 surface of the soil, and not o\er four to six inches from 

 the stalk, usually being in close proximity to it. Each 

 larva is covered with a fine, loose web, to which cling 

 particles of earth, forming a sort of case, and on account 

 of which these insects are known as Web-worms. 



Where the web-worms are present in any number they 

 will often necessitate the second, third, and sometimes a 

 fourth planting, making the corn very late and involving 

 considerable expense. The worms bore into the youug 

 stalks just above the ground, frequently cutting them off 

 entirely. Later on the larger stalks are gouged out at or 

 slightly above the surface of the ground, and the larvae 

 burrow into the folded leaves, which when they unfold 

 have several transverse rows of three to five holes. On 



*See : 



1882. Forbes, S. A. First Ann. Kept. 12th Kept. St. Ent. 111.. 



p. 10. 



1890. Forbes, S. A. 6tli Ann. Rept., p. 71. 

 1892. " " Tth " " pp. 146, 154. 



1894. Webster, F. M. Bull. No. 51 Ohio Ag. Exp. Sta., p. 89. 

 1896. '' " " " 68 '' " " " p 39. 



