INSECTS INJURIOUS TO SMALL GRAINS 



123 



out with the grain instead of going over in the straw. It has 

 Usually been considered necessary to separate and burn these, 

 but Professor F. M. Webster finds that the larvae in them are 

 probably killed in threshing, as he has been unable to rear 



FIG. 103. Swellings made by wheat joint-worms in straw enlarged. (After 



Pettit.) 



adults of either the joint-worm or its parasites from such bits of 

 straw. 



Control. A rotation of the wheat crop is of prime impor- 

 tance in the control of this pest, and where wheat is not planted 

 on the same land 

 and is sown as far 

 from that of the 

 previous year as 

 possible there will be 

 but little damage. 

 It is obvious that 

 the stubble should 

 be plowed under 

 where possible, or 

 burned during the 

 late fall or winter. 

 Cut infested grain 

 as low as possible 

 so as to remove the 

 larvae in the straw. 



FIG 104- Wheat straw- worn: adult of fall genera- 

 tion, much enlarged. (After Howard, U. S. 

 Dept. Agr.) 



Where the stubble cannot be burned, break 

 it down by harrowing in the spring and then collect with a hay- 



