168 FIELD CROPS 



hoppers have no wings; hence they do not travel about much. 

 When full grown they acquire wmgs and fly readily. The 

 eggs are usually laid in pastures, meadows, and in waste 

 land. Late fall plowing and rotation of crops are effective 

 in controlling the hoppers, for many of the eggs are destroyed 

 and others are buried so deep as to prevent the young hop- 

 pers from getting to the surface when hatched. The young 

 hoppers are often destroyed in large numbers, by use of hop- 

 perdozers, or by poisoning with arsenite of soda. 



210. Other Insects. Army worms sometimes do injury 

 to the growing crop, while grain weevils are destructive to 

 the stored grain, especially in the South. These insects and 

 the remedies for them have already been discussed (Sees. 

 131, 135). 



RELATION TO OTHER CROPS 



211. Place in the Rotation. Wheat is one of the best 

 crops to use as a nurse crop for grasses and clover, because 

 it is sown early, at the time when grass seed starts best, 

 and because it does not shade the ground so much as oats 

 or barley. On this account, wheat commonly follows corn 

 and precedes a hay crop. In the main wheat-producing 

 sections, it is very commonly grown year after year on the 

 same land, without fertilization. Occasionally such land is 

 left without a crop for one year and " summer fallowed;" 

 that is, it is plowed once or twice, usually about midsummer. 

 This is a wasteful practice, and is usually discontinued as 

 a country develops and some system of crop rotation is 

 introduced. 



A very simple rotation is: first year, corn; second year, 

 wheat; third year, clover. Such a rotation is adapted to light 

 soils or to building up run-down soils. This is especially 



