112 



Nature-Study Agriculture 



Controlling 

 the Hessian 



fly 



Methods 

 of harvest- 

 ing 



International Harvester Co. 



FIG. 91. The first reaper, invented by Cyrus McCormick in 1831. The 

 reaper has helped greatly to remove the dread of famine from the world. 



does not have much effect. Rotation of crops holds 

 the chinch bug in check. 



The chinch bug is a sucking insect and works very 

 much as plant lice do, by drawing the sap from the 

 plant. On the other hand the Hessian fly, while in 

 the larval stage, damages the wheat by boring into the 

 stem and causing the plant to fall. It is a good plan to 

 delay sowing wheat until after the flies have been killed 

 by the early autumn frosts. Another way of holding 

 the Hessian fly in check is to burn the wheat stubble. 

 But if it were not for certain parasitic insects that live 

 on the Hessian fly and destroy it, we should probably be 

 unable to raise much wheat. 



In ancient times a sickle was used to cut the harvest. 

 The threshing was done with a flail or by the trampling 

 of animals. The most modern implement is a com- 



