INSECTS INJURIOUS TO WHEAT. 97 



Remedies. — Owing to the fact that the Straw-worm is 

 spread only by the summer brood, a simple rotation of the 

 crop Avill keep them largely nnder control. However, as 

 both species pass the winter in the stubble, most of them 

 may be killed by burning the stubble in fall and winter. 



The Wheat Saw-fly Borer {Cephtis pygmmns Linn.). 



The ' ' Corn SaAv-fly '' has been a well-known wheat-pest 

 for many years throughout England, France, and the 

 Continent, but was not noted as injurious in this country 

 till 1889, when Prof. J. H. Comstock published * a very 

 complete account of its injuries upon the University Farm 

 at Ithaca, N. Y., where it had done more or less damage 

 for two years, though Mr. F. H. Chittenden states that 

 he collected a single adult at Ithaca in the early ^80's. 

 Specimens Avere also collected at OttaAva, Canada, and 

 Buffalo, N. Y., in 1887 and 1888, these being the only 

 other references to its occurrence in this country. 



The following is gleaned from Prof. Comstock^s interest- 

 ing account. 



Injury. — No external indications of injury to the plant 

 can be seen until the larva Avithin has almost completely 

 tunneled the stalk, at which time there is a discoloration 

 just beloAV the injured joints. Thus damage by this 

 insect is not readily noticed, it merely dwarfing and stunt- 

 ing the groAvth of the plant by boring in the stem. 



'^If infested straws be examined a Aveek or ten days 

 before the ripening of the Avheat, the cause of this injury 

 can be found at Avork Avithin them. It is at that time a 

 yellowish, milky-Avhite Avorm, varying in size from one-fifth 



* Bulletin 11, Cornell Univ. Ag. Exp, Station. 



