CHAPTER XVIII 

 CEREAL PESTS INSECTS 



THERE are two classes of insect pests of cereals, (1) those 

 that are enemies of the growing crop, and (2) those which 

 attack stored grain. In each class many insects can be 

 enumerated, but the greater part of the damage is done 

 by a few species. 



INSECT ENEMIES OF THE GROWING CROP 



Because of changing climatic conditions, and the greater 

 abundance at certain times of their parasites, the princi- 

 pal insects of growing cereals, such as the chinch bug, 

 Hessian fly, plant louse, and wheat midge, appear to recur 

 periodically. Fortunately, it is rare that more than one 

 of the very destructive insects occurs at one time. 



516. The Hessian fly (Mayetiola destructor, Say). - 

 This is one of the most destructive cereal pests. In 1908 

 the wheat loss in Kansas alone due to this pest was esti- 

 mated to be nearly ten million bushels ; while in Missouri 

 it is reported that in 1914 there was a loss from the same 

 cause of about six million bushels. 



The Hessian fly has been known in this country since 

 1779, and was so named because of the fact that it did 

 some damage that year on Long Island, New York, in the 

 vicinity of a previous encampment of the army of Lord 

 Howe, which included many Hessian soldiers. 



The distribution of the Hessian fly in this country is 



471 



