WEBWORMS INJURING THE ROOTS 113 
The worms feed in a silk tube more or less covered with par- 
ticles of dirt. They vary in color from yellowish to brown, 
are three fourths to one inch long when full grown, and _ their 
bodies have numerous low tubercles. They hatch from eggs 
laid by small, active moths which have the habit of resting on 
grass stems with their wings folded 
around their bodies. The natural breed- 
ing place is grassland. There are two 
generations annually, the moths of the 
second brood appearing in the latter 
part of summer. Winter is passed by 
the half-grown worms in the soil. 
Fic. 77.— Larval cases of a Corn-root 
Fig. 76. — Larval ease of Corn- Webworm, Crambus vulvivagellus Clem. 
root Webworm at base of corn Natural size. The one at the left cut 
plant. Original. open to show pupa within. Original. 
Fall plowing and cultivation will help to hold the pests in check, but 
to avoid injury do not plant corn in land that is just broken up from sod. 
Land that is fallowed in the latter part of summer will not be infested 
the next spring, for the moths will not lay eggs on bare ground. 
The Corn Root Aphis (Aphis maidi-radicis Forbes) 
Colonies of bluish green “lice”? suck the juices from the roots of 
corn, and in certain sections feed also on the roots of other plants, in- 
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