GRUBS OR MAGGOTS INJURING STALK OR STEM 129 



the lower part of the burrow, about the level of the crown. The beetles 

 hibernate in this position, in the uncut part of the stalk. Control 

 of this species is secured by removal and destruction of the corn 

 stubble, taking care to get the lowx^ part of the plant with the remnant 

 of stalk. 



Other species injure corn only as adults. Cavities are eaten in 

 the stalk or through the crown, the punctures showing as the leaves 

 unfold. One of these species passes its larval life as a grub in the bulb 

 of timothy; another in wild sedges growing in wet ground. With 

 these, to avoid injur j^ it is necessar}^ to refrain from planting corn on 

 recently drained ground. If possible, such lands should be burned 



The Western Grass-stem Sawfly {Cephus occidentalis Riley and 



Marlatt) 



In the northwest, in recent years, wheat has been injured by the 

 work of a grub that bores in the stem, causing the kernels to dwarf, 

 and often causing the stem to break over close to the ground. The 

 larva is three fourths of an inch long, yellowish white. The adult is a 

 four- winged sawfly, its abdomen banded with yellow. 



Eggs are laid just below the head of the grain attacked. The grub 

 bores down within the stem, girdles it from the inside not far above 

 the ground, and remains below the girdle until the following spring, 

 when the adults emerge. The native food plants are quack grass, 

 wheat grass, brome grass, rye grass, and timothy. 



Remedial measures consist in keeping down the growth of native 

 grasses around wheat, and in plowing the stubble in fall or early 

 spring so as to kill the insects liiding within it or prevent emergence 

 of the adults. 



The Joint-worm {Isosoma tritici Fitch) 



The presence of joint- worm in wheat is nearly always accompanied 



by distortions or enlargements of the stem at the point where the 



grub is at work. Such parts become hardened, and are apt to come 



out with the grain at threshing. The heads of badly infested plants 



